EYEROCK89

Lately, I've been having random idle and stall problems with me IROC which just about got me killed this weekend. I have an 89 with 350TPI/700R4. One thing is constant and I was hoping someone has heard this before.

Each time the car dies, I get a consistant tapping noise from somewhere under the plenum. Seems to be coming from the rear of the plenum so I'm thinking it is either the FPR or the EGR valve. The fuel pump is new as is the entire EGR system. Of course, I could have put somehitng on wrong or the fuel pump could be bad straight from GM. I don;t have the proper tools to test fuel pressure yet, but I'm just throwing this out there and hoping that someone has heard this noise before and can give me some insight.

MORE INFORMATION:
SES light will come in within the first 10 sec's if it;s going to. If not, car will run forever. However, when the SES light does come on, if I keep the RPM's up and don;t let it idle below 1500RPM's, it will stay running. As soon as the RPM's drop below 1000, car will die no matter how mcuch gas I give it.

smiley23

I would pull off your cap to inspect it and make sure it is seated properly. I have had this appen to me before - since there is only 2 screws holding - it doesnt take much.

Denis.V

Well, my problem is as follows:

When I stop the engine (with hood open), I wait ..1,..2,..,3 seconds and I can hear BRRRRRRR, BRRRRR, BRRR, shhhhhhhtttt, shhhhhhhhhhht, shhhht, shht, sht, SHT!. This sounds seems to be coming from the rear heads/manifold.

Since I'm running lean (looking for the cause), I'm thinking that the combustion chambers (not the coolant) are overheating, coolant around is boiling, air is going to head's top in which head matches with intake manifold and this vapor is going out between gasket, manifold & heads.

The next weekend I 'll try other (used) EGR valve and I'll compare all the conditions again.

EYEROCK89

Smiley - I'm assuming you're talking about the distributer cap? Good idea...but what would cause the tapping if it was the distributer cap?

bigals87z28

sounds to me like your EGR valve is clogged... replace or clean it out... My brother has a horrible idle, and its cause his EGR get clogged quickly because of a very rich idle(leaking injectors). After we cleaned it out, the idle improved greatly and he didnt stall out anymore... he still has some IAC problems, but thats another story....

EYEROCK89

Lol, seems like it;s always another story with our cars. Although, I did replace the entire EGR system a few months ago. Which, now that I think about, this problem has been occuring ever since that time....hmmmm.

bigals87z28

maybe you have a vaccume problem... did you replace everything?

EYEROCK89

Well, everything, but the actuall vacuum lines themselves...maybe I should start there, they are awefully olf. I replaced the EGR solonoid, EGR valve, and the EGR temp switch thing that plugs into the EGR valve.

smiley23

With a mis-aligned distributor cap the rotor will actally make contact with the cap - got one in my garage that did that - the clicking was my first clue.

EYEROCK89

Smiley - Well, there is no clicking while the car is running. The only time I here the clang noise is after the car has stalled and is not running

smiley23

You got me on that one - any way to record the sound and feed it into a wave file?

EYEROCK89

Nah, I really don;t have a way to do that. Tap your fingernail on a flat spot on your keyboard..thats what it sounds like.

mystikkal_69

iTrader: (2)

the clicking is probably a relay that's going south. what code?34? 36?

EYEROCK89

#34 - Generally means that there is a lack of voltage/ excessive vacuum to the MAF sensor.

#36 - Could be a few things. MAF sensor burnoff, Tranny shift problems, problem with ignition timing, or the electric spark timing is missing pulses.

mystikkal_69

iTrader: (2)

are those the codes you are recieving? is probably the MAF burnoff relay that keep clicking. maybe your's is failing? when i turn mine off, i hear 2 distinct clicks after i shut the engine down. that's the burnoff relay doing it job. check all your relays out. that may be your problem.

EYEROCK89

Where exactly is the MAF burnoff realy? Is it one of the three on the firewall near the master cylinder?

mystikkal_69

iTrader: (2)

exactly. as for which exact one is the burnoff relay i'm not sure. if not one chimes in i will listen and see which one is the burnoff relay and not the FP relay.

smiley23

Vader posted a pic in this thread:

https://www.thirdgen.org/techbb2/sho...hreadid=184988