Random Engine Shutdown
Thread Starter
Instructor
Joined: May 2009
Posts: 128
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From: Deptford NJ
Random Engine Shutdown
Just racking your brains, I picked up my '02 Z51 from the body shop where it's been pretty much off for two months. The battery had died and been jumped a number of times yesterday and I didn't think anything of it. Later that evening on a high power run on an empty highway the engine just turned off on me. I know I hadn't hit redline but I was running it pretty hard. I've done this before and never had a problem, this is the first time I've ever experienced this.
I re-started and drove home and re-set the computer DTC codes, yes as a responsible adult I should have written them down but I was half simple at the time.
I am just currious if anyone is aware of a simple situation that might cause this? I have also noticed that oil pressure fluctuates more than it did before and on a high run the pressure is higher than I used to remember it but still well under red line. Will the engine shut off if it detects that the oil pressure is too high? I will attempt to duplicate the situation and if I trip anymore codes I will post.
I re-started and drove home and re-set the computer DTC codes, yes as a responsible adult I should have written them down but I was half simple at the time.
I am just currious if anyone is aware of a simple situation that might cause this? I have also noticed that oil pressure fluctuates more than it did before and on a high run the pressure is higher than I used to remember it but still well under red line. Will the engine shut off if it detects that the oil pressure is too high? I will attempt to duplicate the situation and if I trip anymore codes I will post.
Tech Contributor
Joined: Dec 2006
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From: Van Buren Arkansas
Wounded Warrior Escort '11
Did you by chance check the oil level? That will force a limp home mode. Oil pressure too high won't do it. Now I don't know if indicated oil pressure being too low will trip this mode or not but you only need 6 psi to run although high rpm with that low of oil pressure would be a concern of course.
I'm more thinking that either your battery cables or battery to starter solenoid cables may have an issue or possibly the ignition switch.
I'm more thinking that either your battery cables or battery to starter solenoid cables may have an issue or possibly the ignition switch.
Thread Starter
Instructor
Joined: May 2009
Posts: 128
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From: Deptford NJ
Engine oil level is reading normal from the dipstick but I did notice when I drove it home and got on it a bit the oil pressure would continue to rise higher than I'm used to seeing it and at one point got just below 80psi. I've never had it that high, is it normal for it to climb to those levels and be well below red line?
Tech Contributor
Joined: Dec 2006
Posts: 10,962
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From: Van Buren Arkansas
Wounded Warrior Escort '11
That's probably just a failing oil pressure sender which is quite common and fairly easy to fix, just make sure you get a newer brass one, not the alluminum ones.
Thread Starter
Instructor
Joined: May 2009
Posts: 128
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From: Deptford NJ
I've found that it only happens after a hard run when I put the car into neutral right afterward .. engine just shuts off. I'm afraid the body shop may have jacked the rear of the car up under something they shouldn't have, could damage to the trans. cause this? I have also noticed some sluggish response on the highway at around 60 when the car is in 5th gear, it seemingly hesitates. No codes are being thrown by this problem.
Tech Contributor
Joined: Dec 2006
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From: Van Buren Arkansas
Wounded Warrior Escort '11
I simply don't know in this case. I'm going to suggest a PM to Bill Dearborn and see what he's got to think about this. I've got lots of ideas, but nothing that might point in a specific direction. Still no codes is a puzzle too me and no other indications of faults. I don't wish to point you in the wrong direction. I will say, you probably need a Tech 2 to find out what's going on.
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Check the battery cables on the battery. They MUST be tight. If you can move them by hand, there loose. They need to be 11 ft/lbs for 97-2003 C5's 04's used a top post battery
What MODs do you have on the engine? Have you checked to see if the intake air ducting between the MAF and the TB is tight and secure. NO LEAKS!!
Also make sure that the PVC hoses and fittings are in good condition. The VERY next time that it stalls, before you restart it (if you can do it safely) pull up the DTCs.
BC
What MODs do you have on the engine? Have you checked to see if the intake air ducting between the MAF and the TB is tight and secure. NO LEAKS!!
Also make sure that the PVC hoses and fittings are in good condition. The VERY next time that it stalls, before you restart it (if you can do it safely) pull up the DTCs.
BC
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Thread Starter
Instructor
Joined: May 2009
Posts: 128
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From: Deptford NJ
The car hasn't stalled since, however, I still do get the "slippage" feeling periodically. I inspected the rear of the car and there is no sign of damage from lifting so im confident everything is alright there. I cleaned the air filter (blackwing) and also cleaned the TB and ensured that all hoses and couplers were tight.
I did notice that a line behind the TB that connects to the manifold appears to be damaged. I've never noticed this before so I can't say if it's the cause or not but I personally cannot identify it. The image is below, is this a PCV line? It's cracked at the bend and also where it connects to the manifold and I'd like to replace it. Thanks
I did notice that a line behind the TB that connects to the manifold appears to be damaged. I've never noticed this before so I can't say if it's the cause or not but I personally cannot identify it. The image is below, is this a PCV line? It's cracked at the bend and also where it connects to the manifold and I'd like to replace it. Thanks
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Yep! That would be part of the issue!!!!! It is the PCV valve and the valve is in the rubber thing down from the cracked tube. You have to go to the dealer for a replacement fitting.
I bet ya the car will run a lot better when its fixed. Until you get the part,,,,wrap it with electrical tape.
BC
I bet ya the car will run a lot better when its fixed. Until you get the part,,,,wrap it with electrical tape.
BC
Last edited by Bill Curlee; Oct 25, 2009 at 01:39 PM.
Thread Starter
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Joined: May 2009
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From: Deptford NJ
Ok, I've replaced the PCV valve and repaired the hosing between the manifold and the sensor and that has made a slight difference in the performance but I am still experiencing random shutdowns. Only when the car is at high speed/rpm and then put into neutral does this happen. I've watched RPMs slowly drop down from where they were when the car is in gear but in stead of leveling off at normal idle level RPMs drop to 0 and the engine shuts off. Again this only happens if the car is at or above 5500 and is put into neutral. Would this be an idler gear issue? Maybe for some reason the trans. (or some other component) isn't able to regulate once the car is in neutral? I've talked to a tech. and he is very confused. Maybe someone has an idea on what should be taking place internally during these situations that could gide me in the right direction as to where to investigate? Thanks.
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Have you ever cleaned your MAF and Throttle Body Blade? I would do that first before you start to dig too deep. Use some MAF cleaner or Brake Parts Cleaner.
BC
BC
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Thread Starter
Instructor
Joined: May 2009
Posts: 128
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From: Deptford NJ
If I do have a leak I'll have to do some searching to find it. I know it's not from the location I posted a pic of this morning. I don't feel as bad now, I thought maybe it was too low. I'm wondering if this isn't the onset of the "electrical gremlins" I've read so much about. This evening for the first time I got code C1214 and one of the causes of that is bad ground. I was able to clear the code (took twice) and let the car set off for a while and it went away.
The car set in a body shop for 2 months and when I inspected it the engine bay was COVERED in dust. I did all of the cleaning (filter, TB, MAF, intake duct)
When the car is put into neutral what happens? I thought an idler gear kicked in to allow the engine to continue to turn as needed? I have no issues with engine response while driving or under demand, just this neutral probelm; well that and the intermittent shudder.
My next step is plugs & wires, I really dont want to take a bath on diag. from the dealer but I may have no choice. I will also def. check that coil ground tomorrow.
The car set in a body shop for 2 months and when I inspected it the engine bay was COVERED in dust. I did all of the cleaning (filter, TB, MAF, intake duct)
When the car is put into neutral what happens? I thought an idler gear kicked in to allow the engine to continue to turn as needed? I have no issues with engine response while driving or under demand, just this neutral probelm; well that and the intermittent shudder.
My next step is plugs & wires, I really dont want to take a bath on diag. from the dealer but I may have no choice. I will also def. check that coil ground tomorrow.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
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From: Van Buren Arkansas
Wounded Warrior Escort '11
I'm still wondering about a bad iginition switch. If a pair of contacts in there opens on you or fails under a higher current load, I would think things would shut down. Bill is the expert on them and can better advise you there. Just about everything else would cause a code of some sort. Now I did have a problem years ago when I would make a right turn around a particular corner in a neighborhood and my engine would suddenly stumble badly but only at that corner and no other's anywhere. I replaced all of the plug wires and the problem quit. One other time, I was getting off the freeway here at work and my engine shutdown on me without warning. Coasted to the right shoulder and it fired right back up. That turned out to the the ground pack at the right forward frame rail adjacent to the hood riser. It was lose and then the stud itself, literally fell off when I went to tighten it. I dumped the ground pack and soldered the wires together with a common 12awg wire to the frame. Never happened again.
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Joined: May 2005
Posts: 15,960
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From: West Norriton PA
St. Jude Donor '08
If I do have a leak I'll have to do some searching to find it. I know it's not from the location I posted a pic of this morning. I don't feel as bad now, I thought maybe it was too low. I'm wondering if this isn't the onset of the "electrical gremlins" I've read so much about. This evening for the first time I got code C1214 and one of the causes of that is bad ground. I was able to clear the code (took twice) and let the car set off for a while and it went away.
The car set in a body shop for 2 months and when I inspected it the engine bay was COVERED in dust. I did all of the cleaning (filter, TB, MAF, intake duct)
When the car is put into neutral what happens? I thought an idler gear kicked in to allow the engine to continue to turn as needed? I have no issues with engine response while driving or under demand, just this neutral probelm; well that and the intermittent shudder.
My next step is plugs & wires, I really dont want to take a bath on diag. from the dealer but I may have no choice. I will also def. check that coil ground tomorrow.
The car set in a body shop for 2 months and when I inspected it the engine bay was COVERED in dust. I did all of the cleaning (filter, TB, MAF, intake duct)
When the car is put into neutral what happens? I thought an idler gear kicked in to allow the engine to continue to turn as needed? I have no issues with engine response while driving or under demand, just this neutral probelm; well that and the intermittent shudder.
My next step is plugs & wires, I really dont want to take a bath on diag. from the dealer but I may have no choice. I will also def. check that coil ground tomorrow.
Thread Starter
Instructor
Joined: May 2009
Posts: 128
Likes: 1
From: Deptford NJ
Took it to my tech. who is also a service director for chevy. He has no idea what's causing the problem. We have:
Cleaned TB
Recharged filter
cleaned air tube
ensured MAF sensor is functioning and clean
tested Vac. system pressure. - Pass
tested fuel system pressure - Pass
replaced fuel filter
replaced plugs & wires
routine trans. service.
wheel align. & balance.
*still no DTC codes present.
Our only shot in the dark left is to re flash the ECU with some fresh GM data in the thought that all of the battery failures and jumps while at the body shop for 2 months may have caused a data corruption and the re flash should hopefully correct it. If anyone still has any idea what could cause the RPMs to drop to 0 rather than go to normal idle speed when placed into neutral while the car has experienced a high speed run please comment, thanks again all.
Cleaned TB
Recharged filter
cleaned air tube
ensured MAF sensor is functioning and clean
tested Vac. system pressure. - Pass
tested fuel system pressure - Pass
replaced fuel filter
replaced plugs & wires
routine trans. service.
wheel align. & balance.
*still no DTC codes present.
Our only shot in the dark left is to re flash the ECU with some fresh GM data in the thought that all of the battery failures and jumps while at the body shop for 2 months may have caused a data corruption and the re flash should hopefully correct it. If anyone still has any idea what could cause the RPMs to drop to 0 rather than go to normal idle speed when placed into neutral while the car has experienced a high speed run please comment, thanks again all.
