Zed Head

Are the bleed valves at the top of the calipers? It is possible (and easy) to install the calipers on the wrong sides of the car. This puts the bleed valve at the bottom, leaving a big air bubble that can not be removed by normal bleeding procedures. I've also seen similar symptoms from people who had the reaction disc in the brake booster fall out, but I don't know much about that problem.

I read both of your posts and can't figure out the conditions for the three pulls. You mentioned a single carb, a four-barrel, a ZXT distributor and headers but didn't really identify the combinations used. Could you describe the setup for each pull?

What car? Have you checked the FSM, the ignition system wiring is well-illustrated and described.

You should see the reluctor move. The breaker plate, the plate that has the reluctor (or magnetic pickup coil) mounted on it, is the part that moves. Another way to check it is to remove the screw that holds the vacuum advance module to the housing and slide the module out a little bit, pulling on the breaker plate, which is what the vacuum module does in operation. You will see the breaker plate move and can get a feel for how messed up it is. Don't move it too far or the bearings might fall out. It should move easily back and forth with no gritty feel. Look closely at the edges of the breaker plate for visible ball bearings. What happens is that the thin plastic locater for the bearings breaks and lets the bearings push out under the pressure of the breaker plate mounting assembly. Or maybe they get rusty and then the locater breaks. Either way, no more vacuum advance.

I've seen it described around the internet, and pretty sure I saw it at Hybridz along with some non-Nissan options for seals. Search 240Z, 260Z or 280Z and valve seal and you'll probably find some write-ups. It involves some rope or hose or air pressure to keep the valves up and a couple of tricks to get the seals on without cutting the edges.

I'm using BWD injectors with no issues. Getting ~20-21 mpg avg. now. I got them at Schucks/O'Reilly. I got the cheap $40 ones, but now they have another BWD type for $77. Remanufactured. The remans cost $77, the new ones $40. So your $59 for cleaned and re-hosed is in the middle. 10 - 12 mpg is pretty low. Have you checked your fuel pressure and water temperature sensor resistance? Make sure you check fuel pressure with the engine running also to verify that the pressure drops with intake vacuum. My regulator went bad and mileage dropped to 15 mpg and the car really stunk. Are you actually calculating mileage or just guessing? At 10 mpg I would expect liquid gasoline to be dripping from your exhaust pipe.

Check the vacuum hose from the intake manifold to your fuel pressure regulator. Fuel pressure should be ~30 psi or lower at idle, depending on intake vacuum. You'll run a little rich and gassy without it connected.

Funny, I almost added a comment about the racer types who believe mastering the engine via throttle and clutch control is all that's necessary. Behave beast! The dash pot is a luxury and it does allow easier shifting. Call me lazy. I can take it.

I knew I has seen a thread on this out there somewhere. I just adjusted mine in a turn a few days ago, to give a more consistent feel during shifting. At certain times during warmup, the revs drop faster than usual, causing a "clunky" shift. I've adjusted it in the past to avoid the engine dieing problem kjp... mentioned, but I added a little more fine-tuning for driveability. I think that there is a factory spec. on where it should be, but with my worn engine and throttle parts, I just adjust until it does what I want it to do. It seems to have made a difference, I can't remember a clunky shift since doing it and I can see the tach moving down more slowly. If you can find a pot with a similar form you might be able to rig it onto the bracket. The bracket keeps it centered over the throttle lever. It's just a spring and leaky diaphragm gizmo.

To complicate things even more, most cars use a ported source for vacuum advance. So as soon as you touch the throttle, you're timing advance jumps significantly. Plus mechanical advance which kicks in at 600 rpm. You can be around 30 degrees advance at low RPM, steady cruising conditions, above 2500 RPM you can be in the 40s. And don't forget the idle air adjustment. Idle conditions are their own little world. Not to put a damper on playing with these things, just saying that there are a lot of other considerations. What happens at idle only gets you so far.

I can hear it but it's just a smooth "whir", no racket. I insulated the mounting points with some thin rubber sheet to keep it a little quieter inside. I can barely hear it from outside the car. It sounds like I imagine a good pump should sound. If the "racket" is an erratic, grinding noise maybe you do have a bad one.

June bugs. I remember those guys. They're the big ones, like giant Japanese beetles. Don't have them in the PNW. For what it's worth, I have had an Airtex E8312 (the high pressure FI pump) in my car for 1.5 years and have had no problems. Bought it new at Schucks. Have you pinched the return line to see if pressure rises? It might give you more clues on fuel flow versus weak pump. You can break these problems in to pieces and get to a point where you're more certain what to fix. Edit - changed some stuff.

Actually, you should be annoyed that you don't know for sure what the problem is. Is it a clogged inlet, a bad pump, a clogged pump outlet, a blocked fuel line, an open FPR, etc. Dig in a little and determine what's happening, or not. To FW's comment- what is the brand and model number of the pump you bought? Were you getting 36 psi with your old pump (and dirty tank)?

Tuning for vacuum level that is done at idle will have the "idle enrichment" fuel contribution from the ECU and the TPS. I'm pretty sure that I saw the same type of issue, tuning for idle properties, on the spring tension tuning procedure.

It is a straight transmission for transmission swap for a 280Z. Except for the 4th gear vacuum advance switch if your car is a 1975 Federal, not a California, model. The five speed probably does not have it, so you will need to hook up vacuum advance full-time or rig up a switch. Use all of the parts that you have in there now, except the transmission. Shifter, throwout bearing, everything. The only difference you will notice is the 5th gear. 1st through 4th gear ratios are even the same, if by "earlier" you meant 75-79. I did the same swap in my 1976. 5th gear is nice to have on the freeway, even at 55 mph. Very nice at 70. Edit - tlorber beat me to the punch while I was typing. I think that in your case, your 280 4 speed shifter is the same as the 5 speed shifter. Both transmissions came from 280s and are externally almost identical.

It would probably help you answer your own question if you defined/learned what each item of "crap" is and how it functions. Then you could determine how removing it would affect performance.

Does it have a turbocharger? A question in the same vein just came up in another thread a little while ago. According to the the web site linked below, your combination of P79 head and N42 block will give a 7.4 compression ratio, if the N42 has the stock dished pistons it came with. That would probably be just right for a turbo engine but not so hot for NA. http://www.zcarz.us/TechnicalInformationPage.htm

It won't hurt the module on the G and W pins of the HEI module, where the reluctor wires connect. The module just looks for a voltage signal going from negative to positive across those two pins and fires at the crossing point. If you hook it up backwards the crossing point is off and weak (it will see a strong positive to negative signal instead) so you get poor timing control. This is for the 4 pin module, I think the 7 and 8 pins are opposite, working from a positive to negative voltage. Either way, if you don't know - trial and error. The B and C pins probably need to be connected correctly or damage might occur.

What color are the wires? Red is positive, from the magnetic pickup (reluctor). If you have a rebuilt, they may have spliced wire extensions on that are the same color but you might be able to see the original color up by the pickup. From what I've read, the other way to find out is to just hook it up and watch your timing mark. Apparently, if it's connected backwards the timing will be erratic and unstable. If you get an unstable timing mark, swap the wires and re-time. Make sure that you have a good ground to your mounting posts, they are the electrical grounding points for the module internals.

The voltage meters on these cars are typically inaccurate, so the 15.5 reading may not be right. Have you had a voltmeter on it at high RPM? I wouldn't trust the stock in-dash meter. They can be adjusted via the screws in the back though for future use, but you'll still need an accurate volt-meter to do it. The wiring looks typical of someone jumping the plug instead of cutting the wires. You can check Blue's site to see if the colors are matched correctly. They don't match by color, but by function,and there are several "extra" wires afterward. Is the "11" reading (accurate or not) at idle, at night with the lights on? Or is it while driving? It sounds more like a weak alternator, low idle speed, or too much current drop through dirty connections. The Z alternators put out just enough amperage at idle to get the job done, if everything is clean and working correctly. Even an extra 500 RPM of idle speed can make a difference. I have also found that a 10 year old factory alternator from an old parts car performs better at idle than a brand new rebuilt parts store alternator. The parts store alternators are of generally low quality. I had mine die within a year.

Double post. Love the site, but it's still very slow...

Here is a picture from the FSM. You can see that the wire to the transmission switch is powered when the key is On. Apparently the trans switch is normally closed, so the solenoid is powered in gears 1-3, blocking the vacuum passage to the distributor. In 4th gear, the switch opens, power is cut to the solenoid, and vacuum is applied to the vac advance. If the solenoid doesn't have power, you will have full time vacuum to the distributor advance. So if you don't have the wire to the solenoid, you really don't need to do anything except watch out for the other loose wire end from the trans, which will have power. Or take everything off and connect the vacuum hose directly to the vacuum advance (with one loose wire still to worry about).

Ran fine when parked! Ten years ago. Not mine, just thought someone might be interested. The one side that's shown doesn't look terrible. Ridgefield is about 20 miles north of Portland OR on I-5. http://portland.craigslist.org/clk/cto/2389207775.html

They are fairly easy to twist out of the top of the diff. You might go to a local wrecking yard with a pair of pliers. Don't squeeze too hard if it's a plastic one. I think that the later Zxs came with metal. Maximas and maybe Subarus might use the same went.

The ECU holds the injectors open longer as the AFM vane opens farther. With a vacuum leak less air flows past the AFM, the vane doesn't open as far, so the injector open time is shorter, giving a leaner mixture. The ECU also takes information from the temperature sensors and the tachometer. The Engine Fuel section in the FSM describes it all, with graphics. Fuel pressure can affect the mixture also. Have you checked your fuel pressure and fuel pressure regulator? When mine went bad, the engine ran very rich.