94 Lesabre starts then stops; crank sensor?

[avatar307]

There is another set of fuses and relays behind the passenger glove box. Things like the driver door, fuel pump, and trunk release relays and fuses are back there. The fuses under the drivers dash should be labeled on the inside of the fuse box cover.

You're car actually has the same pin out as my car, it's not OBD-I or OBD-II standard, it's something else that I have yet to get completely figured out. I believe it's probably OBD-II and the wires are just in the wrong place.

FYI, on GMs with the 16-pin connector.....

OBD-II - pins 2,4,5,8,16
OBD-I - pins 4,5,6,8,16. Short 5&6 to get error codes

Our connectors do not match either of those, yours is the second 1994 LeSabre with a connector like mine. It seems the LeSabre and the Regal are the cars GM started experimenting with and sticking things in the wrong order for no known reason.

I can tell you that you will not be able to get OBD-I style error code readouts via the Service Engine Soon light blinking. I've tried shorting every combination of pins in a futile effort to find the right ones. Doesn't work.

I was actually pretty sure the car was OBD-II at that time too, but I it was an exercise in futility one night I found necessary. My best answer is that pins 9 and 14 are in the wrong place. At least one of those should be in pin 2, as that is the pin GM is standardized to use for OBD-II communications.

Now if GM actually started out using a different OBD-II communications protocol, pins 9 and 14 may also need moved to 2 and 10 or 7 and 15. They might even belong in 6 and 14, but it's highly unlikely. Mine you, I have no idea what order they connect in, those are just the pairs.

On day I'll get a wiring diagram, a 3 protocol code reader, and a week of free time, then I'll have it all figured out for good. One day, one day.

Anyway, to change the crank sensor. Well... you'll most likely have to pull the harmonic balancer off to get to the sensor. Which means you'll need a puller. You may also have to take the front axis engine mount and bracket off. Don't know, depends on the year and engine. Grab a Haynes or Chilton manual for $10 when you buy the sensor, that will be more help than someone here explaining it. LOL

Also, the lights and gages will flash and act stupid when the engine dies. As the electrical begins to drop below 8 volts everything will flash and bounce because it can't get enough power. I experienced the same thing when I had a bad battery, the tech was running an alternator test, and my engine died in the process.

[cliffw]

Thanks again. The sticker beside the rad says OBD1 compliant. Saturday I went over all connectors, removed the coil pak, checked for frayed or loose connectors, etc. Car started up, ran good at low rpm, but bad miss at mid range. The gauges went crazy, but alternator showed around 14 volts when measured with a meter, so seems to be charging ok. Car did not stall. Whlle I was sitting in it, contemplating various methods of destruction, hair pulling, the gauges all started working, the service engine light went off and it ran normally. I took advantage of the situation to drive it about 10 miles to a shop where I could work. Ran perfectly. When I shut it off and restarted same problems returned. I have a Haynes book, but from my experience with Chrysler products found it doesn't always tell the whole story. Nothing beats hearing from someone who's done it first hand. I'll go at it again.

[avatar307]

Yeah, so doesn't my sticker. But it doesn't give out OBD-I style error codes or blink the SES light. All OBD-I compliant means is "We can't say it's 100% OBD-II compliant for one reason or another."

Sierra has a 95 Regal (I believe) with a 12-pin ALDL OBD-I connector that only gives OBD-II error codes via a scan tool... that alone it just hilarious. I bet you his ELVI tag states OBD-I on it.

Read the section of the Haynes book related to Driveablity and Emissions Control Systems. That's where the crankshaft, camshaft, EGR, EVAP, MAP, MAF, O2, HO2S, and all the other sensors are discussed. Most likely your problem lies with one of those sensors. Just about every one of them functions differently depending on the temperature of the car, and just about all of them were still having the kinks worked out in 1994.

As far as Chrysler products and Haynes manuals. It's not that the Haynes manual doesn't tell the whole story because it is a Chrysler product. It doesn't tell the whole story because it is a Haynes manual. Haynes and Chilton manuals take the 2000 page factory service manual for 20 years of multiple vehicle models (I.e. 2000 *20= 40,000 pages) and condense it into 200 pages. That would be where all the really important information gets lost.

[cliffw]

Thanks. I'll continue plugging away at it. You're right on about the manuals. I'll post results.

[cliffw]

I was able to get an ECM from identical car at wrecker. Plugged it in and car functioned perfectly. Put old one back in & it continued to run perfectly. It's been fine for a couple of days, several on off cycles and several km. I assume there was a bad connection at ECM. Service engine light still comes on, but hopefully I can get it scanned. I'll take it to the dealer. What a place to put the fuses, under the glove box!! Thanks for the help.