94 C3500 350 cutting out

[tanman_2006]

I bought this truck at 110k, went through the TB, vacuum set up, I did a full distributor, plug wires, and plugs. Only to find out my new fuel pump was toast, put in a new vortec pump and the beast was alive.

Now at 120k miles the truck falls on its face at any more throttle than about 50%. Fuel pump is still pushing fuel under load.

At idle, sitting still, I can free Rev it and at the floor it will cut out until it dies but it revs good about 1/2 way through.

No cats, fresh oil, fuel filter, air filter, timing checked 0, and fuel pressure is around 20 psi.

 

[Breakdown]

Check your throttle positioning sensor if you haven't already sounds like you "may" have a dead spot in it

 

[magimerlin]

^^^x2. Check your tps sensor..

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[tanman_2006]

That was my plan this afternoon but I had a guy telling me to unplug it and see if it ran better? That didn't make a whole lot of sense to me haha

 

[tanman_2006]

Another guy is trying to tell me the vortec pump is flooding my engine

 

[magimerlin]

Another guy is trying to tell me the vortec pump is flooding my engine

Nope.... run vortec pumps in both my old c3500 and my current 94 k1500.. the regulator on the tbi unit takes care of it... who ever you getting that info and the info about disconnecting the tps to see if it works better is an idiot if they think they know anything bout vehicles....

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[tanman_2006]

Ok, idle is .52v wot is 4.2v so it definitely doesn't go as high as it should by my understanding. Seems pretty linear through the throttle action though

 

[tanman_2006]

There is a slight flicker at 3.6v that flashes to 1.x v I blame it on unsteady hands but it seems to do it every time but I can't keep the lever on that spot to get it to hold the 1.x v in mid throtte

 

[C30454]

Are you checking the fuel pressure while the problem is actually occurring?

And unless you've had a custom tune, I can't imagine that the system prefers 20psi to 13psi.



Tom

 

[magimerlin]

Where and how did you check t his death fuel pressure at??

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