Running Rich
 

Running my 75 280Z super rich. About 1000 miles and the plugs foul. Rev it up, and a big ol Plume of gas smelling smoke comes out. Any links to where I can find instructions for leaning it out a bit would be appreciated.

Sounds like you need to adjust your AFM ( https://www.zdriver.com/forums/240z-280zxt-s30-s130-tech-tips-275/js-how-rebuild-your-afm-15277/ )

or check your head temp sensor.

Already put a new head temp sensor in, so has to be the AFM. Thanks for the link man!

Werd. If the AFM gives you probs, let us know... we'll help out.

Well im gonna go out and try this out. Ive also got new wires and cap and rotor coming. Plugs are already new. Fouled out before. Its just running richer than hell. Maybe getting 11-12 mpg. The thing sat for a good long while, ive even switched out the throttle body. The other one kept sticking the idle at 2k RPM. I had a spare in stock. Well, wish me luck! lol!

Ok, I turned that gear, and now the thing is running on like 3 cylinders. Barely does 50mph. Id rather run rich and fast than top off at 5000 rpm, or worse, run on 3 and backfire and be horrible. Is there a way to recalibrate the AFM before I just say screw it and go buy a new one.

EDIT: I marked the cog with a pencil, and it wore off, so am I screwed?

Never mind. Through some extensive Googling, I found this:

http://www.atlanticz.ca/zclub/techti...ion/index.html

You need to be using an air/fuel gauge when you mess w/ the AFM... otherwise you don't get an accurate setting/tune.

Yeah, my cousin has one. Its just a pain to get ahold of him again, and for him to have the time to go to the garage and open it up. I used it last time. But I think I let the sprocket get slacked, and it was a bitch to get it back to 0 again. I just wanna get it back to the regular setting. I can go from there knowing what I know now.

No go after calibration. I give up. I may just buy a new AFM or go MS and get rid of that ancient junk. How accurate can 30 year old technology be afterall?

Man... you're a quick giver-upper!

Ach, I just dont like dealing with old junk, when theres upgrades to be had. I have my cousin coming out to look at it tonight. Those AFM's are just a pain in my book. He has some Z experience under his belt. He wanted to know why I moved the spring tension to lean it out. Also said thats the stupidest thing he's ever heard of. Im tending to agree. Next time i'll just let it run rich. Who cares, as long as its fast. Its not like my eyes were burning, just the poor bastard driving behind me.

if it was running rich, you didnt have to completly let the cog go, you gotta hold on to it, then tighten it a few cogs, then give it a go. and have you checked your cold start valve to mak sure its not stuck open? if your afm is adjusted to tight (which it sounds like now) then loosen it a bit, leave the cover off and go for a drive, then keep adjusting the cog until your close (youll be able to feel the difference when you are close) then make sure it is a bit rich (like 2 cogs) then itll be good till you get the guage.

My cousin has the guage, and will be over in an hour or so. I just lost the mark I made on it. I didnt let it go, I just went a bit too far and lost reference. Hopefully, we get it goin. Ill check the cold start valve just in case. Thanks.

Cold start valve is ok. Checked the vaccum too, ok as well. The AFM itself is not in good shape. We've been back and forth through the "cog" range, and no go. He checked the AFM with a multimeter, and it doesnt register through the whole range of movement. So im thinkin I should just get a reman. AFM. Ill just cut the BS in half. We checked out all the sensors, timing, firing order, etc. We eliminated all other variables. It all came back to the AFM. So wheres a good place to get a remanufactured AFM? Thanks.

Buy one at a junk yard or on ebay before blowing $200 on a reman.

Alright, ill hit the yard this weekend. Thanks man.

Are the ZX's interchangable with the Z? Any other interchangeables that go with this car?? Thanks again!

Yes, the non-turbos are all the same. Just dont get a turbo one... that WON'T fix the prob.

Awesome. Thanks man. Found em for 45 bucks at the local yard. He has no Z's there, only ZX's. 6 of em. I believe all are non turbo. Thanks again. Are there any mods I need to perform to get it in there and working??

Got the AFM. Goin around checking all the other sensors now. Still the same problem remains. Ive changed the cold start valve, and a few others. Changed a few vaccum lines also. I got a nice unopened AFM from the salvage yard. So I know this isnt the problem anymore. Im gonna change out the rubber intale lines also. I rev it up, and its a smoke fiesta goin on. Eye burning gas smoke. The car I pulled the AFM from was a tbone victim, so I assumed it ran before its demise. Any other suggestions welcome. Im goin to the storage where I have my other L28, and am gonna rob all other sensors I dont have from the stockpile I have there. Im just baffled as to why the problem remains. I just changed the plugs and wires also, but I reverted back to the old setup for a process of elimination type deal. I even put the stock coil back on the car. Im runnin out of ideas. Any other ideas?? Thanks!

Checked the resistance in the fuel injectors, 3.2 on all of em. Gonna check the connectors tomorrow. Swapped out to 2 different ECU's also. Checked the fuel PSI, and it was 27 on idle, 35-37 on rev up. Im baffled here. Aside from the checking of the voltage on the injector plugs tomorrow, I am at a loss. It even blows the smoke on idle now. Well prolly check for burnt valves and such. A compression test is in the works tomorrow. Anything else guys??

have you verified your timing?

what color is this smoke? Have you checked compression? I've seen and had cars that smoked like crazy due to a rich condition but none of them had trouble reaching 50mph. Low compression (for whatever reason) can, however.

Also, just because all the sensors/ECU are checking out OK doesn't mean your 30 year old wiring is ;) Pull the ECU connector and run all your sensor tests at the ECU connector. This is the only sure way to tell you dont have a fault in your engine harness wiring.

Yes, well be doin a compression test today. Also be doin the wiring test today. If the wiring harness is crap, thats ok. I have another one of those too. Ive got parts from 2 other z cars that we've had in the past. One of em I cracked up, then sold the parts to my buddy, then he got rid of his 77 for a 75 and stripped the 77. Then he sold me the 75 and all the parts he's accumulated. I have plenty. Oh ya, well be checking the timing today also..

Compression tested ok. 140-150 on all cylinders. Wiring harness ok also. Changed the dizzy on it too. Timing ok. Right now I have an issue with the injectors. Can this be the cause of all this? I pulled the fuel rail and am starting it with a remote starter. the injectors squirt like a squirt gun. I replaced the 2 worst ones and they inject like a triangular mist pattern. More like what I would expect. Im gonna go ahead an keep replacing til I run out of in stock replacements. Im pulling the replacements and testing as I go off of another fuel rail I also have in stock from another unused motor I have laying around. Im just hoping this is it. Im running out of options.