long crank times/hard start

[454ss]

1997 k3500 454/4l80e. cold start fires up like the day i bought it. after its up to temp it starts great within 45 min or less. after 45 min and until its cool again i have to crank it over 2 or 3 times to get it to start and since it doesnt fire right up it wont start with the remote start, it cranks and tries twice but doesnt crank it long enough to start it. when it does start it runs rough for 30 seconds or so like its flooded then its normal. its been doing this for 2 years or so, driving me nuts. this is what ive checked and or replaced, complete never used take off upper and lower intake with everything that bolts to it, mas,egr, injector system,regulator ect., plugs,wires,coil, fuel pump, fuel filter,o2 sensors, cap and rotor, crank sensor,knock sensors,ecm, took upper intake off and powered it up to check injectors-no leaks or drips, fuel pressure is in spec and holds after its shut off so regulator is good, no vaccume leaks found. truck has 190,000 miles, any ideas?

 

[webxfx]

Mines doing the same - its a 2000 with only 95,000 miles

Haven't dug into mine yet - thought it would be the fuel pump or fuel filter. Keep us posted on what else you find.

 

[454ss]

not sure what else to do and both of the shops ive been to just want to look at the stuff ive already done.

 

[webxfx]

might sound dumb, but fuel pump? I know you said your pressure seems to be fine - but mine seem to be making more noice then I expect.

 

[454ss]

ive also swapped that twice. no change.

 

[NacIK]

What plugs are you using? I was suckered into using E3 plugs on my L31 when I rebuilt my engine 2 summers ago and after 20k they are crap. They worked great on my mowers and would crank them up no mater how oil fowled they were, but now they all are working crappy. I am going to put the ACDelco's back in and see if it fixes the problem.

 

[454ss]

oem delcos repaced 3 times

 

[NacIK]

Should be good then.

 

[TXchevyinON]

if its a dog when you stand on it and wont rev up than its ither the pump or filter. easy test is to put your foot to the floor and if it wont rev past 3000 its the pumpif it goes right to redline than its not the pump. anouther way is to put a psi gage on the shrader and if the fuel psi goes down when you stab it its the filter or pump. it needs better than 55psi to start right. psi will go up when you stand on it if all is workin right fuel wise.

 

[454ss]

been through pumps and filters, press checked both running/revved and at shut off and all good.