2000 454 vortec constant problems what to do?

[65nightmare]

I bought this truck last year for a back up and ended up preferring it over my 6.5 truck. It ran great for a while but i put about 1000 miles a week on so stuff is bound to go wrong but ive never had so many wierd problems. It started with it would start and choke of then start and run (once i start it in the morning it runs until i get back home so it never bothered me). Then a couple months ago i would hit the key all the dash lights would come on and the fuel pump would run but no starter so i crawled underneath and jumped the starter it fired up and never choked off (this is a intermittent problem 1-3 days out of 7). Now yesterday i was letting it idle and warm up it ran for about ten minutes and shuts off cranks but no start now and i can hear the fuel pump. Any ideas or should I just dump it or junk it?

 

[Justin S]

You're gonna need to do more testing than just listening for the fuel pump. See if its getting spark, or if the injectors are firing, scan for codes. After that, tackle the idle issue, or i'm sure someone on here would buy it for more than you could scrap it for.

 

[65nightmare]

Fuel pressure is 40psi with the key on and drops to 0 right after the key is shut off but it's been like that for awhile it always still ran good. I'm getting a high voltage to coil code and 2 egr codes I think p0404 and p0405 I'm not by my notes right now the odd thing I found is that it isn't getting constant spark out of the coil when turning over it kind of surges? This is only my third GM so I'm kinda new to this I was always a dodge guy but I got sick of not having heat in winter.

 

[beardeddummy]

May sound crazy but what's the battery volts after sitting?

 

[65nightmare]

Low I've had the charger on it to do the trouble shooting but as of yesterday I never had a battery problem.

 

[beardeddummy]

Have the battery and alternator tested

 

[65nightmare]

I will tomorrow, I put a cap and rotor on it today just because it was pretty corroded and still no go.
I did remember last winter when I would lift my plow after pushing heavy wet snow I would lose electric power for a sec. and my windshield wipers would come on.

 

[beardeddummy]

Try that but sounds like gremlins

 

[someotherguy]

That 40psi is too low for a Vortec 7.4. It should be in the low 50's minimum. It should start and run at 40 though; I've had one that started and ran as low as 30psi it just had no power.

Sounds like besides that you have some electrical problems, like some grounds are loose/missing, with the wipers acting like that and the other things you mentioned.

Richard

 

[65nightmare]

Could it be passlock?