Need Help Badly

[lowdown112]

Sounds like fuel pump. It may be "sort of " working hence the start up and then stumble. I agree with @2 Sweet . Fuel pressure should be on your early agenda. Your truck is about the right age for the pump to be going and yes it is a PITA to change.

Let us know what you find. A completed thread is a good thread.

I honestly cannot remember if I replaced it or not. When I bought this truck it had a broken orange wire going to ecm it wouldnt get primer. After about a year I found that fixed it and started it up. Ran like ****. Took the valve cover gaskets off and I had major oil blow-by and the previous owner probably didnt even change the oil ever at all. Literally couldn't re-use anything. Oil was caked up an inch thick on everything. Hence why the motor and everything is new. I dont mind doing a fuel pump, this isnt my first rodeo with these trucks by any means. I do the hole in the bed method. I feel like I did replace it at some point tho b.c i remember having to re-do a ground to the fuel pump when it broke at walmart

 

[lowdown112]

What kind of pressure should it read if I were to check its fuel pressure? I would just throw a new one on but getting tired of throwing money at it honestly. 94 tbi 350 5.7 Do i check it before or after the filter? I do remember replacing the filter

 

[lowdown112]

Hmm, its odd that its fine when cold (closed loop computer tune) then gets worse once its in open loop.

So, I am seeing stock computer with new engine and various performance parts. Did this engine ever run normal in its current configuration? I'm thinking it just needs a proper tune if it hasn't been done yet...

Honestly its never ran perfect. Ive had it 3 yrs and even after all this **** Ive only put about 8k on it total because im afraid of messing it up worse. I also thought of maybe a tune but idk how to do that

 

[RichLo]

To check fuel pressure on a TBI, you have to unhook the fuel line at the TBI and put a T in line to hook up the gauge. Its a PIA especially to wait until it warms up since you probably dont want to drive it like that. But yea, I agree to do that first.

For the ECM since its never run right for 8k miles I would look heavily into getting it tuned. Do you know the statistics of the new engine? was it a crate engine with cam specs, compression, head info, and everything advertised? Others can chime in on the best tuner for TBI's but if you know whats in the engine any reputable tuner can get you a good tune.

 

[Eveready]

I honestly cannot remember if I replaced it or not. I dont mind doing a fuel pump, this isnt my first rodeo with these trucks by any means. I do the hole in the bed method. I feel like I did replace it at some point tho b.c i remember having to re-do a ground to the fuel pump when it broke at walmart

Well I guess if there is a hole in the bed, you may have changed it . That might be the first place to look and see if there is one. Considering the quality of some replacement parts these days it STILL could be a fuel pump. If you do find a hole in the bed, at least it won't be all that difficult to change.

 

[lowdown112]

No the hole in the bed is my method. I cut a hole in the bed where the fuel pump goes and put a hinge on it and make it like a door. Can open it from top. Its totally covered by my plastic bed cover tho. But anyway checked my fuel pressure. Looks like its sitting at 14.5 or 100kpa cold.

warmed up stayed at 14.5

I remember I did not replace the fuel pump myself because the guy before me told me he did it when he was troubleshooting. 14.5 is high for tbis right? Could it be that he put a pump in for the 96+ trucks?

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[RichLo]

is that after the truck warmed up and it started acting up?

 

[lowdown112]

No that was cold. But when it was warmed up, it didnt change at all. Stayed there until it died out again

 

[RichLo]

ok, What is your new engine? Crate? hot-rodded at all by a engine builder?

 

[lowdown112]

ok, What is your new engine? Crate? hot-rodded at all by a engine builder?

Nope, was told it was a rebuild. .10 over or so if i remember right. i put on everything i listed in OP