Help! Engine stops No start-No Codes

[curvhog]

I'm looking for some help with a mystery problem with my 2007 Convertible with Auto trans.
3 times in the last 500 miles the engine has stopped running and sets no codes that cause the service light to come on. Each time the situation has been different but the symptoms are the same. First time the engine died backing out of my garage (engine cold) and after nearly two hours of waiting for the protection plan tow truck to show up I gave it that one last try and it started right up. Seeing no codes I talked to the service rep and decided to wait for an upcoming oil change to get it checked.
2nd time afer 45 mins or so of steady driving it died getting off the freeway. When it dies it's like someone turned off a light switch on the engine everything else works, the engine cranks but won't fire, no codes set. That was 3 days ago, had it towed to dealer, car started fine when dealer tried it about 2 hours later. Dealer could find nothing stored and with a little urging he replaced the power module relay (his best guess). Picked up the car drove ten miles, had a beer and pizza, got in the car and no start, same symptoms, sputtered a little like it had spark but no fuel. I had the tow truck leave it at the dealer but unfortunately he couldn't figure out how to lock it properly so by the time the service guys got to it this morning the battery was dead not a chance of getting a code and it started, but once again while I was trying to start it I did not see any light saying a code was set.
Dealer has tested everything possible, talked to factory engineers, so far no solution.
Anyone with a similar problem-an idea that makes sense I'm listening.

 

[NORTY]

"Top-tier" gasoline?

 

[curvhog]

Quality of gas probably not an issue. I generally use name brand with only the occasional off-brand fill up. Time frame of about a month between the first and second problems means it for sure wasn't even the same fill up.
Biggest problem is still lack of codes. I tried to start it Monday after I got to the dealer with the service writer right next to me and it would not start. That should have set a code. As soon as I left and the service writer turned her back someone wandered out from the garage to move it from the service lane. It started right up and he drove away. Ran fine for the dealer for 2 days but only lasted 10 miles for me.

 

[c4c5specialist]

Hi there,
I am willing to BET there is something in the data.
Maybe your fuel trims are fluctuating, maybe your MAF sensor is not connected correctly, maybe your CKP sensor is dropping out but there is NO way that there isnt any clues.
3 times in 500 miles isnt much but all these times, it seems like your coming to a stop or the engine is going to idle.
You do NOT tell us how many miles you have on the car, what modifications you have installed or anything else so alot of this is theory.
Did anyone clean the throttle body????
Did anyone install a VDR to monitor the situaton??
If everything was tested, what was your fuel pressure?? Did the test injectors with the AFIT??
These are simple things that could create a condition or at least catch it.
Allthebest, c4c5

 

[curvhog]

c4c5.........I could not agree more that there should be something that reveals the problem. The last incident occurred before I could get home to put my own scanner in the trunk. I had totally forgotten I had the scanner.
Car has 12,300 miles on it. I talked to the tech for about half an hour and among the things he reported was fuel pressure was good. The car has had routine GM servicing up to this point.
Painful as it would be one option is to leave it with the tech to drive and hopefully fail.
I have to disagree with one thing you say. The engine stops running instantly, does not go to idle. Any car that can do this with no warning and leave it's passengers and other drivers in a potentially dangerous situation is not drivable, even if it happened only once. The second time this happened I was getting off the freeway and the car stopped rolling before I got to the intersection. The off ramp was almost a blind corner and in the hour until the wrecker showed up there were many near accidents.
The biggest mystery to me is that it has happened cold after sitting overnight, hot while running, hot after sitting for 45 minutes.
Used to own an 88 and I have say I probably would have solved this on it by now.
Thanks for your thoughts.

 

[LLC5]

Are there any aftermarket accessories on the vehicle such as alarms or stereo, or is it 100% OEM? If it is all original, then leaving the vehicle and using the VDR is probably going to be your best option.

 

[curvhog]

Sorry, left that bit of info out. Car is totally stock. The only thing added since delivery was a 6 disc cd changer which was a GM part and merely plugs into the system.
I'm assuming VDR is some sort of data recorder to which I would say go for it. What has always bothered me is that while I sit there, cranking the engine without even a hint of it wanting to fire not once has the service light lit up or even flickered. My 88 was giving me problems once with cooling fans running earlier than they were supposed to and other quirks and yet no codes were set. Chased the tail of erratic sensors for awhile but it turned out the one electronic part that watched over all others was bad and had no way of saying so unless it was queried.
I'm in my early 60's and have owned and driven many cars including my '88. The only thing that the abruptness of shut off when running it even compares to is when a mechanical fuel pump would totally break.

 

[LLC5]

Yes, it is a vehicle data recorder. When the problem is active you push a button and it records data before and after the event. Sometimes it is installed in the vehicle, and the customer drives the vehicle until the event occurs, and when it does you bring it back to the dealer and he records the data from the VDR. In your case, since the vehicle is suddenly dead in the water, I would leave the vehicle with the dealer and let them test drive it and see if they can duplicate the problem.

 

[curvhog]

One question I have is that when the tow driver left the car at the dealer he apparently left something on which drained the battery. The battery was dead or at least drained enough so that all the dealer got was solenoid click the next am. Is this enough to erase any trouble codes that might have been set?
Haven't checked yet today but the last plan last week was for the tech to use the car and carry his scan tool to grab any data if it fails.

 

[curvhog]

Good news! Car was wired like the space shuttlle and failed on a tech who drove it home last night. Engine started and died right away before he could leave his driveway this morning. Both you guys who responded said the right things. Car set 12 codes and the tech was unable to communicate at all with the BCM. Car still being towed back to dealers shop but even if it starts when they get it there as has been the case before there is something to look at.
Only bad news part might be trying to find cause: bad ground, loose connection, bad wire, short etc. because in all previous tests BCM and all the other modules responded OK.

 

[LLC5]

Good news! Car was wired like the space shuttlle and failed on a tech who drove it home last night. Engine started and died right away before he could leave his driveway this morning. Both you guys who responded said the right things. Car set 12 codes and the tech was unable to communicate at all with the BCM. Car still being towed back to dealers shop but even if it starts when they get it there as has been the case before there is something to look at.
Only bad news part might be trying to find cause: bad ground, loose connection, bad wire, short etc. because in all previous tests BCM and all the other modules responded OK.

I would say it's mostly good news. Getting the tech to verify the problem is a big plus, and if he has any problems diagnosing the problem he has GM tech support to help him. After the repair you may want to ask the tech to drive the car home again and see if he can get it to fail.

 

[curvhog]

I would say it's mostly good news. Getting the tech to verify the problem is a big plus, and if he has any problems diagnosing the problem he has GM tech support to help him. After the repair you may want to ask the tech to drive the car home again and see if he can get it to fail.

Various techs drove it over the course of 4 days before the last one but there's no pattern when it happens. I also would not be surprised if by the time the tow truck got it back to the shop the problem had resolved itself as there is a pattern for that. Be interesting to know if the codes stay stored like they should or disappear.
I'm planning on asking for the specifics of codes set and repairs done for my files if they are not on the service invoice.

 

[curvhog]

Latest update for dealer has me both perplexed and maybe not reassured. After he studied tc's set, modules involved, etc., he has narrowed in on the fuel pump relay in the underhood relay/fuse box where he found a loose connection and (his words) a "hogged out" terminal on one of the spades on the relay. Plan is to replace the box. He's also checking the wiring back to the fuel pump and considering the possibility of an intermittent short in the fuel pump itself.
There seems to be a communication problem on fuel among the modules at times.
My gut feeling all along was it was fuel related but with all the electronics involved I had little to offer except it didn't fire at all.
After thinking some more about what they told me, after numerous tests, wiring in tools, checking circuits, driving the car for the last 10 days including having it fail at their techs home, the message today was they still don't know anything for sure. The problem still remains the engine stops running and 1 1/2 to 2 hours later starts up fine. Apparently nothing in the codes set points right at the trouble.

 

[metoo1012]

Curios about your 88 as I am having issues with my 86, what unit did you replace in the end?

thanks
Earl

 

[curvhog]

On the '88 it's been awhile and I no longer have the records but I believe the ecm was replaced. It's located under the dash on the passenger side. The rebuilt unit was about $150 and the prom from the old one was swapped to it. Essentially I had no service engine lights and wasn't sure it was bad until I asked the dealer to do a diagnostic.

On the '07, I've had the car back for almost a month now and it has been running fine. Biggest problem found was a loose ground on the fuel pump. When wiggled the car stopped running and reproduced the dtc's that the tech pulled when it stopped for him.
Why it never lit up a service engine or service fuel system on the dash is still a mystery. I finally stopped asking, but I do carry my scanner with me for the time being. Most frustrating thing is even with telling the tech it had all the symptoms of a fuel pump quitting and asking if there could be a bad ground somewhere they can't diagnose without the codes.

 

[metoo1012]

thanks for the info, glad to hear you are up and running. Now to check my fuel pump for a bad ground. Mine has been driving me. not too sure where yet! but maybe a simple fix is is store.