bigeZ Posted September 27, 2004 Share Posted September 27, 2004 The other day i tried to drive my car and it wouldnt idle right. I seems to me that one of the cylinders isnt getting a spark. or that the timming is WAY off. it shakes really badly and when i push on the gas it wants to die, and blows black smoke out the back. I already replaced the rotor, cap and sprakplug wires. Maybe the distributer skiped a grear or something. i dont know what to do. HELP......... Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 27, 2004 Share Posted September 27, 2004 Black smoke means you are more likely running super rich, which if severe enough can cause the car to run as you describe... more likely than any ignition problem. First thing I'd do (and you'd be surprised just how often this works for being such a simple thing) is to get a can of electric parts cleaner spray, disconnect all your wiring harness connectors and spray them all off. LOTS of guys here have had pretty bad problems and found that doing nothing more than this fixed them up. If you do this and it DOES work, get yourself some dielectric grease from an electronics store and put it on all of your connections... this will keep them from coroding again. Secondly, get yourself a fuel pressure gauge... if money is an issue get yourself a 'home depot special'... it will cost you about $10 and consists of basically a tee fitting and a water pressure gauge (the one I got reads from 0-100psi). Install it underhood inline with the fuel feed after the fuel filter. If those two don't show you the problem or fix it then you have to start checking all your electrical and spend a bit more time and money. You can verify your suspicion about the ignition with a cheap timing light... if the distributor 'skipped a tooth' timing would be WAY off. Pull all your plug wires one by one while the car is running, observe that a) you are getting spark at each plug) and if unplugging one certain cylinder does not cause the car to run any worse, than the problem is in that particular cylinder. Still haven't found it? Get yourself a voltmeter and a haynes manual/factory service manual and start testing sensors, a bad AFM, TPS, O2, or head temp sensor could all cause you to run rich like that. You didn't specify which year Z this is, by the way. If it's a 280z/zx, unfortunately they can be pretty buggy sometimes when it comes to the EFI... you just have to methodically go thru everything step by step until you isolate the problem. Also, did this just start happening out of the blue? Did it start out minor and slowly get worse? Did you change anything before it suddenly started running badly? Did you happen to recently steam clean the engine bay by chance? Rained lately? The things I suggested shouldn't cost you too much money wise though it will be time consuming, there's a good chance one of them will pinpoint your problem. Good luck. Quote Link to comment Share on other sites More sharing options...
bigeZ Posted September 28, 2004 Author Share Posted September 28, 2004 Its an 83 zx nonturbo. And it did run like this in the past but only on rare ocasions. for instance, It would start and run fine and i could drive, but as soon a i would turn it off and restart it, it would start running like crap. In the past i would let it idle for a while and it would fix itself. but now it won't idle back to normal. I have seen herd of this happening to other Z.s but no reply on what the main problem was. Thanks for the help bastaad525 . ill start trying those things out. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted September 28, 2004 Share Posted September 28, 2004 Sounds EXACTLY like a problem I had with an 81 zx. Turned out to be a bad (sticking) fuel injector. I actually pulled the spark plug on that cylinder, and ran it for a few mins (I was testing a theory) and it ran BETTER on 5, then on 6. I had quite a cloud of gas firing out the no. 5 plug hole though! If it'll stay running by itself still, try using a long screwdriver like a stethiscope (sp?) to listen to the injectors. Likely one will sound WAY different than the rest, and that will be the problem injector. OR; one of the injector clips has cracked and is not making proper contact, which will throw off the computer and it'll try to adjust.. ussually ending up too rich, in my expirience. Hope this helps. Quote Link to comment Share on other sites More sharing options...
bigeZ Posted September 28, 2004 Author Share Posted September 28, 2004 its been running horible for the past 2 weeks with no change, and the same goes for earlier today. But after i tried running it earlier i shut it off and gave up, then i went back out about 2 hrs later and it started right up, and ran good. i drove it around and it seemed perfect. Im confused because i didnt change anything. im going to test the injecters and harnesses tomarrow hopefully. thnx for the ideas... Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 30, 2004 Share Posted September 30, 2004 When a problem comes and goes like that it's 99.9% it's an electrical problem... some bad connection or short in the wiring somewhere. Quote Link to comment Share on other sites More sharing options...
bigeZ Posted October 8, 2004 Author Share Posted October 8, 2004 Well now ive done it. Its been running ok off and on for the past week untill the other night. i started it and it did its usual rough idle, with the shakes, and never wanted to level out. i was in a hurry to a meating so i reved it up to about 2k and still didnt want to idle out, then i got pissed and revd it as far as it would go, bad idea, as soon as i let off the gas it died. and hasnt started since. it cranks over perfictley but wont run, wont even give me sputter. I think i just killed my Z now i really dont know what to do. Quote Link to comment Share on other sites More sharing options...
GabeRoc Posted October 8, 2004 Share Posted October 8, 2004 i've had a problem like this twice on my '81 n/a. both times it was a bad fuel presure regulater. something else to check is the cylinder head temperature sensor. just above the starter, should be a two wire connector. it is just a thermistor, but it is what the ecu uses to adjust the injectors for cold engine. if there is too much resistance (e.g. corroded, unpluged, ect..) the ecu reads that it is a really, really cold engine and pours fuel into the intake. if you unplug the thermistor and the car will idle rough but not run, take annother look at the fuel presure regulater. also, a bit of a duh statement, but one that i wish i had thought of more than once, make sure the rubber boot between the air meter and the intake manifold is secure and not leaking. hope you figure it out and let us know what the problem was. gabe Quote Link to comment Share on other sites More sharing options...
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