99 5.0 starts, runs for a few seconds then dies

[newstylecustoms]

This is actually in a 99 Ranger with the 5.0 swap. I have checked fuel pressure and it seems to be slow to build but stays in 55 psi range even while the engine is sputtering out. My first thought was fuel pump but I should see the pressure drop off, correct? With the MAF disconnected it starts and stay running, revs fine. So is it just the MAF that is bad?

Thanks in advance

 

[Mr. Alligator]

Can you try to clean the MAF?

First idea. Low cost and simple.

Good luck.

 

[newstylecustoms]

I did try cleaning it but it did not help.

 

[newstylecustoms]

SOLUTION! Replaced the MAF, runs fine now

 

[CDW6212R]

Check the fuel pressure again, be sure the gauge is accurate. That 55psi is on the edge of being very lean, it should be closer to 60psi on the low side. My 99 threw a random lean code rarely, and testing it showed 54-58psi three times, and then the next time it was 52psi. I changed the fuel pump, and found the leak in the rubber hose on the pump. It was split barely, and the slight leak lowered the pressure until it finally affected the high rpm running of the engine.

 

[Fix4Dirt]

hows fuel pump? do you have latger injectors?

 

[newstylecustoms]

Stock injectors and I didn't pay very close attention to the exact PSI, mainly I was watching for it to drop off and it did not. Regardless the truck runs great again after the new MAF that that is all we needed for now.

 

[CDW6212R]

Watch for a CEL light, it will trigger when it perceives a lean condition. My CEL came on very rarely over several years, only in the last year did I have a slight loss of power at high speed and WOT. The pressure should be 60-65psi, the 55psi range is lower than it should be. That could be a weak pump, or the FPR which is in next to the pump, or the rubber lines there leaking barely. Thus be sure the fuel pressure gauge you use is accurate, a bad gauge can also cause worries.

 

[410Fortune]

99 ranger it returnless fuel it should be 64 psi +/- 8
55 is low, but on the bottom side of acceptable

The donor 5.0 fuel rail should also be return-less (one fuel line) from a 98-01 5.0, they use 19# injectors that are white from the factory with e46 wiring connectors

Good luck!