Well I was having an issue with my truck losing power on the highway but i replaced my FPR and that part is now fixed but my next issue is when I drive the truck on the highway or around town for an hour or so, when i park the truck and turn it off it doesn't want to start again. What happens is I will try and start it and it will start, rev to 1500 or so and drop to 500rpm, for a split sec then die and will continue to do that. It will eventually stay running but will sit at 500 rpm and just chug and chug and chug and never get the revs up to normal. If I give it and amount of gas it ill usually just die. I have figured out that if I tap the gas slightly very quickly it will work the revs up to about a 100 and then will run at normal 900 rpms or so but run very poorly and will continue to run poorly untill i shut the truck off and let it totally cool down for an hour or so.

 

O and I have codes 181 and 172 but I think those are from the occasional time the CEL comes on while driving which I'm hoping these things might be related.

 

What are the fuel pressure readings?

 

Well I not exactly sure. I bought a fuel pressure gauge to work on the problem i was having before and narrowed it down to the FPR or the pump but i have already replaced the pump so i replaced the FPR and it help out a lot but the pressure gauge i think is faulty cause it just didn't seem to be consistent. It said I was getting between 30 - 50(on occasion) but even after the FPR was replaced it ran better but the pressure still would never change even when pulling the vacuum line to the FPR.

 

How about the fuel filter am I missing where you stated you replaced it in there someplace?

Rent, buy or borrow a good gauge and get a solid reading for fuel pressure (possible you are with the one you have now and due to clogged filter getting erratic readings from it?).

Your codes both state lean and lean at richest adaptive limit meaning it couldn't get a rich mixture when it tried going full rich basically injectors wide open.

Its either not enough fuel or way to much air. Based on your statements about how it runs, I lean and at least for the moment, toward not enough fuel. Either not enough pressure or not enough volume at pressure it requires either one or some combination of both.

 

I have replaced the filter right before I spent the 80 bucks for the FPR just to make sure that wasn't it. I will try and find a gauge. What suggestions would you have for a replacement fuel pump? Is the pump different between the I6 and the other engine that come in the for? I know the I6 runs a high pressure to the rail.

 

You can pinch off the fuel return line right after the fuel rail, rubber section of it, use c clamp or suitable tool to crush it to nearly limit all fuel from returning to tank. Don't want to dead head it but dang near it, pressure should hit nearing 90-100 psi or so.

Do so only briefly, if hits that kinda pressure the pump is working.

If not and have dual tanks you might be suffering fuel transfer problem, fuel from selected front tank being pumped to rear tank via its supply line for example.

Might also explain your erratic fp readings, check valve not fully closed but not fully open either varying amount it's limiting fuel returning to tank.

Speculation at best though as information on your truck has not been provided, beyond it's engine that is.

 

Did have dual tanks but removed front tank and capped of lines using the coupling off of the metal fuel lines feeding into the tank. I will find another gauge and do some testing.

 

Ok I got my fuel pressure gauge back out and hooked it up to see whats going on and hoping it is right i guess cause i cant find anyone with another one to borrow. Fuel pressure is at 36 psi with the truck running and does not change if I pull the vacuum on the FPR which is brand new.

 

What happens if you attempt to give it some throttle while watching the gauge? reading start to drop right off or does it hold at 36psi?

Sounds like a problem in the FPR, it should increase 5 to 10psi with the vac line disconnected. I'd expect to see a 10psi increase with a good fuel pump and fresh FPR.

Limit the fuel return nearly 100% just briefly, to verify the new pump is capable of supplying higher pressures before say condemning the new FPR.

 

After messing with my gauge a little bit I kept having the feeling it wasn't right but i finally figured out the problem with the gauge. Where the two hoses connect there is a valve like in a tire that wasn't getting fully depressed which was causing inaccurate reading. Anyway it is working very well now.

The gauge now always reads 36psi. When I remove the vacuum line to the FPR the needle will rapidly bounce back and forth of +or- 4-5 psi while the engine is running. When I rev the engine it will drop to about 30 - 32 psi

 

Ok that's still not good the fp should raise 5 to 10 psi and hold there with the vac line disconnected from the FPR, hold thumb over end of vac line.

Goosing the throttle wide open then allowing it to close should cause the same, the fuel pressure reading should increase. It should not decrease during either test.

Question remains is your +or- 4-5 psi reading a fault in your fuel pressure gauge or a fault in the system.

 

I also forgot to mention I did clamp the return line with no change either. Could I have just got a bad fuel pump that is only capable of putting out 36 psi? Do the other engines that come in the F150 have different fuel pumps that do put out that much pressure?

 

No that's not good have you done a static pressure test yet.

Connect your fuel pressure gauge to the fuel rail, cycle the key on and off couple times allowing it to build full pressure then turn off the key, then monitor the gauge see how well the system holds pressure.

You have the 300 6 correct? you should be seeing pressure reading of 50 to 60psi KOEO.

Static pressure test, it should hold within 5psi of spec and for 1 minute after turning off the key.

I still kinda question your testing your gauge readings, only you know for sure if they are close to accurate. If any doubt you should get another gauge.

 

I have done a test like that a few times cause i read there is a possibility of leaky injectors but the pressure i do have in the line holds strong.

I have had my gauge hooked up now for a few days and I'm am always getting a consistent 36 psi. It doesn't go up with the FPR vacuum disconnected, doesn't ever build more pressure with the return crimped, and hold pressure after the truck has been turned off.

Just to make sure I'm doing all these tests right the only place I need to be taping into the fuel line for these is the schrader valve on the fuel rail right?

I do have the I6 300 motor.

Do I just have a sissy little pump in my fuel tank?