Fuel pressure problems

[racer5252]

I have a 1986 Grand National with a Caspers hot wire kit, Accufab fuel pressure regulator, and a hood mounted fuel pressure gauge and a DeatschWerks 300 fuel pump. My car was down for a couple of years to rebuild the motor, when I finished everything up and got it back together it fired right up several times and I even took it to a few different car shows and then after sitting a few weeks, I went to go to another show, but all of it would do is crank over but not fire. I noticed the fuel pump would only come on for a few seconds, and then shut off with less than 10 psi.
After doing a lot of reading I put 12 V to the gray wire behind the alternator and the fuel pump came on and the fuel pressure went up to 45 psi, but the car would still not start. Does this mean the fuel pump is good? I’ve done a lot of reading, but I don’t understand how to jump the relays or even exactly where they’re at.
Any help would be greatly appreciated.

 

[TexasT]

I see you have a hot wire kit and that is good. It seems to be priming the system or at lease sending a signal. You might need a helper to do some testing, cycling the key and such. What was done with the hanger and its wiring? The connector at the top of the sender and the in tank wiring has some issues with corrosion in my experience. Was this replaced with the fuel pump? If so what was used as replacement ?
If you have a good 12v at your relay in the hot wire kit(mine is near the rear bumper, yours may or may not be). Then following the wiring up to the top of the tank(will probably require dropping the tank down, also handy to have the helper here). Measuring the voltage there and then pulling the sender up and inspecting those conductors and measuring that voltage.

 

[racer5252]

I did install a new stainless steel hanger kit 5 plus years ago (I don’t remember where I bought it) and new stainless steel lines when I did a complete frame off 15 years ago. I will drop the tank with a helper this weekend and measure voltage.

 

[SCOOBY DOO]

Fuel Pump

 

[racer5252]

I have a new DeatschWerks 300 pump that I ordered a few months ago but was hoping that wasn’t the problem. Now I’m wondering how good they actually are since it only has a few hundred miles on it, but it is 4 years old.

 

[BEATAV8]

check fuses. IGN-ECM
swing by harbor freight and pick up a NOID light kit and a spark tester.

 

[dynoman]

^^^^^^^^^ If you had 45psi at the rail and it still wouldn't start , I would check ECM / ignition issues .

 

[racer5252]

That was only with putting 12v to the grey wire behind the alternator. When I only have the key on or while cranking I can only get 5-10 psi

 

[dynoman]

Did you try to start it with the pump jumped ??

 

[racer5252]

Did you try to start it with the pump jumped ??

Not sure how to do that unless you mean 12v to the grey wire

 

[SCOOBY DOO]

Click where it says Fuel Pump:

Fuel Pump

 

[racer5252]

Click where it says Fuel Pump:

Fuel Pump

 

[racer5252]

Oh, I thought in your previous reply you was just telling me that it was the fuel pump, lol.
That is a very good article and explains a lot, thank you

 

[racer5252]

Update!! After verifying all the voltage was correct all the way back to the fuel pump, I still decided to change the fuel pump after reading several other post. Still no start.
Checked for spark and didn’t have any so I changed out the crank sensor (which only had 50 miles on it ) and then it fired right up.
Now the problem is I have too much fuel pressure and cannot adjust it down enough, I can adjust it anywhere from 52 psi to 58 psi and that’s it. I did check to make sure the return line on top of the fuel tank was not pinched off, but have not pulled the pump back out yet. Any ideas what it could be? It has an Accufab adjustable fuel pressure regulator, I did take a part and everything looks good.

 

[dynoman]

Are you on stock fuel lines ?? Sounds like a restriction on the return line . Some have had this problem of not being able to lower fuel pressure with slightly bigger pumps . The regulator bypasses the extra fuel to the return line , with restricted return lines you cannot bypass enough fuel so pressure stays high .

 

[racer5252]

Are you on stock fuel lines ?? Sounds like a restriction on the return line . Some have had this problem of not being able to lower fuel pressure with slightly bigger pumps . The regulator bypasses the extra fuel to the return line , with restricted return lines you cannot bypass enough fuel so pressure stays high .

Yes, stock fuel lines. I did replace them several years ago with stainless steel but I believe they were stock size.

 

[Chuck Leeper]

Run the return into a fuel jug.
Pressure ok now?

 

[racer5252]

Run the return into a fuel jug.
Pressure ok now?

Yes, now I can adjust my fuel pressure to anything I want. Thank you

 

[racer5252]

Is it OK to use rubber fuel line and worm clamps to adapt to the vent line running back to the tank?

 

[racer5252]

Is it OK to use rubber fuel line and worm clamps to adapt to the vent line running back to the tank?

So that’s probably a bad idea since there were no replies, what is the best way to connect to the vent line?