Here's a tricky one for all you tech-heads. Recently I've been having a problem with starts....about 1 out of every 10 times the engine cranks fine but will not start. I lift the hood and play around with the coil wire and the two connectors on the coil as well as the two connectors on the distributor. After a bit (5-10 min) the car starts just fine. You would think that it was a wiring problem/ignition problem but it never happens when driving - only when the car has been sitting a bit. When it cranks but doesn't start and after the key is turned off I can hear the fuel pump running for about 15 secs and something under the hood runs for about the same length of time....I'm guessing that it's the IAC. What do you think???

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1988 IROC-Z
5-speed (was 7R4)
Edelbrock TES

 

I'm assuming you have Tuned Port! My car has done the same before! The noise you hear under the hood is normal, tho' I'm not sure exactly what it is.....IAC would be my guess too!! Next time your car cranks but won't start.....start pumping the gas while cranking the engine (like you would with a carb)!! If the engine doesn't start then you should probably start by checking your ignition module!! If the engine DOES start using this technique then you have the same problem that I do and I'm not 100% sure but I think it's the EGR valve!! TRY this....it may sound crazy but it works on my car....unplug the computer and leave it unplugged for about an hour and then plug it back in! The next day see if you have the same problems starting the car! The EGR on these cars are run off a vaccuum solenoid and not ported vaccuum like the older cars! The vaccuum solenoid runs off the computer and I think by unplugging the computer it does something to that solenoid!! If your problem is like mine, this is only a temporary fix.....in a month or so it'll be back to the same old tricks!

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1986 Trans AM
305 TPI
4 Wheel Discs
9 bolt Borg Warner Rear
Completely Stock
Soon to upgrade to a 383 stroker w/TPI, pocket ported 64CC heads, ported intake, comp cam, TPI air foil, Adjustable Fuel Pressure Regulator, possibly bigger injectors!
Current project: Keeping my car running until I get the money for the above mentioned project! :-)

 

Probably carbon buildup, clean out the throttle body and plenum and you should be fine. Always works for me.

 

Well, she did it to me again this morning. This time I could tell that the noise under the hood was from the EGR! I know it's not carbon buildup since I had the plenum and TB out and cleaned only a few month ago. I 'fiddled' with the wires again and she started right up. It only seems to happen when she's been sitting for awhile....when she's warm she fires right up. Any other suggestions guys?

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1988 IROC-Z
5-speed (was 7R4)
Edelbrock TES