Start & Run Issue
12-18-2014, 01:06 PM
#1
Advanced
Thread Starter
Start & Run Issue
94 Corvette 14,300 miles.
Starts runs fine for 5 min or 10 then starts misfire & popping like a back fire.
Good battery & Fuel.
Wont restart but cranks.
Wait 30 min starts put it in gear it stalls out! (
Automatic)
Please Help!
Starts runs fine for 5 min or 10 then starts misfire & popping like a back fire.
Good battery & Fuel.
Wont restart but cranks.
Wait 30 min starts put it in gear it stalls out! (
Automatic)Please Help!
Last edited by idprints; 12-18-2014 at 01:21 PM.
12-18-2014, 03:02 PM
#2
When mine went out the car would run <idle> for 5-10 minutes. Car would stall. Then crank no start. Wait an hour for it to cool down and it would start right back up.
This is generally 100-150 part. I got mine at Autozone.
If its not this then you might be looking at the Opti-Spark and this is much more expensive and a lot more work to replace.
12-18-2014, 03:07 PM
#3
Burning Brakes
12-18-2014, 05:03 PM
#4
Post your findings and results
Ozz
12-19-2014, 02:56 AM
#6
Race Director
Just about any auto parts store can test your ignition module. The test should be run about 5 times to get it hot enough to stress the parts a little. Most store people know this, but some don't.
12-19-2014, 05:31 PM
#7
Melting Slicks
Member Since: Nov 2005
Location: Green Valley Arizona
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After engine dies, pull a plug or coil wire to check for spark.....but do not get zpped....it hurts!
This way you will know if it is spark related or not.
This way you will know if it is spark related or not.
12-19-2014, 05:39 PM
#8
Instructor
I have a 1994 as well and experienced a similar problem. Towed it to a garage and they said it was the opti with a $2,000 repair bill. On the advice of a forum member, I towed it home and replaced the coil and the ICM. Total job took me about 2 hours. Total cost $130 using AC Delco parts. I have had no symptoms since and the car runs great.
Perhaps the easiest thing to check is to simply pull the ICM, which sits on the passenger side of the engine compartment in front of the power steering canister. It is held on by 2-6.5 mm bolts. The ICM sits on a metal heat shield that sits atop the coil. Once removed, look at the back of the ICM. There should be a layer of heat sink compound. If it is missing (or worn off as mine was) it would explain the shutting down when hot and starting again when cooled.
Since my parts were original (20 years old) I felt I had nothing to lose and everything to gain. It was really very easy to do and I am glad I didn't replace the opti!
Perhaps the easiest thing to check is to simply pull the ICM, which sits on the passenger side of the engine compartment in front of the power steering canister. It is held on by 2-6.5 mm bolts. The ICM sits on a metal heat shield that sits atop the coil. Once removed, look at the back of the ICM. There should be a layer of heat sink compound. If it is missing (or worn off as mine was) it would explain the shutting down when hot and starting again when cooled.
Since my parts were original (20 years old) I felt I had nothing to lose and everything to gain. It was really very easy to do and I am glad I didn't replace the opti!
12-19-2014, 05:41 PM
#9
Instructor
Be advised, I took my ICM to autozone and had it checked. The tech tested it 5 times and said it passed each time. The problem is that during the testing the ICM doesn't get as hot as it does in your car, so don't be surprised if it passes but is still no good.
Good Luck
Good Luck
12-22-2014, 11:45 AM
#12
1st Gear
Member Since: Dec 2014
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I recently purchased a 1994 Corvette registered in Ca which had a license plate on front bumper. I live in Az and a front plate is not required. I removed the Ca plate and attempted to install the factory "Corvette" cover panel to cover the "hole" in the bumper. But I cant figure out how to attach it. Neither the factory manual or the repair manual cover this. Can you help me? Thanks
12-22-2014, 01:10 PM
#13
Advanced
Thread Starter
12-22-2014, 08:50 PM
#14
Race Director
I had a problem like that once and it turned out to have nothing to do with the ignition.
My problem turned out to be loose pins in the temperature sensor on the front of the water pump. When the car is first started cold, the computer runs the engine in open loop from a set program of injector and timing parameters until the engine and oxygen sensors are up to temperature. Then it switches over to closed loop where it reads the Oxy sensors and the engine temp from that sensor on the front of the engine. As soon as it ran long enough to go to closed loop, it started bucking and choking. The pins were loose and made a bad connection so the computer couldn't read the temp correctly. The car would barely run intermittently when it lost connection and when I'd turn the key to the on position, the digital temperature monitor would always say LOW, even if the needle gauge read normal. I cleaned and tightened the connector & pins and it all got well!
My problem turned out to be loose pins in the temperature sensor on the front of the water pump. When the car is first started cold, the computer runs the engine in open loop from a set program of injector and timing parameters until the engine and oxygen sensors are up to temperature. Then it switches over to closed loop where it reads the Oxy sensors and the engine temp from that sensor on the front of the engine. As soon as it ran long enough to go to closed loop, it started bucking and choking. The pins were loose and made a bad connection so the computer couldn't read the temp correctly. The car would barely run intermittently when it lost connection and when I'd turn the key to the on position, the digital temperature monitor would always say LOW, even if the needle gauge read normal. I cleaned and tightened the connector & pins and it all got well!
