91 Vette not working
Thread Starter
Team Owner
Joined: Jul 2004
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From: Hartford WI
91 Vette not working
A day or so ago, it started after a lot of cranking and half way up a hill, it died. Started it and took it home for work. Today, it will not start at all. Fuel at 42 psi and spark is yellow. Guess it must be spark related, huh? Well, new cap & rotor (Echlin), plugs (NGK) and wires (Accel 300+ from a wrecked Firebird) still didn't fix it. Switched coil with a new one (Wells) and the color was the same for the spark. Checked pick up coil and it was at 800 Ohms so it was still good. Will have to check module tomorrow at GM dealership.
Also, my Auto X-Ray does not seem to be able to communicate with it. No idea why. Could this all be related? Does anyone have any ideas what else it could be?
Also, my Auto X-Ray does not seem to be able to communicate with it. No idea why. Could this all be related? Does anyone have any ideas what else it could be?
Thread Starter
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,279
From: Hartford WI
Doing that I get a code 12 which is all clear. Now, the distributor is not hooked up but I don't see what that would do. Auto X-Ray says that Vehicle is Not Responding when I hook it up.
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Thread Starter
Team Owner
Joined: Jul 2004
Posts: 28,430
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From: Hartford WI
Reconnected the distributor and it sparks. Still yellow sparks and not as much as I would like to see. No start anyways.
I'll have to look at the CTS under the TB and see what gives tomorrow.
I'll have to look at the CTS under the TB and see what gives tomorrow.
Burning Brakes
Joined: Jul 2003
Posts: 868
Likes: 5
If it code 12s the Ecm is ok??
I had to recently replace mine(ecm) and it was giving the 12,just wouldn't throw any bad codes...I replaced everything on my 90 I could think of and it ended up being a bad ECM.Car did all kinds of crazy thing ended up it wouldn't crank.
Jason
I had to recently replace mine(ecm) and it was giving the 12,just wouldn't throw any bad codes...I replaced everything on my 90 I could think of and it ended up being a bad ECM.Car did all kinds of crazy thing ended up it wouldn't crank.
Jason
Drifting
Joined: Nov 2002
Posts: 1,593
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From: Mobile AL
St. Jude Donor '05
Originally Posted by aklim
It cranks and sparks. Just that I think the sparks should be more and blue instead of being yellowish
Could your battery voltage be high enough to crank, but too low for good spark? This is really strange since you've replaced all the ignition parts. I'd look for low voltage or something dragging the battery down. Mebbe alternator.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
I've had quite a few non communication messages from my Auto Xray, but wriggling the harness and moving it up and down gets it working. I always figured it was from sticking too many paper clips in the ADL connector.
Did you check the module?
I'd make sure the MAP or MAF (depending on application) is powered up. You got fuel and spark.
Did you check the module?
I'd make sure the MAP or MAF (depending on application) is powered up. You got fuel and spark.
Le Mans Master
Joined: Jul 2001
Posts: 8,183
Likes: 3
From: Santa Maria, CA
I had a similar problem when I did the HSR and small dist. I had the 4 wire connector off 180*. Normally there is only one way to connect the male and female ends, but mine didn't have the locating tangs. The ECM wasn't recieving signal from the module(purple wire). The ground strap of the spark plug would be a weak yellow spark. Once I got the wires right, the spark was snappy and blue.
Did you switch to the stealthram and small cap dist?
(thanx for the link to stealthram com.....I did not know there was a forum for it now)
Did you switch to the stealthram and small cap dist?
(thanx for the link to stealthram com.....I did not know there was a forum for it now)
Last edited by pablocruise; Jul 28, 2004 at 07:44 PM.
Thread Starter
Team Owner
Joined: Jul 2004
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From: Hartford WI
Well, I will later switch to the Holley Stealth Ram. I had it on my Firebird with a 383 and made about 410 HP at the wheels. Since that car got totaled and I got raped by Geico (No KY Jelly or even a reach around) I will be running the vette the way it is and when I get the whole thing settled, I will stuff the 383 in it and get Grumpyvette's modified top for the HSR.
In the meantime, a shop has diagnosed it as a bad ECM and alternator. They suggest that the alternator might have spiked the ECM. They could start the car but when they pressed on the ECM, the car stumbled and died. Further I was getting code 12 with the paperclip and "Not connected" on Auto X-ray. Hopefully I can run it home tomorrow and change out the alternator and then the ECM and life will be good. In the meantime, the shop is removing the "starter disable" aka bad starter relay that was fused and the moron owner (previous) rigged a push button to crank it. They ysed wires to bypass the relay and the car started like it should.
In the meantime, a shop has diagnosed it as a bad ECM and alternator. They suggest that the alternator might have spiked the ECM. They could start the car but when they pressed on the ECM, the car stumbled and died. Further I was getting code 12 with the paperclip and "Not connected" on Auto X-ray. Hopefully I can run it home tomorrow and change out the alternator and then the ECM and life will be good. In the meantime, the shop is removing the "starter disable" aka bad starter relay that was fused and the moron owner (previous) rigged a push button to crank it. They ysed wires to bypass the relay and the car started like it should.
Thread Starter
Team Owner
Joined: Jul 2004
Posts: 28,430
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From: Hartford WI
Originally Posted by 89 Paul in Cal
I had a similar problem when I did the HSR and small dist. I had the 4 wire connector off 180*. Normally there is only one way to connect the male and female ends, but mine didn't have the locating tangs. The ECM wasn't recieving signal from the module(purple wire). The ground strap of the spark plug would be a weak yellow spark. Once I got the wires right, the spark was snappy and blue.
Did you switch to the stealthram and small cap dist?
(thanx for the link to stealthram com.....I did not know there was a forum for it now)
Did you switch to the stealthram and small cap dist?
(thanx for the link to stealthram com.....I did not know there was a forum for it now)
Thread Starter
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,279
From: Hartford WI
OK. It now has an new ECM and new alternator. In the meantime, the battery is getting a full charge.
Seems to run but I still cannot use Auto X-Ray to link up with the ECM. Anyone know why and what to look for? TIA
Seems to run but I still cannot use Auto X-Ray to link up with the ECM. Anyone know why and what to look for? TIA