Fuel Pressure too high

[Lone_Domino]

I am trying to find out why my transplanted 84 t-type motor is running so rich. Hooked up a fuel pressure guage today and when idleing I have 85-88 psi. That would do it! When the key is turned off it goes back down to 42 where it is supposed to be set. This is without the vaccum line attached, attached it is 88-90 psi. The adjustment screw makes no difference when it is running, only when off but key in on position to power up the pump.

Any suggestions?

Summit Racing external pump (43 gph, 85 psi max)
Accufab adjustable regulator

No scantool yet, still recovering from the tranplant costs.

 

[Jerryl]

I am trying to find out why my transplanted 84 t-type motor is running so rich. Hooked up a fuel pressure guage today and when idleing I have 85-88 psi. That would do it! When the key is turned off it goes back down to 42 where it is supposed to be set. This is without the vaccum line attached, attached it is 88-90 psi. The adjustment screw makes no difference when it is running, only when off but key in on position to power up the pump.

Any suggestions?

Summit Racing external pump (43 gph, 85 psi max)
Accufab adjustable regulator

No scantool yet, still recovering from the tranplant costs.

Suggstions;
Verify that the return line from the FPR to the tank is unrestricted.
Keep the boost low, and get a TT chip and a scantool.

 

[Lone_Domino]

Suggstions;
Verify that the return line from the FPR to the tank is unrestricted.
Keep the boost low, and get a TT chip and a scantool.

I can blow through from the fpr to the tank with compressed air at low pressure so that is okay.

Boost is turned way down since this is my 16-year-old's car

With the key on but not started it is set properly, why would it go up 40psi when running?

Scantool is in the plans, just going to take a bit.

 

[dees75z]

I would say possibly might be regulator, or is it brand new??

 

[Lone_Domino]

I would say possibly might be regulator, or is it brand new??

Not new, it came with the engine. I threw away a good stock regulator last year I'm going to see if a buddy has a spare I can borrow before buying a new one.

I can adjust the pressure on the accufab as long as the engine is not running. Once it is started, the pressure goes up and the adjustment screw makes no difference.

 

[dees75z]

There has to been some type of return restricition going on there. That sucks about throwing away a good stocker, lol. Keep us updated, I am interested as to what the solution is.

dee

 

[Lone_Domino]

Tonight I will disconnect the return line by the filter and port it to a gas can and see what happens, that will narrow things down.

 

[Chuck Leeper]

??

Tonight I will disconnect the return line by the filter and port it to a gas can and see what happens, that will narrow things down.

You aren't saying the return goes thru a filter, are you?

 

[Lone_Domino]

You aren't saying the return goes thru a filter, are you?

No, by the fuel filter the supply and return lines have unions with the hard lines that go to the back of the car. I will disconnect the return line there and check if that makes a difference.

 

[dees75z]

Sounds good man I know what you ment, lol. Let us know

dee

 

[Lone_Domino]

Where the return line goes into the tank hanger, there is a reducer and a deflector. The reducer was only about 1/16" in diameter vs. 1/8" on the t-type hanger. I opened it up (it's brass), cleaned it up thoroughly and re-assembled. All is well! Now it idles correctly and I get no SES light at idle.

 

[dees75z]

Well, congrats man!!! I knew it had to be some type of return restriction there!!! Glad you can find it, and hope that he/she can drive it now!!!!

dee

 

[Lone_Domino]

I hope the gas mileage goes up to where it should be! It was averaging 14 with me driving, 11-12 with my son driving.
thanks!

 

[dees75z]

Don't know how the fuel milage is on these things, but I would say it will be alot better than that man!!! lol

(Haven't even driven mine a mile yet, lol)

 

[Jerryl]

I hope the gas mileage goes up to where it should be! It was averaging 14 with me driving, 11-12 with my son driving.
thanks!

Glad you got it fixed.
FWIW; I see anything from 11-16 in town and 22-25 on the hyway.