'76 280Z Question on dist/manifold vacuum, dist timing, fuel pressure, brake booster

[Jennys280Z]

Hey guys! Quick update again. Not sure how some might feel about me posting my mundane stories but so long as just one person can get something out of it, I suppose I might as well.

Thanks for the heads up on the frozen bolt, guys! I probably would have just started torquing on it without thinking and I believe if I had done that, I would have probably rounded it off or caused an even bigger problem in the threads because it was definitely frozen in there. I got some Aero Kroil from a friend a couple years ago. This stuff is used in commercial and military aviation and isn't available for retail sale so despite my love of WD40 I realized there might be better penetrators out there and remembered this stuff. I was always fascinated how when you spray WD40 on a rusty bolt, you can see rust lift off the surface immediately when the oil runs down something it's rust colored, where rust remover like Phosphoric acid doesn't do that. When I sprayed this other stuff on the bolt it bubbled and seemed to penetrate right before my eyes, creeping away into the recesses under the bolt head. So after a double shot of that and an hour, I used my same trusty technique I used to free a seized alternator bolt, a rubber mallet. Putting some light torque on a ratchet, I just hammered the end of the ratchet at least a few hundred times (the alternator probably 1000). I could feel ever so slight movements of the bolt in the hand that was holding the ratchet and finally I was able to move the bolt with the wrench. Another shot of Aero and it came off quite easily.

Okay so I took the thermostat housing off and the thermostat came off with it. It was definitely stuck open, more than half way open at least. And it was jammed into the housing at an angle and I got lucky that I was able to yank it out by myself. The flange of the thermostat was even bent from the force of the coolant. Don't know why this happened. Maybe someone didn't seat it right the last time they installed it so that it worked for a while and then failed like this, or maybe this is how they sometimes fail when installed correctly...

So I got the OE 180degF thermostat from NAPA. Put it on already and it works great. My car heats up perfectly. The temperature gauge is reading normally like it used to and rose to about 180 degrees and held. The first time I fired up the motor with the new thermostat installed, it idled perfectly for about 15-20 seconds. At least I think it was longer than 8 seconds, but maybe it wasn't. It was a smooth idle at 800RPM like it should be, and then after that 15 or so seconds the RPM sunk to 500-550 again and it was a slow rise back to 800 again. Though with the new thermostat it took a lot less time for the idle speed to increase to normal. I had to idle the car for 30-45 minutes to get to 800RPM before where now it took like 5-10 minutes.

I noted my fuel pressure now when running the motor is about 32-33psi. And 36.3 when not running.

The vacuum hose to the fuel pressure regulator is present, connected well, not cracked or split, and feels like soft fresh rubber compared to any of the other hoses under hood I haven't replaced yet.

I sniffed for vacuum leaks in a few other places I hadn't already...that hose to the FPR, the vac diaphragm on the distributor, and the purge line, and again, and again no audible effect on my idle at all in any of those places. Wherever the vacuum leak is, it's doing a brilliant job of hide and seek. I should acknowledge that I read the yogurt cup technique and have that on my list. Usually I'm very conservative in my approaches to fixing my car so this is intimidating for me to just jump into and I want to replace all of my vac lines and clamps before resorting to such a measure. Every millimeter, as previously advised. I'll do it though if necessary, but I need to think, plan, do homework, maybe ask stuff on here , and especially list things out on paper because I get kindof scatter brained and usually omit steps if I don't have a plan to follow.

Let's see...I did another vacuum check with my engine fully warmed up (180-185 degrees) and some good news is that I'm hitting 15inHg now so I gained over an inch already just replacing the thermostat! I tried to test the vacuum while the motor was running at first, and pulled the tape off the brake booster line at the manifold and I quickly heard a hard sucking sound and my engine almost stalled out. I got scared and quickly put the tape back on and rescued it, and decided it's be better to turn the motor off, attach the gauge and then restart it. I did that, and hit 15 so I'm happy about that. Like a bonus treat for my labor!

Also some good news, the engine feels a lot more powerful now. It's a lot better, but not BETTER. It still has a brrrr-brrrr-brrrr-brrrr behavior instead of the silky brrrrrrrrrrrrrrrrrrrrrrrrrrr that I want. That we ALL want.

So yeah I love my car. And I'm realizing more and more that if folks are going to own old cars like this, we better know how to work on them ourselves. I suppose some people are moneybags and know a good mechanic. But it's so rewarding to do stuff myself, and I love doing it. And I love to learn. It feels a little like caring for the elderly. But old school doesn't mean slow school.

Items on my list for now are to clean the connectors on my fuel injectors (scared of one of those clips going flying and losing it under the hood somewhere) and under some of those round terminal covers I was asking about earlier; and of course replacing all of the vacuum lines. There's a lot of petrified rubber in there and even though I don't see any cracks or holes or can "sense" any leaks, it might be a hundred little nano-leaks that all new vac lines will improve. If the difference between 13 and 15in is this remarkable, I'd love to have 17inches! I'll be happy with 17. I don't ask for much. I really don't, I just want him to put the seat down!

Just a few minutes ago, I added more fuel injection cleaner into my gas, torqued my spark plugs from 10 to 15 lbft and refilled the radiator with that 1/2 gallon I drained. Tomorrow is time for a wash and wax! The first time she's going to get a bubble bath in years. New upholstery for Christmas yaaaay!

I'll post some pictures of my spark plugs I took the other day from cylinders #1 and #3 (before I cleaned and gapped them of course) and old/new thermostat stuff.

I'll also semi-close this thread for now because I've made some progress, have gotten tons of help from you guys and feel like I owe you some little Christmas presents. Of course I'll absorb and hang onto every word you guys say here, no matter if it's irrelevant or whatever. Yes my car is probably running lean still and isn't purring like a kitten yet but she's getting there. I'm feeling better about my car today than I have in months.

Luvs you!

Edited December 4, 2010 by Jennys280Z

[FastWoman]

Congrats on tackling that frozen bolt! The danger isn't rounding off the head, so much as snapping the shank. Rust and age take their toll on these old bolts, and they're often not as strong as they used to be, while having to stand up to enormous torque when twisting them out of a corrosion-packed hole. You'd be very smart to buy a set of stainless steel bolts and nuts to replace the original ones. Alternatively, you can find a surprisingly good assortment of stainless fasteners at most small-town Ace and True Value hardware stores -- much better than at the big stores like Home Depot. When using them in aluminum, you'll definitely need to use nickel anti-sieze. Also you can't use stainless for some of the really high-demand applications like manifold and head bolts. However, you CAN use the anti-sieze.

I suspect your original thermostat wasn't seated carefully when it was installed. I've never see a thermostat jammed into the housing that way, but of course I've only replaced a handfull of thermostats in my lifetime. The water pressure shouldn't be enough to bend a thermostat. My guess is that the thermostat was bent when it went in, which was why it didn't seat properly. Either that, or it was somehow bent when the shell was bolted down on the improperly positioned thermostat.

Your spark plugs look a bit like mine did when I was running very lean. I was fooled by the carbon buildup on the plugs, but I think the cause for that was the incomplete combustion of my lean mix before the exhaust valve was opened. Lean mixtures burn much slower than proper mixtures. I think the really slow burn was also what resulted in the hard puffs in the exhaust. (I think the continuation of the burn even when the intake valve opens is what detinates the intake gasses, resulting in backfire.) My engine was full of carbon sludge, BTW, probably from the same problem. Now that my fuel /air mixture is richer, I'm getting more rapid, complete burning. My plugs look much, much cleaner now. Anyway, what the plug-reading charts don't generally show you is the appearance of a plug in a super-lean-running engine.

Vacuum hoses: Yes, keep replacing them. You should have them all replaced. I guarantee you they're worse than they look. Don't forget to check whatever is hooked to the vacuum lines for leaks too. For instance, my HVAC control system was leaking. I even had some unplugged vacuum hoses under the dash. I started a thread a while back about how to refurbish the vacuum controller switch (the HVAC mode selector). It's easy, but requires a bit of disassembly to get to it.

Also, if you're not going to take off the AFM to do the vacuum check, at least make sure to check the big rubber boots for cracks and splits. Use a mirror to check their undersides, and stretch the bellows a bit to look at the folds deep inside. If they're split, you can buy a new pair (should probably replace in pairs) from MSA for about $100. If they're not, consider yourself lucky, and spray them lovingly with a bit of Armorall or (better) silicone oil spray to keep them soft.

Electrical connector clips: They're not as prone to fly through the air as you might expect. The best approach is to undo one side, rotate the clip partially around the connector, so that the wire on the other side pulls out slightly, and then hang the end of the clip on the side of the connector. You can then unplug the connector without the clip coming entirely off. Reseat the clip immediately afterwards, so you don't lose it. IF you lose the clip, you can duplicate it with some spring metal. I don't know whether you can find a paperclip fine enough to work, but you can certainly find some suitable spring wire at a hobby shop (which would work much better). Just bend yourself a new one.

Just a bit of perspective on the lean/rich thing... with which many people might take issue: If you're going to race this car (not implying you're going to), you can do huge damage to the engine by having a mixture that's too lean. However, for ordinary street use, it's not as huge a deal. The intake backfiring does beat up the AFM, but generally not beyond repair. (You DON'T want backfiring!) The hot running is rather hard on the valves, but won't immediately kill them. Your engine will last longer between rebuilds if it's running right, but lean running is nothing that will kill your engine tomorrow. Performance will of course suffer.

Just remember that MOST Z engines don't run very well, because they're not in proper repair. As evidence of this fact, my engine was running a bit worse than yours, from what I can tell, when I took it to my local Z guru to have him fit a new exhaust. I asked him go over the car from stem to stern to find anything else that needs addressing. His summary was that "The car runs really good." (Hmmmm.... OK.) So I drove it home and got to work on making it run the way I wanted it to. NOW, after havng fixed a massive intake leak (intake/head junction), replaced a coolant temp sensor (reading too cold), replaced cracked intake boots (big leak), adjusted the AFM (idle mix screw way out of kelter), replaced a frozen (open) cold start injector, replaced the injectors (dribbly/leaky/VERY old), replaced the fuel pressure regulator (too low by a few psi), replaced all of the electrical connectors (some of which had fallen apart), and adjusted the mixture with a variable resistor, I've gotten it to run "really good," with far more power and far cleaner exhaust. The engine runs smoothly, with no hesitation, misses, puffs, etc. It's feels/sounds a lot like the little BMW Z3 I recently sold, except with somewhat less power (smaller engine, half the valves, a few generations less sophistication). I'll go further to mention that the Z3 ran to the satisfaction of dealer mechanics before I replaced a coolant sensor and cracked intake boot and freed some sticking valves with a few motor flushes. After I was finished, it ran like a Ferrari.

My point is that most people, including professional mechanics, don't know how an engine should run. They feel if an engine is old or has lots of miles on it that it can't run well, and that you should be satisfied that it gets you down the road at all. People drive engines like that for many years, and the engines manage to deliver, even in a state of perpetual disrepair. So your engine probably isn't going to fall apart if you continue driving it the way it is. It just won't be performing to its full potential.

Keep chipping away, and your engine will run better and better. Meanwhile, don't be afraid to take it out and enjoy it.

[Jennys280Z]

Hi guys (and m'lady!)

Re-reading through this thread, it makes me wonder how the mechanics at the local Z shop here would handle this...and what their expectations would be to make my car run right. My car was just a few starts away from running awesome until "something" happened to it. Maybe it had a mental breakdown in the silence of the garage while it was waiting to be started up again?!?!

Against recommendations, I disconnected the intake manifold and throttle body vacuum hookups from the carbon canister. All I have is a single hose going from the dist to the throttle body and no 3-way connector going back to the canister. I did this because I was going to replace the hose anyway, and need it in hand to take to the parts store to match up, and well, might as well test the vacuum with the canister taken out of the circuit, right? I suppose that all the vacuumy hookups that aren't readily visible under the hood coming out of the intake manifold are connected behind the firewall from the canister somewhere. HVAC stuff and whatever... I sure don't see any vacuum lines coming out of the intake going behind the firewall. There's nothing coming off of the brake booster either. I think some Z cars have a t-connector there near the brake booster check valve but not mine. So it's nice to isolate all of that from the loop to see if my vacuum is any better. And well, this time I just hooked up the gauge to a cold engine and started the motor with the gauge hooked up right away and read the vacuum the whole time.

The engine behaved the same way. The first 20-30 seconds of what I previously called "normal" idle, it was hitting right about 10inHg. Then after that when my idle takes a nasty plunge into the 500RPM range, I was only getting about 6inHg! I didn't bother warming the motor up all the way to see if I could break 15inHg with the carbon canister out of the picture because it almost broke my heart to see this and I could barely stand to watch the gauge anymore. The motor was behaving just as bad as the last time I ran it, so I assume the ending reading would have been no different than it was (almost 15). But with vacuum this bad at startup it's no wonder my car even runs.

Yes it's running half-decent now AFTER it heats up but I'm a follower of FastWoman's school of perfectionism, which makes my comparative lack of knowledge particularly dangerous. I just don't want to drive a car with vacuum/lean issues like this and fry my valves or worse. And no I'm not racing my car or anything like that. I only drive it through the neighborhood at this point and rarely exceed 30mph.

Is the low idle causing the low vacuum like that or is the low vacuum causing the low idle? Or could it work either way? I think the low vacuum is causing the low idle and that's the only way it can work, within parameters at least. I noticed that while I was running the car yesterday with the vacuum gauge, it was extremely stubborn to get past 16inHg. Even throttling up to a steady 2000RPM the gauge would barely exceed 16.

Could faulty spark plugs or a faulty spark plug be causing low vacuum?

I also wondered if my PCV hose was clogged up with gunk. It felt like it was when I squeezed it. And some other guy on Youtube was having symptoms very similar to mine and he replaced his hose that was blocked and solved his problems. So I disconnected the intake manifold end of that hose and ran a screwdriver most of the way into the hose and scraped around a little to see if any crud came out and it was clean with barely a drop of oil. I suppose it could be clogged in/from the crankcase itself which would cause less oil to be present in this hose than there should be, but with no experience (frame of reference) I can only speculate. I do have oil seepage around my oil pan gasket which I've always basically ignored, but while I have no oil leaks at all, I thought the hose was worth testing. Glad it's not blocked and that I don't have to buy a new one for $35. The PCV hose looks to be in good shape. Eventually I'm just going to spray some carb cleaner up into my PCV valve and put the hose back on and call it good.

But for now, I want to block my intake manifold at the PCV hose too, and just let the PCV hose vent to the atmosphere for a limited time here while I'm chasing after vacuum gremlins. I don't have a catch can, nor do I want the end of the hose touching my header which it is doing unless I hold it up (with string at the moment). I hope this is okay to do for testing purposes and that there doesn't need to be some kind of vacuum force pulling gases out of the crankcase or something. The crankcase supplies its own pressure, it should vent itself if there's an opening to do so. All I really should be doing is eliminating another source of air into the intake and running like a PCV valve is non-existent (as if opened). I'm not sure how much oil will come out of that hose that's pointing up at me. I don't want to get hot engine oil in my eye or on my paint! I"m such a noob . I suspect there will just be basically oil vapors coming out so I'm brave enough to fire the motor up this weekend like this.

I'm also looking into cozye's suggestion to jump the pins on the throttle positioning switch to enrichen the mixture and test those results on how the motor runs then. But what should I use as a jumper? I use jumpers on computer boards so I know what they do but I don't have any wires or whatnot to jump pins for the car.

Here is an article on HybridZ of someone messing with his TPS. I won't bend anything like he did..it's against my religion! But, if anything there's some nice pictures there in that article. I see what looks like a metal ball that runs in a plastic track around a curve I suppose this thing rotates as the throttle is applied. Am I right so far :stupid:

http://forums.hybridz.org/index.php/topic/86041-tps-throttle-position-sensor-adjustment-preguide-76-280z/

Then there are three "arms" there that go up to the edge of the box. The metal ball can travel from the end of one arm to the other, which I assume corresponds/ ranging from idle to wide-open throttle. But there is also an arm in the middle which may look to "touch" the metal ball in various degrees as it moves from one end to the other under increasing throttle. But having had a look inside this thing, I can't guess how I'm supposed to jump it. I am not even sure how to get the cover off without breaking something like the guy at that website did. I'd at least like to take the cover off and clean it all with some contact cleaner.

I'll be replacing some vacuum lines this weekend, the big 5/8"/16mm ones heading to the throttle body. At least the straight ones without the dreaded 90degree elbow that I don't know whether I'm going to be able to bend a straight hose enough to mimic.

Anyhoo, frustrated again! But I'm also stripping the fake chrome off my tail light trim and have everything completely disassembled on the rear of the car...lots of cleaning to do and I was happy to see that my car doesn't have any rust in any of the metal in the back or that ledge at the rear of the hatch. I guess with all the bad news comes some good news to keep me going.

I intend to do a compression test on my cylinders before my next oil change. Or before...if these vacuum gremlins keep getting the better of me. I presume that'll be something like a final exam for my motor to rule out any unfortunate mechanical issues that could be causing this vacuum phenomena that's killing me softly.

I read on another thread here that cozye (or was it someone else) tested that their distributor vacuum capsule was holding vacuum and not failing (I read on another website this is the most common place of all where Z's have vacuum leaks) and I guess I should ask how to test if it's leaking vacuum or not?

:classic:

Luvs

J

Edited December 11, 2010 by Jennys280Z

[cozye]

do you have a mighty vac ?

[FastWoman]

Jenny, you can think of the engine vacuum as a reflection of the efficiency at which your engine is running. No running = no vacuum. Efficient running at the right mix = about 19" vacuum. The faster your engine runs on a little bit of air, the more vacuum it's going to pull, because it's essentially behaving like a vacuum pump. Anyway, all a low vacuum means in your case is that the engine is running too rich or lean (in your case too lean). So in direct answer to your question, it's the low idle causing the low vacuum -- sort of. However, if you raise the idle, you'll still have a low vacuum because you're introducing more air and still running ineffeciently.

Carbon canister: It probably won't make a huge difference either way. I'd leave it connected. Just make sure it's not a source of vacuum leakage. (The only real vacuum line is the little hose to the cap.)

Could faulty spark plugs cause low engine vacuum? Yes. Anything that decreases engine efficiency will lower the vacuum. However, it's probably not your root cause. That said, you could have fouling spark plugs due to misfires (like I did), but the spark plugs would be a secondary issue. I doubt you have spark plug issues.

The PVC valve: You need to have that connected, or else you'll have a huge vacuum leak out the top of the valve cover and into the throttle body. PCV valves are very cheap and plentiful, BTW. It's probably not a bad idea to install a new one. It unscrews from the bottom of the intake manifold. BTW, I don't think you'll end up ejecting any hot oil out the PCV hose, and don't worry about oil on the paint (which will wipe off and won't do any damage). However, you don't want the vacuum leak.

Throttle body jumper: Just use a wire. Any wire will do. You can even use a twist tie with the ends stripped bare. Just make sure you make good electrical contact and don't touch the wire to any other metal parts.

The TPS: It's just a switch. There's a little spring arm that fits into the wiggly track. When the throttle is closed, the middle arm is pushed against one contact. Opening up slightly, the arm moves to the middle and doesn't touch either contact. At higher throttle, the arm is pushed over to touch the other contact. You would introduce a jumper between the wires connecting to the middle arm and the second (higher throttle) contact.

Goodyear EZ Coil: This is a stainless steel slinky-like product you can fit over the 5/8" hose to put a 90 deg bend in it without it collapsing. You can also just do a sloppy, sweeping bend in the hose. I hate the way the hose looks, so I made a pipe out of 1/2" copper pipe and elbows from Lowes:

Hatch rust: Congratulations! I have some rust there I have to address. Not fun. Spring project.

Distributor advance: He was probably talking about how the breaker plate freezes up inside the stock distributor. Take off the distributor cap and rotor, and you'll see a magnetic, star-shaped cam (for lack of a better word) and a coil beside it. The coil is fastened to a metal plate. The plate should rotate to the right (?) under high engine vacuum. Most Z plates won't rotate at all and are frozen/rusted in place. Give it a twist with your hand to see if it moves. Then try moving the plate under vacuum. If you can suck pretty hard, you can just attach a tube to the vacuum advance and suck away. The breaker plate should rotate. If it doesn't, your vacuum advance doesn't work. The cheapest/easiest fix is to pick up a rebuilt distributor from AutoZone -- about $100, lifetime warranted, which is a good deal for this troublesome part. You'll need to take them your old one to be rebuilt for someone else (and to get your core charge back). Make sure the cam at the end of the shaft doesn't wobble. Sometimes they bend that shaft when they rebuild it. The distributor lifts out after you completely remove the bolt you loosen to adjust your timing. I believe you also have to transfer the base plate to the new distributor. (I'm describing all this, BTW, because your distributor is more likely bad than good. I understand most are bad.)

Phew! You've got your work cut out for you!

Edited December 11, 2010 by FastWoman

[Jennys280Z]

Thanks Fastwoman! That was an excellent lecture on vacuum to help me understand it correctly! Just like you said, I upped the RPM with the gas to a more normalized 800-900 and the vacuum didn't noticeably improve.

Wow your engine looks so beautiful! Thanks for sharing that. Your car

I pulled the cap and rotor head like you said too, lightly sanded and cleaned the rotor head. It looks a lot fresher than it did so that might make a bit of difference. But the vacuum advance...I sucked into the line as hard as I could and the plate didn't budge at all....and I tried to move the plate with my thumb twisting on the coil(s) (since those are fastened to the plate..right? ) and other than having about 1/16" play in either direction it didn't budge at all. I suspect this has been defective for a while though, and that might explain why a mechanic in the past set my car right at 10deg BTDC as a good move to "deal with" the lack of vacuum advance without costing the customer a new distributor.

There are two vac lines coming off my carbon canister actually. One is the 7/32" purge line that goes right to the intake manifold. The other is a 5/32" vacuum line that shares a 3-way connector with the distributor advance and throttle body. Interestingly, some of the '76 280Zs had this setup (California models ironically, which my car is NOT) and other 280Zs which have the transmission controlled vacuum advance (opening vacuum to the distributor in 4th gear only).

Got all my vacuum hoses replaced..except for one... still working on the tricky one with the bends going to the throttle body. NAPA sold me another hose which has a few bends somewhat similar to the one I need, but it's bending the wrong direction and just won't work so either I'm going to use an EZ coil or two which they sell there (thank you!!!), or I'll just use the same old hose with some new clamps. The old hose is rather hardened but it looks to be in great shape otherwise.

Of course the parts place won't recommend such a thing when you explain your problem to them over the phone. I have to come here instead.

For posterity's sake, the three sizes of vacuum hose for '76 280Zs are 5/32", 7/32", and 5/8" in standard measure replacement hose sizes.

The guy at NAPA sold me this expensive 500psi multi-purpose hose to go out of the valve cover because he said the hot oil from the engine would eat away the rubber of the vacuum/heater hose they sell for a lot cheaper. And I wouldn't want this regular hose going to my throttle body either. Well I don't believe him. I CAN'T believe him because the MP hose is impossible to install without the incredible hulk and even then we would break something with the force required to slide that unyielding hose over the protruding ridge on the nipple. I have a section of that MP hose on right now, the one with the flame arrestor in it, and I almost died trying to get it (only most of the way) on the 3-way connector.

I pulled the PCV hose off at the intake manifold and sealed the valve-opening shut with masking tape and just let the crankcase vent, started the motor and it stalled out almost immediately. First time my motor has ever stalled out so it apparently didn't like that too much. I reattached the hose, started it again to make sure that's what it was...and it didn't stall. I suppose you're right that the motor won't run without the PCV attached but I don't really understand this since some people who drive Zs and don't have to pass emissions use a "catch can" from the crankcase. But they also turbocharge their motors so maybe it's something to do with the turbo...:stupid:

Looking at this picture of the TPS, I drew a little pink line on where I think I should wire the jumper. Is this the correct position? Thanks!

http://i81.photobucket.com/albums/j219/amiamelodramatist/aaaaa-1.jpg

Edited December 14, 2010 by Jennys280Z

[cozye]

Looking at this picture of the TPS, I drew a little pink line on where I think I should wire the jumper. Is this the correct position? Thanks!

http://i81.photobucket.com/albums/j219/amiamelodramatist/aaaaa-1.jpg

Wire the jumper on the connector between the outside and middle pin. no need to jump the delicate contacts of the TPS innards. Just take a 1" copper wire, strip 1/4 off each end and shove it in the connector ends. For the test you don't actually need to have the tps connected

[Jennys280Z]

Wire the jumper on the connector between the outside and middle pin. no need to jump the delicate contacts of the TPS innards. Just take a 1" copper wire, strip 1/4 off each end and shove it in the connector ends. For the test you don't actually need to have the tps connected

Cozye ohhhh okay thanks you! When you say the outside pin, that is the forward pin...the pin closest to the front of the car, correct?

This is a cool idea btw! I can't wait to see what happens...hopefully this weekend.

[FastWoman]

You're making some good progress!

You'll need a new/rebuilt distributor. It's very cheap and easy to replace with a rebuilt one from AutoZone -- about $100. It won't solve your idling problem, but it will give you better fuel economy when cruising and more power at higher RPM (from the centrifugal advance). You probably won't feel much of a difference, but this is still an item you will need to replace to make your engine "right."

When you install your new distributor, make certain you turn it the right direction. I think the key and slot on the shaft are offset slightly to one side. You'll see what I mean when you take it off. A good way to make sure you've installed it right is to note the direction the rotor points in the old one when you take it off, and to make sure it points the same direction (and not 180 deg the other way) when you put the new one one.

Carbon canister lines: It's the second line (the one going to the T-connector) that you want to check for leaks. Just suck on it and see if it's tight. It probably will be. If it is, just hook it back up. I doubt the canister really does much, but it's required by law and probably doesn't do any harm.

The big valve cover hose: Yes, you need fuel-rated hose and not heater hose. That's correct. You'll have a much easier time slipping hoses onto fittings if you heat them a bit first. Also lubricate them a bit. Use a thin oil like WD-40 to lubricate a hose going on an oily part (like the valve cover) and dishwashing detergent to lubricate a hose going on a water fitting (e.g. radiator hose).

The PCV thing: You can disable the PCV system, but you'd have to block off the passages AND put a breather filter on the valve cover, instead of that hose that leads to the throttle body. Then your engine innards wouldn't be under vacuum, and the engine wouldn't die. That said, the PCV system helps keep your engine clean. It's a very good thing to have operational.

TPS: Yes, I believe those are the two arms. However, as Cozye said, you plug the jumper into the connector at the end of the wiring harness, not the TPS assembly itself (which would be unplugged).

Good luck, and stay warm!

[cozye]

Cozye ohhhh okay thanks you! When you say the outside pin, that is the forward pin...the pin closest to the front of the car, correct?

This is a cool idea btw! I can't wait to see what happens...hopefully this weekend.

I forget which outside pin. You can do either, but only one will make a significant fuel enrichment. One is "idle enrichment" which adds lust a touch of extra fuel when the throttle is closed. The other is "full enrichment" which adds a significant amount of fuel when the throttle is pressed significnatly (like 40% or more maybe). You can figure out which one is which by just unplugging the connector with the car off, then take an home meter and measure on the pins from the TPS. Check for continuity between the middle pin and one of the outside pins at full throttle. Whichever one that is, that's the one you will need to jump on the connector for the test. Also, you can drive it around with that plug undone and that jumpered just to see how it feels. It won't hurt anything, worst case it will just be running rich.

[FastWoman]

... except that if she has the closed-throttle side jumpered, it will go into throttle cut mode above a certain RPM range (as I think I remember reading somewhere). But the side where she as the pink line drawn seems to be the correct side if she just figures out the corresponding pins on the connector.

[Jennys280Z]

Hi All, quick update here...

I used a longer 5/8" line between the 3-way and throttle body even though the hood presses on the top of it when I close it. I can get a clip and tie it together with the harness...or leave it, or just put the old hose back on. But for now while I'm diagnosing issues, I will leave all the vacuum lines as new.

Except one question...where does my A/C connect to the vacuum circuit? I can't find anywhere where this connects...I will look through my manual again in case I missed something but if there are a lot of other places in the A/C or Heater under vacuum I want to separate those from the motor pronto. I disconnected the belt from the A/C compressor anyway...so no A/C for me. Disconnecting this belt while not disconnecting any A/C related vacuum lines wouldn't have caused any possible issue relating to a vacuum leak would it?

I've ordered a new PCV valve, fan belt, and spark plugs online, hopefully will have these by Christmas. I'm replacing these GR5's with BPR7ES's. It's my understanding that running a colder plug can be beneficial in the lean state my car is running in right now. A 5 is hotter than an OE plug, and the projected tip makes it even worse. Combine that with a lean mix and it's not a healthy idea to keep running my motor like that. Whether it makes any difference in the way the car runs or not, who knows. But I'll feel better with the colder plugs for now. Whatever carbon and whatnot was built up in my engine in the past, those hotter plugs probably took care of already anyway. I might even get a smoother idle. I might even discover a defective plug. Wouldn't that be good!

I ran the car with the TPS jumped to idle enrichment to little or no effect. I might have gotten about half an inch Hg of vacuum on the gauge, up to about 15inches, but my car didn't seem to run any differently/better when I took it out. And you guys were right that the throttle cut out on me, when I was somewhere around 2800RPM in 2nd gear. I don't think it was the RPMs but the amount of throttle I was applying that mattered and cut it off. When I tested the vacuum with WOT enrichment my vacuum was between 16 and 16.5 in Hg. I always have a slight shake in my vacuum readings. It always fluctuates up and down about 0.4" either way. But I was getting maybe 16.5 or higher at best. That's about a 2 inch improvement with the full enrichment setting jumped. And 18" at 1700RPM. The car idled very healthily with this enrichment but it was pouring out grey smoke too. My idle speed was over 1000RPM in fact. But when I drove the car this way, it still ran like a helicopter instead of a tuba, and smelled like gasoline badly. It felt a lot better at idle and lower RPMs but seemed to have lost a bit of pickup in the upper RPM range. I didn't drive it long enough to know this for sure, it's more of an impulse "feel" that I got right away. I'm not sure if it was as willing to rev higher, or if it was me and my reluctant right foot.

The dist at Autozone is about $120 with a $30 core charge. I found one online for $100 and I think a $20 core charge. Warranty is an issue so I'll shop s'more and find out what to do there.

I'm confident of replacing my brake booster now and don't foresee any major issues with doing that although I dread touching those brake fittings underneath the master cylinder. I HATE working with flare nut wrenches and with brake fluid in general. Oil and gas are fine. Brake fluid is just BLECH! I'm hoping that I only have to bleed the system from the master cylinder itself after I get the new brake booster installed, instead of having to bleed each wheel cylinder. The FSM doesn't mention bleeding at the wheels and I hope there's a good reason for that.

Replacing a distributor myself...I dunno. Don't really know how. Do I just pull it out? When I make sure the rotor is facing the right direction, does that mean the rotor head or something else that's "keyed" in one of two directions down in the shaft near the bottom? I also see loose wires in pictures of these rebuilt distributors...where do these wires connect to (disconnect from)? Also these A1 Cardone remanufactured units all say that they do not include a capsule. A capsule? Are they talking about the vacuum capsule that all of the pictures I've seen of the rebuilt units SHOW in the photos (false advertising?) or are they referring to the distributor CAP, which would make a lot more sense, and jive with the photos too. I've never heard of a distributor cap referred to as a capsule but what do I know? Only what you folks tell me

Since I don't have vacuum advance...I want to test to see that I have centrifugal advance...and I'm guessing I do that by hooking up my timing light as normal to cyl#1 and applying throttle while watching the marks and I should see the timing advance considerably when the throttle is applied, correct?

Also I'm wondering if advancing my timing a few degrees from where it is...say 12 or 13 degrees...would make any improvement.

Some other considerations I have to help my motor improve include:

Adding a resistor to my water temp sensor

Setting valve lash

Checking for a stretched timing chain/cam timing

Coil

Distributor

AFM Connector corrosion

AFM itself

Internal leak in the throttle body (why did I hear that hissing sound while adjusting my idle speed?)

There's a lot more than this...but this is all I can think of for now.

xxx

Edited December 20, 2010 by Jennys280Z