I have a head scratcher. Whenever I fill up, truck is low on power for the next 20-30 minutes. The truck will usually die, ONE TIME, the first time you let off to stop. This can be one mile down the road or twenty miles. Cranks right back and won't die again. We have tried not topping off the tank, leaving cap off, and fueling at different tank levels. Lift pump is new. Truck runs fine with full power after 20-30 miles. Power comes back gradually, it's not like flipping a switch. Engine temp doesn't matter.

Thanks

Ok, he blew air through supply line and return line. Didn't help. Going to check vent lines now.

The vent on the top of the tank can plug easily. There is a MOPAR solution to this, but I haven't gotten around to installing it on my truck yet.

The vent on the top of the tank can plug easily. There is a MOPAR solution to this, but I haven't gotten around to installing it on my truck yet.

ya know.... this ^^^^^   made a lght bulb  go off here!       a  full tank  would  quickly build a lot of  vacuum..     and  sure  could  cause  his   problems!

ya know.... this ^^^^^ made a lght bulb go off here! a full tank would quickly build a lot of vacuum.. and sure could cause his problems!

I may be wrong but he said he left the cap off and it still did it

I may be wrong but he said he left the cap off and it still did it

 

 

sigh..  yep you're right.   Light bub  is  now  burnt out.

    I would open the valve on the fuel filter and see if there is any water. When was the filter changed last?

Ok guys I'm bringing this thread back up. Truck still has the issue of dying, ONCE, after every fill up. It will die the first time you slow for a turn or stop sign. Truck cranks right back and usually will not die again. It is very low on power after filling up, but power gradually comes back 30-50 miles down the road.

To date we have:

Changed fuel filters numerous times

New lift pump (under the hood)

Rebuilt CP3

Blew through all lines and vents

Dropped the tank to check for debris

Cleaned intake screen on fuel canister

We have found filling to 1/2 tank does not cause the issue.

Anything y'all think we missed?

Are the lift pumps on the 3rd gens inside the tank? Or someplace else? If it is inside the tank, when it is filled up maybe there is fuel getting inside the pump? I know that the CP3 is able to pull its own fuel but if there is a problem with the lift pump, could it die out like that? Just trying to think outside the box a bit.

I believe it's a controlled vent cap.  Perhaps the cap is NG.   

I would be getting a live data tool and watching the rail pressure and lift pump pressure and see what's going on.

 

I know that 3rd Gen's have rail pressure sensor which I'm not exactly sure how it effects the trucks performance if it bad.

 

Russ has a good point of the fuel cap being possible. Tank vent's are typically vacuum release but not pressure. So now I got to ask is it possible there is cylinder pressure leaking back into the fuel tank through the return rail of the injectors. Most likely a bad copper shim?

We had a car once that got a piece of the aluminum seal, that comes on bottels of injector cleaner, down inside the tank. For the most part it drove great, but every now and then the car would just die. It was too big to get sucked through the lines. Just a thought.

I think it may be "air bubbles" in the fuel.  

 

Which is more likely after a fill up.

We had a car once that got a piece of the aluminum seal, that comes on bottels of injector cleaner, down inside the tank. For the most part it drove great, but every now and then the car would just die. It was too big to get sucked through the lines. Just a thought.

 

A very long time ago, I had a 76 Datsun P/U...  back when the gas station attendants pumped your gas.  The little truck would randomly shut off.  I switched to a glass bowl filter thinking it might be water condensing in the fuel (right on the coast).  I found when it stalled, the only thing that would get it restarted was to swap out the filter element.  I collected the gas in a sealed glass jar but never found any water.  I could even dry out the filters in the shop (and the rubber gaskets which would swell but return when dried out).   Eventually I dropped the tank & fished out the cardboard seals from dry gas from the tank.  F*ckin gas jockeys.  

Conclusion:  opening the filter broke the vacume & allowed the cardboard to float away from the pickup tube.    

 

Not sure this applies the problem in this thread. 

Edited March 13, 201510 yr by flagmanruss

I would be getting a live data tool and watching the rail pressure and lift pump pressure and see what's going on.

 

I know that 3rd Gen's have rail pressure sensor which I'm not exactly sure how it effects the trucks performance if it bad.

 

Russ has a good point of the fuel cap being possible. Tank vent's are typically vacuum release but not pressure. So now I got to ask is it possible there is cylinder pressure leaking back into the fuel tank through the return rail of the injectors. Most likely a bad copper shim?

 

I think this is the only logical next step is to get some live data.. It sounds like something is aereating the fuel causing low rail pressure which eventually works its way out  I have seen a graph somewhere of how the CR fuel system works.. Mike may have it in the archives somewhere???

 

Any changes, or modifications made around the time this started happening?

Edited March 15, 201510 yr by angus

I think this is the only logical next step is to get some live data.. It sounds like something is aereating the fuel causing low rail pressure which eventually works its way out  I have seen a graph somewhere of how the CR fuel system works.. Mike may have it in the archives somewhere???

 

Any changes, or modifications made around the time this started happening?

 

 

 

If there is air in the system post FF/CP3 the CR fuel system purges the air out.  If the air is in the tank and/or the lines, you can get a low FP situation or even a no pumping situation depending on the pump.  I would also check the fuel cap and the tank vent.

I thought I read back toward the beginning of this thread where he actually left the cap off and it still died?

 

That would seem to rule out the cap, or the vent right..??   So what happens when a tank is topped off? The return line is submerged, The return encounters some slight backpressure?  How is the returm line regulated?

 

Just looking outside the box... cause it looks like the op has covered all his bases short of getting some live data..

Ok, he blew air through supply line and return line. Didn't help. Going to check vent lines now.

 

There are several return lines around the engine. Did the head return line get checked?