Stangas

also noticed a slightly kinked return line from the pressure regulator... but i cant see a this causing low pressure.. if anything it would restrict the return flow

When i replaced the regulator i did blow through it to check there was flow, and definitely was

Stangas

thinking out loud...

There was definitely flow to the inlet of the pump without the rear pumps pumping.. so gravity i would have to assume..

if i disconnect the supply to the inline pump and turn the ignition on.. you would expect an increased pumped flow?? I might go try that now..

If you see the explosion from Iowa you know it went wrong..... LMFAO!!

fltdriver

Does this happen with both tanks (stalling, dying, etc..)? If so, and since it appears that you covered all of the other possibilities, I would guess that the high pressure pump isn't doing it's job properly. Whether this be because it's going bad, or an air leak before the pump so it's pumping gas and air, or because it's just not getting enough gas from the tank pumps. If I can see an explosion from here you had WAY to much gas in the tank.

Stangas

lol... just did some more brain storming..

your right.. i can switch tanks and that tank empties.. it is the same with both tanks.. so it has to be on the common side of the line.. therefore the rear tank pumps must be working, otherwise i wouldnt be able to select, it would just take from a random tank or not work at all.

That is the theory that i was using this morning and the reason i replaced the HP pump and the filter.

I also replaced the hose from the filter to the fuel rail

Ford 4x4

I would be looking at the chassis pump, or the tank selector valve, or reservoir that is on the rail. Otherwise I have to say bad computer as well. My 89 had a bad computer and it pinned the injectors wide open and it was dumping fuel into the engine. It was sputtering and stalling and everything and it had normal fuel pressure, it was just dumping everything into the cylinders

Stangas

ok... both rear tanks are working fine.. did the dodgy disconnect the fuel line and turn the key on... pumped good.

The main pump (new one) is now pumping 35psi with engine off... and 30psi with engine running and increasing to 38psi with the vacuum disconnected from the regulator.

The bible (Blue Ford Manual) says this is the expected pressures. Note: the dodgy made in china fuel pressure gauge i am using could be erroneous.

SO.. fuel pressure is higher than before, and within specs..

SOOOO... still have the stalling on just off idle and when pulling to a stop.

Need to re-investigate the ECU that the mechanic said.. will have to take back the comment about mechanics.. LOL

Stangas

This does sound like the same problem i am having... ECU hey?? and it fixed it??

Chris_1

iTrader: (1)

Fuel pressure is still a little lower than I would have expected from a brand new pump, so the ecu keeping the injectors open is possible. ecu is an expensive guess though, you'll want to test whether they are pulsing properly or not before spending that.
Test the throttle position sensor for a flat spot in the voltage, clean the idle air control and test that it's getting proper voltage. Those won't cost you much to check.
There is a o-ring type gasket at the tank which seals the sender unit plate to the tank. That could be the source of your air leak (which will be a gas leak when the tank is full). If the lines are all the way on and don't leak, you should be fine. Don't forget to put the retainer clips back on.
Best we can do from here is long range guessing you understand, but we'll try to help you work through it. You just never know if it's one simple thing or a combination...

Aktech

Etc? Sounds like it runs good when it is cold.

Chris_1

iTrader: (1)

Just to back up to the beginning for a minute - did you try unplugging the O2 sensor ?