# Bypassing FPR control unit



## Zen31ZR (Mar 24, 2004)

Is there any harm in doing this or will it blow the diaphragm on the FPR unit itself. Supposedly the control unit allows the FPR to see boost but not vaccuum, or something like that, from what I read in the FSM..... I have my suspicions that mine is not working, IE: not letting the FPR see boost pressure to ramp up fuel pressure.


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## JAMESZ (Mar 12, 2004)

What is happening to make you think this?


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## Zen31ZR (Mar 24, 2004)

JAMESZ said:


> What is happening to make you think this?


After putting the car back together, I took it for a test drive. Seemed a bit sluggish, so I looked around under the hood, and that's when I noticed the FPR signal line went to the controller on the driver fender and then back to the manifold. I hadn't paid attention to that before, so I went and read the FSM for awhile..... 2nd test run, I hooked the FPR straight to the manifold signal side. Much better acceleration and shorter spool up time..... Therefore that the controller was dead was my conclusion. I just wonder if I can leave it like that without damaging the FPR units diaphragm. I doubt they make the controller unit anymore, and I wouldn't want to pay the price they'd want for one anyway.


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## 0341TODD (Nov 15, 2003)

I bypassed all that stuff on the drivers fender....so has MarcZ31.......There arent any side effects except for the fact that you have to worry about less stuff breaking......if that really is a side effect. Just hook the line from the fpr to the plenum. The vacuum will regulate the fpr like a normal application would- it works just fine. I wouldnt replace the fpr though- the ecu does use the temp sensor thats built in to make decisions.


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## Zen31ZR (Mar 24, 2004)

0341TODD said:


> I bypassed all that stuff on the drivers fender....so has MarcZ31.......There arent any side effects except for the fact that you have to worry about less stuff breaking......if that really is a side effect. Just hook the line from the fpr to the plenum. The vacuum will regulate the fpr like a normal application would- it works just fine. I wouldnt replace the fpr though- the ecu does use the temp sensor thats built in to make decisions.


 That could be bypassed too, with a resistor........ The ECU only makes decisions concerning the fuel temp during a hot start situation. Pretty much useless any other time. But yeah, that's good to know. Just wanted to make sure I didn't blow the FPR and end up sucking fuel through the vac line, that can't be good......


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## 0341TODD (Nov 15, 2003)

No, but I heard somewhere that its a problem with our cars? People end up sucking gas into the plenum through the fpr? Ever heard that- I think I read it on Z31.com.....It should be fine though---- I used to have a resistor hooked up on my other car when it was cold outside b/c it was acting up- I cant remember what ohm it was, but it was basically matched to like 185 degrees Fahrenheit.


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