Code 54...

[flipster125]

ok, so I've been having problems with my 89 blazer (4.3 TBI) and have already made a post with all the problems...

http://www.automotiveforums.com/vbul...d.php?t=395790

Basically it won't idle when cold, and when cold will stall if you give it too much gas. (You have to accelerate very slowly) Once warm it is better, but still nowhere near what it should be...

Then yesterday while driving home from work, I got a code 54. (Fuel pump voltage under 2 volts while motor running) however the truck did not stall or run any worse then it has been... the code has since gone away, but it at least gave me a clue (I hope) as to what's wrong.

As far as I can tell by looking at the circuit diagram, if the fuel pressure remained high (from say a blockage) the "oil pressure switch" in the diagram (which I assume is actually measuring fuel pressure) wouldn't send voltage to the pump, giving a code 54. Am I right? if so, what could be blocked? the fuel pump was replaced last month (albeit from a scrap yard, but it was in A-1 condition, and I can hear it going for 2 seconds when you turn the ignition on) The fuel filter is brand new last week. The injectors are from another truck that was running fine. I should point out that the truck had been sitting for 4 years before I got it, and the old gas was so bad that it ate through the old fuel pump and jammed the injectors. Even the fuel filter was so badly jammed that you couldn't blow through it no matter how hard you tried. (hence those 3 things (including the entire gas tank) being replaced) Is there anything else I need to change? I don't know anywhere else that could be blocked... (if that's even my problem)

Anyways, any help would be MUCH appreciated

Thanks, Thomas

[s10blazerman4x4]

why couldnt you just post it in that thread instead of starting a new one

[blazee]

Why didn't you post in the original thread?

Code 54 is a problem with the fuel pump circuit. Check all the wiring including the relay (swap it out with one you know is good) There could be a loose or corroded connection somewhere considering it sat as long as it did.

The oil pressure switch is a back-up to the relay and a safety feature. It does monitor oil pressure (not fuel pressure). When the oil pressure reaches 4psi the switch closes suppling power to the pump, bypassing the relay. Also if your oil pressure drops below 4psi it will kill the power to pump, killing the engine and hopefully preventing serious damage.

[BlazerLT]

Thread closed, post this in your original thread.

No need to make another thread.