Fuel Pump Blues (I think)

[SnowDogg]

Hi everyone,

2007 4.7L. Base issue is excessive cranking time (occasionally). I have also seen a code thrown for cyl 7 misfire (cleared it and it has not reoccurred, so thinking fuel pressure problem). If I turn key on for 10 seconds, then off for 5, then back on it will start immediately.

Checking fuel pressure at the rail, reading with key on is zero. Start up and pressure is 46 steady, shut engine off and goes to zero immediately.

I'm guessing bad check valve in the pump assembly and plan to replace the pump. It was replaced a couple years ago by Firestone, then failed and was replaced again. Can't remember the brand they used, but am looking at the Denso unit at RockAuto.

Advise requested: am I on the right track or is there anything else I should check? I don't look forward to dropping the tank.

Thanks!

 

[SYKRAMMAN]

I believe your on the right track, dropping the tank isn’t as bad as you would think, do it on an empty tank if you can, the tanks are pretty light in comparison to the old metal ones. Just soak the bolts with some pb for a little while before removal for ease if they are crusty or not.

While you have it all down, check the lines/connections for dry rot, corrosion, etc, put some dielectric grease on the weather pack connectors. That’s about all I have, others know more about it if you can wait for more replies. Gl bud.

 

[Ramnewbie]

I believe your on the right track, dropping the tank isn’t as bad as you would think, do it on an empty tank if you can, the tanks are pretty light in comparison to the old metal ones. Just soak the bolts with some pb for a little while before removal for ease if they are crusty or not.

While you have it all down, check the lines/connections for dry rot, corrosion, etc, put some dielectric grease on the weather pack connectors. That’s about all I have, others know more about it if you can wait for more replies. Gl bud.

I've heard many reports that it's a lot easier to lift the bed rather than drop the tank. I've never done either so can't verify this but if I was in need of replacing my fuel pump I'd be checking this option out.

Sent from my XT1650 using Tapatalk

 

[Jason G Slabaugh]

Removing the bed takes a few people to lift it back but yes it's less time to remove than a fuel tank

 

[Jason G Slabaugh]

I've done this before as well, just takes 4 people to pick up and move the bed back enough to access the pump, much easier than dropping the tank etc.

 

[SnowDogg]

Update:
Got job done over the weekend, I did drop the tank as I wanted to do a clean-out and I don't have the impact tools probably need for the bed bolts. Now that I've done it and seen where everything is I could probably do it in a couple hours. Anyway....

Replaced with the Delphi unit (bad unit was Carter). Carter had good review, but as it started failing less than a year in I'm happy I didn't go that way. Pressure now good at 58 lbs, and holding after shutdown. Engine running great with immediate start. In-town MPG even went up by a couple whole numbers!