No Fuel Pressure

[TType85]

Yes , and after being in the automation electrical field for 39 years , I'm surprised that more solid state relays are not used for higher current applications like fuel pumps & cooling fans . No moving parts , no contacts to burn . We us them in many high current / high cycling applications like mold machine heat control , bulk plastic dryers .

https://www.amazon.com/SSR-60DD-3-32VDC-Output-5-240VDC-Plastic/dp/B09H7B8P6N/ref=sr_1_2?adgrpid=1332608663915570&con

Since I ran all new wiring for my dual pump setup I went to a MSD SSR and since it has 4 ports I also wired my dual fan setup in to it. It cut down on a lot of extra wiring and it works great.

 

[NoVA_87_GN]

Got an update and more issues. Got the new relays in, plugged it in, turn the key to start, fuel pump kicked on, turned car over it started right up. Turned it off and started it up again, let it warm up, sprayed some test alky as it’s been sitting for a few days still ran fine. Turned it off, moved other cars so i can take it out for a spin, tried to start it back up, won’t start. I hear the fuel pump kick on, looks like i got 34 lbs of fuel pressure, but it won’t start, just turns over. Fuel pump still keeps coming on like it should, but back to no start issues. Any ideas on this one? Thought i had her figured out.

 

[Mr.Spool]

Got an update and more issues. Got the new relays in, plugged it in, turn the key to start, fuel pump kicked on, turned car over it started right up. Turned it off and started it up again, let it warm up, sprayed some test alky as it’s been sitting for a few days still ran fine. Turned it off, moved other cars so i can take it out for a spin, tried to start it back up, won’t start. I hear the fuel pump kick on, looks like i got 34 lbs of fuel pressure, but it won’t start, just turns over. Fuel pump still keeps coming on like it should, but back to no start issues. Any ideas on this one? Thought i had her figured out.

Fuel pressure is low
If volts are good and you have spark
Pump may be on it's way out.

 

[scgnx2]

So, what did the bad relay that you replaced look like ?

 

[NoVA_87_GN]

Since i might be replacing my fuel pump, is there a good external one that i should be looking at? The car has a sumped gas tank which feeds a fuel filler and then this Holley fuel pump:

Holley 12-1800 200 GPH Dominator In-Line Billet Fuel Pump

Need to feed some serious horsepower? Have a nitrous or forced induction powerplant that also sees street duty? Holley's Dominator™ in-line fuel pumps are the answer! The patent pending twin pump design allows you to use one pump for cruising and both pumps when you activate the nitrous switch...

www.holley.com

 

[Chuck Leeper]

has a sumped gas tank which feeds a fuel filler

What's the info on that filter?
HAS to be in the 100-micron range. If it's a 10, it has to be after the pump.
Time to take the tank down and do some checking.
Even at 34psi, it should start.

 

[TexasT]

Is that filter cleanable? When was it last cleaned? Is there anything in the tank like a sock?
X2 on the should start with 34psi but pressure doesn't equal volume. Can you verify it is pumping fuel or not?

 

[Mr.Spool]

Since i might be replacing my fuel pump, is there a good external one that i should be looking at? The car has a sumped gas tank which feeds a fuel filler and then this Holley fuel pump:

Holley 12-1800 200 GPH Dominator In-Line Billet Fuel Pump

Need to feed some serious horsepower? Have a nitrous or forced induction powerplant that also sees street duty? Holley's Dominator™ in-line fuel pumps are the answer! The patent pending twin pump design allows you to use one pump for cruising and both pumps when you activate the nitrous switch...

www.holley.com

Aeromotive brushless spur.

 

[NoVA_87_GN]

Went back out to see if I could see why it wasn't starting, put the car in the "on" position, fuel pump kicked on, pressure got up to 34, tried turning her over but still wouldn't start. Noticed the fuel pressure gradually dropping from 34 all the way down to 19. Dropped slowly, 1 psi at a time, seemed to level off at 18-19, I'm assuming pump is done. Ordered a replacement pump and filter, nothing high end, just need to get car to wife's house in the garage, then I think I'm going to swap out the sumped tank and external pump with a new fuel tank and in-tank pump, this will fix my fuel gauge not working issue also.

 

[Chuck Leeper]

Noticed the fuel pressure gradually dropping from 34 all the way down to 19. Dropped slowly, 1 psi at a time, seemed to level off at 18-19, I'm assuming pump is do

If that brown wire is the ground to the relay coil make sure its a good connection to the metal it's bolted to that looks a bit suspicious.

FOR SURE!

 

[NoVA_87_GN]

***UPDATE***

Not sure where to go from here.

Thought fuel pump was bad, ordered a new pump and filter, installed both, fuel pressure when from low 30s which trickled down to 19 in old pump to 6 trickle down to 0. Measured the voltage on the fuel pump post to see if i was getting power, 0v. I'm getting 12v on the hotwire kit RED wire coming from the alternator, but once it goes through the relay, nothing on the other side. I just ordered two new relays, both showed 0v when i tested the connectors that connects to fuel pump. So thought harness might be bad, ordered a new hotwire harness, hooked it all up and......nothing. Still little to no fuel pressure and can won't start. Again, 12v on the RED wire from the alternator, but when i touch the post on the fuel pump it reads 0v. This is a brand new harness from racetronics, doubt it's bad.

I'd really like to fix this myself and not take it in, but at this point I have no idea what's going on.

 

[TexasT]

Gonna have to do some sleuthing and follow where that wire goes and where it looses it's power on the way to that relay or pump. Not sure how you're looks but I'd get it up on some stands and get the vreaper out and a good light and do some observation up under there where the wires are run.

 

[NoVA_87_GN]

Gonna have to do some sleuthing and follow where that wire goes and where it looses it's power on the way to that relay or pump. Not sure how you're looks but I'd get it up on some stands and get the vreaper out and a good light and do some observation up under there where the wires are run.

That's where I'm getting confused. The wire hooked up to the alternator, running back through the hotwire kit, has power right before the relay, but it appears (based of checking for voltage on the other side of the rear relay) that there is no power to the connector that i hook up to the post. What's also weird, is when I turn the car to start position, i hear the pump come on, but again power reads 0v at the pump post and i have no fuel pressure.

 

[TexasT]

Did you determine the pump was good? Did you determine the oil pressure switch is good so it doesn't require a lengthy cranking to get it to give pressure? Are we working with a stock ecu? I'm old so hard to remember all the parameters. What about the relays on the fender? Are they sending the signal for that rear relay? Might need a helper to be cycling the key while you are under there and under the hood with that meter to see or jump those relays out and see what it does for fuel pressure with the pump running full blast.

 

[Chuck Leeper]

What's also weird, is when I turn the car to start position, i hear the pump come on, but again "power reads 0v at the pump post and i have no fuel pressure".
Unless you have a 2nd hand to turn the key, while you are checking for + at the pump, you won't see voltage there once the prime cycle is done. The ecm HAS to see rpm signal to restart the pump.
Furthermore, if there's no fp showing during prime cycle, even tho you hear the pump, there may be an in-tank leak.
You DID take the Schraeder valve out of the rail when you hooked the ga up, right?
You don't have the new wiring/pump wire backwards, do you?
Power to the hotwire relay only 1 side? Jump it.
Question on oil pressure sw? Jump it.
Alone? Make a long test light and see if the prime cycle is working at both sides of the rear relay.

 

[NoVA_87_GN]

Thanks for the reply Chuck.

What's also weird, is when I turn the car to start position, i hear the pump come on, but again "power reads 0v at the pump post and i have no fuel pressure".
Unless you have a 2nd hand to turn the key, while you are checking for + at the pump, you won't see voltage there once the prime cycle is done. The ecm HAS to see rpm signal to restart the pump.

Did not know that, I do have a second hand that I can have turn the key while i check voltage. So I will only see voltage for the few seconds it's priming, but will i see any while the engine is cranking?

Furthermore, if there's no fp showing during prime cycle, even tho you hear the pump, there may be an in-tank leak.

In-tank leak? So i have a sumped tank that runs to an external fuel pump, hose come out towards the bottom, no leaks in any of the connections.

You DID take the Schraeder valve out of the rail when you hooked the ga up, right?

That I have not done, will do today. Was going off the pressure reading on the Fast XFI screen.

You don't have the new wiring/pump wire backwards, do you?

Nah, the pump has a red and black post, they are hook correctly to the harness.

Power to the hotwire relay only 1 side? Jump it.

Can i power straight from the "Hot" wire from the alternator to the fuel pump and by-pass the harness relay and try to start the car? I know this isn't long term solution.

Question on oil pressure sw? Jump it.

Oil pressure reading of the Fast XFI screen reads 60 lbs when i'm cranking her over. Should I still jump it? and what exactly am I jumping?

Alone? Make a long test light and see if the prime cycle is working at both sides of the rear relay.

I have a second pair of hands, the wife will love helping me, she just doesnt know it yet.

Thanks again for all the help.

 

[salvageV6]

The pump should run if you jump the fat wire in the loom that goes to the fuse and alternator post, jumped with the fat red wire that goes to the pump itself. You would need a high current jumper wire 14-16 gauge.
Take the tape off that relay and post up some more detailed pictures of what you have.
Again, the factory fuel system relay, oil pressure output, prime wires, are the trigger for the added hot wire relay and you should have +12 on the hot wire relay coil connection of that relay near your fuel pump when priming and running the car or when fuel pressure goes over 4psi. ASSUMING all the factory stuff was wired into your system which I am doubting now.
That relay needs a good ground connection on the other coil wire terminal at all times.
The fuel pump itself needs a good ground at all times on the black connection, check that too.

 

[dynoman]

Get the grey wire with a connector on it that is just behind the alternator ( it's just hanging there unterminated ) , and apply battery voltage to it . It will bypass the key on pump prime sequence and apply 12v to the pump circuit until you disconnect it . If that keeps the pump running , and it should , disconnect power from it and remove the schradar valve on the end of the fuel rail ( it will have pressure on it ..... maybe ) . Then put a hose over the end of the rail to a bucket or gas can and connect the bypass circuit . If it pumps , see if it dies off in volume after it's pumping for a few seconds . Also be aware that you should clamp the hose on the end of the fuel rail so it doesn't blow off and spray fuel everywhere .
Hope this helps .

 

[SCOOBY DOO]

Slide over to 1:05 time stamp on my vid. It'll show you the wire Dynoman is talking about and an easy way to plug 12 volts into it.

 

[Chuck Leeper]

Good coverage, guys!