1991 Bonneville Rough idle & run when cold
shilohin
03-27-2008, 06:05 PM
My Bonne recently started idling & running rough when the engine is first started. More like cutting out than an individual miss, like it's flooding, but no stalling at all, like it runs smooth for a second and then stumbles. The exhaust also smells funny when it's doing this, not like gasoline smell, but more like a chemical smell. When the engine warms up, it runs fine. No Service Engine Soon light and no codes besides code 12 (not running) when you check the ECM. I replaced the oxygen sensor, didn't make any difference. Has had the timing chain/gears replaced last year, new alternator last year, new spark plugs and new fuel filter 2 months ago. Checked for a vacuum leak but couldn't find one. I had an 87 Bonneville that had the MAF sensor go bad and it ran rough like this only it would die too (this one does not stall) and someone told me to peck on the MAF sensor and if it was weak or going bad it would cause the engine to stall. Tried it on this Bonne and it didn't stall or make any difference so I don't think it's the MAF sensor. The MPG is normal and hasn't dropped any. I've done all my own work on my Bonnevilles and normally anything like this would throw a diag code. Suggestions on what to check next, anyone? Thanks!
jdq
03-27-2008, 11:52 PM
How bout catalytic converter, does exhaust smell like rotten eggs.
shilohin
03-28-2008, 08:21 AM
Hi,
No, the exhaust doesn't smell of rotten eggs. I had a new catalytic converter put on about 18 months ago. The "funny" smell is more like paint or lacquer thinner. I was wondering if the EGR valve was stuck open would it make it run like this, rough when cold and normal when warmed up? When the EGR went bad on my 87 Bonneville, it threw a code and made the SES light come on but the 91 Bonne shows no codes and no SES light. Thanks!
No, the exhaust doesn't smell of rotten eggs. I had a new catalytic converter put on about 18 months ago. The "funny" smell is more like paint or lacquer thinner. I was wondering if the EGR valve was stuck open would it make it run like this, rough when cold and normal when warmed up? When the EGR went bad on my 87 Bonneville, it threw a code and made the SES light come on but the 91 Bonne shows no codes and no SES light. Thanks!
jdq
03-28-2008, 12:07 PM
Check vacuum leaks and clean IAC valve under throttle body.
shilohin
03-28-2008, 06:16 PM
I checked THOROUGHLY for vacuum leaks, replaced one elbow and one line that were spongy but I don't think they were leaking. Still idles rough and surging. Cleaned the IAC and seat area. It was dirty. No change. I removed and blocked with gasket material the EGR valve so that it was still connected to the system but no exhaust gas was allowed into the intake. No change, still idled rough and surging.
The engine starts up immediately. Seems like it runs rough quite a bit when the engine is cold, and as it warms up, it cuts out and surges less and less as the engine gets warmer until it runs fine when the engine is at normal operating temperature. I will be checking back for more suggestions. Your help is greatly appreciated! Thank you!
The engine starts up immediately. Seems like it runs rough quite a bit when the engine is cold, and as it warms up, it cuts out and surges less and less as the engine gets warmer until it runs fine when the engine is at normal operating temperature. I will be checking back for more suggestions. Your help is greatly appreciated! Thank you!
HotZ28
03-28-2008, 09:48 PM
You need to check the coolant temperature with a scanner. The ECT sensor is a thermosistor, and as the coolant temp gets higher the resistance drops. The ECM supplies the sensor 5v and measures the voltage drop through the thermosistor to determine temperature. Some resistance vs. temperature values shown below:
*F--------Ohms
210----------177
158----------467
104----------1459
68------------3520
32------------9420
-4-------------28680
-40-----------100,700
The sensor is used for open/closed loop operation and is used in the calculation for fuel and ignition. It acts like a choke on a cold engine. The colder the engine, the more fuel required to operate smoothly. If the ECT is not providing the correct information to the ECM, the ECM will try to compensate, hence the surging back & forth until it warms up.
*F--------Ohms
210----------177
158----------467
104----------1459
68------------3520
32------------9420
-4-------------28680
-40-----------100,700
The sensor is used for open/closed loop operation and is used in the calculation for fuel and ignition. It acts like a choke on a cold engine. The colder the engine, the more fuel required to operate smoothly. If the ECT is not providing the correct information to the ECM, the ECM will try to compensate, hence the surging back & forth until it warms up.
shilohin
03-29-2008, 04:04 PM
Hi again,
Since the ECT sensor is rather difficult to get to under the throttle mechanism and since it's a relatively inexpensive part, I decided to just replace it, which I did. No change, still stumbles and surges when cold which gradually smooths out as engine warms up and when at normal operating temperature, the engine runs smooth like normal at any rpm range. This engine has 135,000 miles on it, but when I replaced the timing chain, gears & oil pump last year, the parts did not look worn much at all. The engine uses about 1/3 quart of oil between 3000 mile oil changes (regular using Castrol GTX) and gets decent mpg. Even when the engine is running rough when cold, it doesn't seem to have loss of power. I use injector cleaner fairly regular, probably every 3rd or 4th tankful of gas. Any other suggestions? Thanks for your help, everyone.
Since the ECT sensor is rather difficult to get to under the throttle mechanism and since it's a relatively inexpensive part, I decided to just replace it, which I did. No change, still stumbles and surges when cold which gradually smooths out as engine warms up and when at normal operating temperature, the engine runs smooth like normal at any rpm range. This engine has 135,000 miles on it, but when I replaced the timing chain, gears & oil pump last year, the parts did not look worn much at all. The engine uses about 1/3 quart of oil between 3000 mile oil changes (regular using Castrol GTX) and gets decent mpg. Even when the engine is running rough when cold, it doesn't seem to have loss of power. I use injector cleaner fairly regular, probably every 3rd or 4th tankful of gas. Any other suggestions? Thanks for your help, everyone.
shilohin
04-01-2008, 07:13 PM
Well, I replaced the computer (Electronic Control Module) behind the glove box and it did not make any difference, the car still runs rough when first started, gradually smoothing out until the engine is at normal operating temperature, at which time it runs smooth.
I'm wondering if the coil would act this way? I have never had a coil go bad on a Bonneville but others probably have. Would it misfire when first started and then operate normally as the engine warmed up? Thanks for any help!
I'm wondering if the coil would act this way? I have never had a coil go bad on a Bonneville but others probably have. Would it misfire when first started and then operate normally as the engine warmed up? Thanks for any help!
auto trainy
04-01-2008, 07:33 PM
Just one quick question, are you losing any amount of anti freeze?
Jrs3800
04-01-2008, 09:06 PM
Thats a very good question.. With a car of this age it may be due for intake gaskets.. But I don't think he's using any coolant but will await an answer on that one..
Does your 91 Bonneville have the original Magnavox DIS system? I have at times seen these go bad... And if its damp of very cold they can have a hard time starting and or idling until they warm up or dry out, but that does not mean its the problem you are having..
You need to look at what the car is doing via a scan tool... Not always easy to get to a scan tool tho unless you know someone that has one..
Are there any codes at all stored in the ECM?
Does your 91 Bonneville have the original Magnavox DIS system? I have at times seen these go bad... And if its damp of very cold they can have a hard time starting and or idling until they warm up or dry out, but that does not mean its the problem you are having..
You need to look at what the car is doing via a scan tool... Not always easy to get to a scan tool tho unless you know someone that has one..
Are there any codes at all stored in the ECM?
shilohin
04-02-2008, 08:23 AM
Hi,
Not losing any antifreeze and no excessive exhaust steam or water in the oil. My Bonneville does not have the Magnavox DIS system. I do not have access to a scan tool.
As I have stated before, the car starts right up, but idles rough. When I start to move the car, seems like it runs rough, then will run smooth for a second or two and then rough and then smooth for another second or two, almost like it's surging only when it surges it is running smoothly. When the engine is warmed up to normal, it runs fine. In fact, I think I'm getting better mpg since I put the oxy sensor in.
Since the car has started acting up, it has not thrown any codes at all. Thanks for your comments and suggestions! Appreciate it!
Not losing any antifreeze and no excessive exhaust steam or water in the oil. My Bonneville does not have the Magnavox DIS system. I do not have access to a scan tool.
As I have stated before, the car starts right up, but idles rough. When I start to move the car, seems like it runs rough, then will run smooth for a second or two and then rough and then smooth for another second or two, almost like it's surging only when it surges it is running smoothly. When the engine is warmed up to normal, it runs fine. In fact, I think I'm getting better mpg since I put the oxy sensor in.
Since the car has started acting up, it has not thrown any codes at all. Thanks for your comments and suggestions! Appreciate it!
Mickey#1
04-02-2008, 10:45 AM
Coils are a possibility. You can check the resistance of the primary & secondary side of all three coils. All three readings should be close.
Jrs3800
04-02-2008, 02:08 PM
This is the Delco Type 2 Ignition system..
http://img.photobucket.com/albums/v294/Jr3800/91%20Misc/DIS3800Painpeel002bc.jpg
Lower left hand corner is the Magnavox Ignition System
http://img.photobucket.com/albums/v294/Jr3800/Engine%203800C/HPIM1246.jpg
Just being sure..
If I was near you I'd say bring it over and we'd scan it to see what it was doing.. Wish I had more thoughts to offer
http://img.photobucket.com/albums/v294/Jr3800/91%20Misc/DIS3800Painpeel002bc.jpg
Lower left hand corner is the Magnavox Ignition System
http://img.photobucket.com/albums/v294/Jr3800/Engine%203800C/HPIM1246.jpg
Just being sure..
If I was near you I'd say bring it over and we'd scan it to see what it was doing.. Wish I had more thoughts to offer
shilohin
04-02-2008, 02:56 PM
Hi,
Hmmm. My coil pack does have the "three square" coil like the middle photo with the spark plug wire terminals on both sides. However, it does not have any type of display on the left side of the temperature gauge on the instrument panel. It does not have the "Delco type 2" coil pack. I actually have one of those (Delco type 2 coil) here that a friend gave me several years ago.
Also just to clarify, when I say that the engine runs rough when I start it cold, I mean when the engine and components are the ambient air temperature which may be 50 or 60 degrees. If I drive the car and it sits for 30 minutes and cools down (but not COLD), when I restart it it will run a little rough until it warms back up to normal operating temperature.
Also, I have a digital VOM and know how to use it but I have never tested a coil like this before so I don't know which are primary / secondary terminals.
In any case, thank you for continuing to offer help & suggestions! Appreciated muchly!
Hmmm. My coil pack does have the "three square" coil like the middle photo with the spark plug wire terminals on both sides. However, it does not have any type of display on the left side of the temperature gauge on the instrument panel. It does not have the "Delco type 2" coil pack. I actually have one of those (Delco type 2 coil) here that a friend gave me several years ago.
Also just to clarify, when I say that the engine runs rough when I start it cold, I mean when the engine and components are the ambient air temperature which may be 50 or 60 degrees. If I drive the car and it sits for 30 minutes and cools down (but not COLD), when I restart it it will run a little rough until it warms back up to normal operating temperature.
Also, I have a digital VOM and know how to use it but I have never tested a coil like this before so I don't know which are primary / secondary terminals.
In any case, thank you for continuing to offer help & suggestions! Appreciated muchly!
Jrs3800
04-02-2008, 04:12 PM
It almost does sound like there is an unhappy sensor... Almost as if the ECM thinks its in Closed loop when its really needing to be in open loop.. That would be one reason I'd love to Throw a Scan Tool at the car, I would love to see what the ECM is seeing as opposed to the dash gage..
The interesting thin is that on the later years GM went to a single sensor for both the dash gage and the PCM..
When you get to testing the coolant sensor let us know what you find..:)
The interesting thin is that on the later years GM went to a single sensor for both the dash gage and the PCM..
When you get to testing the coolant sensor let us know what you find..:)
shilohin
04-02-2008, 05:03 PM
Hi again.
I didn't test the old ECT sensor as it was difficult to get to, so I just replaced it with a new one. It didn't make any difference. I also replaced the ECM, which didn't make any difference. Hasn't thrown a code yet. Thanks!
I didn't test the old ECT sensor as it was difficult to get to, so I just replaced it with a new one. It didn't make any difference. I also replaced the ECM, which didn't make any difference. Hasn't thrown a code yet. Thanks!
Jrs3800
04-02-2008, 05:59 PM
This is a start after my Bonneville had sat for over 24 hours...
Notice How it starts and how it idles while cool.. Vid is a tad long... Please forgive the current carnage of the car as it had a new windshield installed..
http://img.photobucket.com/albums/v294/Jr3800/91%20Misc/th_MOV02657.jpg (http://smg.photobucket.com/albums/v294/Jr3800/91%20Misc/?action=view¤t=MOV02657.flv)
Does you'd idle anything like this? Faster, Slower... Or the same just runs crappy?
Notice How it starts and how it idles while cool.. Vid is a tad long... Please forgive the current carnage of the car as it had a new windshield installed..
http://img.photobucket.com/albums/v294/Jr3800/91%20Misc/th_MOV02657.jpg (http://smg.photobucket.com/albums/v294/Jr3800/91%20Misc/?action=view¤t=MOV02657.flv)
Does you'd idle anything like this? Faster, Slower... Or the same just runs crappy?
shilohin
04-03-2008, 11:00 AM
Hi,
Thanks for posting your vid. I couldn't really tell that yours wasn't running right. However, that gave me the idea of posting my own vid. In my vid, the car has just been started, sounding chuggy and I have indicated on the vid where you can hear the engine surging. Although the vid is only a short one and doesn't show or hear the engine running smoothly, it does run smooth as silk when it is warmed up and does NOT sound like it has a bad muffler like you can hear in the video. Maybe being able to hear the engine run will give someone an idea of what might be causing it. This car has been VERY reliable and has mostly run like a charm.
http://s284.photobucket.com/albums/ll8/shilohin/engine%20vid/?action=view¤t=Enginerunrough.flv
Last year, I had SES light come on repeatedly with a camshaft sensor code. I replaced the sensor about 4 times, each time it would run fine for a few weeks and then throw the same code. When I replaced the timing chain & gears, the sensor magnet on the camshaft had totally disintegrated into a pile of magnetic particles. I replaced it and fixed that problem.
Hopefully someone can help me figure out what my current problem is. Appreciate the help! Thanks!
Thanks for posting your vid. I couldn't really tell that yours wasn't running right. However, that gave me the idea of posting my own vid. In my vid, the car has just been started, sounding chuggy and I have indicated on the vid where you can hear the engine surging. Although the vid is only a short one and doesn't show or hear the engine running smoothly, it does run smooth as silk when it is warmed up and does NOT sound like it has a bad muffler like you can hear in the video. Maybe being able to hear the engine run will give someone an idea of what might be causing it. This car has been VERY reliable and has mostly run like a charm.
http://s284.photobucket.com/albums/ll8/shilohin/engine%20vid/?action=view¤t=Enginerunrough.flv
Last year, I had SES light come on repeatedly with a camshaft sensor code. I replaced the sensor about 4 times, each time it would run fine for a few weeks and then throw the same code. When I replaced the timing chain & gears, the sensor magnet on the camshaft had totally disintegrated into a pile of magnetic particles. I replaced it and fixed that problem.
Hopefully someone can help me figure out what my current problem is. Appreciate the help! Thanks!
Jrs3800
04-03-2008, 03:30 PM
Wow... That Video does help...
You have a dead on Miss of some sort... Either an injector or you have a Bad coil... I am almost leaning towards the coil..
I think you had said you have replaced that coil pack before, and if so what brand? Also what kind of Plugs are currently in the car?
I am almost tempted to tell you to get a Delco Type 2 Ignition system from the wrecker... Hard to say for sure thats what the problem is without being there to look at it closer.. But its sounding a lot like an ignition problem
In my Vid you can see that I gave the engine a few revs and it didn't skip a beat..
You have a dead on Miss of some sort... Either an injector or you have a Bad coil... I am almost leaning towards the coil..
I think you had said you have replaced that coil pack before, and if so what brand? Also what kind of Plugs are currently in the car?
I am almost tempted to tell you to get a Delco Type 2 Ignition system from the wrecker... Hard to say for sure thats what the problem is without being there to look at it closer.. But its sounding a lot like an ignition problem
In my Vid you can see that I gave the engine a few revs and it didn't skip a beat..
shilohin
04-03-2008, 04:16 PM
No, I have not replaced the coil. It still has the original coil that came installed with the car. Here's a photo of the coil that is in the car now:
http://i284.photobucket.com/albums/ll8/shilohin/coil/coil.jpg
<p>
This is a coil that I have that a friend gave to me a few years ago. It was pulled from a working 1990 Buick Century with a 3.1 engine:
http://i284.photobucket.com/albums/ll8/shilohin/coil/coilspare.jpg
They both use the same connector but someone told me you HAVE to replace the coil with exactly the same model, which is why I haven't swapped it out with the spare I have. Any ideas?
Also, I have Champion plugs. I installed a new set about 3-4 months ago. The car had some brand of platinum plugs installed when I bought it and they would miss after about 4,000 miles. I got rid of them and installed copper Champion plugs. My first car was a 1968 Buick Riviera GS that had Champion plugs in it when I bought it. Later I replaced them with AC plugs thinking they would be better since they were what GM recommended. The AC plugs would start missing after about 3-4,000 miles so I put Champions back in it and never had anymore trouble. I've been sold on Champion plugs ever since. BTW, when I recently replaced the Champion spark plugs in my Bonneville with new Champion plugs, the old ones had probably 35,000 miles or more on them and you could hardly tell them from new ones. No fouling, not burned, looked excellent. I replaced 'em anyway. Thanks for your help!
http://i284.photobucket.com/albums/ll8/shilohin/coil/coil.jpg
<p>
This is a coil that I have that a friend gave to me a few years ago. It was pulled from a working 1990 Buick Century with a 3.1 engine:
http://i284.photobucket.com/albums/ll8/shilohin/coil/coilspare.jpg
They both use the same connector but someone told me you HAVE to replace the coil with exactly the same model, which is why I haven't swapped it out with the spare I have. Any ideas?
Also, I have Champion plugs. I installed a new set about 3-4 months ago. The car had some brand of platinum plugs installed when I bought it and they would miss after about 4,000 miles. I got rid of them and installed copper Champion plugs. My first car was a 1968 Buick Riviera GS that had Champion plugs in it when I bought it. Later I replaced them with AC plugs thinking they would be better since they were what GM recommended. The AC plugs would start missing after about 3-4,000 miles so I put Champions back in it and never had anymore trouble. I've been sold on Champion plugs ever since. BTW, when I recently replaced the Champion spark plugs in my Bonneville with new Champion plugs, the old ones had probably 35,000 miles or more on them and you could hardly tell them from new ones. No fouling, not burned, looked excellent. I replaced 'em anyway. Thanks for your help!
Jrs3800
04-03-2008, 04:36 PM
Ok here is the deal..
The only V6 offered in the 1990 Buick Century was the 3300 Buick V6, Little brother to the 3800...
The coils you have would work, but the ICM( Ignition Control Module ) will not work with your Bonneville... The Bonneville is a SFI( Sequentially Fuel Injection ) car...
The 3300 V6 was a batch fire MFI system, iirc this system fires 2 injectors at the same time.. The Module from the buick will also be keyed differently..
You would have to have a 3800 V6 ICM to be able to use that system.. The Delco system does fire a bit hotter than the original Magnavox system.. I have ran everything from AC Delco Plugs to NGK TR55 Plugs with good results on the Delco System...
Bosh Plats are a no no with the 3800's..
If you have any questions at all i will be more than glad to help you with them:)
I also neglected to ask.... Are these the wires on the car now?
http://i284.photobucket.com/albums/ll8/shilohin/coil/coil.jpg
If these are the wires on the car, they are all original and most likely should be replaced..
I still your problem in ignition related... Possible coil or wire( if original )
The only V6 offered in the 1990 Buick Century was the 3300 Buick V6, Little brother to the 3800...
The coils you have would work, but the ICM( Ignition Control Module ) will not work with your Bonneville... The Bonneville is a SFI( Sequentially Fuel Injection ) car...
The 3300 V6 was a batch fire MFI system, iirc this system fires 2 injectors at the same time.. The Module from the buick will also be keyed differently..
You would have to have a 3800 V6 ICM to be able to use that system.. The Delco system does fire a bit hotter than the original Magnavox system.. I have ran everything from AC Delco Plugs to NGK TR55 Plugs with good results on the Delco System...
Bosh Plats are a no no with the 3800's..
If you have any questions at all i will be more than glad to help you with them:)
I also neglected to ask.... Are these the wires on the car now?
http://i284.photobucket.com/albums/ll8/shilohin/coil/coil.jpg
If these are the wires on the car, they are all original and most likely should be replaced..
I still your problem in ignition related... Possible coil or wire( if original )
shilohin
04-05-2008, 09:41 PM
The spark plug wires were original, yes. I changed them today with some new spark plug wires and no more cutting out. Fixed!
It's really nice to have someplace to seek help with a problem and have friendly and knowledgeable people offer advice and suggestions. And I've learned a few things too. While I always have done my own maintenance and repairs on my Bonnevilles, some things I've never had to work on. I didn't even know the car has an Idle Air Control (IAC) motor, nor did I know it has an Ignition Control Module (ICM). I thought that the ignition was totally controlled by the ECM but it isn't.
Anyway, thanks to everyone who offered advice. Especially to Jrs3800 for coming back over again with more comments and advice. Appreciated muchly.
It's really nice to have someplace to seek help with a problem and have friendly and knowledgeable people offer advice and suggestions. And I've learned a few things too. While I always have done my own maintenance and repairs on my Bonnevilles, some things I've never had to work on. I didn't even know the car has an Idle Air Control (IAC) motor, nor did I know it has an Ignition Control Module (ICM). I thought that the ignition was totally controlled by the ECM but it isn't.
Anyway, thanks to everyone who offered advice. Especially to Jrs3800 for coming back over again with more comments and advice. Appreciated muchly.
Jrs3800
04-07-2008, 05:17 PM
The spark plug wires were original, yes. I changed them today with some new spark plug wires and no more cutting out. Fixed!
It's really nice to have someplace to seek help with a problem and have friendly and knowledgeable people offer advice and suggestions. And I've learned a few things too. While I always have done my own maintenance and repairs on my Bonnevilles, some things I've never had to work on. I didn't even know the car has an Idle Air Control (IAC) motor, nor did I know it has an Ignition Control Module (ICM). I thought that the ignition was totally controlled by the ECM but it isn't.
Anyway, thanks to everyone who offered advice. Especially to Jrs3800 for coming back over again with more comments and advice. Appreciated muchly.
Glad to be of help... If you have one bad wire it can wreak havoc on the GM DIS system as its a waste spark system... And just like it says it really does waste a spark.... It takes more to fire the plug on the compression stroke and less to fire the plug on the exhaust stroke... So more of the power will go to the cylinder on the compression stroke.. When everything is in good working order the system works very well..
Glad you got it fixed:)
It's really nice to have someplace to seek help with a problem and have friendly and knowledgeable people offer advice and suggestions. And I've learned a few things too. While I always have done my own maintenance and repairs on my Bonnevilles, some things I've never had to work on. I didn't even know the car has an Idle Air Control (IAC) motor, nor did I know it has an Ignition Control Module (ICM). I thought that the ignition was totally controlled by the ECM but it isn't.
Anyway, thanks to everyone who offered advice. Especially to Jrs3800 for coming back over again with more comments and advice. Appreciated muchly.
Glad to be of help... If you have one bad wire it can wreak havoc on the GM DIS system as its a waste spark system... And just like it says it really does waste a spark.... It takes more to fire the plug on the compression stroke and less to fire the plug on the exhaust stroke... So more of the power will go to the cylinder on the compression stroke.. When everything is in good working order the system works very well..
Glad you got it fixed:)
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