I have a 1998 pont. bonneville in the shop. Fuel pressure good after a few mins. or less it will shut off like turning the ignition off. No codes are present, when it shuts off there is no spark at coils. I have checked live data with my snap on scan tool and have cam sensor data, ect. It will eventually start, but problem appears to getting more frequent. Another shop had replaced ignition module but problem persits, now I'm trying to diagnose and repair. Could this be an ignition switch problem ?
The anti-theft system has nothing to do with spark . When it won't start check for B+ voltage at the ignition module . pin P a pink wire . Check pin K for a good ground . Check the 18X & 3X crank sensor signals to the PCM . It's good you have a snap on scan tool an can check sensor data , but to check cam an crank signal's you really need a scope ! Does your snap on tool have a lab scope ( oscilloscope ) Do you know what this is ?
How to test crank sensor on GM 3800 engine 3x and 18x signals
Do you have access to wiring diagrams ? Check electrical distribution in an out of the ignition switch .Free wiring diagrams here
http://www.bbbind.com/free_tsb.html Enter vehicle info Year , make , model and engine size . Under system click on electrical distribution , then under subsystem click on power distribution . Click the search button , then the blue link ! I wouldn't think the ignition switch being the problem but you never know without testing ! Do you know how to do automotive electrical testing with a DVOM - digital volt ohm meter ? Using a wiring diagram to pin point areas for testing ?
Electric Testing Techniques You Need to Know
TSB'S that GM may have on this car. For what ?
SOURCE: 1994 pontiac bonneville fires up but stalls imediatly
WOW a 94 with 46K on it thats rare. Your computer may be bad it sends the pulse to the injector.
SOURCE: 98 firebird no spark new
Did you replace the oil sending unit? It will kill spark to the engine to stop engine damage when the oil pump goes out.
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No security light, This customer has driven the car for several days at a time with no issues then it will shut off and sometimes will re-start right away and other time she said she will keep trying to start it and it eventually start. I have monitored the fuel pressure at all times while idling in shop. When it shuts off it has no fire from any coils. I did check on another post on here that there is supposed to be an eprom update for this issue that has to be performed at the dealership, but I 'm an independant and I don't believe my dealers will help me with this. They would want the car to be brought to their shop, which if the update has to be done I have no choice. This customer is a student and is from out of town, so I'm trying to help her as best as I can. I also seen on another post about ignition wires or connections at the switch that could cause same symptoms, which I will try to check out tomorrow. I did unplug the cam sensor and tried to start and it ran with it unplugged, never seen that before. After re-installing the connector of course I had a fault code, which I cleared. I was leaning toward a possible engine computor failure, but in my past experiences, generally there is no communication with my snap on scannner, so I have kind of ruled that out, but not sure about this eprom update. I have no acces to any TSB'S that GM may have on this car. Thanks..
I did have a grand am in about 2 weeks ago that had a no start issue, and it was a security problem which I figured out. The bonneville will run fine at times and for days, then will shut off and not re-start at times.
when it dont start do you have a security light on or flashing if so i think i can help
is your security light on or flashing when it wont start?
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