QuestionQUESTION: My son inherited a 91 Bonneville SE, 3.8L with 160,000 miles. It always would occasionally (not very often) die when taking off from a stop sign and I never could find the cause.
Last month, after driving about a block, it sputtered, lost power and stalled consistantly when you slowed down or stopped but would start right back up. When I read the codes it had: 13 -Oxyden sensor, 26 -Quad driver 1 error, 41 -cam sensor, 44 Oxygen sensor, and 48 -Mass Air Flow Sensor. When I checked, I could see that the cam sensor magnet came off. I replaced it using the "cheat method" and used JB Weld to install a new magnet but it still loses power and dies when I slow down to turn a corner after about a block. The magnet is still there and (using junkyard parts) I have replaced the Mass Air Flow sensor, cam sensor and oxygen sensor but it still stalls.
When I installed the magnet, I was careful not to break the tabs/stops off the sides of the magnet, but with the JB Weld on the sides of the magnet, I could not see the tabs when I installed it. (There is no JB Weld on the face of the magnet).
Is it possible that the magnet is installed too far inward? It is kind of hard to see but I am quessing that it is about 1/8" away from where it would hit the cam sensor. I have driven it a couple of blocks about 5 or 6 times and I am not getting any codes at all so I am not sure what the problem is. Can you help me?
ANSWER: Hi Gary:
The cam sensor will not cause a stall problem. That puts the car isto sequential fule injection. It will run odd but it will not cause a stall condition. is it still setting the cam sensor code? The only one of the codes you mentioned that would/could cause a stall would be the mass air sensor. The quad driver code is odd also one of the solenoides on the engine is bad or the wiring to it that will cause a quad driver fault.. These engines are noted for Crank sensor issues. tap on the sensor with the engine running and see if it stalls if so you found the fault. Also on those older cars the ground wires to the engine computer under the ignition module assembly were noted to go bad corrode/loosen up or just plain break off. The computers on those older onew would go bad as well. if you get a jun yard one to try make sure you swap out the prom inside it with the one from the current one in the car. Good luck and happy holidays!
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QUESTION: I am not getting any codes now, I wish I was so i would know where to look. Like you suggested, I replaced the Mass air flow sensor, checked the ground wire connections and replaced the computer -- it still is stalling. I don't know how to tap on the crank sensor with the engine running. How can I since it is behind the crankshaft harmonic balancer and has a cover over it? Is there any other way to test it? Can I disconnect it to see if it runs any differently?
ANSWER: There is really no way to test it untill the car stalls but if it starts right back up then testing it is useless because the engine will run. to tap on it use a very long screw driver and tap on the electrical connector GENTLY and see if it stalls. BE CAREFUL OF THE BELT you don't want to get the screwdriver stuck in the belt with the engine running. If you disconnect it the car will not run. that is the main input to the ignition module to allow the car to run. Have you check fuel pressure as well when it stalls? when it stalls is it just like someone turned off the key or does it chug then die? if it just quits it's an electrical issue like the crank sensor/ignition module engine control module... if it chugs it's a fuel delivery issue.
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QUESTION: I tested the fuel pressure and after relieving the pressure, it stays at 0 (no pressure) with the key on. When I start it, it goes to 35 in about 2 seconds. When driving, it stays at about 35 and then when I slow down and then step on the gas it will start to stall and then die at about 15-20. It stays there until I restart it and then goes right back up to 35. It idles just fine. When shut off, the pressure drops down to about 25 in an hour.
I read on the internet that to test the pressure regulator, remove the vacuum hose and it should go up 8-12. When I did this test, it went from 35 to 44, so I guess the regulator is ok.
I also read that there is a wire with a green connector located next to the battery that when connected to the positive battery terminal will run the fuel pump. I found the green connector located by the horn, but I wasn't sure if I should try it.
Any ideas as to what to do next?
AnswerThe fact that you monitiored the fuel pressure and it drops down to 15-20 PSI before it stalls is a clue. I think you may have a fuel pump issue where the pump is cutting out or it's loosing the ability to keep up with the volume it needs to run the car. You may have a bad power feed or ground going to the pump and under certain conditions the bad connection is making the pump either run slower or cut out all together. That connector is the one I belive it has a red wire in it or grey.
