I have a 92 Bonneville SE. Very well kept, about 180k miles, L series VIN.

I'm having trouble getting it started. It cranks very well every time the I turn the key.

When the car does start,one of two things can happen :
1. It runs perfectly until I turn it off. Then it'* a matter of luck if it will start the next time I need it to. It seems completely random.

2. It starts, but will stall shortly thereafter with no rhyme or reason (ie: Could be doing 60mph could be idling, makes no difference.)

If the car doesn't start on the first try, I've learned to give it at least 30 minutes at least before trying again. Repeatedly trying to start it never works. When I do get anxious and give it about 3 tries, I do smell a little fuel.

It seems these symptoms started after running out of gas once and progressively got worse.

Any advice for this problem?

I do have a multimeter, but if when giving instructions about where to place the leads, please be as detailed as possible. I'm a bit dense with the whole electrical system in the car.

I've taken it to the local autoparts store to get them to diagnose it with the handheld, the only codes I got were RPM codes, which led me to change the camshaft sensor. I did have trouble starting it after change the cam sensor, but after I got it started, it ran well.....for one day.

In reading these boards for the past two hours, I've read many other people having similar problems. I'm a little weary of changing good parts because I've read people changing the ICM, crank sensor, coils, etc. and not getting any help from them. Maybe I missed the thread that had the definitive answer. The symptoms I have are almost identical to many others here. Getting the car to start has also became more and more troublesome as the weather has gotten warmer.

I will check to see if the magnet is still in the cam, but from reading through the pages here, it seems like that'* only a problem on the 93s and up. It'* worth a look though. I'll report back tomorrow. I've taken the a vacation week because I need this car running by the fifth when my wife starts her new job.

How do I go about turning the cam manually? I've read the crank bolt, but I'm not sure I know where that is. I'm assuming it'* the bolt on top of the crank sensor? I've only got a little socket set, can I turn it with that?

Things I'm thinking it might be from reading here include:
Crank Position Sensor
Ignition Coils
Ignition Control Module

But I've read about people changing all of them with no luck.... Kinda makes me hesitant.

My battery is less than one year old and I cleaned the connections when I put it in, and I do hear the fuel pump priming when I turn the key to the on position. Also, I changed the water pump about 2 years ago. From reading here, this seems to be a common theme with this problem.


Things i have already done it try and fix thisi:
Changed spark plugs
Changed Oil
Chane camshaft postition sensor
Changed Engine Control Computer


Any advice will be greatly appreciated. I love my Bonny, I just wish it would run like it use to.

Few more notes:

When it starts and runs good, the idle is perfect. Tacked around 700.

When it starts and runs poorly (ie: stalls soon), the idle is bad, but not harsh. Just not exactly tacked. Goes from ~500-750.

Thought this might help.

If I can think of any other symptoms, I will add them.

Thanks again.

Have your fuel pressure checked.
You could have a bad pump or a leaky injector/*

or could be your fuel pressure regulator. to check that pull the vacuum line off of it to see if there is fuel coimg out of that erea, if there is then replace it.

Todd

I'm going to pick up a fuel pressure gauge tomorrow to check that.

If it were the pump, would it still be able to run perfectly at times?

Because once in a while when I get it to start, it runs like nothing was ever wrong with it.

This has been the hardest thing for me and my buddies to get a handle on when diagnosing it. We'll be out there thinking up new ideas, and BOOM, it starts and we can run it up and down the highway and through suburban neighborhood like it was a brand new car.

I've never had a fuel pump issue in any car before, so I'm not an expert on that part of the process, but from what I hear, it would effect the cars performance at all times.

Thanks for the reply though, I am going to check the pressure tomorrow. I finally broke down and bought the Haynes yesterday so I don't have to look for everything by sight.

On intermittent problems like yours, it is very likely wiring related; I'm talking about loose (female) pins in connectors and/or corrosion at connectors and even grounding points. I'm sure parts fail, but my 93 has had more than its fair share of connector problems.

I'm (slowly) putting together a procedure to troubleshoot and fix such; since a recent batch of failures, I have found them to be caused by at least one loose pin on the PCM, 2 on the cam sensor plug & 3 on the ICM plug.

Advise: Next time it fails to start, double check that you have fuel pressure by doing a bleed at the fuel rail schrader valve. Don't expect a mighty fountain, though. Also, check to see if you are getting spark. At least you can zero in on the right general area to dig further.

TIP: If you decide to check for loose connector female pins try this. Use a standard size paper clip with one end bent straight. On the suspect connector, compare "fit" into each pin. I find that most of them will fit well, but then one or two will be looser. Also, the paper clip is the right size for the PCM, ICM, Cam & Crank Sensors. It may not work in some of the others.

And the "bolt" you are looking for to turn over the motor and check the cam sensor is the big honker on the crankshaft (bottom) pulley. If your belt is fairly tight, you may be able to cheat and turn the alternator pulley and get the motor to turn. May have to manually add pressure to the belt to get it to bite better.

thanks for the reply. This morning I went and picked up a big ol can of dielectric grease and some other toys from advanced, I'm going to check the common points of corrosion (ICM plug, bus under the driver side plastic floor panel by the door, and few others).

I'll give the paper clip a shot. Can't hurt at this point. I'm really weary of taking it to a mechanic. Last really the last option for me since I don't know one I trust (does anyone? )

I'm pretty sure it'* something like you've explained. Anything else it wouldn't make sense that sometimes when it starts it runs like a champ.

Thanks for the reply. After the wife gets back from the doctor I'm going to go check everything out.

I am going to have to hunt down a paper clip. For the life of me I can't think of where we might have one in the house.

How do you fix the female pins if you find them to be loose? Do you have to replace the whole unit?

Pins on the PCM harness connectors can be "unlocked" from the front and pulled out the back. The lock tab is in the extra hole directly to the outside of each pin hole. With it at the top, you insert something like a jeweler'* screwdriver and press the tab to the left. NOTE: the piece of metal you see near the edge of the hole is not the tab, The tab is about half way in. You need to wiggle the wire in and out while unlocking the tab, until is releases and the pin and wire come out. Once out, you will see an "hour glass" shape to the female pin, a "waist," if you will. Slightly compressing the waist gives it the grip it will need. Correct any damage you may have done to the tab before re-inserting so it will not slide out when you push the connector back on.

However,
I think the ones on the ICM harness push out the front, but also have to be "unlocked." I'm investigating all that. Once you get them out, you can re-tighten the gripping area. You can try to tighten it while still in the plug but it is not always the most long lasting fix.

Worst case, this will tell you that there is a loose pin and might save you from bankruptcy due to parts swapping.

Thanks RedSled. I'll report back after I check out everything I can. Any other common grounding spots I should look for corrosion? Keep in mind I won't have access to jackstands until the weekend, so I'm working on the pavement here.


I'm loving the forum here. I was up most of last night reading it. This is my second Bonneville, and it use to run sooooo damn good for the mileage it had. It was a one owner who, like me, loves Bonnevilles so he was going to trade it in for a 06 and when the dealership only offered him $600 for it, he posted a sign on the bulletin board at work.

He had it factory serviced it'* whole life, but I'm not a factory service kinda guy, I'm not even a repair shop kinda guy. If there'* something I can't fix, I'll usually scrap it and buy a new one.

I never buy a car I can't afford to fix or scrap.

Also a Jeep 4x4 fanboy, but that'* a problem for another forum......*sigh*

I think the 93'* still used the ICM mounting bracket as a ground. Remove the ICM & ICM mounting plate from the bracket. Clean all the corrosion off the top of the mounting bracket, both sides of mounting plate & bottom of ICM. Coat all 4 surfaces with a light coat of dielectric grease & reassemble.