Mechanics

ENIGNE HARD TO START

2000 Pontiac Sunfire • 210,000 miles

2000 pontiac sunfire 2.2 car was running great. Shut it off, really hard to start. Had to hold gas to floor, would chug for a few seconds then take off & run great. Now it turns over, smells like it is flooding, backfires a little through intake.

Car was cranking & running great. Last night shut the car off for about 2 hours, went to re-start vehicle to use it, had to hold gas pedal to floor & when it finally caught, it chugged for about 30 seconds before it finally started running. Idle is smooth, no miss & once it is running it runs great.

Went to start it this morning. Turned car over, it tries to catch after about a minute of cranking, smells strongly of gasoline, back fires through the intake, still wont run.

HELP ME PLEASE : -)
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CSA1
December 22, 2011.




Check to make sure the fuel pressure regulator is working. It could be allowing too much pressure to the engine. Also, when it doesn't start, make sure you are getting spark to the plugs.

It is firing, else woudnt back fire thru intake I believe. How do you check the fuel pressure regulator on one of those?

Tiny
CSA1
Dec 22, 2011.
Took spark plugs out. They soaked in fuel. Cranked engine over with plugs out to clear out the cylinders. Put in new plugs. Cranked engine, again it tries to start, but wont. Checked plugs again, again soaked in fuel. Thinking fuel pressure regulator or crank sensor? Not able to check the fuel pressure. I believe it has spark as it is trying to start. Kinda stumped at moment. Any advice or suggestions?

Tiny
CSA1
Dec 22, 2011.
Either you have a weak spark or are getting too much fuel. Check to make sure the spark is a hot blue snapping spark. A weak spark won't do it.

Also, check fuel pump pressure and check the fuel pressure regulator.

Put new plugs in. Car cranked & ran like a new car. Drove it around for an hour, parked it at home, went to start it & same thing. Turns over, wont run. Pulled plugs out, they soaked in fuel. Again, changed plugs. Car ran fine. No miss, no hesitation, nothing. Runs perfect. Shut the car off, once it cools off it wont start & floods it. Dealers mechanic is telling son nothing wrong with the car & he just starting it wrong, which I know is BS. Did do a spark test, when car is warm it has a great white/blue spark. When cold, has a weak orange spark & you can smell fuel under the hood. Im sure the pressure regulator needs changed, but what about the cold start weak spark?
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Tiny
CSA1
Dec 29, 2011.
The coil could be getting ready to die. It could have high internal resistance when cold and normal resistance when warm.

Rent or borrow a fuel pressure gauge from a store such as Advanced, Autozone, or O'Reilly's. There should be a fitting that looks like a tire valve near the pressure regulator. That's where you check fuel pressure.

Rivermikerat
Jan 2, 2012.
Ok, Tested fuel pressure. 98psi to the regulator. Put in new regulator. Replaced both coil pack with new ones. Replaced ignition wires, & spark plugs. Had ignition module tested, they cycled it 25 times, each time it passed. Put it all together & tried to start the car, acted like it wanted to fire & run, backfired through the intake a couple time & again, cylinders are flooded with fuel. Also now there is oil/fuel in the air breather.
What should we try next?

Tiny
CSA1
Jan 2, 2012.
Oil/fuel in the breather means that the cylinders are getting far too much fuel and the fuel is running into the crankcase, mixing with the oil and being blown out the crankcase into the breather.

Check the timing. The backfire through the intake tells me you might have slipped a timing belt.

Use a test light to see how long the injectors are being pulsed for. Or, if possible, use a scanner that can poll live data and check it. The fuel-soaked plugs means there is still too much fuel entering the cylinders. Check the voltage during cranking (and running, if possible) at the MAF/MAP sensor.

Rivermikerat
Jan 2, 2012.
I don't think it's the timing belt. Reason I say this is for the following. When you put new plugs in it, it will crank & run. The first few seconds it struggles, chugs, sputters & bucks, but if you hold gas pedal to the floor, it finally picks up & runs & idles perfect. No miss, no hesitation plenty of power. Will go all day like that. But you shut it off & it sits a few hours, you go to crank it & under hood smells strongly of fuel & wont crank, pull plugs out & they literately are dripping of gasoline. To get it to start again, we have to pull the plugs, using a propane torch, warm them up till gas evaporates, pull the fuel pump relay, crank engine with plugs out to clear it of excess fuel ( and a bunch sprays out) let it sit & air out for about 20 minutes, put plugs back in & start the process over again till it runs. I did test light the injectors. They kept the light lit for aprox. 2 to 3 seconds & shut off. We cant test the MAP sensor, as you have to take the throttle body for the air intake off to get to it. We also change the oil & filter, was very diluted with gasoline. I was pondering the thought that maybe it is the ignition module even though it tested good. Will do another spark test tomorrow. But also wondering why after changing the fuel pressure regulator, it's still flooding out? Any chance it could also be a crank or cam sensor? Im stumped.

Tiny
CSA1
Jan 3, 2012.
It could be an intermittent crank or cam sensor. But I doubt it.
Our reference, provided by GM, says that fuel pressure spec is 52-58 PSI. 98 is way too much. That's where I'd look.

Rivermikerat
Jan 3, 2012.

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