91RS idle issues

[top_down_camaro]

I have a 91 camaro RS convertable, 170K miles.
This car has been maintained and runs like a jewel up until now.
I drove to the store lastnight without any issues. When i came out, the car wouldnt fire, I had fuel for i could smell it without a doubt. I ended up leaving the car and made arrangments to have it towed the next day. Upon arival, surprisingly it started. But while i was letting it warm up, i noticed the idle shot up irriticatly then droped back down 1500, this lasted about 15 seconds.I drove the car home ( 1-2 mile) without any issues. I decided to let the car run in the driveway. After about 10 min, it stalled as if shut it down. It would start back up but once again it would shut down after about 10 min of idle time. Does this sound like an O2 sensor?
I tried to get a code ( if any ) but wasnt succesfull to even get 1 flash. I grounded #6 and #12 post, then tried #5 and #12. Was i checking the right post for a read out?

[top_down_camaro]

seems the issue worked itself out for now. I drove the car tonight and hasnt repeated. It will idle without stalling. Not sure what was going on but would still like some input for i dont like to be stranded

[2x4]

Doesnt sound like a o2 sensor at all, that wouldnt make it not start or stall. With a bad o2 sensor yous get bad mileage & a rich engine.

What you can do is check things like the IAC motor, TPS voltage and minimum air rate(idle speed). I'm leaning towards a dirty or bad IAC motor. Your IAC is basically the "choke" in a fuel injected application. When the car is cold & you first start it, the IAC pushes a plunger out into a air bleed passage in the T/B, restricting the flow of air into the T/B. As the car warms up, it pulls the plunger back in, increasing airflow. It also speeds up the motor when the engine is loaded down, like when you pop on the A/C. You can remove it & clean the plunger & the bore with carb cleaner & a q-tip. Possibly not going to fix it, but it cant hurt any!

To check your trouble codes, youd jump the upper right 2 pins on the ALDL (hey, you were close!). If the check engine light wasnt on, you shouldnt have any codes in the memory.

If this happens again, try holding the gas pedal down 1/4 of the way & start it.

[top_down_camaro]

Thanks 2x4 for the info,
I also did some research and found out O2 sensor wasn’t it as you stated. What I did find out was the module itself is known to quit from time to time and then work normal and was a sign it should be replaced soon. Not sure how true this statement is. What I have done since this episode was, I pored a can of "sea foam" in the tank. I have heard allot of good things about this product for cleaning the fuel system. So far I have put about 60 miles with this product and I have seen mileage improvement so far but I wasn’t having an issue with mileage anyhow.

I have a heavy background in computers and thinking about hooking my laptop into the car's computer system. My question is can anyone point me in the direction for cable connection and software for dynastic?

Thanks in advance

[2x4]

You could snoop around www.thirdgen.org and www.chevytalk.com both boards have good people. Also www.camaroz28.com

[Doug000]

It has been a few years since I have worked with a GM TPI system. What you experienced is a sensor failing. Check your engine tempurature sensor. I suspect that is telling the ECU that the engine is few degreees warmer than it really is. A lowtech method of checking this is listen to when and how often your cooling fans are turning on. Once you check your engine codes, realize that the important thing is that there is a code...not what the code is. This generation of ECU's are notorious for telling trouble codes for the good sensors, and forgeting to mention the bad sensor, because the ECU only knows that the 2 sensor readings do not mesh, and it displays the code of the more likely culpret.

[top_down_camaro]

I received an code “32” from the ECM’s memory.
If I remember correctly, this is either a fault in barometric pressure sensor circuit, Or
fault in exhaust gas recirculation valve diagnostic switch, Or
fault in electronic vacuum regulator valve. Not sure if this ties in with my previous issue but it hasn’t recurred since that day.
Also I have found the cable/software I was looking for my laptop, for the price they wanted I could get a new laptop!
:22yikes:

[89IROC&RS]

The egr is a good place to start, if it is faulty, your O2 sensor, plugs, wires, and some other thigns tend to follow suit. its kinda a chain reaction. when the EGR dosnt work, the O2 sensor goes nuts, richens the mix, and winds up making things worse, fouls the plugs, and in extream cases, can burn plug wires. but the IAC is a good place to look, it shoudl be on the passenger side of the throttle body assembly, and will unscrew with a socket, 13/16ths if i remember right. dont twist it, or remove the spring, hose it down with brake cleaner, and GENTLY push it in and out as much as its happy with. also, i dont mean to talk to anyone like they are four years old, but have you done the basic stuff, like check your plug wires. i drove my IROC from arkansas to virginia thinking it was perfectly set up, only to realize my idle was messed up, and it was having trouble starting in the morning in cold air, turns out the previous owner had crossed the number 6 and 8 wires, still ran, just rough, and wouldnt idle well. kinda sounds like what your into. anyway, thats my two cents, hope it helps.

[Evilinside]

This sounds very similar to the problem I am having right nowwith my '90 RS.

I can drive to work (About 40 minutes away) leave the car for 4 hours till lunch. Drive to 7 eleven (5 minutes away) then go back out after work and get about 10 minutes down the road before the car shuts off and wont restart.

The motor does not sputter and die just dies like the ignition was shut off. If the stereo is on I wont even notice until I step on the gas.

I will then sit for an hour (waiting for my wife to get to me) and it still will not start. The next morning I will go back to the car and it will start just fine and get me back to work.

I have had it at the mechanics and they have hooked it to the computer and checked all sensors and such but they have found nothing wrong and cannot recreate the problem. They tell me it runs great. (I think they think Im lying now and just want to give them money to hangout with them)

Help me please.

PS: Recent tuneup (Plugs, wires, cap, rotor, filter) oil change, fuel pump done last year.

[89IROC&RS]

hmmm, thats a bit trickey, again, take my adivice with a grain of salt as im doing this from the seat of my pants without ever seeing either of the cars. um, could also be the air filter, i know, its simple, and applies more to an idle situation, if the car dies while driving, then i would sayits an ignition problem, and you might need one of several things, a HEI control module, for the distributor, possibly a new ignition, um, yeah, im a bit stumped on that one, gimmi some time to think about that one.

[Evilinside]

Any insight would be appreciated. I have just spoken to the repair shop and they are still stumpped as they have not been able to see the problem in action (or inaction for that matter).

They have suggested starting by replacing the ignition module as they think that might be where the problem lies. However, they want to charge me $260.00 to do it. The good news is that they say that if that doesnt solve the problem they will take it back out and try something else so that it doesnt start costing me an arm and leg in new parts (just labour).

The piece I have a problem with is them telling me that the part will cost $218.00 yet when I call Lordco I am told the over the counter price is $149.00 and my cost is $89.00.

So how hard can it be to replace the module myself and save about $200.00 after taxes?

PS: Sorry for hijacking your thread top_down_camaro but maybe we can both get some answers on a similar situation.

[StingRay_68]

I had a 76 Corvette with the same problem. I went to my car from the train station and it would turn over beautifully... fuel got dumped into the carb... I was just pissed off so I started fixing it american style. Got the bluntest object I could find in my car and started smacking things with it. Smacked the distributor a few times.... got depressed and tried to crank over my engine one last time. Fired right up.

Turned out it was a bad ignition coil. Got a new MSD coil for 40 bucks..installed it in less than 20 minutes..and never had the problem again. 3000 dollars in other repairs and I kissed the piece of crap barbie car goodbye for good though.

Try that technique if it ever happens again.

[89IROC&RS]

stingray might be onto something, sometimes bad coils can act up now and again, broken windings that come in and out of contact, could be your problem. as far as the cost aspect, look at the markup on the part from the price you are getting, and the over the counter price, its a 50% markup about, the repair place does the same thing, they buy the part, from probly the same type parts store your going to, and then they mark up the price again, and thats how they make their money, labor is a set time, and its usually lower than the time it actually takes to do the job (spoken as a chevy tech) so they make their money by marking up parts. also why most places that do repair work preferr to order their own parts, rather than install ones you bring in. now to answer your question, installing a new ignition module should not be that difficult, if you have a basic understanding of all things automotive, are good with a wrench, and can follow instructions, you should be able to handle it. it should just mount in the stock location, and plug into the stock plug on the wiring harness. aint no biggie. so i would just buy it yourself, and put it in yourself, but then again, if that isnt the problem, you bought a new one for no reason, and you could have not waisted any money. so its your call. good luck

[Evilinside]

I have no problem with marking up the part but if i can get it for $89 they can get it for less so why an almost 300% mark-up?

Thats all Im saying.

Anywho thanks greatly for your insights, I think we're on the right track here.

[StingRay_68]

Because they can, and you will pay for it.

Stop paying for it, and they'll lower prices.

God economics is wonderful!