Motor shut down

**2kflhr** · 02-19-2008, 10:35 AM

My son just acquired a voluntary repo '97 SS. When buying a car out of a repo lot before it goes to the auction block you only have the opportunity to listen to it run and cannot take it for a test drive. It had a slight misfire so we figured it was in need of a tune up and thorough look over. At the price (4k)you can't be too picky. Anyway, It was low on fuel when we picked it up so we filled it up and drove it home. Later that evening he went for a ride and the vehicle shut down about the time it was shifting into 2nd. It started right back up and and ran decent the rest of the night. Next morning he heads off to work about 3 miles away with no problems. He leaves for lunch and gets about 1.5 miles form work and it dies again. It will not crank. We have it hauled to a friend that works at a repair shop. He looks at it first thing Monday morning and it cranks right up. The fuel pressure is at 42 psig and steady. It had an oil leak from the oil pressure sensor and also a pin was found bent on the sensor. Change the sensor and fix the leak. Checked the codes and there were multiple codes of which I'm not sure of what is current or not. When the car was first cranked up after sitting at the repo lot it smoked black for 30-45 seconds and cleared up so we're thinking this itself could have created some of the multiple codes. One code showed a misfire on cyl. 1, we check the wire (good), change the plug (OK) and checked the compression (good). Still slight miss, change the injector with a spare we had and it helps but does not correct entirely. We cleared the codes and decided to drive it some and see what happens and if any further codes are displayed. We considered and issue with the Opti-Spark but I had a '94 Z that had a Opti issue and the codes specifically pointed it to the Opti.

Today it shut down again about the time it was shifting into 2nd. Since the fuel pump appears to be OK due to the steady pressure we decided to replace the fuel pump relay just in case the relay was going south.

Any suggestions for what to check next?

Sorry so long, just wanted to include the details to better diagnose.

Thanks in advance for any help!

**2001NBMZ28** · 02-19-2008, 10:50 AM

Since the codes were cleared I'd drive it some more and read it again.

**0rion** · 02-19-2008, 04:40 PM

I would still suspect the opti. Those things are notorious for going out.

**2kflhr** · 02-19-2008, 05:02 PM

Originally Posted by 0rion

I would still suspect the opti. Those things are notorious for going out.

I agree the opti has a long history of trouble. Only thing is when my '94 opti went out it threw a code directing the problem to the opti. Still can't rule it out though.

Well, tonight it sat in the garage for awhile and when he went to crank it up, it won't crank. I'll try changing out the ignition module and get my mechanic buddy to come by while it has the problem. Hard to problem when it's working like it should.

**0rion** · 02-19-2008, 05:05 PM

if it's not cranking now would be a good time to pull a plug wire and verify that it's not getting spark.

**9t8z28** · 02-19-2008, 05:59 PM

First of all, how many miles are on the car?

I would certainly check the plug wires and check the coil harness. LT1 engine compartments get real hot and aalot of the plastics and rubber break down and loosen up.

Clear the codes completely and see what pops up.

**2kflhr** · 02-20-2008, 06:24 AM

Originally Posted by 9t8z28

First of all, how many miles are on the car?

I would certainly check the plug wires and check the coil harness. LT1 engine compartments get real hot and aalot of the plastics and rubber break down and loosen up. Clear the codes completely and see what pops up.

We checked the wires and it is firing, cleared the codes and will check today to see if any have appeared. The car has high mileage (181k). I can tell the intake has been off a one time due to a mismatched bolt. I found the retainer from the harness to the ignition coil broken off so I temporarily put a tie rap on it to make sure it the stays seated. I swapped out the ignition coil with one that I robbed off of one of the 2 spare LT1's we have last night to see if that made a difference. Probably need to go ahead and change the wires anyhow.

I have a set of GM service manuals on the way hopefully that will help.

**Spaz** · 02-20-2008, 06:58 AM

sounds like the optispark got some coolant in it...

**twozs** · 02-20-2008, 08:03 AM

make sure you have the right keys (if the key has a chip in it, or should) i had a 98 blazer that i got from a dealer with the wrong set of keys(no chip at all) and didnt even know it had a factory security system on it and the effing thing would just not start . it left me stranded at least 5 times . it would run for a second and just die. not sure about a 97 ss as far as a factory security system

**9t8z28** · 02-20-2008, 03:26 PM

Originally Posted by Spaz

sounds like the optispark got some coolant in it...

Yes, that could be close to the issues he is having but you would for sure see some anti-freeze or smell it.

**9t8z28** · 02-20-2008, 03:29 PM

Originally Posted by 2kflhr

We checked the wires and it is firing, cleared the codes and will check today to see if any have appeared. The car has high mileage (181k). I can tell the intake has been off a one time due to a mismatched bolt. I found the retainer from the harness to the ignition coil broken off so I temporarily put a tie rap on it to make sure it the stays seated. I swapped out the ignition coil with one that I robbed off of one of the 2 spare LT1's we have last night to see if that made a difference. Probably need to go ahead and change the wires anyhow.

I have a set of GM service manuals on the way hopefully that will help.

Make sure the pins on the harness are in good shape. As the vehicle is running, try wiggling the harness at the connection to the coil.

**blue02Z** · 02-20-2008, 04:30 PM

whats a motor

**9t8z28** · 02-20-2008, 04:32 PM

Originally Posted by blue02Z

whats a motor

its slang for engine

**2kflhr** · 02-20-2008, 04:57 PM

Originally Posted by twozs

make sure you have the right keys (if the key has a chip in it, or should) i had a 98 blazer that i got from a dealer with the wrong set of keys(no chip at all) and didn't even know it had a factory security system on it and the effing thing would just not start . it left me stranded at least 5 times . it would run for a second and just die. not sure about a 97 ss as far as a factory security system

We only have one set of keys but it does have the chip inset and works in the ignition fine the other opens the doors and hatch with no problem. The only thing on the key less entry that works is the panic button none of the others work even after changing the battery in the fob.

Ignition module has been suggested as the culprit more than anything else. There is a TSB on the EGR valve for cars in the VIN range as this one. It says it can corrode internally and cause stalling and cranks but fail to start.

Codes are 100 MAF, 300 Miss fire, 400 EGR

**z28punk** · 02-20-2008, 07:11 PM

u should give it a good induction service to maybe help the misfires. clean the throttle, put some injector cleaner in the tank, and seafoam the top end of the engine. sometimes that gets rid of random misfires.