85_TA_WS6

iTrader: (1)

Hey guys. I've been messing with this for three days now and I still can't figure out why I have no pressure at the rail ( there is a gauge on it). Here is the chain of events which got me to where I am now...

First: Fuel pressure regulator died because the car sat for too long and ate the diaphrams. I replaced that with a Holley AFPR and tried to start it, but then the fuel pump wasn't turning on.

Second: Since the fuel pump wasn't turning on I checked the fuse, and it was bad so I replaced it with a new 20 amp. The fuel pump still didn't turn on.

Next I replaced the fuel pump relay, because I could not hear the old one clicking over.

I put 12 volts right to the pump and it ran fine. I then had somebody turn the key and I checked the voltage to the body connector for the fuel pump, and I only had a little over 6 volts coming out... Which two wires to I touch to get the proper reading at the body connector? I touched them in every combination and still only got 6 volts.

Why would I have lower voltage going to the fuel pump at the body connector? What else do I check now in order to get this rectified? Any help would be greatly appreciated.

85_TA_WS6

iTrader: (1)

Ok update on the problem. I now have 12 volts to the connector, the pump works when I put 12 volts right to it. So it would have to be the connector not transferring the power. I put power to the pump for about 5 seconds and then checked pressure, and it was only 10 psi though. I'm thinking I have the AFPR adjusted way off and it isn't letting it get high enough. Which way do you turn the Holley afpr to raise pressure?

Guest

Some of the locals here have been having problems with lines getting clogged from presumably fuel additives. I wonder if that isnt the problem instead of something else.

D's89IROCZ

regulator ....lefty losssy ...righty ...tighty. Do a continuity test on all wires in the system .

I am guessing here ( someone chime in please) but I am thinking the pump on gets a certain voltage vs throttle position ????? like at idle maybe 6 volts ....wide opes 12 volts ???

Something to look into anyhow.

Guest

Nope, full voltage all the time, no variable voltage unless something is wrong.

85_TA_WS6

iTrader: (1)

Thanks for the help. I messed with the connector and straightened out the pins, cleaned up the connectors and put dilectric grease in and now the pump turns on. Now that the pump is turning on correctly it has become glaringly obvious that my fuel pump is toast. The best way I can describe the noise it makes is a dying whale. So advance auto has a pump in stock so I'll throw that in tonight and hopefully be on the road tomorrow.

Todd Chastain

If you get that thing put in the same night you get it let me know how.

85_TA_WS6

iTrader: (1)

Well I got rained out on the pump install seeing as my dad's corvette gets garage priority over mine. In about an hour I got the exhausts off and all of the suspension dropped so all that is left is unbolting the tank, disconnecting the lines and lowering it out. That will have to wait until another day though because I have too much going on this weekend.

soultron

iTrader: (2)

I'm having the same problem, but my pump is new. I have no pressure on my gauge, but my pump primes and I seem to have correct voltage. If the pressure regulator goes I'd have no pressure?

midniteplowboyy

iTrader: (1)

Plug or crimp off the return line and see if you get any pressure, FPR might be sticking open.

My 91 when I bought it had sat in a barn for about 5 years, when I went to crank it the fuel pump would run but no pressure. The rubberline in the tank on the pump had busted.

Breazlan

iTrader: (1)

Replaced the fuel filter?

Breazlan

iTrader: (1)

I've dealt with the bad rubber lines too. Amazing how sticky the rubber gets.

soultron

iTrader: (2)

The fuel filter is only a few months old... I haven't tried checking in the tank as I just changed the pump, but maybe the little connector piece could be loose. Fuel flows out of the engine side of the filter, but not out of the hoses on the engine. Maybe not enough pressure to make it there? Also the voltage to the pump is around 7, but the battery is still at 12.35. I'm hoping it's just clog somewhere, but it's driving me bonkers.
edit - almost forgot. Is it normal for the oil pressure gauge to peg if I'm just switching to the ON position?

Breazlan

iTrader: (1)

If I was to test for a plugged line, I would connect air pressure on the engine connections and blow it back to the filter. Hard to imagine a plug in the line.

If the pump blows gas out of the filter it should have no problem pushing it to the engine bay.

soultron

iTrader: (2)

I blew air threw the line, but it seems ok. Pretty much the same results. Turn key, pump primes, relay clicks off. no pressure in the rail. I'll have to check the tank tommorow, I'm seeing some folks tonite.

What am I missing?

85_TA_WS6

iTrader: (1)

Well I ended up changing my fuel pump and everything works perfect now. In my case the pump still worked, but was only supplying 10psi, which is no good. I put the new pump in and instantly got 40psi at the rail with a turn of the key. So just because the pump turns on, doesn't mean it is still ok.

RobClassic

If you cut an access panel at the pump in the floor it’s quick and easy

OrangeBird

iTrader: (1)