mjr45

Zed, I'd be happy with a good solid all around driving 16MPG.

Captain, they were a few days ago. I'm not sure what I did, but they do look better, I'll see what all the others look like tomorrow.

Blue, just to make sure that I get the best out of the Z, I believe I'll order some new injectors, I'll have to scour the club because I know I've read about which ones were the best. The other option is to send the old injectors off to be be re-done per se, but that'll leave where I'm at with this until they come back, hmmm. The "richer" looking plug was from #3, I'll recheck all 6 in the AM to see if maybe the front 3 are different from the back or any other differences. I kinda thought the #4 plug looked better.

Chickenman, you and Blue are way over my head in this post, I know spark, air and fuel much past that and I start getting lost, but this an interesting read and informative for dummy's like me.

Blue, the numbers I can find are on one side RIN 163 on the other is 7092, hope that helps. Fastwoman, I did your ultra lean test, no change when I cracked the oil cap also when I removed vacuum from the FPR, vacuum off it idled up faster. Also today in talking with the guy who redid my exhaust(today) he said they had a similar problem with a FI car and it wsa due to too much fuel pressure and suggested an adjustable FPR. There is no altitude switch on my car since it was not a Cali car, but I'll try6 to do what you suggest, just not real sure how to connect 9 & 12, I assume you mean to put a SPST switch and run one side to 9 and the other to 12 by opening up the connector and wiring them thru that. I took her out today for a 100 trip amd didn't notice any reall change in performance (by butt dyno) as I've said it runs well just really bad MPG. On the ignition, there is almost like a miss that occurs randomly noticable at idle, it is totally irregular but it is there. Also, today after I got home, I tried fingering the wiper in AFM, pushing CCW almost made it die and going CW could move it a fraction maybe 1/16" the idle would go up and anymore would make it try to stall out Site, I changed the coil to a Crane coil reccomended for the ZX plugs are BPR6ES. Here is a pic og #'s 3 and 4 the others look basically the same, this after a 100 mile run(not constant, 50 mi. down 50 mi. back) today. They actually look better than couple of days ago. On a worse note, I suspect I need rings, saw some blue smoke out of the new exhaust, so I may be in for a lower rebuild. However I want to get the EFI fixed 1st., I can wait on the rings. I mean its not blowing a lot just a very faint blue haze. Thanks Mike

Fastwoman, the exhaust doesn't blow hard but does spit out sooty drops of water, taking off the oil cap makes RPM drop I haven't tried just cracking it to see, I'll try the other two tomorrow and let you know. When I have fingered the wiper to the rich side in the past it runs worse which would mean to me that it is running rich already. The vacuum reads between 14 and 15, but at 9000' that is OK so I don't think Ithere is a vacuum leak and checked with a propane torch(no flame) to see if I could get any increase in RPM and nada. If its really running too lean, I can try the pot in the CTS line to get it richer, I may do it anyway as a test to see if it helps. I just had another thought(at my age they sometimes take awhile to hatch). This car has always "appeared" to run rich, plugs have always been black and sooty and when decelerating at times you get a good whiff of fuel smell amd has died twice from overfueling(the CTS got disconnected). Thanks Mike

jonathan, the injectors were new about 18 mos ago, I'm pretty positive the AFM flap is moving easily and is not bent and yes she fires on all 6. I may have to look at new injectors, but I'm just not there yet. Holy crap this has gone on for 4 pages! Mike

Charles, you could be right, I never had them flow tested or checked when I bought them new. Maybe I'll just slap the old ones back in and see what happens. Zed, I'm not real I want to mess with resistors and switches quite yet. I had the Z out to warm it up and check some fuel rail pressures, ata idle with vacuum 32-33PSI, if I clamp off the in line, pressure drops to 10 in about 90 seconds then slowly bleeds down to 0. If I clamp the return line pressure stays up as long as the line is clamped on release goes to 0, if I clamp the CSV line pressure drops much more slowly but goes to zero, if I clamp both in and return line, pressure very very slowly bleeds down. I'm not sure what all that tells, bad FPR bad CSV whole thing is bad, what? Unfortunately my assistant had to go to town for a massage so I couldn't work three or four clamps at the same time. Blue, yep all the plugs look relatively the same, sooty black.

Thanks Blue for all your help, I may just have to adjust that spring to get it to lean out. It doesn't make a lot of sense to me as to what could be going on, AFM, CTS are checking out good, which means maybe the injectors, FPR and CSV are leaking, but I don't think they are(they are all new), but also not sure how to check except by the rail pressure, the rail right now does not hold pressure for more than a few minutes, I'll try clamping off the CSV to start and go from there. rossiz, I replaced the CSV because it was leaking, same with the FPR(wouldn't hold any vacuum) so maybe I'll try claping the CSV fuel line and see what happens. Thanks for all the help. Mike

Fastwoman, I thought I had adjusted the TPS correctly and in looking at the contacts and the adjustment I made yesterday it still appears correct. The CTS checked out as reading correctly based on ohm #'s, but I guess it could still be off. I checked all the parts at the ECU connector. As far as runnibg better, its hard to say, the roads up here are all muddy and I don't take it in the mud, so I just drove about 800' and never got it up to running temp. I'll let you know tomorrow when I have to take her out fro a new exhaust, just hope the roads are dryer or I can avoid the mud bogs. Since I'm not a whizz electrical guy, what size resistor and exactly hwo would you wire it in. Bottom line is I'd rather have too rich than too lean. Thanks Blue, I've seen that diagram in my FSM, but never paid much attention to it. So my question is, if the ECU is only seeing #1,2,3,4 section of the diagram, its running rich most of the time, correct? Thanks again to all. Mike

It looks to me that the TPS maybe is to blame, if the WOT is not being seen by the ECU that it would be running at the idle mixture setting all the time which would make it run rich. Correct?

So are you saying that because the 6&8 pin reading could be a bad air temp sensor even if the air temp check was OK(2530 ohms @ 61° was about right by the Bible)?

OK folks, here are the test results I got today: Timing w/o vacuum - 15°, mechanical advance approx.21-22° CTS - 3110 ohms @ approx 60°, I don't have a thermometer that goes below 100° AFM - measured @ the ECU connector pin # 6 & 8 - 198.6 ohms, should be around 180 pin # 7 & 8 - 179.6 ohms pin # 8 & 9 - 112.4 ohm, should be around 100 Air Temp Sensor - 2530 ohms @ 61° F Fuel pump relay circuit - 63.6 ohms ( measured on 200 scale on my meter) Air regulator and fuel pump circuit - 43.4 ohms (200 scale) Fuel pressure - 36-37PSI @ idle w/o vacuum, 30-32PSI @ idle with vacuum TPS - checked OK @ no throttle, at full throttle checked out as NG, smae result after trying minor adjustments, so maybe this is the culprit. Fastwoman, the mechanical advance in the dizzy works, turns easily and I checked to make sure the weights move easily. Zed, I think I may have figured out the brown goo on the heat shield since I agree that if it was fuel it woulda caught fire before now. I think it was coolant leaking from that two wire gizmo(don't remember what its called) that had something to do with advance of the dizzy on the older 280 dizzy which I had disconnected after trying to repair it. I got the injectors off of Ebay from a TX company and don't recall the name and can't see any numbers on them. Here is a pic of the wiper in my AFM, hope you see the tracks from the wiper arms and the worn off spots on the carbon trace. I gently cleaned the wiper arm contacts and very minutely bent them to make a little firmer contact with the trace.

Zed, yes the mechanical advance is working, but the vacuum diaphragm on the dizzy is shot, thats why its disconnected and from what I've read it doesn't matter that much and may lead to a vacuum leak. On the fuel side of things, I've clamped the line from the fuel filter to the rail with a pressure gauge in place (permanently attached between the filter and the rail) and pressure dropped slowly, so I replaced the check valve in the pump as well as the O rings with no real change in pressure drop. I also tried clamping from the rail to the filter after the gauge and the drop was a little faster which leads me to believe the problem lies somewhere in the rail, as I said I believe there is a microscopic hole in the rail by the #1 injector, the rail was actually bent and had a break in it where the nipple to the injector is and when straightened, a hole was there whichI had brazed by a guy who does it for a living which is not to say it might not have a hole or it could be the FPR is bad which is new but who knows. There is no obvious fuel leak (no gas squirting out) but the dried brown goo which keeps appearing on the heat shield makes me wonder. If there is a tiny drop in fuel pressure when running would that make the ECU deliver more fuel and thus run rich? I haven't tried checking pressure when running, basically didn't want to run, lines up to the widnshield and leave the hood up and go for a drive. Thanks. Mike

Thanks Blue, prayers are always always appreciated and I believe truly do work. Mike

Zed, I do have the ground wire that connects directly to - post of the battery hr369, I don't have either of those ground wires, I do have a ground wire on the battery side to the car body, but I believe it comes from the other wire harness in the engine bay that goes to the interior, not the EFI, but I'll check it to be sure. rcb, I don't very often run it up to 5800, usually just about to 4000 when accelerating and normal cruising around RPM. The plugs have always been sooty black even when I checked them after running hard. I live at 9000' up in the Rockies, lots of hills and twisty's not much flat terrain around here. The altitude also gives some low numbers on vacuum and compression, but when corrected for sea level they are pretty much right on. Blue, Fastwoman, my carbon trace doesn't look quite that clean and there is a slight wear spot on the carbon trace from the wiper, so maybe when I clean it, it just may help at least a little. Just as another note, I've always had a rich condition. One time caused it to die from over fueling, but that was due to a faulty connection to the CTS which I corrected and check on often to make sure its OK. I'm trying to get her running prefectly to sell it on to raise money for my son's cancer treatment as much as I hate to part with her, but you gotta do what you gotta do. You guys are awesome and I appreciate all the help. Mike

Thanks FastWoman, I knew you would chime in with some good info. I'll try cleaning the wiper and test it again and see what happens. I've looked at the vane before and it didn't appear to be bent and it moves easily. I haven't had a front fire but that doesn't mean it couldn't be bent. Blus, I may try to tighten it up after doing what Fastwomwn posted. Thanks for that diagram, it helps a total electrical novice like me to kinda get the idea. rcb, you're correct there is no altitude swicth or at least not one that I could find. Thanks

Len I'm in serious need of the HellFire. Mike

hr369, I've looked and looked for that ground wire and the FPR is new, look at my reply to Zed. Zed,there is no cam, just stock. The FPR is new but that's not to say it can't be bad, my fuel pressure drops to zero in about 8 minutes after shut down, so its loosing pressure somewhere, I suspect there is a microscopic hole in the fuel rail under the #1 injector, there is some brown goo dried on the heat shield that I've cleaned off a buncg of times but keeps coming back. With all that said, that shouldn't cause it to run rich I don't think. The CSV is new, but could be a problem, maybe its leaking, but taking it out of the circuit electrically doesn't make a difference, Thanks Mike

OK folks I will try to answer the questions in order: Blue: the injectors were new about 18 mos. ago, don't remember the type, but know they wern't for a turbo or high flowing. the whole wiring harness has new connectors and the ones that couln't be cleaned were replaced, male/female etc the FPR is new and fuel pressures: idle no vacuum 36-37 psi with vacuum 30-32 psi the TPS points lighhtly cleaned and adjusted per FSM, not sticking etc. the AFM is stock and the number on it checks out as correct, has new harness connector don't know about the Air Temp Sensor CTS is new and checked per the Bible at the ECU connector and the CTS wiring, OK'd the ground on the EFI harness is ? since I can't find a ground wire after peeling open the entire harness back to the firewall, I know its supposed to be there and ground out on the harness holder. the ECU looks good and the connections are all clean ignition has a good nice blue spark with a new Crane coil, dizzy cleaned up, has no vacuum advance, the vacuum line has been deleted. new battery new NGK plugs and wires Haz: Right on Brother! Carbs in my humble opinion are so much easier, but I really want to keep this at least semi-original. Zed: Resistance readings on #1 test pg 49 of the Bible were 189 ohms, #2 test was 218 ohms and #3 test 112.4 ohms, thus the 12% wrong number. Also see answer above about the CTS. Captain: I changed to another ECU I have and no difference. As for the injectors, they were sold as for the 75-78 280Z, but I can't remember the name or the number, so they could be wrong. I also wish you were closer rossiz: I agree, I had a 76 and it ran like a charm topped it out one nite a long long long time ago at about 170mph on a "dark deserted highway." site: It ran well when I bought the car, but that engine took a crap on me so I have a 79 block with a 75 N 42 head(rebuilt by a guy who does nothing but head work) so its hard to make a comparision. As I have said, the car runs well now, starts right up hot or cold except if it's started cold and left to idle, after about 5 minutes, the idle drops down to about 500 instead of the 900 I have it set at and if driven to warm up the idle stays at 900 so I never let it sit and warm up. I truly truly do appreciate all you guys and women (won't say gals, not poltically correct) that have given me so much help over the last couple of years. I'd been lost and much deeper in debt without you. Thanks. Mike

The FPR is new and I forgot to add that CTS is new and checked out correct by the Bible. I did the "beer" can calibration of the AFM and as stated it is out of spec by about 12% per the bible and you are right messing with "wheel" in the AFM is just screwing it up, but that was a last resort to try to get it to lean out. The only other question in my mind has to do exhaust, the guy who did the exhaust put a 2" pipe from the header back to the muffler which he put in the tranny tunnel and then for whatever reason ran a 1 1/2" from the muffler back to rear end. I know that logically that setup should increase back pressure but I don't think it should effect the rich/lean of the EFI. Just for grins, I switched the thermotine and the CTS wires, car ran like crap. I also have a 3rd option, fill the gas about ahlf full of black powder and light'er up! Blue, I try to drink all the beer I can when working on the beast! Maybe that's whats wrong. Mike

It's been awhile since I've done anything with the Z due to some bad stuff going on with a family member, but to refresh, I have a 75 280, 79 ZX dizzy with E12-80 module vacuum advance disconnected, Crane coil no ballast, AFM calibrated per Atlantic Z, fuel pressure 36-38 at idle w/o vacuum 32 with vacuum, all new fuel lines and clamps, timing at 15°, new CSV, new CSV, thermotine checked out OK so did the TPS(by the Bible). It starts and runs well, but stumbles at about 5800(timing I'm thinking), problem is it runs rich as hell gets about 10mpg(50 miles on 1/3 tank), plugs are sooty black and black soot at the exhaust. I've adjusted the AFM as much as 12 teeth to lean side after fingering the AFM and no difference, the AFM measurements by the Bible show its off about 12%. I'm at the point of junking all of it and either 1) sell the car for parts or 2) dumping $1000 into carbs. Any help would be appreciated. Thanks for all the past help for all of you. Mike

Its been awhile since I was back on the club site, had lots of other stuff(not good stuff) and got involved in wood turning to raise money for cancer treatment for my oldest son. Haz you're doing a great job, if you ever bring her up to Pikes Peak give me shout, Id love to see her in person and maybe enjoy a ride up to Cripple Creek, we'd turn some heads for sure. Mike

Tom, I've got a set that you can have for the shipping, they are not in great shape, but could probably be R&R'd pretty easy, I'll take a pic to send you if you're interested. They are out of my 75.

Haz, that is some amazing work, can't wait to see it completed. If I can help let me know. I live up in Divide but don't mind a road trip every so often but I don't take the Z out in the winter I've put in way to much work to end up in a ditch if you know what I mean, scheesh Colorado drivers!