No start 1999 Pontiac Sunfire 2.2


Asked by Aug 17, 2017 at 01:47 PM about the 1999 Pontiac Sunfire

Question type: Maintenance & Repair

My daughters Sunfire shut off I have not been able
to get it started I am a mechanic this one has me
stumped I have checked fuel pressure it's 41psi I
have cked spark at all cylinders that's good I have
cked all injectors for pulse all good I replaced plugs
just because they were old .I have no codes no
security issue I cked compression at all cylinders
there all good  so I have great spark good fuel
pressure what could be cause .One thing it will do if
I hold throttle to the floor it will run super rough and
shut off any ideas are welcome thks all

7 Answers


I also pulled throttle body off and cleaned cked Iac cked throttle positioning sensor and cked all vucumm hoses


When you used the fuel gage, after you built pressure, did you turn the key off and see if pressure will hold for a bit? If it drops like a rock, check for fuel pressure leak. When you put pedal to floor, it may go into clear flood mode. Is it trying to flood? Did you check sparks plugs after cranking, are they wet, bone dry? You do have spark at all spark plugs?


Yes when I cked fuel pressure it dropped slowly . I cked spark at all plugs after trying to start so many times they were fouled when I put new plugs in I tried to start it pulled plugs back out they were dry


I also pulled all injectors out to see if fuel was spraying into cyl. They were .What was weird is the car started with the injectors out ran for about 3 seconds and shut off I have pulled intake off cked for anything plugged nothing found .I was thinking maybe convertor problem removed O2 sensor in front of converter still no start


This might sound weird but would shift sensor do this.? Maybe a safety switch malfunction..seen a dodge truck do this once..and it would start in neutral but not in park ..just a thought


i tried that the weird thing is I have great spark at all cylinders,correct fuel pressure I know the injectors are working I removed fuel rail and watched them spray out, the timing is right . Correct compression at all 4 cylinders. I've worked on cars for 25 years and I cannot find nothing wrong that would make this car not start


Another scenario ..possible the engine got vapor locked ? Would explain fuel pressure and injectors working fine ..also why the car temporarily starts after pulling the injectors..but why it would do that outta no where is a mystery

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