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Discussion Starter · #1 ·
I have a 91' Z24 with about 130,000 miles on it. I purchased this car about a year ago and everything was going fine until a couple of nights ago. I was backing out of the garage (not applying any gas) and all the sudden it shuttered really hard and died! (The engine was cold when i backed it out of the garage) It's never done this before and has actually been a very smooth and reliable ride. When it is in DRIVE and im not applying the gas, it sorta jumps and the RPM's go up and down and it acts like it wants to die. Does anyone know what could have went wrong and/or how to fix it? Please help me:roll: Thanks
 

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Did it set any trouble codes?
Try cleaning the trottlebody, as per the instructions in the how-to section.
Could be a sticking Idle control valve too, or numerous other things...but check that out first.
 

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I had that problem before on my 86 cavalier z24. I was backing out and the engine cut off when it was cold. It happened when i was a little premature with cars and my dad took it to the shop. They said it was the coil and should be replaced. Once they replaced the coil, everything was fine!

Hope that helped
 

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Discussion Starter · #4 ·
Ok, I will try cleaning the throttle body and take it from there. Does anyone know about how much it costs to get the coil replaced in a 91 Cavalier Z24. Thanks alot, I really appreciate all the help
 

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Well, actually, there are a total of three coils, and if one is actually bad, it probably wont be all three. If it is a coil thats causing your problem, you can narrow it down by testing for spark. If the 2 plugs are dead coming from the same coil, its probably that coil that is dead.
 

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Discussion Starter · #7 ·
Well, I cleaned the throttle body very well. I cleaned in the areas you specified and every crack with Q-tips, a toothbrush and lots of carb cleaner. Lots of gunk and sludge came out, it was in need of a good cleaning and I think it helped the overall health of the car. I think it may have helped the idle somewhat, but it is still jumpy when idleing. It runs very smooth until I am approaching a stop sign/light and I begin to brake. At this point it begins to jump a little, but when i come to a complete stop, the RPM's dive down and it acts like it wants to die, but it hasn't been as bad since i cleaned the TB. What is my next step in getting to the bottom of this problem, should i get it tuned up? Thanks alot, i really appreciate everyone's help!
 

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Discussion Starter · #8 ·
Oh yeah by the way, my engine light hasn't been coming on and never has since i've owned the car. I guess thats what you mean by "is it setting any trouble codes?" Thanks
 

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Glad the TB cleaning helped some
When you are coming to a stop and it wants to die, what happens if you throw it in Neutral? Does it still exibit the same behavior?
 

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Discussion Starter · #10 ·
When I threw it into neutral coming to a stop it sorta helped. Although it did idle smoother, it was still idleing well below its normal RPM's.(could this have changed since i cleaned the TB) My dad thinks the only reason its idleing better in neutral is because its not under the strain of the transmission. Now when im idleing in DRIVE, the RPM's are around 500. When i kick it into neutral, the RPM's come up to around 800. I think before it used to idle around 1,100 RPM's but im not positive. I guess i'll try the idle control valve next, is it electronic? Does the idle control valve just need a good cleanin or does it have to be replaced? What are my next steps, sorry the info is kinda wishy-washy but its the best i could do.....Thanks a ton
 

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I would first check to make sure you have spark to each cylinder. What happens when you aren't at idle, does the car run smooth when driving faster or can you still sense some hesitation (compared to before the problems started). Does the car always run bad now, or is the problem intermittent? I would look at these things but it may change depending on the questions I asked above. EGR, Coil(s), Wires/Plugs, TB (but you already cleaned that), ECM, and Fuel Pump (you can check fuel pressure at the rail for this). I have seen this problem twice before and both times a weak fuel pump was the cause.
 

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Discussion Starter · #12 ·
The car runs good when I accelerate and is very quick. Its been idleing bad for a week straight now so its not intermittant. Thanks
 

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So you didnt clean the IAC as well, when you cleaned the TB? Yes, definately clean that. It is electronic (and could be bad), but it is probably just caked with carbon buildup as well.
 

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Discussion Starter · #14 ·
I cleaned the IAC very well along with every other piece of the TB various times. The cleaning hasn't helped my idle problem. Thanks
 

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hrm..... scratches head
May be time to starting checking something fuel or ignition related, as mentioned above. Since its not setting any codes, it hard to say. Fuel filter or pump, plugs, wires, coils...
 

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Discussion Starter · #16 ·
Well, I thought I would be able to fix this problem without taking it to a mechanic, but I think its inevitable. I would like to thank everyone who responded to my S.O.S. I'll take it in and see whats wrong and see how much it will cost to fix. I'll keep everyone informed as to what the problem was, once again, thanks
 

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Discussion Starter · #18 ·
I took it to the mechanic and told him I had an idle problem. He then asked me if I recently changed had the battery changed, I told him no but I had recently unhooked to remove an alarm. He then told me that was my problem. When you remove the positive terminal from the battery, it resets all the computer information including idle control. I didn't know unhooking the battery could have such a drastic change. Oh well, I'm happy to know that my car will be better soon. Thanks to all who helped!
 

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My car has had both the dying when backing out problem (haven't replaced the coils yet and it still does it on rare occasion) but the other problem of it jumping and trying to die when stopping sounds like another problem I had. It was caused by a faulty TCC Solenoid in the transmission. It is what controls the car going into and out of overdrive. When one becomes faulty it keeps overdrive engaged when you're trying to stop....thus the brakes are directly fighting with the engine...needless to say that is bad. I had The solenoid replaced for $125 and haven't had a problem since. A good way to test this is if you're on the highway and the car is warm and you're going up a decent sized hill. As you go up the hill apply the brake...if the rpm's jump up like it is coming out of overdrive then the TCC probably isn't the problem, but if they go down slightly that is because it is locked into overdrive. Hope this helps.

--Mabe
 

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I know the TCC problem all too well I was consiering mentioning this problem, but from his description, I didnt think it quite sounded like that was the problem, since it would actually stay running when stopped and just idle bad. If it was the TCC, the car would die imediately upons slowing to a stop, and keep dieing as soon as the car was put into drive, in a very harsh way, until it cooled down enough to unlock.
 
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