HELP! Ok i have a 96' GMC Suburban 5.7. trouble starting. 1)When i turn the key the wants to turn over but it is just flooding. 2) When i turn the key and pump the gas pedal it just flooding. 3)when i turn the key and hold the pedal to the floor(not pumping) it tries to turn but takes est. 10-15 seconds and starts. now once its started i can drive anywhere it seems. But when i turn it off same thing all over again to start it. in last 6months i put a new fuel pump and filter in it. someone said it is a cold cranking problem,but i can go out in the cold and hold the pedal to the floor,turn the key and after 10-15 sec of it trying to turn over it will start. just dont why it wont by just turning the key.


Asked by Nov 18, 2013 at 11:43 AM about the 1996 GMC Suburban K1500 4WD

Question type: Maintenance & Repair

new fuel pump and fuel filter 6 months ago

6 Answers

John Saffrahn

Holding the pedal to the floor puts the engine into what's called clear flood mode, just like with the old carbureted engines it prevents the injectors from opening, sounds like either one of the injectors is stuck open or the fuel pressure regulator diaphragm is ripped and fuel is pouring into the intake

1 out of 1 people think this is helpful.

Fixed Problem it was a Coolant Temperature Sensor. Located on front top of block next to the Thermistat. i put a Code Reader on to see if it was showing any codes which it wasnt. So then I started looking at different Data readings it was showing. My wife had ran an errand about 10 minutes before i looked at the Suburban so I knew it would be hot. But the reading for the Coolant said 5 degrees F. Thats what lead me to the Coolant Temperature Sensor. Hope this helps someone.

3 out of 3 people think this is helpful.
John Saffrahn

So it was stuck in open loop, odd that it idled fine.


John sorry if i made you think it idled fine, it didnt. it stayed idle once you got it started but it sounded horrible. but thanks for all your help i appreciate it.

1 out of 1 people think this is helpful.

Can someone please help. I have a 96 GMC Sierra 1500 with a 5.7 Vortec. It died as if you tuned off the key. So here's what I've done thus far and it still won't start. With a spark tester I checked the plug wire, no spark, with the same tester I checked the coil and coil wire, I have spark at the coil wire,so I replaced the distributor cap and rotor button....the engine still won't start.I have also replaced the crankshaft sensor and the camshaft sensor,spark plugs and I'm getting some spark to the plugs but its not constant....I returned the cap and rotor and replaced it again and I still have the same issue...


Spider injector

1 out of 1 people think this is helpful.

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