83 ZXT "CURE" FOR LEAN CONDITION, OR DEATHTRAP?

[Guest jjohart]

Well, I maybe the crybaby kindergartener for all the whining I've done here and w. local mechanics in Boston area, the last (independent Nissan shop owner/tech) whined back at me that my car is running lean, and if I "just twist the fuel return hose, the car runs fine again", well, I got to "thinking", gee, maybe I don't have to spend hundreds more in tech time to find the true source of the lean condition. So, in the high point of my mechanical abilities (maybe your nadir, folks), I "found" the hose he was talking about, bent it a bit, but not completely, and used a piece of a vertical blind clamp to hold it that way, and voila, my car doesn't sputter or buck, cold or on warm restarts! I still feel a vague power on hesitancy on throttle applic., until the boost comes in, so I wouldn't be surprised if the low end is still weak, but until I get the shop to put on my fuel pressure gauge, and AFM gauge, and I take the courage up to try to tweak that afm to rich, aren't I really smart?...and really stupid (entymological nightmare-this really bugs me!), b/c now the tech says, oh that's dangerous, you'll rupture a fuel line or pop a cylinder. IS that TRUE? Seems to me if my car was running as lean before as it was (picture Mr. Magoo/C.C Bang Bang/Ryan O'Neal's Paper Moon transportation for a clue), seems to me I've temporarily settled the score with whatever the HELL the CAUSE is, that all these so-called highly qualified techs here in Boston area could care less about finding, except for buckets of cash!!

Who's right..who's wrong...my god, what have I done?!!!?

John-83 ZXT, I/C, CAI, Greddy ProB, Adjust. FPR, what next!!!?

[Guest SpyderZ]

I believe I replied to one of your post about your running lean problem. I have had over 7 280ZXTs over the time I play with Zcars. I still have 3 280ZXTs now and once in awhile I have that same problem with the car running lean especially under boost. It's the electrical plugs at the ECU not making good contacts and caused confusion to your ECU. You can do your own test to figure it out. Just open the kick panel and drive your car. If it spits and sputter use your left hand and pinch and push on the connectors to see it helps or not. What I ended up doing for all my 280ZXTs was cutting the 300ZXs computer plugs and replace my old ones. There will be a couple pins that the 300ZX plugs don't have. You will have to chop up your 280ZXT connector and get a few pins from there and plug them into the 300ZX connectors to complete the swap. Be sure to cut and swap 1 wire at a time so that you don't get them mix up. Good luck..

BTW I've found a few ZXT in the junk yards because of problems like this.

[Guest jjohart]

Ok,

for my kindergartener's knowlege of Z mechanical issues, this one seems a no brainer, but I noticed no one even mentioned the chief defective component (if not primary culprit-granting there might still be "something else", I am sure as hell not going to keep paying big bucks to find!) for my car's stumbling...turns out to have been the oxygen sensor. I also noticed that no one thought of suggesting the fix/band aid for this, of wiring the ox. sensor wire to the ECU to ground. This came after several hours of tech checks for air leaks, TPS, etc...so obviously this is not a backyard mechanic's car when a problem has no easy diagnosis. Nevertheless, perhaps this "tweak" of tying off the 02 sensor, might be more readily disclosed to future Z owners having driveability problems...it ain't always the AFM or ECU connectors, nor is it adjustable FPR's, larger injectors and other Hybrid Z-Nirvana ineffective panaceas!!!

John-83 280ZXT..kicking so-called Z experts in the afshins!!

[VinhZXT]

I didn't know you have the A/F mixture install or not. If you have it then you can tell right the way the O2 sensor is bad or not. You should have kick yourself in the butt for not getting the A/F mixture gauge lol.. Congratulation on finding the problem.

[280Zen]

kindergartener's knowlege of Z mechanical issues

I thought I was the only kindergartner in this group! welcome to the fingerpainting class.

[jeffp]

I have just looked at your posting regarding the zxt and boy what a hard time you created for yourself.

A few things every 280zxt guy needs to properly troubleshoot the eccs system.

fuel pressure gauge and fittings.

fluke meter.

various hand tools.

hot water.

Factory service manual, it will tell you how to test most of the components.

 

You can track down any problem with those parts.

The )2 sensor should give you about .5 volts at idle and you should see anywhere from .3 to .9 volts depending on engine load. if you get .02 volts or higher, and the voltage doesn't make it into the tenth of a volt ranges when it gets hot, the sensor is bad.

use hot boiling water to test the cylinder head temp sensor.

use the ohms part of the meter to check the TPS.

and if the car is not firing use the volt part of the meter to check the crank angle sensor, and AFM.

this is a basic quick answer, but you get the idea.

[randy 77zt]

jjohart-the repair shops dont want to work on old cars.due to the mitchell manual time per job system the shops are only interested in work that involves removing and replacing parts.since the coming of cars with obd2 most techs only know how to plug the scan tool in and change parts.so you are either forced to learn your cars efi and other systems or get a late model car.a good book to get if you can find it is the 81zxt (will work on 82 or 83)factory tech supplement for turbo cars.it was a nissan dealer manual that was a supplement for the factory service manual.i have 1.i wont sell it -its a rare find.unless you can find a nissan only shop with a grey haired old z tech i wouldnt bother with repair shops.if you are lean there are many things to check.fuel, pressure WHILE driving-not just idleing.most old z's were sold before the gas had any injector cleaner added-if you have old injectors get them cleaned & flow tested.visual inspect connectors-for corrosion.if you short the o2 sensor output then the ecm goes to full rich at closed loop-best to fix the correctly.

[VinhZXT]

Jj,

You may want to check out this post

http://forums.hybridz.org/showthread.php?p=539141#post539141