Fuel Need Guidance on no FP reg reading

Gnfanatic · Oct 22, 2023

Please help me out guys. I have a brand new 302 build with the BBK fuel rails (blue ones). I have a no start condition on this new build and need help!
I purchased the rails and regulator used so I do not know the history, the issue is the FP reg gauge shows 0 no matter what I do with adjustment, I also tried another gauge. I have spark, my plugs are wet and the dist is installed properly. I am wondering if the 0 fp reading has something to do with my no start cond? The plugs are getting fuel and spark but maybe to little or to much fuel? The vac line going to FP is dry. please help!

Monkeybutt2000 · Oct 22, 2023

Do you have the stock regulator? If so put it on and try it.

Mcmahst · Oct 22, 2023

If you’ve eliminated the question of the fuel pump, sounds like the regulator is running in the open position, returning the pumped fuel. If you do not have access to a known good regulator, try and restrict the return line just to see if it will start. If it does, I would replace the regulator. Don’t use that setup for more than this test.

Gnfanatic · Oct 22, 2023

hi guys, I do not have another reg. It looks like the reg was leaking where it sits on the BB mount which is a known issue. I am not sure if I should junk these rails and find something better. wish I never sold my stock one, dumb move.

AeroCoupe · Oct 22, 2023

Unfortunately the BBK rails and regulators do kit have the best reputation. Stock rails will support about 550 fwhp. I know people have made more wit them but I wouldn’t push them past the 550 mark.

Mcmahst · Oct 22, 2023

Yes, learning is always costly. But, it sounds like you have the solution. Good luck, let us know how it turns out.

Gnfanatic · Oct 23, 2023

Good morning gentlemen. Looks like I was not thinking to much yesterday due to mental exhaustion. I remember putting the feed line in a bucket and turning ign on . I was surprised how it was not High pressure at all but was coming out. Also, my aeromotive fuel pump assembly was very quiet. You could hear it but sounded like stock. Very possible the pump is not doing its job. I am going to check the voltage and my fuel pump Relay wiring when I get home.

General karthief · Oct 23, 2023

Check fuel pressure with a gauge.

Gnfanatic · Oct 23, 2023

I did but at reg. I am going to check at pump tonight

Mcmahst · Oct 23, 2023

Check the pre and post filters to the pump as well, those suckers can be the real source of the problem. Don’t ask me how I know .

Gnfanatic · Oct 23, 2023

Ok guys. 0 psi at the feed! I hooked a multimeter to newly installed fp relay. I get 12.5 volts for 3 seconds then it goes to 0. While cranking the volts stay at 0? Like relay is not getting signal to turn on

nickyb · Oct 23, 2023

Did You check the fuel pressure cut off switch?

Mcmahst · Oct 23, 2023

And, just for fun, replace that relay in case it’s just a bad relay. I also suspect the collision sensor. A
so, could you post pics of the FP relay and wiring?

Gnfanatic · Oct 23, 2023

guys, looks like I had blockage in my feed line but not all issues resolved. I removed feed filter in back and hooked gauge to line, I got 100 psi within seconds. The filter was clean internally so I blew out both ends of the feed line after the filter and now I get 100 PSI at engine with filter back on. For the voltage., I bypassed the factory harness with the relay, relay gets signal from the black/pink wire coming from fac relay under driver seat. So now when I prime pump with ign it goes to 100psi

nickyb · Oct 23, 2023

Mcmahst said:
And, just for fun, replace that relay in case it’s just a bad relay. I also suspect the collision sensor. A
so, could you post pics of the FP relay and wiring?

Fuel pressure cut off same as collision sensor. Tomatoe, tomato

Gnfanatic · Oct 24, 2023

Good morning. I will take pic of relay tonight. I still do not have voltage going to pump during crank. I downloaded some Diagrams and will be checking wiring tonight.

Mcmahst · Oct 24, 2023

As I remember, the ECU see the run/crank signal from the pink/white wire. So, when you turn the key to the run position, before turning it to the start position, you get the pump prime cycle? Then, at start, the relay goes to zero? If you release the key back to the run position, does the power return to the relay? And when I say power, I’m referring to the signal power. What weird is that, there isn’t a separate “start” indicator to the ECU. So, for it to lose signal power, that’s hard to understand, unless it’s related to the starting circuit; battery connections, bad solenoid, wiring for those items.

I realize the attach diagram may not exactly match your vehicle, but it illustrates the Ford design for the fuel pump relay. If the pump is priming on the run position, that’s being activated by the ECU. As you can see, there isn’t a different activation path for the fuel pump relay for run verses start. I think you‘re on the right track to discover why you’re losing power to the relay at start. Good luck.

Gnfanatic · Oct 24, 2023

Hey, I am looking over my fp relay that I installed and I think I screwed up. As of right now I have the pink/blk wire going to pin# 86 on my relay and then pin 85 on my relay is a permanent grd. I think this is wrong.

Mcmahst · Oct 24, 2023

I don’t think it matters, as long as 85/86 are the triggered source and “ground”. The Bosch pin diagram shows it both ways. Is your wiring to the FPR similar to the diagram I posted? You should have 12v at all times to post 30, and 85/86 being the trigger. That source voltage should be coming from the ECU. If you’ve wired around the ECU for controlling the FPR, I would reconsider that decision.

Gnfanatic · Oct 24, 2023

Thanks for the info. I will be home at 5 and will double check. If everything is fine on relay end why would I not be getting fuel pump voltage during cranking?

Fuel Need Guidance on no FP reg reading

Gnfanatic

Monkeybutt2000

Mustang Master

Mcmahst

Gnfanatic

AeroCoupe

lube between the nut and the face. I know my lubes

Mcmahst

Gnfanatic

General karthief

wonder how much it would cost to ship you a pair

Gnfanatic

Mcmahst

Gnfanatic

nickyb

I gotta say i never painted my nuts, Never Ever

Mcmahst

Gnfanatic

nickyb

I gotta say i never painted my nuts, Never Ever

Gnfanatic

Mcmahst

Gnfanatic

Mcmahst

Gnfanatic

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Fuel Need Guidance on no FP reg reading

Mustang Master

lube between the nut and the face. I know my lubes

wonder how much it would cost to ship you a pair

I gotta say i never painted my nuts, Never Ever

I gotta say i never painted my nuts, Never Ever

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