Engine stalling out HELP

[Gunny Davis]

Recently finished the 5.3/4l60e engine tranny swap out of a 99 Silverado in to my 72 Blazer 4X4. I swapped everything i could get my hands on...
Enigine, Trans, Wireing Harness and PCM, Under hood Fuse Block, Fuel lines and in tank pump, Instrument cluster...Everything. Had the Vats removed by Brendan LT1SWAP.

The swap has been running great. Better then great. For one full tank. Filled up with gas headed for the lake and got 2 miles and began to stall under a load. If I accelerate, go up a hill, even power brake the thing wants to cut out. occaisionaly sputters and jumps, but tends to stall out. Starts right back up, idles like a champ, sounds great just does not want to take off.
WTF????????
I really need some help on this one.

checked the O2s, Maf, Fuel pump, nothing seems to have come unplugged. Just don't know what to look for next.

[68GMCCustom]

sounds like a fuel problem....verify fuel pressure at the rails?

[Gunny Davis]

My suspition as well. Gotta ask... How can I verify / check fuel pressure on the 99 vortec? I just don't have any experience on that subject.

Thanks

[68GMCCustom]

should be a schrader valve on one side of the fuel rail...

[ls1nova71]

Originally Posted by Gunny Davis

My suspition as well. Gotta ask... How can I verify / check fuel pressure on the 99 vortec? I just don't have any experience on that subject.

Thanks

You'll need a fuel injection fuel pressure gauge, and then like 68GMC said, hook it to the schrader valve on the passenger fuel rail. You should be somewhere around 58psi.

[Gunny Davis]

picked up a loaner Scanner and Pressure guage from Autozone. Scanner is giving
P0135 -O2 Heater circuit malfunction bank 1, sensor 1.
Pressure guage sits right around 50psi

Is the fuel pressure a problem?

I checked the heater circut in the O2 sensor with meter and it seems fine, checked plug {power and ground are good.

I recently was tightening some wires up and wrapping up some loose ones. Guess I developed a short; so I pulled all that apart and everything seems good now. resoldered the fuel pump connection...

Took it for a drive and seems to run great so far but still showing the P0135 code. Can this be intermitant or could this be giving me a problem once it warms up? Seems it would be the opposite but everytime I had a problem was when the engine has warmed up.... I get away from the house a couple of miles before it goes to ****.

[nacho55]

i dont know about the codes someone smarter will chime in on those, but which fuel pump are you using? I am using the ACdelco EP381 and have a little higher pressure at idle like 55-56psi, i was also having some stumbling problems and stalling problems and it this may not be your problem but on my swap my fuel filter keeps getting pluged up, and i was having a gounding issue where it was cutting out the motor, the ground wires are really important on these motors, i found that out the hard way, now mine runs great just having a dirty tank issue

[BR3W CITY]

If I ran into that code, I'd try a new sensor. Its either that or the connectors are corroded.

The sensor is really the only thing that can flip that code.

[Gunny Davis]

Thanks guy for all your help... did some research and found a very common thread to be dirty MAF from K&N style filters.

Got some MAF cleaner and gave it a good once over
Swaped L O2 for R O2
Cranked it up and runs like a champ smokin tires and everything.
No more codes
Fuel pressure still at 50 but doesn't seem like its starvin