Gremlins aboard
05-14-2010, 12:19 PM
#1
Gremlins aboard I'm having a strange problem with my 99Z28. The car has been running fine until last weekend. I bought one of those Accutron or whatever code readers to clear a code from the PCM. The code was for a 1-2 shift solenoid and I replaced the solenoid so I then deleted the code. When I took off after deleting the code the car died. It started right back up and was ok for the hour drive down to my folks.
When leaving that day the car wouldn't start; it would turn over but would not start. Jut for the hell of it I removed the neg bat cable. When I tried to start it it started and ran fine for the hour and a half drive back home. Weds I go to start it same thing, wouldn't start; took off the neg cable, still wouldn't start; took off the pos cable, reconnected and it started. Turned the car off. Went to start it again and it started. Took it out to my painter to get some touch up work done. He gets the prep work done and is gonna drive it to the spray booth; wont start. Take off the cables, nothing. Still turns over but won't start. He's going to call it a night but I ask him to check fuel pressure. When he turns the key with the fuel pressure gauge installed the car starts and he's able to take it to the booth. Not sure what pressure readings he was getting; will check on Tues when I go get the car (hour away)
What the heck can this be? Would the accutron device do something strange to the PCM? Do I have a PCM that's about to die?
Any and all opinions would be greatly appreciated. I'm taking the car on the Power Tour in 3 or so weeks and need to get this problem solved...
Thanks
When leaving that day the car wouldn't start; it would turn over but would not start. Jut for the hell of it I removed the neg bat cable. When I tried to start it it started and ran fine for the hour and a half drive back home. Weds I go to start it same thing, wouldn't start; took off the neg cable, still wouldn't start; took off the pos cable, reconnected and it started. Turned the car off. Went to start it again and it started. Took it out to my painter to get some touch up work done. He gets the prep work done and is gonna drive it to the spray booth; wont start. Take off the cables, nothing. Still turns over but won't start. He's going to call it a night but I ask him to check fuel pressure. When he turns the key with the fuel pressure gauge installed the car starts and he's able to take it to the booth. Not sure what pressure readings he was getting; will check on Tues when I go get the car (hour away)
What the heck can this be? Would the accutron device do something strange to the PCM? Do I have a PCM that's about to die?
Any and all opinions would be greatly appreciated. I'm taking the car on the Power Tour in 3 or so weeks and need to get this problem solved...
Thanks
05-17-2010, 09:44 AM
#5
A flashing security light when you're trying to start it may be a problem with the VATS system. You may have to replace the ignition cylinder.
I had a problem like that once with a car that would not start and had a flashing security light,I could sit with the key on for about 5 minutes the light would stop flashing and the car would start. I replaced the ignition cylinder and never had the problem again. The orange wire from the cylinder to the VATS module was not making good contact and would occasionally not allow it to start.crank but no start,I think it cuts the fuel pump relay. I have heard of people bypassing the VATS system but I have never done it.
Just a thought that may help.
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05-22-2010, 10:40 PM
#10
still acting up Went to pick up the car and didn't start again. Pulled off the battery cable; it started the 3rd try; drove it home and parked it in the garage. I did notice that the security light wasn't flashing while I tried to start it so it's prob not the VAT's.
Tried this morning; wouldn't start. Had 50psi in the on position; 58 cranking.
It started tonight, and had 58 while running.
What else can this be? Could the scanner I used to turn off the engine code be a possible problem? Could it have done something to the PCM?
I'm at a loss here guys; please shoot me any other checks I can try....
Tried this morning; wouldn't start. Had 50psi in the on position; 58 cranking.
It started tonight, and had 58 while running.
What else can this be? Could the scanner I used to turn off the engine code be a possible problem? Could it have done something to the PCM?
I'm at a loss here guys; please shoot me any other checks I can try....
05-23-2010, 06:14 AM
#11
Same **** this morning. Motor cranks as normal but will not start. Note: when the car has started since the beginning of this problem it runs fine at all speeds, idle thru WOT. I will check spark at each plug and check each coil resistance this morning.
05-23-2010, 08:43 AM
#12
Took the pos term off. Waited a few mins. Fired on the 3rd try. Turned car off. Started back up. Turned car off. Started back up. I know if it sits for awhile it will do the same thing. I noticed when it does restart it's not a real "strong" start. Normally the car starts real strong. Fuel pressure is good!
Anybody?
Anybody?
05-29-2010, 12:00 PM
#13
update I put a new Optima battery in it because I got a great deal on it and figured maybe the old battery might be the culprit. Did this on Tues. Thursday went to start it and it took the 3rd turn of the key to start it. Started fine for the rest of the day.
Friday morning I took it to the tuner (Mike at Straightline Performance in New Lennox) to have the po751 deleted from the PCM (1-2 shift solenoid) I kept getting a false SES light. Started up fine; drove the 2 hour trip with no problems; the car runs perfect. He does the po751 delete; I go to start it; doesn't start at first; then starts buts dies. Start up again, seems ok. Mike said that was normal for the PCM to have to tune itself again. Drove it home, stopping at 2 or 3 places; started up great every time.
This morning the wife and I are going to go for a cruise; jump in the car; turns over but won't start....
What the hell can this be???? The Power Tour is a week from now and I'm planning on doing it but I'm not so sure now.
Fuel pressure is fine.
The car runs great once it's started.
Maybe a ground somewhere?
Fuel filter?
Crank Sensor?
Not VATS because the security light isn't flashing.
Please....any ideas or hints????
Friday morning I took it to the tuner (Mike at Straightline Performance in New Lennox) to have the po751 deleted from the PCM (1-2 shift solenoid) I kept getting a false SES light. Started up fine; drove the 2 hour trip with no problems; the car runs perfect. He does the po751 delete; I go to start it; doesn't start at first; then starts buts dies. Start up again, seems ok. Mike said that was normal for the PCM to have to tune itself again. Drove it home, stopping at 2 or 3 places; started up great every time.
This morning the wife and I are going to go for a cruise; jump in the car; turns over but won't start....
What the hell can this be???? The Power Tour is a week from now and I'm planning on doing it but I'm not so sure now.
Fuel pressure is fine.
The car runs great once it's started.
Maybe a ground somewhere?
Fuel filter?
Crank Sensor?
Not VATS because the security light isn't flashing.
Please....any ideas or hints????
05-31-2010, 03:25 PM
#14
update part deux Did a few searches and quite a few people had similar probs; one fix was to swap the starter and ignition relays. I did that and the car started right up. So I went ahead and bought 2 new relays (both the starter and ignition are the same p/n) and kept the old starter relay as a spare. The new ignition relay seems to be the fix; the good thing is it's only a $12 part and it took a minute to replace.
08-08-2020, 07:52 AM
#16
Same issue I just had the same problem. One day wouldn't start. I would eventually get it running, but after shutting off it was hard to start. Switched the starter and ignition relays and it fired right up. I have ordered two new ac delco relays. Thanks for the info...saved my life.
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