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86 Turbowagon fuel pressure regulator?


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11 replies to this topic

#1 baccaruda

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Posted 03 February 2004 - 06:51 PM

anyone know where the fuel pressure regulator is on an 86 turbowagon? in reference to this earlier post of mine regarding the throttle cutout..
i took the car to a REAL MECHANIC :P and he verified that something is shutting off the injectors at 2300RPM.
we agree that it occurs as the turbo is starting to do its job. He is inclined to blame the 2.5" freeflow exhaust on my car. I am inclined not to, as many of you have similar setups without similar problems, and the problem is a more recent development than is the exhaust anyway.
He suggested the MAF based fuel cut, but again, i don't agree because the turbo isn't even on yet. I also switched out the MAF and ECU last weekend without affecting the problem.
He eliminated the throttle position sensor as a cause.

So he suggested that I check on a boost sensor for the turbo or for a fuel pressure regulation problem. anyone know where in the engine bay these are?
Thanks..

#2 Subarutex

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Posted 03 February 2004 - 07:30 PM

The fuel pressure regulator is not car specific... it is intake manifold specific. If you look at that mass of steel hoses underneath your spider intake, it is there. Gold in color, has a vaccum line and some fuel lines going to it. On a normal MPFI intake it is also on the steel hose mess. Off to the driver side of the mess.

Are the injectors not firing? or are they not passing fuel? If they are firing, but not passing fuel... I'd think it was the regulator.

If they just aren't firing... sounds like a sensor/wiring/ecu problem. Have you upgraded the grounding? Maybe consider reverting to stock to see if that fixes it.

I doubt its the fuel cut, seriously doubt it. How it cuts out isn't fuel cut like...

#3 rallyruss

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Posted 03 February 2004 - 08:19 PM

did you or your mechanic check what fuel pressure actually did?
that would tell you alot right there. before you replace parts(too late) Iwould look at fuel pressure.

my last instructor would not answer a drivability question untill you had checked fuel pressure.

#4 Skip

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Posted 03 February 2004 - 08:20 PM

Andy, did you make sure there is an intake manifold connection at the FPR?
If it has no connection from the intake manifold, it will not increase the fuel pressure, could be just not enough pressure??
Did the mechanic test the fuel pressure?
OR how about the two pressure switches for the ECU being reversed?? The high pressure switch where the low pessure one and visa versa? This is a vane style MAF correct?
Just some random thoughts


#5 baccaruda

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Posted 04 February 2004 - 05:19 AM

i will look at the FPR under the intake tomorrow.

skip, this is an 87 xt engine with 86 wiring harness, 86 TPS, and 86 CTS. air flow meter and solenoids are original to the engine. 86 flappy MAF as well. thanks.

#6 Skip

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Posted 04 February 2004 - 08:38 AM

So during all this swappin and such, lets say, the boost cut pressure switch gets inadvertently plugged into the turbo light switch harness.
Now when the turbo out put causes the intake manifold to go positive, instead of the light lighting the ECU (CTS????) thinks it's over boosting and engages the fuel cut map. Probably would happen about 2500 RPM. And fits with your statement
"i took the car to a REAL MECHANIC :P and he verified that something is shutting off the injectors at 2300RPM.
we agree that it occurs as the turbo is starting to do its job.
"
Why do you call it a CTS? Computer Timing System??
Did you keep the knock control unit?
Do you have access to an Air fuel ratio meter.
Has anyone messed with the internals of the flapper door and it's spring and potentiometer?
How do you like doing homework?


#7 calebz

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Posted 04 February 2004 - 10:07 AM

I'm guessing that by CTS, he means Coolant Temp Sensor..

I recently assisted in a motor swap on a GL-10 turbo,, after swapping intakes and putting the motor in, we ran into some problems similar to what Andy is having. The owner took it to a shop and it turned out to be a boogered FPR.

However, I don't find that to be a common problem and I really like Skip's idea of the hoses to the fuel cut switch and turbo light being swapped. Elegant, simple and free:D

#8 Skip

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Posted 04 February 2004 - 10:29 AM

Caleb, thanks for the clarification of CTS.
And to further clarify it's the wiring to the two identical pressure switches not the hoses.
Simple test of this is to look for the "TURBO" light.
If it lights at the correct time, well then the FPR and a FP test is in order.


#9 baccaruda

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Posted 04 February 2004 - 01:11 PM

hi.. sorry about the acronyms, caleb's right :P

the turbo light comes on properly when the turbo starts pushing, when the engine's cold.
BUT
the mech fiddled with the vacuum deals on the PS strut tower while showing them to me, and then the car did better on the way home. so i think i may just go to the JY and change those and inspect the vacuum lines... i'll eyeball the FPR anyway though. thanks so far, i'll update soon.

#10 Subarutex

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Posted 04 February 2004 - 01:55 PM

get some hose from hosetechniques.com redo all the vaccuum hosing. Thats my suggestion.

#11 calebz

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Posted 04 February 2004 - 03:00 PM

Tex, did you buy one of the kits? if so, which one?

#12 Subarutex

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Posted 04 February 2004 - 04:41 PM

no, I haven't boughten one yet. I've gotten a few feet of the stuff from the local rice shop. Edrach got a kit from hosetechniques... I think he got the universal kit.




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