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Question one is if the fuel pressure was at the very bottom of the normal range could it cause a rough idle? The car had problems with it dying. The shop where I took the car to the mechanic determined the ignition module was bad and replaced it. It still has a rough idle though which it had when I took the car in. They can't find any problem except for the low fuel pressure.
Question two is the ignition module. This will be the third one the car has had in about 4000 miles. My understanding of the module is heat is harmful to it and they located it right on top of the motor. It's just a box with wires. What would happen if I relocated the module to the fender or someplace cooler and just extended the wires? The only other thing I've thought of is to stuff some asbestos paper between the engine and module. There is maybe an inch space there.
Background on the car is I've replaced all of the sensors connected with the ignition plus the coil pack. I've also replaced the timing chain and had a valve job done on the heads. Compression is good on all cylinders. Before I replaced the timing chain and had the valve job done the car had sat for a couple years. It has since had a half dozen or so tanks of gas run through it. After it had sat I took all the fuel injectors off and tested them and all were good. I cleaned them and put them back in the car.
What are you referring to as the ignition module? Don't relocate the coil packs or anything else. If there are components dying because of excessive heat you have an underlying problem.
Why did you replace the timing chain? The timing chain on the 3.8l v6 should be good for the life of the engine.
It seems like that mechanic is just shooting from the hip. I would be hesitant to trust them.
Have you pulled codes from the ALDL yet?
You can either take your car to an auto parts store to have the codes read, or you can do it at home. Use a paperlcip to short the A and B terminals of your Assembly Line Data Link to flash the codes. Do this with the key in the run position.
The Check Engine light will flash 1,2 1,2 1,2 and then it will flash any codes that are stored. It ends with 1,2 1,2 1,2 and then repeats.
What are you referring to as the ignition module? Don't relocate the coil packs or anything else. If there are components dying because of excessive heat you have an underlying problem.
Why did you replace the timing chain? The timing chain on the 3.8l v6 should be good for the life of the engine.
It seems like that mechanic is just shooting from the hip. I would be hesitant to trust them.
Have you pulled codes from the ALDL yet?
You can either take your car to an auto parts store to have the codes read, or you can do it at home. Use a paperlcip to short the A and B terminals of your Assembly Line Data Link to flash the codes. Do this with the key in the run position.
The Check Engine light will flash 1,2 1,2 1,2 and then it will flash any codes that are stored. It ends with 1,2 1,2 1,2 and then repeats.
The timing chain was the type that had plastic tips on the gear. Over the years the tips came off and it almost completely stripped the teeth off the gear. The gear was made out of aluminum or something similar. Then when it jumped time the pistons hit the valves bending them a little so I had the heads done. The car had about 103,000 miles on it at the time.
You are probably right about the mechanic or mechanics. I don't trust any of the mechanics in my town. This Chevrolet dealership with the last chance so I'm back to working on the car myself. I plan to pick up the car this afternoon. As far as codes, I have an OBD1 scanner and I wasn't getting any codes prior to the recent ignition module change. The car was running really good but had a rough idle.
If it’s burning up if Ignition modules is be curious what the resistance is across the primary coil winding. What exactly is the module failure? Does it die, and then restart once things col down? Are you replacing the module with quality parts?
Low fuel pressure can definitely cause drivability issues.
How many millions of those engines have been built with the module on the engine? If engine heat/vibration was a issue, GM would have relocated it years ago. Something else is causing your problem. How have you determined the module is bad?
Last edited by matt69olds; October 1st, 2020 at 09:59 AM.
You say you have low fuel pressure?.
Have you done anything about it?. Perhaps replacing the pressure regulator & pump might address your poor idle problem. My 1987 Olds 88 had an ignition module failure and I needed to clean the air flow sensor, other wise the only ignition related work has been replacing the plugs and plug wires.
When the air flow sensor was playing up I found disconnecting it led to a smooth but too fast idle, and the check engine light came on. A shade tree mechanics diagnosis I'll readily admit, but it did allow me to pinpoint the problem. I can't just pick up stuff from the local parts shop, it's the wrong side of the Atlantic.
I got the car back today and they put an AC Delco ignition module on it. While it was in the shop the starter Bendix went out and they couldn't start the car to see if it was fixed. They old ignition module was made by NAPA.
Another question: The man that waited on me at the shop said when I get the car started to bring it back because the couldn't set and adjust the ignition module. Is that really true because the NAPA ignition module, I just put it on there and connected the wires and I was done. I don't see any way to make adjustments on it. Maybe I ruined the module by not finishing the job, I don't know.
Matt69olds: When I went to put the car in the shop I had to drive about seven miles into town and it died twice while driving at freeway speed. It quickly re-started so It wasn't too much of a problem Then when I got into town I had to drive about 2 miles through town and and it died ten or twelve times and was more difficult to re-start. I thought I was going to have to get a wrecker to get it the rest of the way to the shop. I will look into how to check the resistance across the primary coil winding. I have an Ohm meter but don't know how to check that.
Rustyroger: I don't know what the fuel pressure is or what it's suppose to be. They just told me at the shop the fuel pressure was at the bottom of it's acceptable range. I'm pretty certain it is the original fuel pump the car was built with. That close to maybe failing I will probably soon replace it anyway. The car used to be really dependable for the first 18-20 years. I hope to make it dependable again. The air flow sensor has been recently replaced working on the car. When the timing chain was going bad I was convinced it had an electronic problem and ended up replacing all the sensors before the timing chain went bad enough I could tell it was that. When I did change the timing chain I replaced the spark plugs and wires. This is what has been so mysterious. Almost everything is new.
It’s been a long time since my Buick dealership days, but I do recall replacing lots of crank sensors for random engine stalling. I don’t remember if your year car is one of the problem years. Since the crank sensor needs to be removed to do a timing chain, ho is to say they adjusted it right?
Speaking of adjustment, what possible adjustment could need to be done to a ignition module? It’s all electronic, there is no adjustment.
Ask what the fuel pressure actually is, and find out what the minimum spec is
It was early last year when I replaced the crank sensor but I don't believe there was any adjustment to it. Just bolts on. The ignition module I don't believe there is any adjustment, it's just what the guy said. I won't be going back to this shop for anymore repairs so I won't ever know what their thoughts were. They had the car for a few days less than two months. I searched online and was bombarded with advertisements for fuel pressure regulators. I'm wondering if I should replace it first and see what happens.
There is absolutely an adjustment, the crank sensor opening needs to be centered over the windowed ring on the back side of the balancer. If the balancer actually touches the crank sensor, it can cause the stalling/rough idle concern. There is a special tool to align the sensor, I wouldn’t be surprised if there is a tool you can rent at the parts store. I’m willing to bet there is also a shade tree method, maybe a couple layers of thin tape over the balancer ring use as shims to space the sensor?
My dad, too, is having electrical issues with his 2000 Buick Park Ave with the 3800. Always had a bit of a rough idle and we changed everything, too, except the orig numbered coils. Now code thrown and misfires under load (P0306?) #6 misfire so we put all new coils and it got worse. ICM has been replaced many miles ago and we are trying to get O'Reillys to test(they have the equip. to test but no one knows how to use it!) Hopefully its the infamous ICM but if not, checking wire and plug (not very old) next. ICM has no adjustments I can think possible. Crank sensor for sure does. Hmmm, maybe cam sensor.
I really think the orig. slightly rough idle may be due to a hidden vac line I have yet to replace (did all the rest). I remember seeing one described as being hidden under the air intake box.....
I dont see you mentioning that the fuel filter has been replaced?
There is a tool for adjusting the crank sensor to the right place.
I haven't mentioned the fuel filter but it's been changed a couple of times since the car sat for a couple years.
I'll look at the crank sensor but I don't believe there is any adjustment to it. I believe it just bolts into place.
Found something else replacing the starter today. The vacuum lines running to the charcoal canister were plugged up and one joint was so loose it fell off so I had a vacuum leak.
More than one person has said there is an adjustment needed on the crank sensor. You can just bolt it on and hope for the best. If your mechanic wants to argue, find another with a more open mind.
Watch this, about the 14:30 point. We aren’t making this **** up.
Yea, that was different than I installed the sensor I put on. Took me over a week and had to buy new tools to get the center bolt off. I had to get a 3/4" breaker bar and socket and jump up and down on the wrench all day to get the bolt loose. Maybe the next time will be easier. I also didn't remove the plastic cover. I believe the sensor I bought came with the sensor mounted on the bracket and I just bolted it on. It may have been adjustable, I don't know. Certainly worth checking.
Update, the problem with the rough idle was due to the throttle position sensor. I told the mechanic that worked on the car I thought it needed to be properly adjusted but apparently he didn't do it. Running smooth now.
Update, the problem with the rough idle was due to the throttle position sensor. I told the mechanic that worked on the car I thought it needed to be properly adjusted but apparently he didn't do it. Running smooth now.
Thanks for letting us know.
I don't think I'm alone in finding it irritating that people ask for help and advice on this and many other forums, but don't let us know they have found the fault and fixed it.
Others with the same problem might find the same fix will work for them.
Btw, how do you adjust the TPS?.
Thanks for letting us know.
I don't think I'm alone in finding it irritating that people ask for help and advice on this and many other forums, but don't let us know they have found the fault and fixed it.
Others with the same problem might find the same fix will work for them.
Btw, how do you adjust the TPS?.
Roger.
Apparently I was premature in calling it fixed. I had drove the car a few times close to my house and it functioned perfect. Then I took it to town last night and came home via wrecker service. It worked perfect ten miles into town and when I came out from the store it wouldn't start. Since I had been tinkering with the throttle position sensor I went back in the store and bought wrenches to adjust the sensor again and I did get the car running but when I started home it quit before I got out of the parking lot. I worked on it again and got it running and it sat parked and ran for ten minutes or so smooth as silk and then died suddenly and wouldn't re-start.
I have the belief now the problem is with the fuel pump. I have all the repair tickets on the car since it was new and there is no record of the fuel pump ever being changed. Then the last mechanic that worked on the car told me the fuel pressure was at the very bottom of the normal range. I think from time to time the fuel pressure is dropping too low. There is ignition so I at least know it's fuel related. I just can't be sure the problem is mechanical or the computer is starving the car. 33 year old fuel pump, pretty good chance it's mechanical.
September 30th, 2020, 08:08 PM
