Engine/Transmission (1994 - 1998) OF Valve Enumero Dos en route...

[biggy238]

I'm buying one more valve. If this thing doesn't suit me, I have half a mind to pull a Gene (Sled Puller) and put an onoff valve on it. Maybe some new lines here and there. . (everywhere)



If i'm going to throw money at it, i want to see results that I like.



AQP hoses all around. . Electric pusher pump... maybe FASS. . I dunno I haven't looked into them yet. I guess I can deside next week when this valve doesn't fix it either.

(anyone think i'm frustrated yet?)

 

[BTighe]

i was thinking the same thing as far as the FASS system. just changed the fuel filter and had to put it together 3x because of the seal that sits on the filter wouldnt go on right. its started leaking again today. would a FASS system have any benifit for a 12v to justify the cost?



sorry to hijack your thread but its the same topic.

 

[Joe G.]

The stock 12 valve fuel supply system will supply enough fuel to make 800 HP in Joe D's sickly old '97. If you have tried more than one OF valve and still have the problem then you are barking up the wrong tree. I've listed several times the things that may go wrong and cause problems. If you are methodical and do the necessary tests you can find it. Probably cheap to fix too.

 

[biggy238]

You've been patient with me Joe.

Just let me try thise one out and then I will go elsewhere on my search.

Like I said, I just don't get it. No feul anywhere it doesn't belong, new filters, And I drove on this last valve for 8000 miles.



My mistake last time was with the spring. I played with this old valve enough to get the psi back out of the teens during heavy throttle but then it also idles up into the 60's. It's too broad a range to just pinpoint ya know?



I don't see how a leak ahead of the lift pump could drop the psi under throttle-to the point that it does- and then idle to the tune of 60psi. I shouldn't be able to suck the lines dry one second and then blow them out the next. All i've done is slide the plate. . It shouldn't be that much fuel moving.



We shall see.

 

[Joe G.]

I would truly like to see the OF valve fix it, but I suspect that it won't. If you have an air leak before the lift pump then you are trying to pump fuel with air bubbles in it. Screws things up to say the least. If the leak is not too bad then you won't see anything to indicate that there is a leak.

 

[biggy238]

Well... I got my new overflow valve on Joe. 16 psi all the time. idle, Wide open throttled, cruising. I have noticed about 200* higher egt top end and heavy throttle.

Before, it took everything I had to get 1030* and now I can hit it easily, who knows about what it would do towing. Also more smoke at a kickdown at highway speed, so it's difenately getting fuel. I'm impressed that I can't suck the pressure down with the pedal anymore. The only time I noticed it come off 16psi was when it brakes. I can't actually duplicate the situation consistently (yet) but the psi drops down into the 9psi range. If I can figure out how to duplicate the situation, i'm thinking an airleak in the fuel pickup maybe? It seems to only happen at a long drawn out stop, like a stop light. 70-0mph stop. I just wanted to throw that out there to you.

I've never doubted you, I just wanted to get my pressure back out of pressurized explosion range. Any new thoughts? When the temp drops i'll get under it and start looking for obvious trouble spots.

 

[Joe G.]

16 PSI is way low so you have not solved the problem. You should be seeing at least 18 PSI at idle. It should run down the road at 25 PSI or more. The OF valve is supposed to open at 25 PSI according to the service manual. Have you done anything other than change OF valves?

 

[biggy238]

Not at this point, I haven't changed anything else. Like I said, I just wanted the pressure back down from the (pegging a 75psi gauge) range it was in. When It's cool enough to lay on the concrete i'm going to check the compression fitting on the frame and the new hose I ran from the fuel heater to the lift pump. I don't want to sound belligerant or too foolish i'm just trying to do what I can as I can.

 

[JAmos]

What about the possibility of a pinched/kinked/plugged fuel return line? It would seem to produce the same symptoms that you have because if you pinch the return line the pressure would be high and the overflow valve might not be able to relieve any/enough pressure, highly likely if the kink is after the overflow valve. At wide open throttle you might be burning enough fuel to bring the pressure back down, especially if the lift pump isn't putting out a lot of volume. I know that you mentioned changing a fuel line, I have heard that the rubber lines can deteriorate inside and choke off fuel flow. Hope this might help.



Jordan

 

[biggy238]

My pressure is too low now.

Actually, what started all of this back in about march was that the return hose had been replaced by A piece that was about a foot in excess. When I replaced the fuel filter(8000miles ago), the new one caught the line between it and the output line from the lift pump.

Before All of this, I had good pressure.

I tried replacing my OF valve first before I caught that the line was pinched. I've fixed it but my fuel pressure never returned. I replaced my lift pump, a wasted effort from what i'm told. The body of the new lift pump is shorter than the old one so it had the input line folded to the point it was restrictive. I replaced it. I mangled the spring on the (then new) overflow valve and salvaged one good valve from the two I had and it held good pressure up until I changed fuel filters again. After this fuel filter change(1000m ago), my pressure jumped again, but the return line is clear. I removed the overflow valve, this being the one I hacked together, and it looks like the spring has cocked itself over to one side and won't let the check ball ride up the bore naturally. I put the brand new, virgin overflow valve on this morning, and it is holding 16psi under all load conditions. As joe suggested, among other things, I think it has an air leak. If it doesn't. . I don't know.

 

[biggy238]

And yes, everything is helpful.



Joes checklist:



Fuel supply and return hoses

Partially checked and replaced



Overflow valve spring less than 1/2" long

New Part- 3/4" long



Fuel heater

Not messed with yet.



Fitting on top of fuel heater

Checked



Pre-filter and fuel heater gaskets

????? Needs looked into.



Fitting on input to fuel filter

Checked



Curved hose between pre-filter and lift pump

New Parts



Sticking fuel solenoid

Checked Fine



Lift pump O-rings

New Parts



Lift pump

New Parts



I can't lay on the fender to work on the fuel sytem much due to rescent surgery so it will be a week or so before the rest can be tended too.



When I find the failure... I'm burning whatever it is after it's replaced. I popped the compression fittings loose when my pressure was too high to check the lines and I think it might be suspect.