92 Lesabre...intermittently dies..cranks but no start

[spinne1]

Hello. I have a very tricky problem on one of my Lesabres (my wife's). About a month ago, my wife called me because the car just quit running on her as she pulled into her work parking lot (after a 15 minute drive). It would crank but not start. The cranking seemed much faster. It gave no hint of firing up. I checked for spark which was present. [FYI, at the time it gave me a Code 31 and a Code 58--the Code 31 is the Park/Neutral Switch, which is no big deal because it still cranks in Park or Neutral, and the Code 58 is the Pass Key II system--which is part of the problem perhaps] After attempting to fix it I had it towed to my house. After it sat all day, it started right up and seemed fine. Then it stalled again later. I decided it needed a new timing chain, crank sensor, cam sensor, fuel filter, and water pump because it had 193,000 miles on it and because I know these things contribute to this type of symptom. After getting it all apart, I discovered the cam sensor magnet was falling apart. It actually disintegrated in my hand. I felt good having taken it all apart because I knew it was vital no matter what caused the stalling. I replaced that and carefully put it all back together with the new parts. However, the crank sensor broke when I was bolting it together. The fit of the part was defective, so I put the original back on, which showed no signs of wear on the plastic. I never loosened the original therefore it fit perfectly spaced for the harmonic balancer fins to go between. I inspected and cleaned the wiring to the crank and cam sensors. I lined up the timing parts perfectly (both when taking off and putting back on).

After all was back together, I cranked it and it started right up. Problem solved so I thought. NOPE. Later, it stalled and would not restart in the exact same way. It also reset a Code 58 again at some point. I now turned my attention to the Pass-Key system. I checked the wiring for the resister on the key portion of the ignition switch, which was fine. I checked the Pass-Key module to see if it was getting the 5 volts from the PCM (it is). I checked to see if it was pulsing the 5 volts to ground to get a 2.5 V signal on the dark blue wire (229). It is. It never stopped giving the correct voltage even when it would only crank and not run.

For some reason it just started working correctly for over a week and I thought the problem may be gone, but then this morning, my wife said the car would not start after having just started it and moved it 20 feet up the driveway. I checked for codes and this time no Code 58 was present (after more than a week of driving it). It used to only stall after warming up, and it would restart after fully cooling down, but this time it had sat overnight and was fully cool and it did the same thing. The only variable different was that the air was moist and cool from Hurricane Rita's leftover weather traveling over Tennessee.

I knew the ECM was getting the right signal from the Pass Key module and therefore should be sending the fuel enable circuit the correct signals, but it was still not working right. I then pulled the computers out of both of my 92 Lesabres and swapped them (I kept the correct PROM chips with each car's computer). Before resetting each computer by pulling the ECM fuse under the hood, the bad Lesabre (with the good Lesabre's computer) would still not start, but only crank. The good Lesabre (with the bad Lesabre's computer) started and ran normally.

Next, I pulled each car's ECM fuse and waited 30 seconds or so. Now, both cars started and ran normally. This is where I stand now. I am ready to take it into a good Buick dealer we have here and get them to look at it.

I have no idea what is causing the stalling and I don't know when it will return, but I do not believe anything is fixed. Does anyone have any ideas as to what could be causing this?

Possibilities I have thought of are:

Ignition Module--but why would I have spark if it was this?
Crank Sensor--wouldn't I get an engine code for this?
Other engine sensor-- " " " " " " " "?
Fuel pump--why would it work perfect most of the time and not at all at other times?
Wiring between the ECM and the injectors (and any circuitry between)--I don't know of the exact wiring involved and tracing it is a bear

Again, any insight would be appreciated.

[stuzman]

Originally Posted by spinne1

Hello. I have a very tricky problem on one of my Lesabres (my wife's). About a month ago, my wife called me because the car just quit running on her as she pulled into her work parking lot (after a 15 minute drive). It would crank but not start. The cranking seemed much faster. It gave no hint of turning over. I checked for spark which was present. [FYI, at the time it gave me a Code 31 and a Code 58--the Code 31 is the Park/Neutral Switch, which is no big deal because it still cranks in Park or Neutral, and the Code 58 is the Pass Key II system--which is part of the problem perhaps] After attempting to fix it I had it towed to my house. After it sat all day, it started right up and seemed fine. Then it stalled again later. I decided it needed a new timing chain, crank sensor, cam sensor, fuel filter, and water pump because it had 193,000 miles on it and because I know these things contribute to this type of symptom. After getting it all apart, I discovered the cam sensor magnet was falling apart. It actually disintegrated in my hand. I felt good having taken it all apart because I knew it was vital no matter what caused the stalling. I replaced that and carefully put it all back together with the new parts. However, the crank sensor broke when I was bolting it together. The fit of the part was defective, so I put the original back on, which showed no signs of wear on the plastic. I never loosened the original therefore it fit perfectly spaced for the harmonic balancer fins to go between. I inspected and cleaned the wiring to the crank and cam sensors. I lined up the timing parts perfectly (both when taking off and putting back on).

After all was back together, I cranked it and it started right up. Problem solved so I thought. NOPE. Later, it stalled and would not restart in the exact same way. It also reset a Code 58 again at some point. I now turned my attention to the Pass-Key system. I checked the wiring for the resister on the key portion of the ignition switch, which was fine. I checked the Pass-Key module to see if it was getting the 5 volts from the PCM (it is). I checked to see if it was pulsing the 5 volts to ground to get a 2.5 V signal on the dark blue wire (229). It is. It never stopped giving the correct voltage even when it would only crank and not run.

For some reason it just started working correctly for over a week and I thought the problem may be gone, but then this morning, my wife said the car would not start after having just started it and moved it 20 feet up the driveway. I checked for codes and this time no Code 58 was present (after more than a week of driving it). It used to only stall after warming up, and it would restart after fully cooling down, but this time it had sat overnight and was fully cool and it did the same thing. The only variable different was that the air was moist and cool from Hurricane Rita's leftover weather traveling over Tennessee.

I knew the ECM was getting the right signal from the Pass Key module and therefore should be sending the fuel enable circuit the correct signals, but it was still not working right. I then pulled the computers out of both of my 92 Lesabres and swapped them (I kept the correct PROM chips with each car's computer). Before resetting each computer by pulling the ECM fuse under the hood, the bad Lesabre (with the good Lesabre's computer) would still not start, but only crank. The good Lesabre (with the bad Lesabre's computer) started and ran normally.

Next, I pulled each car's ECM fuse and waited 30 seconds or so. Now, both cars started and ran normally. This is where I stand now. I am ready to take it into a good Buick dealer we have here and get them to look at it.

I have no idea what is causing the stalling and I don't know when it will return, but I do not believe anything is fixed. Does anyone have any ideas as to what could be causing this?

Possibilities I have thought of are:

Ignition Module--but why would I have spark if it was this?
Crank Sensor--wouldn't I get an engine code for this?
Other engine sensor-- " " " " " " " "?
Fuel pump--why would it work perfect most of the time and not at all at other times?
Wiring between the ECM and the injectors (and any circuitry between)--I don't know of the exact wiring involved and tracing it is a bear

Again, any insight would be appreciated.

It sounds like you have a good handle on the PassKey II system, but I would be interested to know why it still throws a code 58. Although it sounds like you have troubleshooted the circuit and appears to check out, I would take another look to see why this code keeps popping up and as you know, this would prevent the car from starting. Since I suspect this is an intermittent problem, everything appeared okay when you checked it. Here is a site which may give you some more insight to the workings of this system. Hope this helps you out!

http://www.motorage.com/motorage/dat...09/article.pdf

[spinne1]

Thank you for your response and the link. The article was very helpful. I suspect now that one of two things is happening. One, the keys and/or the contacts in the ignition lock are getting worn and every so often fail to read the correct resistance. Or two, the small wires coming out of the ignition lock are slightly damaged such that they lose their continuity every so often.

I think my first solution will be to solder in a resistor that matches the resistance of my key. However, I have found that I have two slightly different readings based on whether I read the key directly (about 8.22 kOhm), versus reading the resistance on the two wires that connect to the key contacts that read the pellet resistance (it was about 9.38 kOhm). Also of note is that both my wife and I have original keys to the car and both have failed to start the car during this ordeal, so I'm not sure it is the key, unless both keys are worn to the point of intermittent failure. Based on my above resistances, I'm not sure which range of resistance my car is supposed to be in. There are two that are close. I guess I could just buy two resistors and use the one that allows me to start the car.

I also now need to reprogram both computers as I swapped them, which procedure was given in the article you linked.

I feel like I am getting close to solving this because:

a) if the wires in the ignition are crimped/failing, then soldering in a resistor bypasses the ignition PassKey wiring, and
b) if the soldered in resistor fails to work, then I know that the problem has to lie in either the PassKey module, the PCM (unlikely since I swapped it and the problem repeated--but a reprogram should tell the tale on that for sure), or the wiring to the fuel enable circuit (trickier as I have yet to fully identify the physical location of all wires and parts of the circuit).

[maxwedge]

When the pass key system fails I believe there is no cranking, also this would not cause a stall either. The starter enable system is interrupted, but you get cranking and no start , right?

[spinne1]

Originally Posted by maxwedge

When the pass key system fails I believe there is no cranking, also this would not cause a stall either. The starter enable system is interrupted, but you get cranking and no start , right?

I get cranking but no start. It never fails to crank. The starter is always active when turning the key.

[HotZ28]

OK, so far I have gathered from the previous post that you have a 92 Buick that stalls occasionally and when trying to start, (starter turning) it does have spark, but will not start. It seems like you need to do a fuel pressure test when it is in one of its no start moods! With ignition on, you should have full line pressure prior to starting. When you turn the ignition on, the fuel pump enable relay should kick in and provide the necessary pressure to start the car. You can buy a fuel pressure test kit cheaper than throwing parts at it. I agree with Maxwedge on the VATS system diagnosis however, I forget whether the 92 has the fuel pump disable capabilities as part of the VATS system. Even if it does, it is highly unlikely that the starter would turn and the fuel pump relay would not also get the signal to enable. If you do not have a fuel pressure tester before it happens again, get a can of carb cleaner or brake cleaner and keep it in the car for the next stall. If it stalls, remove the rubber bellows on the throttle body and open the throttle while spraying the carb cleaner in the throttle body during the starting process. If it starts on the carb cleaner, you have a fuel related problem. It could be something as simple as the fuel pump relay!

[stuzman]

Originally Posted by spinne1

I get cranking but no start. It never fails to crank. The starter is always active when turning the key.

Researching the PassKey system a little deeper, it does appear that the starter circuit is disabled when the PassKey circuit is activated. In that case, Max and HotZ are probably correct with looking into another system such as the fuel system. However, it is strange that you are getting a code 58 for your PassKey system and yet the starter is turning.

[spinne1]

I checked the fuel system when the car was functioning normal (it is so rare to not work right that it could be a week or a month before it breaks again), so the test may not have revealed anything, but the pressure was at 40 PSI with the pre-start priming, and about 38 after starting it. All is normal there.

As for the Pass Key system, I thought the way it worked is that the starter is only disengaged when the system determines that a theft is occuring. But when it simply has a wiring or module or ECM problem with the correct key inserted, it will simply not start but the starter will engage.

Correct me if I am wrong.

[HotZ28]

The VATS system disables the engine starter if the systems module detects an incorrect, or non existent resistor value at the time of ignition. That could be caused by a bad key resistor or resistor reader as well as additional resistance due to a damaged wire.

[davey 58]

did anyone fixthis problem mine does same thing

[spinne1]

Originally Posted by davey 58

did anyone fixthis problem mine does same thing

Yes, the problem is fixed. I'm not certain that the VATS system had anything to do with it, so I'm not sure that my bypassing the VATS system fixed anything, however, I took it to a Buick dealer and asked them to diagnose it and they said that my ignition module was bad. I replaced it (about $200 from a Car Quest parts store) and it has been fixed ever since.

[davey 58]

got mine running today hope it stays that way it was bcm/ecm thanks for all the post on this problem

[Bassasasin]

I thought a VATS problem will let it start then die... If it dies running down the road a intermittent key might do that..
I had trouble with phantom die no start for 7minutes... turned out to be the CRankshaft sensor.. but the code said Camshaft sensor.. Wierd huh?