: still puzzled...



ZX_man
03-25-08, 04:48 PM
Alright I've been having hard start issues for sometime now, also a problem at full throttle above 5K rpm mark. The hard start issue seems to happen when the truck sits for a period of time, or when it it hot. I basically have to crank it over several times before it starts, and then it will hunt for idle and sound like it is about to die before it smooths out. The full throttle problem almost sounds like a miss along with detonation (minor) above 5K. I've done a full tune up, including T-body cleaning, new plugs (proper gap), new plug wires, fuel filter, and cleaned the AEM intake. I've had the truck scanned and it throws no codes. I have an Optima battery and voltage also checks in at spec. Any suggestions? I'm not ruling anything out at this time, so please give me some advice as to what to check next.

Thanks

Walter

hcvone
03-25-08, 08:22 PM
Is there anything on the MAF wires, some times the aftermarket filters can cause an oily buildup of dirt and debris on the sensor wires

DaveH28
03-25-08, 10:00 PM
Walter,

I don't know what year your truck is but I'm betting it's an 02 or an 03.. My first guess would be the fuel pump.. it would cause pretty much all that you described.. when the check valve in the fuel pumps go bad, you'll have an extended crank when the vehicle has been sitting awhile, and also possibly once the pump/vehicle gets hot...

in addition, if the truck is starving for fuel, you could get that high rpm miss and detonation..

have your fuel pressure checked and go from there..

ZX_man
03-25-08, 11:21 PM
Thanks for the info. Anyone know the best way to clean the MAF leads without causing any damage? As for the possibility of it being the fuel pump...i was leaning that direction, plus it makes sense as you described it. I'll check fuel pressure first, anyone know spec on pressure? Is is possible to remove the pump and replace the check valve, or better to just drop the dime on a new pump? TIA

Walter

hcvone
03-26-08, 07:27 AM
Contact Cleaner will do the job on the MAF wires

DaveH28
03-26-08, 10:07 PM
as far as the pump goes..

the check valve is part of the pump.. it's not something you're going to find separately.. however i will tell you that fuel senders for late model escalades are very expensive (the fuel sender is the whole kit with the pump, level sensor, etc..) that's the only way GM will sell it, so you can either pay big bucks for it, or look for an aftermarket pump and install it in your existing sender kit..

as far as fuel pressure, i am not 100% sure but if memory serves me it should be at least 40 psi..probably more like 50+ above idle..