Fuel Problem

[RedsRam]

Hello and thanks for having me here. My truck is a 04 ram 1500 5.7 qcsb 4x4. Today when I was leaving work my truck started first turn as normal and then just fell on its face. With key on the truck hits 50 psi fuel pressure at the rail. When I start it's the pressure drops to 0 psi in about 2 seconds. When i turn the key off and then back on it jumps straight to 50 psi and the process repeats.

I used my Genysis OTC and did a all dtc scan. I did a security sweep. (Maybe key lost signal). In live data stream everything was reading just fine except it never showed fuel pump relay "on". My initial response was to replace the relay and check all fuses.

I'm normally great at diagnosing other peoples vehicles but when I comes to mine I'm always at a loss.

 

[xb1230]

Fuel pumps are notorious for failing on the RAM. It may still be working just enough to build initial pressure but cannot supply enough to maintain it during running conditions.

Get a good replacement if that is the issue, most folks here will tell you to avoid Airtex.

 

[RedsRam]

I would suspect a fuel pump if it had low pressure before. On key it jumps straight to 50 psi with 0 hesitation. I forgot to mention I I do work on vehicles. Just not as familiar with gas ram truck. Am I mistaken that these trucks have problems with there fuse boxes?

 

[RonJon '06]

Could be the Auto Shut Down (ASD) relay and yes the circuit boards are prone to corrosion because they aren't protected well from the elements underneath. I would start with inspecting the board and try swapping relays.

 

[Kevnic]

I just went thru hell diagnosing electrical problems with my truck. Took the fusebox apart to find massive corrosion. New it is 600 dollars, so I did some improvising.

 

[RedsRam]

Relays have been swap/replaced. I will inspect for corrosion this morning. Thanks for the direction guys.

 

[RedsRam]

FIXED! Corroded wire at the fuel pump hosting

 

[RedsRam]

*housing