2002 Buick Century - Intermittent No Start

[GFORCEAUTO]

Hello all, Got a 02 Century 3.1L/J that intermittantly will crank and not start. Murphys law we could not get unit to act up. Checked the fuel pump wave pattern on the scope and it was showing a weak pump. We suggested that a pump would not hurt and our expierance tells us thats most likely what the problem is. customer oked FP. Delphi pump installed and connector was changed also fuse for FP .Worked ok for 2 weeks and whamo no start for 6 to 7 times then it starts.Customer called and it was acting up.drove to his location and checked Spark was ok. Sprayed carb clean in snorkle and it runs. customer dropped off and we had for a week and drove unit everyday same sinerio and workes ok for us would NOT act up again. Started every time. WE checked the wires at the accumilator for rubbing all ok and replaced the FP relay. chased the wiring to the relay from the PCM and cleand all grounds, Fuel pressure is with in spects and only drops 10 psi in that hour soak even over night it dropped to 15 psi and on key up pressured right up to 55 psi. Still could not get to act up.Has customer switch keys with wife also. Customer takes car and 4 days later would not start for 25 min they gave up and got a ride home. They were here first thing in the AM. We go to get the car and after sitting all night starts up all ok. It's here now any Ideas ?? HELP
Fuel pressure ok
Spark OK
7 x crank sensor all ok
Wiring all ok to pump and to relay from PCM
No codes
No security codes

[liljoe]

If possable check the coolant temp reading when it won't start. Might be reading high and not giving enough pulse width. I have a thing called CRecorder that hooks up to the OBD2 connector and records most of the data with time stamps on it. It will record for 24 hrs and then you download the info to the pc and look at all the data. You can play it back in real time or speed it up and look at data or graph it and see what is going on. It has its limits, but is neat addition to the tool box. Cost is only like 70 or 80 bucks.

[steven kiser]

you sprayed carb cleaner into it and it started, was there fuel pressure? if yes then i would check the pcm for updates and re-burn. there were a few instances where the injectors wouldn't pulse because of pcm issues. i believe there have been issues with the cam sensor wiring and it caused an intermittent no start as well. there may be an updated harness available for this. i'de check the grounds that break out of the harness and ground to engine. if there is corrosion or a loose connection that may be your issue. good luck. don't let it kick your butt............

[Tim Martin]

These intermittants are sooooooooooooo nice to us guys.

I've seen cam and crank sensor issues with them as well. But an intermittant like that is tough to catch. Yeah, I'd also be lookin at a computer reflash as well.

[GFORCEAUTO]

OK sorry for the delay just wanted to let all of you know what fixed the issue. Had the customer come back and we reflashed the PCM to the latest calibration and whamo it has not been back for the no start condition. the customer stopped by and told me it has been fine since. Thank to Steve for reminding me of a simple thing we used to do all the time at the dealer.

[Jeff @ Able Auto]

Thanks for the follow up!

[a&mauto]

Better late than never..................

[ricmorin]

Did you have to relearn theft after flashing?

[Bobt1]

We have found in the past that relearning the theft system can get you anywhere from a day to a year, we always do a real good check on the passkey sensor and ignition lock cylinder, From our experience the problem is usually there.

Good Luck