I've been having an odd issue with my 2008 Grand Prix base model. Sometimes it will not start in the morning (strangely usually after it rained all night). If I try to start it a few times with a pause in the middle between tries it eventually catches and starts.
Example of problem:
- Car starts and runs fine for days or weeks.
- Car sits over night, seems to co-inside also with rain over night
- Go to start car, turn key to start let go, starter runs, engine turns, sounds like engine has compression from the sound it makes, engine doesn't catch engine continues to try to start for about 5-10 seconds then stops automatically.
- Wait for a second, turn key to run so fuel pump can prime in case that is the issue, fuel pump is clearly heard running then stops when primed
- Turn key to start again, same engine starter running noise, clearly has the pistons moving can hear the noise and compression noise from it, 5-10 seconds system auto stops trying since it didn't catch and fire
- repeat step 4 and 5 again, same result
- repeat step 4 and 5 again, engine catches and starts fine and will work for weeks again until this randomly happens again
What I've tried to do to solve the problem or other maintenance work done recently:
- Changed plug wires but not plugs, plugs didn't seem like they needed changed yet, car only has 69,000 miles on it
- EGR valve was replaced a year ago, was throwing codes, solenoid valve was stuck and valve wasn't working, codes stopped after replacement
- Cleaned MAF a few months ago, I do this about once a year
- Replaced intake air filter and cabin air filter with OEM filters
- Oil changed with full synthetic oil
- Coolant was flushed and replaced with dexcool coolant again
- Back flushed the heater core due to low heat (good bit of junk came out)
- Last time this happened I thought the fuel pump was going out, so had it replaced, so it's under a year old
- Replaced relays for fuel pump (just in case they were going bad) with OEM ACDelco relay
- Replaced Headlight beam relay (had an odd issue where the headlights would just turn off out of no where at night)
- Removed ground from chassis to negative battery jumper from chassis, cleaned it in case it was corroding, sanded the paint of the chassis where it touches to improve the ground since it had very little clean contact minus the nut and bolt connection. after that was on and tightened back up covered it with dielectric grease to keep water off it
- Cleaned battery terminals and wire connectors with acid cleaner / indicator, wire brushed them clean also
So, what is left? Fuel line somehow plugging up? bad injectors? CAM or Crank position sensor? since this happens so randomly but eventually fires trouble shooting it has been a pain
Edit: more info
* There are no check engine lights, never seen one after the EGR valve was replaced
* Gas mileage is down to 13 MPG city, use to get 18+ MPG city, highway I get still about 22 MPG
Originally Posted by Fivefingerdeathpunch
), heated leather, autostart.
