91 stopped running today? whats wrong?
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
91 stopped running today? whats wrong?
I was driving my vette home today and the car jerked a few times then just turned off. I got it onto a side road and started poking around to see what the problem was. I was getting spark and the fuel pump was working, but the car didn't want to start up, it would just crank. If i let it sit for a few minutes it would turn over like it wanted to start but then it would turn off again. I checked all the fuses and they were good, then i poked around with the dist. I unpluged that wire coming out of the main loom by the computer(dont know what its called, but its the wire you have to unplug before you set the timing) and it would want to start but the most i got it to idle was for a few seconds. and when i cranked it would want to start up but didn't. Anybody know what the problem is? I am stumped
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: 91 stopped running today? whats wrong? (DarkoStoj)
You need air, fuel , and spark to run. Check for spark and for spark at the right time (both can be verified with a timing light). Check for the proper fuel pressure on the fuel rail with a fuel pressure gauge. Unplug the injectors one at a time and put a low power 12v lamp across the socket and crank the engine, the light should pulse. Disconnect the hose off the MAF to allow air to enter (air filter could be clogged) and attempt a start if spark and fuel are ok.
Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
Re: 91 stopped running today? whats wrong? (jfb)
Disconnect the hose off the MAF to allow air to enter (air filter could be clogged) and attempt a start if spark and fuel are ok.
Drifting
Joined: Jul 2001
Posts: 1,751
Likes: 1
From: Miami, FL, USA
Re: 91 stopped running today? whats wrong? (TA)
Its most likely a sensor connection or maybe the VATS.
I had a similar thing happen to me once, it was the coolant temp sensor under the TB. THe connector was loose, and it had the same symptoms. Once I got it back on, it started right up.
I had a similar thing happen to me once, it was the coolant temp sensor under the TB. THe connector was loose, and it had the same symptoms. Once I got it back on, it started right up.
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
Re: 91 stopped running today? whats wrong? (BIG JIM 54)
I messed around with it today. I tried to get the codes, but i must not be bright, becuase there is no way i could figure out what it was trying to tell me. If you let the car sit for a few minutes then try to turn it over it will run for 2-3 seconds. after that it tries to turn over but just doesn't want to start.
Could this be a fuel filter problem? the car ran fine with no problems then just stopped working. Would the performance of the car deteriorate slowly if the fuel filter was bad?
well i am off to the store to buy one now anyways, since the car has 108,000 on it, so a new filter wouldn't hurt.
Where is the filter located, and how is the best way to get to it? should i remove the spare tire carrier, or do i need to take out the wheel well?
Could this be a fuel filter problem? the car ran fine with no problems then just stopped working. Would the performance of the car deteriorate slowly if the fuel filter was bad?
well i am off to the store to buy one now anyways, since the car has 108,000 on it, so a new filter wouldn't hurt.
Where is the filter located, and how is the best way to get to it? should i remove the spare tire carrier, or do i need to take out the wheel well?
Burning Brakes
Joined: Jun 1999
Posts: 862
Likes: 0
From: Auburn WA
Re: 91 stopped running today? whats wrong? (DarkoStoj)
Do yourself a favor (and all the rest of you guys that think you can diagnose your car using a Vulcan mind meld instead of proper tools :lol: ) and buy one of these too http://www.madvet.com/shop?store=1&c...y=66&frame=172
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
Re: 91 stopped running today? whats wrong? (Redmenace)
ok I changed the fuel filter, and went to take the fuel pump out, but it definately is working and has pressure. I took the throttle body off and cleaned the IAC and still get the thing to work. It sometimes starts if i rev it a lot and it will eventually turn off. I know it can't be the gas flow now, its gotta be something electrical, any ideas? I checked all the connections and they all seem good
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Drifting
Joined: Jul 2001
Posts: 1,751
Likes: 1
From: Miami, FL, USA
Re: 91 stopped running today? whats wrong? (GusBustamanteJr)
Its most likely a sensor connection or maybe the VATS.
I had a similar thing happen to me once, it was the coolant temp sensor under the TB. THe connector was loose, and it had the same symptoms. Once I got it back on, it started right up.
I had a similar thing happen to me once, it was the coolant temp sensor under the TB. THe connector was loose, and it had the same symptoms. Once I got it back on, it started right up.
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
Re: 91 stopped running today? whats wrong? (GusBustamanteJr)
ive checked all the connections on the car and they looked good.
How would I go about checking the VATS?
i took off a few of the spark plug wires to check for spark and it seems like i get good spark. also played with the timing a little bit.
I got a scantool and no codes showed up from the computer, even though the service engine soon light was lit up? Whats up with that?
i looked at another function on the scantool and it said the minimum idle requirement was 3830 rpms??? whats up with that? I know the tps is good, i cleaned out the Iac, i haven't checked the pressure at the scradner valve, but i do have a new fuel filter, and the fuel pump is definately working, and when i push down the scradner valve i do have pressure.
Could it be possible that something is messed up with my computer? I was just driving down the road and it turned off out of nowhere and wouldn't start back up.
anybody have ideas?
How would I go about checking the VATS?
i took off a few of the spark plug wires to check for spark and it seems like i get good spark. also played with the timing a little bit.
I got a scantool and no codes showed up from the computer, even though the service engine soon light was lit up? Whats up with that?
i looked at another function on the scantool and it said the minimum idle requirement was 3830 rpms??? whats up with that? I know the tps is good, i cleaned out the Iac, i haven't checked the pressure at the scradner valve, but i do have a new fuel filter, and the fuel pump is definately working, and when i push down the scradner valve i do have pressure.
Could it be possible that something is messed up with my computer? I was just driving down the road and it turned off out of nowhere and wouldn't start back up.
anybody have ideas?
Drifting
Joined: Jul 2001
Posts: 1,751
Likes: 1
From: Miami, FL, USA
Re: 91 stopped running today? whats wrong? (DarkoStoj)
Take off the distributor cap and check the rotor, make sure its on, and intact. Also check the leads that go from the distributor to the ECM, its a brown wire.
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
Re: 91 stopped running today? whats wrong? (GusBustamanteJr)
i had a old prom chip from a vette i didn't really know anything about and i thought i might as well give it a shot and swap it in(it was a hypertech chip). I put it in then started the car and it wouldn't hold an idle, but it didn't turn off if i kept the rpms up. I plugged in the scan tool and a code came up that said i have a incorrect prom installed.
I turned the car off and installed the origional prom and the car started to idle by itself, but would idle rough. Now i have the origional prom back in the computer and the car runs but very rough like some cylinders aren't firing, but they all are.
I took it down the road and about 100' from the driveway the car just shut off again like it did the first time, but then it started right up and went back to the rough idle.
any more ideas?
I turned the car off and installed the origional prom and the car started to idle by itself, but would idle rough. Now i have the origional prom back in the computer and the car runs but very rough like some cylinders aren't firing, but they all are.
I took it down the road and about 100' from the driveway the car just shut off again like it did the first time, but then it started right up and went back to the rough idle.
any more ideas?
Drifting
Joined: Dec 2000
Posts: 1,474
Likes: 0
From: alexandria LA
Re: 91 stopped running today? whats wrong? (DarkoStoj)
You can have spark but not have it regular or strong enough. You can have fuel pressure and it not be strong enough. You need to find a pressure guage and a spark tester and test them the right way.
When was the last time you got gas? Could it be bad?
Have you checked the timing?
Have you had more than one plug wire off?
When was the last time you got gas? Could it be bad?
Have you checked the timing?
Have you had more than one plug wire off?
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
Re: 91 stopped running today? whats wrong? (Black85L98)
You can have spark but not have it regular or strong enough. You can have fuel pressure and it not be strong enough. You need to find a pressure guage and a spark tester and test them the right way.
When was the last time you got gas? Could it be bad?
Have you checked the timing?
Have you had more than one plug wire off?
When was the last time you got gas? Could it be bad?
Have you checked the timing?
Have you had more than one plug wire off?
the timing was set at 12* BTDC, but when i checked it the line on the balancer was bouncing between 8* and 12*, so i left it where it was at.
ive had more then one plug wire off, what does that have to do with anything?
The spark is strong, but how would i test it to make sure it is firing at the right time?
Burning Brakes
Joined: Jun 1999
Posts: 862
Likes: 0
From: Auburn WA
Re: 91 stopped running today? whats wrong? (DarkoStoj)
i haven't checked the pressure at the scradner valve, but i do have a new fuel filter, and the fuel pump is definately working, and when i push down the scradner valve i do have pressure.
anybody have ideas?
anybody have ideas?
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Re: 91 stopped running today? whats wrong? (Redmenace)
Try the "bang on the ECM" test. Might need replacing. Mine did the same thing and had to replace the ECM. Been fine ever since. :smash:
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
Re: 91 stopped running today? whats wrong? (Goody)
for all the people that thought i couldn't diagnose the fuel problem myself, i went out and got a fuel pressure tester and when i turned the ignition key to on i got 40 psi, then when i started it, the pressure stayed around 35-39 psi.
i checked the dist cap, rotor, plug wires they all look like new, i put bosch platinum 4 plugs in about 15-20,000 miles ago, so those should be good, doubled checked the firing order, put in a different coil i had laying around and it had the same symptoms.
I dont know what to try next. I have tried everything i could possibly think of and now im absolutely stumped.
all the wires get spark, while the car was running i took each plug wire off and they were each getting spark.
i am real frustrated now, i need to get this fixed, it is the only thing i have to drive right now :banghead:
i checked the dist cap, rotor, plug wires they all look like new, i put bosch platinum 4 plugs in about 15-20,000 miles ago, so those should be good, doubled checked the firing order, put in a different coil i had laying around and it had the same symptoms.
I dont know what to try next. I have tried everything i could possibly think of and now im absolutely stumped.
all the wires get spark, while the car was running i took each plug wire off and they were each getting spark.
i am real frustrated now, i need to get this fixed, it is the only thing i have to drive right now :banghead:
Le Mans Master
Joined: Jul 2002
Posts: 5,818
Likes: 2
From: Alive and well in Burlington NC
Re: 91 stopped running today? whats wrong? (DarkoStoj)
Will it hold the 39 to 35 psi after you shut it down? How long? Leaky injectors are a possibility if it's not holding pressure
Thread Starter
Racer
Joined: Mar 2002
Posts: 252
Likes: 3
From: Rochester MI
Re: 91 stopped running today? whats wrong? (Steel Blue 91)
after i turned the car off i let the car sit for about a minute so i coudl see if the pressure stayed up. and it didn't budge at all