starting issue with my 96

hi. i am having a issue with my 96 . when i go to start the engine it seems to need to crank way to long . and when i let off the key and try agian the engine will usually start right up . this seems to be worse when at cold start. also when the engine is hot it will start right up but seem to flood and run rough untill i clear it out. and then it runs fine. i have replaced the plugs and wires and ran a bottle of injecter cleaner thru tank and still no help. there are no codes showing. any help apreciated. thanks. mark.

Check your fuel pressure. It sounds like it is leaking down when it is shut off or not building up fast enough when you go to start.

Fuel pressure regulator is probably bad. Watch the fuel pressure after turning off the engine.

//2000CAYukon

thanks i will check into that this week end. mark.

ok i checked fuel presure it did drop fast after shut off . i replaced fuel presure rregulator. it still does the same thing. any other things that could cause this???

What engine and engine code?
You need to run a full fuel pressure test.

Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

ok today i have a new issue maybe all related???? for the first time it turned on the service engine light on the highway and when i try to pass someone it seems like the trans is slipping. it threw a po131 and a po151 . i ran the codes and came up with o2 sensor codes. bank one and two. sensor one both sides. could this possiably act like a trans slipping??? could this be all my issues finnaly comming to a head. any help would be great . i have five kids and this is my only transportation so i cant stay down long.

Those are lean codes, could be related to low fuel pressure, as suggested have you checked this?

i checked fuel pressures. i have 50 psi when i turn key to on. i have 51 psi when eng started. i have 51 psi at idle. fuel pressure raises at take off to 61 psi. on highway the pressure stayes stable at crusie at 61 psi at 60 mph. pressure at shut off was 51 psi and held for as long as thirty minutes and was still the same until i pushed release at gauge. i had no issues untill i got on highway and then it seemed to slip when trying to pass agian but i got no new codes . i cleared them before i started out. what you think????

Should be 60+ always. sounds like a bad pump.

Pressure is low.
Make sure your gauge is right.
Engine running should be 60-66 lbs pressure depending on engine load.
Check direct fuel pump pressure at fuel filter line.
Or.
Full pressure with return pinched off should be 75-85 or more.
If not your pump is weak.
MT

finnaly got time to loook at burb. i pinched off return at tank and gauge only went up to 58-59 psi. im thinking i need a pump. i put this pump in only two years ago. its a ac delco. i think i may try bosch this time. thanks i will let you all know what happens. mark.

Mark: I don't see in any of your posts where you've changed the fuel filter. Just thought I'd add that to the equation

I am pulling the same exact codes on my 96, I am about to replace the pump so let me know if it helped out in your situation. The sooner the better 3 am planning on dropping my tank this weekend and I would hate to do it if it is a waste of time. As far as the tranny slipping it is just the ecm switching into safe mode, chances are your tranny is fine, mine does the same thing plus I have problems going up long hills. Good luck, and if you do find the problem make sure you post back with the fix, this issue is driving me crazy! Thanks in advance.

the filter was changed two years ago with the pump. i will change it this time also. along with the strainer. the sad thing is im a forklift road mechanic, i have a service van so the suburban gets low use just weekends and evenings. so i know there's not many miles on the old pump. but who knows maybe i picked up a bad tank of crap. thanks.

Use only GM fuel pumps.

Here is some good news,Carquest did change fuel pump manufactuers and they are the only ones that did.Carquest did away from Airtex and switched to Delphi whom makes GM's fuel pumps.I saw this recently and it says on the box with the Delphi logal in it.

ok i changed out the pump yesterday . pressure got better but i still had the same issue. today i bought two new o2 sensors 1 . i replaced this afternoon and i took on test ride tonight. all my troubles are gone it starts right up and pulls hard on the highway. thank you everyone for your help. mark.