Last post on Jul 30, 2011 at 11:54 PM
You are in the Pontiac Bonneville
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Pontiac Bonneville, Engine, Sedan
#1 of 28 Engine Surging Issues
Mar 21, 2007 (8:22 am)
I have a 2000 Bonneville SSEI with 60,000 miles and I am experiencing a engine surging issue. While on cruise control at 60MPH everything is fine untill you start up a mild to moderate grade and the RPM's start surging from 2000 to 1500 back and fourth and the vehicle starts bucking but if yuo take the car out of drive into third the problem stops with the higher RPM's. This vehicle has recieved a new fuel pump, TPS, and new coil packs as one was corroded and I recently changed plugs and wires. Any Ideas? Help please.
#2 of 28 Re: Engine Surging Issues [brumby]
Sep 08, 2007 (5:55 pm)
I have the same problem and I will tell you the same thing I was told. I went the same route to stop the problem as you did but here's the test. Next time you are driving up an upgrade & this starts, gently push the brake while you are still on the pedal, just enough to activate your brake lights, see if the surging stops. If so, you will feel the engine cut back & go on wihtout the surge. If this works on you also, then you have the same problem I do, torque converter lockout issues. The only way I know to correct is to change out the torque converter or have the lockout disabled, but you will loose your overdrive & there will go your gas mileage.
#3 of 28 Re: Engine Surging Issues [myssei]
Sep 09, 2007 (7:38 am)
I'm just going on what you said... there is a problem with the torque converter lockup. It is locking and unlocking allowing the engine rpms to vary greatly.
However the lockup has nothing to do with going in or out of 4th gear, commonly called overdrive. And the lockup is not 100% on the 4T65E's. It varies in percent of lockup to give the great power variation and the smoothness this transmission has. The lack of total lockup smooths engine vibrations that might be sensed at lower engine rpms and higher load.
There may be a problem with the control valve for the lockup percent control. There may be a problem with a sensor. That sensor could be with the motor or transmission. The sensor could be as simple as one that tells the PCM not to lockup the torque converter because the motor is too cool or too hot.
The car needs to be checked for trouble codes and I don't know if transmission trouble codes show on the Actron type readers they use at Autozone or Advance Auto. But it would be worth a shot. Those people are great and gracious as long as you don't come in at a typical rush hour for them so a counter person is free to come out to your car and do it. I suggest getting the codes, if any, and not buying any fixit parts. Come back to a forum and run the codes by someone who can troubleshoot what it means and save you putting on unecessary parts.
#4 of 28 Re: Engine Surging Issues [imidazol97]
Sep 09, 2007 (9:00 am)
I notice a few complaints in similar years about ground straps under the rear seat where a fuse block is located and the bolt being the ground circuit but screwing against a painted floor area. The threads on the bolt had corroded slightly where the ground contact would be made. Cleaned. Installed star washer for good contact.
Another is a spark plug wire touching the oxygen sensor. Move so it doesn't touch.
#5 of 28 Re: Engine Surging Issues [imidazol97]
Sep 14, 2007 (11:27 am)
My 94 Bonneville was doing the same thing. It was actually the throttle position sensor hanging up. It came up as some type of tranny code in the computer. My mechanic hit it with some WD-40 and the problem disappeared.
#6 of 28 Re: Engine Surging Issues [mlane18]
Sep 16, 2007 (6:46 am)
That's good to know. Thanks for reporting it.
#7 of 28 car bucks like a mule
Jan 23, 2008 (10:06 am)
Hi, I've got a 92' SSEi and the bucking and surging is driving me crazy. I am going to try the WD40 trick but is there a relay in the control center that could be weak and disengaging when hot. I stopped the car for ten minutes and the surging went away for some time but rears its ugly head yet again. HELP,I love this carbut am not going to let someone tell me the tranny needs to be replaced. Any help will be much appreciated, and thank goodness there are forums like this .
#8 of 28 Re: car bucks like a mule [gmonly4me]
Jan 23, 2008 (5:29 pm)
Without feeling the kind of bucking, I can't sense whether it's transmission, engine, engine/transmission mounts, spark plugs, plugs wires, a plug wire close to O2 sensor on the back of the motor on the exhaust pipe, MAF sensor, TPS sensor, fuel pump, clogged fuel filter...
You also didn't mention how many miles. That can help.
Another factor on lots of cars is the battery sometimes have bad cells, or broken connectors internally, and MOST often the connection of cables at the battery is corroded. The positive cables on some H-bodies at double; there's one on top of the other. The corrosion between them can keep the top one from getting proper power. It varies with humidity, temperature, etc. Also the cables can have battery acid eat into the copper down inside the plastic insulation. You need to slice the insulation down a little ways to take a look. IN an extreme case battery acid from a seep around the side terminals actually had wicked all the way down the positive cable to the starter and affected the connection at the bottom end.
You can make your computer read out the codes since you have ALDC 1. You can use a code reader but ALL you have to do is connect a paperclip between terminals A and B on the connector under the dash close to the steering wheel. The letters for the connections are in the black plastic next to the openings. Then turn the key to ON. The radiator fans and other things will turn on in diagnostic mode to show that they can work. The Check Engine light will flash 1 then 2, and repeat that for a total of three times. Code 12 is normal. It's a check for the computer. Then the system will flash codes for any others it has in the memory. Write them all down. When it's done with codes it returns to the 1-2 code.
I would turn off the heater system before I did this, along with radio, wipers, etc.
Remember a code doesn't mean a bad part there. It means a symptom. It takes diagnosis.
Another thing that could be wrong with a 16 year old car and especially in some climates is the crankshaft position sensor. It's next to the balancer on the 9 o-clock or 3 o'clock position. Some people splash cold water on them when they suffer a hot shutdown and strange restarts. Cooling it makes it work again.
You might have a camshaft sensor where a magnet moves past a sensor to tell the computer what position the camshaft is at.
You might have a problem with the ground buss on the driver's side of the car under the door sill plastic just where it meets the front A-pillar. If you are in a wet climate where salt and moisture are carried into the car onto the carpet in that area keeping it wet in the winter, sometimes the metal buss bar corrodes. But you didn't mention any other problems such as electric door locks not working, or seat, or windows, or AC system turning on or going into default mode at times....
That's some things to look at.
Start with the easiest. Plugs within last 30K miles? Proper wires OEM quality? Within last 3-4 years?
#9 of 28 Re: car bucks like a mule [imidazol97]
Jan 24, 2008 (2:29 pm)
Hi, thanks for the quick response.the car has 291,000 km and I have done all the normal things when I purchase a used car. New battery rated for all the options and cold weather, new fuel filter, o2 sensor,plugs and wires, tranny fluid check, oil changed, and auto wrecker coils. Just did that this morning and started just fine but need to test drive. Had a friend do the code reading and it threw the codes for crank and cam sensors. would a dirty oily build-up cause any problems? or do I just pull the balancer and change them out?why would cooling down the car for only 10 minutes change anything if it was these sensors?Is there a relay that operates the TCC in the tranny? Oh ya, the car takes a fair amount of starter turning to fire it up. Could that be a weak fuel pump? Thanks again for your knowledge and effort helping me sort this out.
#10 of 28 Re: car bucks like a mule [gmonly4me]
Jan 24, 2008 (6:03 pm)
To test for a weak fuel pump or leakback of pressure when it's off, turn the key to ON and after 3 seconds you'll hear the fuel pump stop. Turn the key OFF and then back ON. Do that total of 3 times. That should repressurize the system. Then turn to START.
If it starts quickly that's a good sign you've got a problem with the fuel pump and the pressure valve.
The camshaft sensor is different than the crankshaft sensor. The symptoms worry me. They could be the ISC, the part that controls the three coil packs. Some people have had trouble with them.
Don't throw parts at it. At 188,000 miles you can have many problems. But most likely you have one problem.
The transmission could be the problem. Without driving it I can't tell. Does it do it when left in 3rd gear?
I'll send a longer list of things to your email box that's a part of Edmunds. Your user name plus carspace.com is your address. You access it in the gray bar across the top of each page has white text. The third from the right is your mailbox. You should be able to read an email from me there. Then you can respond here in the forum.