'95 LeSabre Dies Without Warning

I went down to the parts store last night and bought a Haynes manual for the car to see how difficult it would be to replace the crank sensor ... it says you have to remove the vibration damper, and that you need a special tool to realign the sensor when you put it back on. I'm reasonably savvy but this looks like it might be something I don't want to tackle on my own ... how difficult did you find this to do? What special tools might I need?

It indicates that removing the vibration damper involves taking off the right front wheel and fender splash guard, and that it's a two-man job ... then it cautions about realigning the sensor so it doesn't contact the vanes on the damper, which is what worries me ...

I see now why you tried other things first ... this is quite a thing to undertake on the "chance" that it is going to fix the problem. Yet, based on your experience, it seems at least a 50/50 ...

Del

I didn't do the work myself on this recent problem I had with my '95. (I did it on my older '89 a couple years ago.)

I don't recall needing any special tools. I do remember the worst part was trying to get the pulley off to get at the sensor. Two words: "cheater bar." I'm guessing the key to "aligning" the sensor is simply to make sure the air gap between sensor and vanes is correct. I'm pretty sure I "eyeballed" mine. Perhaps you could use a gauge (the shim style) for gapping plugs to check the gap on the original sensor before putting the new one on. But being such a shade tree mechanic (and not a very good one at that), I would defer on this issue to the more knowledgeable folks on the forum.

On my '95, the crank sensor replacement was $150 total, parts and labor. I felt like it was worth it at that point. I was at a frustration point where I just didn't want to work on the car for a while--I needed a break from it, so I let the boys at the shop take their third crack at it. Third time was the charm. I will say that if the ECM had done its job and set a *crank* code in the first place, it would have been fairly likely that I'd have tried doing it myself at that point.

If you have access to a portable oscilloscope (not likely), you could monitor the outputs of the crank sensor while cranking or driving. Essentially that's what my shop did to catch it in the act. If your car dies or won't start and the outputs of the crank sensor are doing what they should, the problem lies elsewhere.

I was faced with the choice of replacing the ECM or the crank sensor there at the end. I chose ECM (wrongly) for several reasons:

a) It was by comparison an easier replacement
(as you point out, the crank sensor poses a
bit more of a challenge)
b) More people I'd talked to thought it was the
ECM that would ultimately be at fault. And
those thoughts weren't without some merit.
c) My shop had been unable to catch the crank
sensor malfunctioning for a perod of two weeks
while they had my car the second of the three
times.

If I were you, I would go ahead and go for the crank sensor replacement. If it still doesn't work, you're only out your time and the cost of the sensor, and look at it this way--your car is 10 years old now, and it may still have the original sensor on it. If you put a new one on, it may be several more years before you'll have an inevitable crank sensor failure. Let's face it--these things are made of plastic, and they're in a very abusive environment. The thermal cycling alone is extreme.

Best of luck, and keep us posted on your progress.

I replaced the crank sensor on my '87. I did not have to take off the vibration damper. You may want to turn the crankshaft until the vanes on the back of the damper are not in the slot of the crank sensor. There are two bolts holding the sensor bracket to the main block.
If you have to take off the damper, visegrip the flywheel in the little hole at the bottom of the engine and get out your big wrenches, but I dont know what you would use the second man for. As far as aligning, I eyeballed mine so the vanes went through the middle of the gap. That may have been a mistake, because the new sensor caused it to "miss", and I put the old one back on. I would advise to set the gap the same as the old one.

It rained all weekend so I didn't do anything with the crank sensor ... I did talk to a shade-tree mechanic friend of mine about having him do the replacement, and he said (in his opinion) there's no way it's the crank sensor. He said in his experience this is most likely caused by the MAF (Mass Air Flow) Sensor. I don't see anyone else here talking about that ... is this something anyone else tried? It's easy to get to, I may just replace it and see. Oh, by the way this morning my car ran like brand new, didn't falter once ... perhaps it likes the cool humid environment of Tampa after three days of rain ...

I dont think the crank sensor could cause all the lights to flash (especially temperature)

I've been paying a little more attention to that, and I think that what is really happening is ... the lights (temp / oil) just flash when the car is trying to stall ... the same as when the key is on but the car is not running. If it does stall, they stay lit, otherwise they just flash for a second at the same time as the speedometer is jumping. The service engine soon and anti-lock brakes lights are staying on most of the time now. Service engine probably means a code has been set, and anti-lock brakes may be totally unrelated.

I guess if the crank sensor said the engine was not turning, the computer may turn on the lights the same way it does when you first turn on the key. and then before it really dies, the sensor starts working again and the lights go out..mmm..?

delhsn, my speedometer juked and my dash lights would wig out just like you're describing. I would agree w/rustbucket: the ECM/PCM is probably doing its bulb check. (Why your ABS light stays on is not clear--mine didn't.)

I would read the codes out first. If you don't have a reader, most of the parts houses will read 'em out for you. If you have a *cam* sensor code, I would sure replace the *crank* sensor at that point. I have it from several sources that a bad cam sensor circuit won't kill a running engine. I know firsthand that a bad crank sensor will.

I would not be in a hurry to replace the MAF sensor unless you're pretty certain that's it. Those are fairly expensive. Seems like when I needed one for my '90 a couple years ago, it was $200 to $400 depending on where you got it. In the case of my '90, to confirm I really needed one I swapped the one off my '89 with it and the problem followed the sensor, so then I went to the salvage yard. I plopped down $50 and got a whole 3800 throttle body with all the sensors and controls attached. I'm betting if you had the factory manuals, you could look up the proper voltage output range for the MAF, and then just make a simple check with a multimeter, too.

He all....great thread. I've been trying to get at my CPS to replace it but I'm having a difficult time removing the Crankshaft pulley bolt. It's a 91 Lesabre or maybe a 92' per the guy who put a new windshield in it...anyway...I tried a 250 lb air wrench and a breaker bar. Part of the problem is getting the pulley to keep from turning. I put a big screwdriver in the power steering pulley to jam it from moving but it doesn't keep totally still. Any ideas...bigger hammer with more torque? I tried a 250lb'er with a 2 gal pancake compressor....I know...pretty small...I use it more for shooting nails and pumping up the kids bicycle tires. The shop quoted $200 plus tax for the job. The part was $30-35 bucks....and I'm cheap.

Thanks for the help.

I bought the Haynes manual for $17 at Discount auto, I believe it recommends putting a screwdriver into a spot on the flywheel to keep it from turning, will look tonight when I get home. Did you have to take the front wheel and wheel shroud off to get to it? The more I read the more I think the CPS is my trouble too, I just can't see it being the MAF ...

My manual didn't mention anything about how to keep the pulley from moving. I did not have to remove the wheel. Just a splash shield. It had a few plastic retainers that pop out with a screwdriver. You can buy replacements at the local auto parts company.

I don't buy off on the MAF sensor either.

!!! Dont try clamping or stopping the serpentine belt from moving while trying to turn the crank bolt!!! It will ruin the damper. I did it that way when replacing my timing chain and after I got all done, I had this terrible clanging, ran fine, but made a racket while at a stop. Turned out the damper internals had shifted enough that the support parts were hitting each other. $218 for a new one. Try vise grips on the flywheel. You might have to take off a little plastic cover to get to the flywheel. I used a 250 ft lb torke wrench with a pipe extender. I actually couldnt get it by going out through the wheel well, I was sitting on the windshield. with no extenders on the socket.

The instructions for removing the vibration damper state: (paraphrased)

1. Disconnect the neg. batt. cable (caution re: Delcolock stereo ... )
2. Loosen lug nuts on rt. frt. wheel
3. Raise vehicle / support on jack stands
4. Remove rt. frt. wheel
5. Remove rt. ft. fender inner splash shield
6. Remove drivebelt
7. Remove the lower bell housing cover plate and position a large screwdriver in the ring gear teeth (see illustration) to keep the crankshaft from turning while an assistant removes the crankshaft balancer bolt. The bolt is normally quite tight, so use a large breaker bar and a six-point socket.
8. The damper should pull off the crankshaft by hand. Leave the woordruff key in place in the end of the crankshaft.

That gets the vibration damper out of the way, then its a matter of replacing the CPS, being careful to align it properly so it doesn't touch the vanes on the vibration damper when its reinstalled.

Ditto what delhsn says. Under the "Vibration Dampener Removal" section in my Haynes manual, it says: "Remove the lower bellhousing cover plate and hold the crankshaft with GM tool J37096 or equivalent, or position a large screwdriver in the ring gear teeth to keep the crankshaft from turning while an assistant removes the crankshaft balancer bolt. The bolt is normally quite tight, so use a large breaker bar and a six-point socket."

(This may be where the "two-man" job comes in, as was questioned in post #68.)

Thanks that did the job. I got the bolt off but the dampner is being stubborn. I've tried to gently knock it free with a hammer and extension from behind but no luck. I'll give another shot later today and post the results...but if anyone has any suggestions I'm all ears.

I can't help you with that because I chickened out ... I went this morning and bought the part for $30.05, got out my jack and stands and got ready to start, then I decided to call Firestone and ask what they would charge to replace it ... they said $151 including the part. I decided a day of sweating and swearing and frustration wasn't worth $119 to me, so I made an appointment to have them do it tomorrow morning and I'm on my way to return this to the parts store. Hope you got it figured out ...

That's funny delhsn.....maybe I should have taken your lead. I spent a few hours today trying to get the damper off with no luck. I even came up with a brain child and called the local Autozone to see if they had a tool that I could borrow. They did!! However, I should have paid better attention and not taken home the first thing they gave me. It was for Chrysler and Mitsubishi. I went back and got the one for GM cars and it looked just like the one in my Haynes. It didn't work either. There are supposed to be 3 bolt holes in which you attach the puller to....there aren't any bolt holes....just three slits. I looked inside and saw some very small holes and tried to rig it to work with some lag bolts I had laying around. Nope. I'm going to look for some generic pullers and go from there.

Got it done finally. I went ahead and changed the Camshaft position sensor too. I had to use the same puller and throw in some .25 in. bolts and washers to get the damper off. I may have bruised it up a bit it vibrates a little at idle but looks fine if you give it some gas.

The main question is ... is it fixed? I don't know the answer to my own question yet, as Firestone kind of let me down ... I got a call about 4 PM telling me that "the part they received isn't the part they ordered" or some such ridiculous excuse ... and that my car won't be ready until sometime tomorrow. I had previously told them that I absolutely needed it today, as my wife and I have to be at opposite ends of the city tomorrow morning at 8:00, but obviously they fell through, and we had to make some quick arrangements to take care of tomorrow. Hopefully, they'll come through and I'll have it back tomorrow, running like a dream ..... we'll see.

Del

Well that is the million dollar question or should I say $200 in my case...I'll post an update later in the week.

It started this morning when it was wet out...and she normally would not before.

Lets hope.

Well, in my case ... it may be a bit premature to claim victory, but I'm about ready to anyway. I went and picked up my car today at Firestone and they gave me my old part ... or half of it at least! They said when they pulled the vibration damper off, the other half fell out ... it was obviously deteroriated from the heat. Here's a picture of what I got back ... http://www.feedbacklive.net/images/cranksensor.jpg ... I would say this is proof that our diagnosis was correct!

I owe a debt of gratitue to automotiveforums.com and especially to timrice and the others on this thread who have shared their experience for the benefit of others like myself. I believe the $151 I spent at Firestone was a bargain, and hopefully will let me get a lot more life out of my newly paid off car ... instead of looking for a new one at a time when I really cannot afford to. Thanks to all.

Del in Tampa
www.feedbacklive.net

I would try a wrecked vehicle module... Very easy to change out.. 4 screws and its out.. under the kick panel passenger side.. I swapped mine.. obviously if the car wrecked it worked..

If you put a 12 v lamp (or voltmeter) between the green tabbed fuel pump test connector and ground, it lights when the fuelpump is receiving a signal to run. If the bulb lights when it is supposed to, that eliminates the fuel circuit. (ie the fuel relay is receiving an "on" signal from the ECM, and the relay is working and the wiring to the pump is OK)
Did you ever resolve this problem of engine dying?? If so, what finally fixed it? My '91 LTD does same thing. After replacing fuel pump, filter, and pressure regulator: O2, coolant, oil press. and crank sensors: ign module, coil pak assy (six pack), plugs, wires, alternator, nothing changed. Replaced solenoid on top of fuel canister, which solved stumbling on hiway, but still dies without warning coasting to corner. starts right up again, and acts like nothing happened, then may go good for days. I have 185K mi. This has gone on for 2 years. Thanks, Huey

Did you ever find out exactly what caused your dying problem? I have a 91 limited with same problem, and have replaced almost everything thinkable and still does it. Thanks Huey

Did you ever resolve this problem of engine dying?? If so, what finally fixed it? My '91 LTD does same thing. After replacing fuel pump, filter, and pressure regulator: O2, coolant, oil press. and crank sensors: ign module, coil pak assy (six pack), plugs, wires, alternator, nothing changed. Replaced solenoid on top of fuel canister, which solved stumbling on hiway, but still dies without warning coasting to corner. starts right up again, and acts like nothing happened, then may go good for days. I have 185K mi. This has gone on for 2 years. Thanks, Huey

Hi Huey
The only thing I changed was my EGR valve about a month ago, From the wrecking yard for $45.00 (NEW $180.00) and it hasn't stumbled,missed or stalled since, I now have about 217,000 and going strong. Good luck Rick

Hi Rick, Thanks for the reply. Was yours the digital EGR valve? Mine is, has 3 little electrical solenoids, spring loaded to hold 3 valves closing 3 holes, normaly closed. Had mine off for cleaning, and all seemed free, but no way to tell if they are receiving signal, or working right. Huey

Hi Rick, Thanks for the reply. Was yours the digital EGR valve? Mine is, has 3 little electrical solenoids, spring loaded to hold 3 valves closing 3 holes, normaly closed. Had mine off for cleaning, and all seemed free, but no way to tell if they are receiving signal, or working right. Huey

Hi Huey
Mine is called a linear EGR valve assembly page #6-14 illustration #8.5 of the haynes manual #19020 complete repair manual, I took it off for cleaning also and found nothing and it moved freely, So it had to be in the electronics of it and I can't test that so I had to gamble with 45.00 and I am sure glad I did, The one I got came off a ??98/99?? pontiac bonneville with an identical engine compartment as far as I could tell.
Good luck Rick

Thanks, Rick, Naturally, my digital one is to be checked with special scan tool by a dealer. A trip to dealer would probably be around $1000, the way they operate around here, always sell way more than you need, and they know they have you, cuase you don't know which part you really need, and they're not telling. I'll try to find one at salvage. Guess it could still be an ECM problem too, as one of the other guys mentioned. EGR easier and cheaper Huey

Hi Huey
I strongly suspect it's the EGR Due to it's exposure to the harsh/hot exhaust gases constantly, and my local parts house used the scan tool they have (nothing special ?) and after about 10 months of looking and guessing it showed its first code anf the check engine light came on for the first time the code said intermittent miss detected and EGR pintel circuit, That's when I took the chance and I am sure glad I did, Please post if it works maybe we can save someone else the headache
Rick

:smile: Tim, your string saved my Buick. My 95 Custom experienced the identical problem as yours. It stalled after 10 miles on the road after sitting all night, then it would take 3 to 30 minutes to restart. The crank sensor was changed last week and the car runs great.

Gilligan89, I appreciate your response, and I'm pleased to know that things went so smoothly for you. Stories like yours help me feel like all the time, money and frustration wasn't all spent in vain. That's why I put my saga down in words--to help other people avoid getting burned by mediocre mechanics or having their do-it-yourself repairs drag out because of diagnostic mistakes. That's what these forums are all about. Some mechanics put these forums down, saying that nobody on the forums knows what they're doing. In some cases, that's true, but if enough of us are willing to put the facts and details down, it can be a very powerful thing. And very liberating.

By the way, no GM engineers have responded to my standing question about why the ECM/PCM reports a cam sensor code when the crank sensor has failed. There *may* be a good explanation...I'd just like to hear it.

Ok, I was wondering if this guy ever resolved this issue b/c this is the exact same boat I'm in and I'm about to blow the car up. I have a 95 Firebird w/ a 3800 Series II as well. A couple weeks ago the car started dying while driving. Cutting off spark to the car. At first it would start right back up. But then became unpredictable to whether it would start right back up, or if you were gonna try for 45 minutes before it started. I had just replaced the crank sensor (b/c the week before that it was having RPM flunctuations and threw the crank sensor code). After replacing, it stopped the fluctuations and a few days later started this stalling crap. It got worse and more frequent. Now I'm on week two. So far I've replaced the crank sensor (as mentioned), the cam sensor, the ICM, checked the ground wires. I recently found that the ground for the ICM was slightly loose, and tightened it. Thought that was my problem as that day the car did not stall, however the RPMs did dive bomb once as though it was going to stall but picked back up. (which it also was beginning to do before tightening this ground). Another day went by w/ NO incident at all and I began to think I was on the right track w/ the wire, and had helped it but maybe that there was a break in the wire. Well then today it died on me three times, trying to kill me at some of the busiest intersections in this city. So I'm back to thinking that wire had nothing to do w/ it. My only thing left to think is the PCM, but after reading of your experience, I'm not sure. Of course when I can get somewhere to hook up a Tech II, the car won't stall, it'll run for a half hour straight. What disuades me from believing it's a wire is that it doesn't seem to do it when I hit a bump, I've even run the car in the driveway and wiggled all the harnesses, bounced the car up and down, side to side, and it has no effect. But yet while idling in the driveway, after awhile it will die. I'm so frustrated now I want to just send it off a cliff. Any ideas? Would like to hear what the original poster finally found out about his car.

Nina

Nevermind, I see he found it to be a crank sensor (should've been his first instinct). I've already done that. All the common/simple things like that have been replaced... Looking for something more obscure/rare/ridiculous/expensive/annoying.

Nina

What about really hard braking, will that cause any reaction? Perhaps a problem with fuel delivery. Sounds dumb but easy enough to try out. The problem is that almost anything shorting to ground can cause the computer to bomb and reset itself. Any of the sensors if they fail the right way or any wire harness to/from the PCM can short such that they drop to ground momentarily.

All the common/simple things like that have been replaced... Looking for something more obscure/rare/ridiculous/expensive/annoying.

Couldn't have put it better myself.

CRANK POSITION SENSOR was it.. $25 self done.. $150 shop.

I busted my ass on swapping, tracing, coding, EVERYTHING.Drove me nuts..

Car was NO CODES stalling. .usually a little after warmup. took time sometimes to restart..8 minutes usually sometimes sooner.

Hope this helps someone out there like me.. My hair is growing back now.


Bass

there are two crank sensors. one behind the balancer and one on the back side of the motor

Nevermind, I see he found it to be a crank sensor (should've been his first instinct). I've already done that. All the common/simple things like that have been replaced... Looking for something more obscure/rare/ridiculous/expensive/annoying.

Nina

Yeah, it's *always* my first instinct to change a crank sensor when the OBD code that comes up indicates the problem is with the CAM SENSOR!!! (Are you listening, GM?)

It's the same instinct that tells me that up is down, black is white, etc.
Very logical. So obvious.

Everything's so much clearer when it's already been fixed and documented, isn't it...

funny, your attitude is indeed, hilarious.

maybe you should think of something, on some vehicle, the cam sensor
and the crank sensors are on the same circut. so what may come up
as one, may be another... so quit with the arrogance

funny, your attitude is indeed, hilarious.

maybe you should think of something, on some vehicle, the cam sensor
and the crank sensors are on the same circut. so what may come up
as one, may be another... so quit with the arrogance

:smile:

For all I know, that *may* be true on some vehicles. But I don't believe it's true of 1995 Buick LeSabres. Pull the ALLData schematics on it. The two sensors do share a common ground and supply voltage feed from terminals M and N of the electronic ignition (EI) module. *If* one of those wires were broken, then yes, both sensors *could* be disabled at once, depending on where the broken spot in the harness was. That was not the case in my story. It's the output signals that mattered.

The cam and crank sensors each have their own output signals:
CAM sensor's "A" terminal goes to EI module's "J" terminal (CAM IN)
CRANK sensor's "A" terminal goes to EI's "H" terminal (SYNC)
CRANK sensor's "B" terminal goes to EI's "G" terminal (CRANK)

The EI module sends the CAM signal out from terminal "F" and the SPARK REFERENCE out from terminal "C" to the PCM / computer, which is responsible for turning on dash lights and setting codes.

I think the issue I have with the whole thing, looking back, is: "too bad the design isn't such that the PCM could report a diagnostic code that distinguishes between the two sensors (one just for crank, and one just for cam)." Especially since replacing the crank sensor is a higher degree of difficulty than the 10-minute cam sensor swap. The PCM doesn't read either the CAM or CRANK signals directly from the sensors. It does get the CAM signal or some scaled version of it "echoed" from the EI. Having worked with transmission controllers and their software, I know that sometimes there are reasons not to create diagnostic codes (warranty claim risks, increased wire harness costs, difficulty debouncing fast signals, the controller's out of digital or analog input channels, etc.), so maybe there's a really good reason GM couldn't or didn't make a separate crank sensor code. I would like to know what it is.

There certainly are shades of gray involved, but ideally speaking, if OBD system design were better, car diagnostics and repair would require a lot LESS instinct. Thank goodness some have, but not everybody grew up having their "instincts" honed building drag racers or restoring classic cars. Not everyone is vitally interested in the details of how their car works--they just want it fixed. I dare say that's the majority of drivers, and no doubt describes many visitors to this forum. Wanting my car fixed, plus a desire to help others out as I learned how is what brought me here in the first place.

:smile:

For all I know, that *may* be true on some vehicles. But I don't believe it's true of 1995 Buick LeSabres. Pull the ALLData schematics on it. The two sensors do share a common ground and supply voltage feed from terminals M and N of the electronic ignition (EI) module. *If* one of those wires were broken, then yes, both sensors *could* be disabled at once, depending on where the broken spot in the harness was. That was not the case in my story. It's the output signals that mattered.

The cam and crank sensors each have their own output signals:
CAM sensor's "A" terminal goes to EI module's "J" terminal (CAM IN)
CRANK sensor's "A" terminal goes to EI's "H" terminal (SYNC)
CRANK sensor's "B" terminal goes to EI's "G" terminal (CRANK)

The EI module sends the CAM signal out from terminal "F" and the SPARK REFERENCE out from terminal "C" to the PCM / computer, which is responsible for turning on dash lights and setting codes.

I think the issue I have with the whole thing, looking back, is: "too bad the design isn't such that the PCM could report a diagnostic code that distinguishes between the two sensors (one just for crank, and one just for cam)." Especially since replacing the crank sensor is a higher degree of difficulty than the 10-minute cam sensor swap. The PCM doesn't read either the CAM or CRANK signals directly from the sensors. It does get the CAM signal or some scaled version of it "echoed" from the EI. Having worked with transmission controllers and their software, I know that sometimes there are reasons not to create diagnostic codes (warranty claim risks, increased wire harness costs, difficulty debouncing fast signals, the controller's out of digital or analog input channels, etc.), so maybe there's a really good reason GM couldn't or didn't make a separate crank sensor code. I would like to know what it is.

There certainly are shades of gray involved, but ideally speaking, if OBD system design were better, car diagnostics and repair would require a lot LESS instinct. Thank goodness some have, but not everybody grew up having their "instincts" honed building drag racers or restoring classic cars. Not everyone is vitally interested in the details of how their car works--they just want it fixed. I dare say that's the majority of drivers, and no doubt describes many visitors to this forum. Wanting my car fixed, plus a desire to help others out as I learned how is what brought me here in the first place.


Great point. GM needs to step up their ODB design.
Most of the problems I have ran into NEVER even set a code.
NO Service Engine Soon light....
Unless that is I unplugged the sensor(s) itself.

dark orange

Everyone that is having problems with your car dieing out and dash board lights going out.... i had the same problem until the answer was found... I read all Tim Rices forums. The problem the crank shaft Sensor...... Money saved by reading Tim Rices forums.....

Thank you so much Tim..

Shirley from Flint Mi

delhsn, I hope you get it right the first time (unlike me). My speedometer flaked out a little when I was having my trouble, too. For sure, let us all know how yours turns out.

Nice word, verbosity.
--------------------------------------------------------------

Tim,
I scanned your postings and have had a similar problem with my 94 Buick Regal GS. It also has a 3.8L engine the same as yours. I also have a problem with the engine dying at times, missing at around 2000 RPM, and sometimes won't start after driving somewhere, turning off the engine for a short while, and then trying to restart it. I have replaced all the ignition parts except the crank sensor and the ECM. I have had a shop monitor all the signals and I have looked at it myself. I do know that when the engine won't start, there is no spark, as I pull the spark plug wire, plug in a plug and ground it, then have someone turn the engine over.

Now maybe it is possible that crank sensor output gets weak at times, but I believe that the problem is with the ignition modules. GM mounted the ignition module to the engine and it gets pretty hot. I replaced the ignition module once before and now I have the same problem again. When the car won't start, I can wait an half hour to and hour, and it will start again. If I just swap out the ignition module with the old one, it starts right up. If it was the crank sensor, I think it would still not start. So my belief is that the AC Delco module does not function right because of the heat. I can't understand why GM mounted it to the engine, but they did. It is a well known fact that heat is not good for electronic components and not only makes them act strange, but shortens their life. I also think my 14 pin connector to the ignition module was not always making a good connection, so I replaced it. Sometimes when the engine would not start, I would have someone turn the engine over, and I would wiggle the connector, and the car would start right up. Nobody ever thinks of the connector, but it is tin plated, while the module's pins are gold plated. Tin oxidizes and after 10 years, it could be not always making a good connection on some of those 14 pins.

Anyway, I am really interested to find out if your problem returns, because I suspect it will, but I could be wrong. The crank sensor is just a magnet that uses the Hall Effect principle, so is basically simple, and really shouldn't wear out, unless the magnet gets weak when it gets hot. The ignition module is an electronic circuit which does not like heat. Also, the ground wire is in the harness that connects to it and goes to the battery through the wiring. I tried running a separate wire to the ignition module directly to the battery which did not make any difference.

I have contacted Buick about this problem, as I know others have it also, and it is very difficult to diagnose.

I hope the crank sensor was the real problem for you. Let me and others know if it works. If the problem returns, please go to Buick.com and let Buick know so they can look into the problem. I believe it is a design flaw and it needs to be fixed somehow.

Dear tim,

I have been laughing my ass off at your story, I have the exact same problem you have with your car.

I have a 94 Buick Lesabre, I have changed the Cam and Crank sensor, EGR Valve, ICM plate, Wires and Plugs. I am ready to take a grenade and fix it for good.

I dont know what else to fix.

G.Gore
Missouri

Sharing this similar stalling problem with others, I worked on my '94 LaSabre today and tried changing the Crankshaft sensor. The toughest part of this job was getting the "pully" off the end of the crankshaft. I thought I was ahead of the game by having a wheel puller in hand. However the pully was not equipt with any threaded holes to accomodate the puller. I had to tap it off.

- First I removed the RH tire & rim.
- Then the plastic inner fender
- Next I removed the plastic cover over the edge of the bellhousing
- I then used a screwdriver in the teeth of the flywheel to hold the crankshaft from turning.
- I removed the capscrew which secured the pully to the crankshaft.
- With no way to use the puller tool, it took me about an hour to tap the pully off the crankshaft. I would tap on the lower edge of the pully and then manually rotate the crankshaft a quarter turn and tap some more.
- When the pulley finally came off I removed the plastic sheild from behind the pulley.
- Two screws hold the crankshaft sensor on the end of the engine.
- A small dowel pin was used to position the sensor, as well.
- I was glad to see the dowel pin knowing then the sensor would be self aligning. No adjustment needed.
- Reversing the order of disassembly my new crankshaft sensor was installed.

All this and NO CHANGE. The engine still died while I would coast to a stop sign or into a curve. Unlike some My '94 will always start back up right away.

I suddenly realized that even though my '94 LaSabre will idle in Park forever, smooth as silk, maybe it was not getting enough fuel when it was coasting. I got to thinking that maybe if I turned the idle up a notch or two this would do the trick....SO FAR SO GOOD. IT'S WORKING!

It's always embarrassing to realize that you should have thought of this first, a fuel pump, sensor, and $200 later. However, I am happy to admit the foolish error if my '94 will quit stalling. I'll let you know.....

Turning up the idle turned out to be a symptomatic fix only. My fuel economy really began to stink. I bit the bullet and took my '94 LaSabre to the dealer. Turned out to be a bad Engine Control Module (ECM). I waited a while before posting to ensure I finally got 'er fixed.

I posted my story regarding my 94 Buick Regal GS previously and wanted to tell of my finding. I had a problem with losing the spark as I described and believed it was the ICM. I never replaced the PCM or the crank shaft sensor, but I did replace all the other ignition parts. After I replaced the ICM connector with the part that GM offers, it seemed to temporarily go away, but later my car started dying again or not starting. There never seemed to be any reason or rhyme to it when it happened. Anyway, the replacement connector part from GM had crimp connectors to attach to the ICM wires when the ICM connector is cut off. I did not do a good job of crimping the connectors since I did it again and made sure that they were tight and connected the wires well. Since then my car has not had any problem starting or has not died once. I believe that it is fixed and that the problem was not a crank sensor, cam sensor, or ICM.

If any of the wires from sensors, PCM, power, etc., do not make a good connection with the ICM through the multi-pin connector, it makes sense that there will be a loss of spark. This part is one part that is not normally thought of being replaced, but it has tin-plated pins that use spring pressure to connect to the ICM pins. After many years of heat and oxidation, the connector will not always make good electrical contact. Sometimes replacing the ICM will seem to fix the problem, but removing and replacing the connector on it will possibly and temporarily make the connections better.

It is difficult to prove that the connector is at fault, but through the connector, the power is supplied to the sensors, the sensors signal outputs are supplied to the ICM, the PCM ICM override output and ICM reference input is supplied, as well as the power to the ICM. Any of these signals not being connected well will cause an intermittent failure and can make the sensors appear to be at fault.

I wanted to let this known because I was blaming the ICM on getting hot and failing, when it turned out to not be that at all. The connector part is not that expensive and can be purchased at gmpartsdirect.com if you know the part number for your make of car.

It seems to me that this problem is very common in Buicks with and ICM.

just fixed my 96 lesabre. same prob. there is an 8 way connector in front pass side rail underneath carpet. If car ever in a flood or spill water in pass front carpet, connector corrodes. controls fuel pump,pw, and power seat. clean, apply grease, wrap with tape.
I spent 1500 on fuel pumps,relays,etc, all for naught.
Goodyear and Firestone don't know squat!

I am having the same problem with my '96. When the fule pump quits (no pressure at Schrader valve, power windows and seats do not work). After a few hours pump, seats and windows work normally. Should I just pull the passenger seat, back seat, carpet and traverse the rail looking for the connector?

Thanks

got the same thing with my 95 still working on it reading all the posts. This is a good post hope I can find the help I need

I wanted to add my experiences with this problem. I had the same problem as timrice. 1995 shutting off while driving every day to and from work. Usually on I95 going 65mph. Drifted to the side of the highway and restarted the car. Sometimes the car would idle rough sometimes it would run fine. Sometimes there would be a check engine light sometime not.
Reading these posts I concluded to try the crank sensor first. I also asked about this on one of the on line expert sites. The response was this problem on these cars was common and usually the crank sensor.
I replaced the crank sensor over the weekend, took that long to get the pulley off, and the car has been running fine.

Bump

Bump

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I was posting to this because it help me.I saw another person with the same guestion about dies without warning. Bumped so it would show on the first page.Thank you.

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