Intermitting No Spark problem...

1994 LaSabre, 84,000 Miles, 3.8L VIN: 1G4HR52L6RH506620
I will be driving down the road and all of a sudden the engine will just stop, I get the “service engine” light that comes up on the dash along with the oil and battery light that comes on too just as if you had turn the key on to run. Each time this happens, I check for spark at each plug and find no spark. Wait a minute or less and will start and run OK with no “Service Engine” light.

I have checked the computer for codes but unable to retrieve any due to some malfunction in OBD1 Diagnostic Link Connector (DLC) 16 pins. (Late 1994, early 1995). Also Scanners do not work.
When I jumper Pins 4 & 5, am unable to pull any codes not even 12.


Replaced following with tested parts:
Ignition Module.
Plugs and wires.

Got a 95 Regal 3.8l doing the same thing. There are several post on other models for similar symtoms. So far the crank shaft sensor seems to be the most likely cause.

Carl......... :banghead:

Another situation where not all of the symptoms are being considered. I would look into the problem of not being able to pull codes from the system. Is there no 12 volts to the ECM? Is there a missing ground? If the 12 volts or ground are missing, nothing will operate the engine unless this is fixed. It is possible for the processor in the ECM to have problems, causing this issue. The crank, cam or other sensors will not prevent the extraction of codes. Code 12 is the system's way of saying that everything is fine. Ray

1994 LaSabre, 84,000 Miles, 3.8L VIN: 1G4HR52L6RH506620
I will be driving down the road and all of a sudden the engine will just stop, I get the “service engine” light that comes up on the dash along with the oil and battery light that comes on too just as if you had turn the key on to run. Each time this happens, I check for spark at each plug and find no spark. Wait a minute or less and will start and run OK with no “Service Engine” light.

I have checked the computer for codes but unable to retrieve any due to some malfunction in OBD1 Diagnostic Link Connector (DLC) 16 pins. (Late 1994, early 1995). Also Scanners do not work.
When I jumper Pins 4 & 5, am unable to pull any codes not even 12.


Replaced following with tested parts:
Ignition Module.
Plugs and wires.
I had the excact same problem with my 94 Lesabre. Turned out to be the ECM.

Another situation where not all of the symptoms are being considered. I would look into the problem of not being able to pull codes from the system. Is there no 12 volts to the ECM? Is there a missing ground? If the 12 volts or ground are missing, nothing will operate the engine unless this is fixed. It is possible for the processor in the ECM to have problems, causing this issue. The crank, cam or other sensors will not prevent the extraction of codes. Code 12 is the system's way of saying that everything is fine. Ray

Thanks Ray for your reply.
As for not being able to pull codes by jumpering the DLC, it's because it's a late 1994 and only allows the codes to be pulled via a OBD1 scanner. I was using the wrong scanner.
Now the good news. I was able to get this car to quit in my driveway. Poured cold water on the crankshaft sensor and it started! Will change out the crank sensor tomorrow.
Thanks to all.

I had the excact same problem with my 94 Lesabre. Turned out to be the ECM.

Thanks for your reply.
For $26 bucks I'll change the crank sensor since my cold water trick worked twice.
If need be I'll chage the ECM for $112 bucks. Time will tell.

Pins 4 and 5 are ground wires. Your 1994 is a OBD2 hybrid. It was alittle of ODB1 and OBD2. Your 16 pin connector gives that away, you cannot get flash codes all you might do is blow a fuse trying.

The reason you get no codes stored is becuase when the crank sensor sees no crank movement it thinks the engine is off.

Pins 4 and 5 are ground wires. Your 1994 is a OBD2 hybrid. It was alittle of ODB1 and OBD2. Your 16 pin connector gives that away, you cannot get flash codes all you might do is blow a fuse trying.

The reason you get no codes stored is becuase when the crank sensor sees no crank movement it thinks the engine is off.

Now comes removing the Harmonic Balancer, how does one remove the 28mm bolt that holds the pulley on. Seems like there's a way to keep the engine from turning while unscrewing the bolt? Your help please.

1994 LaSabre, 84,000 Miles, 3.8L VIN: 1G4HR52L6RH506620
I will be driving down the road and all of a sudden the engine will just stop, I get the “service engine” light that comes up on the dash along with the oil and battery light that comes on too just as if you had turn the key on to run. Each time this happens, I check for spark at each plug and find no spark. Wait a minute or less and will start and run OK with no “Service Engine” light.

I have checked the computer for codes but unable to retrieve any due to some malfunction in OBD1 Diagnostic Link Connector (DLC) 16 pins. (Late 1994, early 1995). Also Scanners do not work.
When I jumper Pins 4 & 5, am unable to pull any codes not even 12.


Replaced following with tested parts:
Ignition Module.
Plugs and wires.
Crankshaft Sensor

All is well. It appears that the Crankshaft Sensor was the problem.
Thanks to all that responded.

Got a 95 Regal 3.8l doing the same thing. There are several post on other models for similar symtoms. So far the crank shaft sensor seems to be the most likely cause.

Carl......... :banghead:

I got a 95 Regal 3.8L with 145000km doing pretty much the same thing.
I was able to read the error codes from the computer:
-361 EST Line not toggling
-321: 18X interrupts lost
-341: intermittent CAM signal
(I've connected ny computer laptop to the ALDL interface through a special cable
and software)

I've cleared the codes 4 times after each new car stall and they came always the same ones.

I've replaced the spark plugs/wires and CAM sensor to not avail - it happens again.
Some times after having big problems starting the car the car finaly start with CHECK ENGINE light on and with very rough drive (no more than 60- 70 km/hour).
I'll try to do the test with poring cold water over the crankshaft sensor when it doesn't start after stalling; not sure that I located the crank sensor correctly though :uhoh:

Can anyone give another cause of this problem? Any suggestions are very welcome and much appreciated...

F.C.

F.C. where did you get the cable and software?

Carl

F.C. where did you get the cable and software?

Carl

I've ordered it from this guy:
http://www.akmcables.com/

he has several options - from ready made for $90 to $35 kit to make it
yourself (without ALDL connector). Please read carefully his page and order what you feel is right for you. I've ordered the chipest one $35 and assembled it myself; if you have some experience in electronics or want to get one :p you can go this way...
It might be better to buy a ready made one with ALDL connector. Andrew is very friendly guy, he responded to my e-mail, though I'd suggest to read carefully his site first.

As for software I've used "Car bytes" (there is a link to it on Andrew Mattey 's page). Apparently with the cable I built only this software worked (which is fine with me). One thing though - that cable (which includes a printed circuit bord) needs external power (from 12 V lighter, or from an external source, anything from 6 to 15 v will do it). INitially that was not clear to me - optionally the circuit bord takes the power from your computer's serial interface specific circuits, but some software does not keep these circuits always up so it's better to have an external power. I've used a sigarette lighter connector to my car.

For this software you'll have to define "ALDL streams", because basically what you get in responce from your computer will be just a stream of bytes which you'll have to decode into meaningfull error codes... You might want to by the software from Andrew Mattey, which already has all these definitions...

Finaly... My car stalled completely and I've towed it to the dealership.
The error codes were still the same so I insisted them to replace the crankshaft sensor. It worked and the car started from the first.
If it runs for another 2-3 weeks, I guess that was the root cause of the problem...

Good luck,
F.C.

F.C.
Thanks for the update and info. If you think about it in 2 or 3 weeks post again and tell us how it's going. I have been waiting for mine to completely die for 3 or 4 years now. I'm just about ready to take it to the shop and tell them to replace my sensor also. At least if that doesn't fix it, I'll know what it's not :)

I've ordered it from this guy:
http://www.akmcables.com/

he has several options - from ready made for $90 to $35 kit to make it
yourself (without ALDL connector). Please read carefully his page and order what you feel is right for you. I've ordered the chipest one $35 and assembled it myself; if you have some experience in electronics or want to get one :p you can go this way...
It might be better to buy a ready made one with ALDL connector. Andrew is very friendly guy, he responded to my e-mail, though I'd suggest to read carefully his site first.

As for software I've used "Car bytes" (there is a link to it on Andrew Mattey 's page). Apparently with the cable I built only this software worked (which is fine with me). One thing though - that cable (which includes a printed circuit bord) needs external power (from 12 V lighter, or from an external source, anything from 6 to 15 v will do it). INitially that was not clear to me - optionally the circuit bord takes the power from your computer's serial interface specific circuits, but some software does not keep these circuits always up so it's better to have an external power. I've used a sigarette lighter connector to my car.

For this software you'll have to define "ALDL streams", because basically what you get in responce from your computer will be just a stream of bytes which you'll have to decode into meaningfull error codes... You might want to by the software from Andrew Mattey, which already has all these definitions...

Finaly... My car stalled completely and I've towed it to the dealership.
The error codes were still the same so I insisted them to replace the crankshaft sensor. It worked and the car started from the first.
If it runs for another 2-3 weeks, I guess that was the root cause of the problem...

Good luck,
F.C.

The car never stalled after crankshaft sensor replacement. It runs smoothly, almost 1 month after the replacement.
There are no ant error codes on the dashboard.

I'd conclude that this WAS the root cause of the problem...
F.C.

That's good news F. C. Thanks for the update..... I think I'm going to have mine replaced next time I have it in the shop........

Carl.......

Crank shaft sensor replaced - problem fixed... :rofl:

Thanks for all the help, Carl...........

Hello I am wondering where do i locate the crankshaf sensor and how do I change it. I have a friend with an 87 Lesabre and it seems to have all of the above problems...crank no start..no bad codes...new battery new plugs..so I want to start with CSS and hubby has no time to do it.
Brandi

Look for a couple wires going in behind the harmonic balancer. (The harmonic balancer is the big weight on the end of your crankshaft. It will be the biggest pully at the lowest part of the front of your engine. Should see a couple wires right up next to the engine inside wire loom. The --should-- lead to the crankshaft sensor.)

Thanks for the help we are changing it this afternoon and will hopefully get his car going for him.

Lady Dineega
"Get a taste of religion, Lick a witch"