91 buick regal 3.8 replaced crank sensor,module,fuel psi was a little low,replaced fuel pump,strainer and filter,starter went out during all this so we replaced starter,we installed a new computer yesterday,it starts cold but doesnt want to idle after a minute or so it dies and wont restart cranks over ok backfires like its out of time no fault codes all tps,aic,mass air, all read correctly,tried unplugging the mass air sensor no change checed all the grounds took the harness apart and checked all the splices HELP

SOURCE: buick lesabre nightmare

Need to get a scan tool and look at the data stream while it is running for alot more info.Also any trouble codes.Sounds like initially,the engine isn't getting any fuel.I would have a pressure gauge connected to the fuel rail on the engine,so i could monitor the fuel pressure while all this is going on.Items to look at on the data stream would be timing,what timing is the PCM commanding for the engine.Also,have you checked for continuos power feed to the coils during this no start condition,and fire at the plugs while cranking.You could possibly still have spark,but maybe it is extremely weak?I have seen bad ignition switches cause weird problems before too.Many things power up through the ignition switch,just a thought.Have also seen bad PCM's cause strange problems..38 volts is a little on the low side for GM.Usually see those at,at least .50 and up,and rise steadily while pressing the throttle,up to just under 5.0 volts.Potentiometer with 5 volt supply.Vacuum leak can be checked with engine running at a steady idle speed,spray brake cleaner all around the intake manifold and listen for engine speed change.

SOURCE: buick lesabre no start

Hi you have replaced allmost everything ,(try fuel pump relay)

Colin Stickland

• 22516 Answers
• Posted on Jan 11, 2009

SOURCE: 1989 Park Avenue dying after 60 miles, restart immediately then

sounds like the ignition module but it could be a fuel problem

SOURCE: My 95 Buick regal with 3.8 engine stalls while i am stopping.

Sounds like the EGR valve is bad.

SOURCE: i can't give my jeep much gas or it will backfire

Have your fuel pressure checked. It may be a bad regulator.

Try cleaning the throttlebody and air filter.

Check your spark plugs, coil and wires.

Check and make sure all of your injectors are clean.

Also you may want to check your o2 sensors. You can unplug them and drive a bit. If the problem goes away then they need replaced.