truck falls on its face under hard aslcceleration....

[draggin95niss]

I have a 96 ecsb w/350 an it falls on its face under hard acceleration so i scanned it and came up with po441, po155....not really sure what to start looking at from here....

 

[1993GMCSierra]

Well, let's start with the codes.

A code P0441 could mean one or more of the following has happened:

Bad vacuum switch
Broken or damaged EVAP line or canister
Open in PCM purge command circuit
Open or short in Voltage feed circuit to Purge Solenoid
Faulty purge solenoid
Restriction in EVAP solenoid, line or canister
Corrosion or resistance in purge connector
Bad PCM



A code P0155 may mean that one or more of the following has happened:

O2 Heater element resistance is high
Internal short or open in the heater element
O2 heater circuit wiring high resistance
open or short to ground in the wiring harness


So, you might want to try to replace the O2 sensor first. If it isn't working right, it can make the truck run too lean, or too rich, causing the problem you are having. I would recommend replacing it with an AC Delco one. Not sure how well the "parts store" brands work.


The EVAP code likely isn't causing this issue, so I wouldn't worry about that one right off the bat.

 

[draggin95niss]

Well when i scanned it the 1st code was the p0441 but then i looked thru the enhanced codes and listed the p0155...could one code cause the other to pop on? Meaning only one or the other is the problem...

 

[draggin95niss]

Well i replaced the 02 sensor an new gas cap an cleared the codes, no more codes but the truck still runs the same...i checked the fuel pressure an its 60 psi, but funny thing is the gas that dripped from the gauge hose after testing the fuel pressure was piss yellow, could this b bad gas? Pretty sure gas is pretty much clear but in a bottle has a brown tint...

 

[1993GMCSierra]

Any way you can monitor the fuel pressure while driving? If so, punch it and see what it does. Might be time for a fuel pump.

Have you changed the filter?

Had a '95 Caprice that for YEARS would never start on the first try.

Had to turn the key forward, wait a bit, and it off 2-3x, then try.

Replaced the filter when dad gave it to me, and it literally started in under half a second.

 

[draggin95niss]

The fuel pump and filter are 6 months old....

 

[Johnbalderas90k1500]

Sound like a fuel problem to me, how does it run at an idle?

 

[draggin95niss]

I agree its fuel related, ive swapped the pump twice in 1 week, so far ive got 60psi on prime then drop to 58, then jump to 60 while cranking, then drop to 56 while idling, it jumps to 59-60 when i hit the throttle...ive been told several pressures by several different people...not sure what to believe...the chiltons say 60-66 but the dealer says 54-62....

 

[stroker52]

man everything you just said sounds about right..

 

[Red91]

From my experience when vehicles fall on thier face under hard acceleration it is dumping way too much fuel. It sounds to me like it's running rich. I would test the o2 sensor and see where you are at. Just my .02.