Fuel Fuel pressure issues(UPDATE)

J

JDFoxbody91

Member

Jul 30, 2020

8

1

13

South Carolina

Jul 30, 2020

#1

• Jul 30, 2020

• #1

I need some assistance guys. Just bought a one owner 91 LX that has been sitting in the garage for about 3 years. It would turn over but would not start. It was running when it was parked. The car was in good condition overall so I bought it anyway. I started working on it today and I cant get any fuel pressure. I dropped tank and cleaned it out. Installed new fuel pump, fuel filter and fuel pump relay. Checked the fuel switch in the trunk also but I still have no pressure at the fuel rail. I also checked voltage at the pump and its good. Any other ideas??

(Update) Problem solved. First, thanks for the suggestions guys. Second, it would help if I looked at the right print for my year model. I started over and had 12 V on the pink wire but relay would never click on. Checked voltage at the PCM relay and had 12V on the yellow but the relay would never engage. The problem ended up tracing back to the ignition switch. Replaced ignition switch. I also decided after the fact to replace the PCM relay also. It worked but it looked rough so I replaced it while I was thinking about it. Even though it had been sitting a few years it fired right up. Now its time for a tune up(wires, plugs, etc). Thanks again for the suggestions .

 

Last edited: Aug 2, 2020

General karthief

wonder how much it would cost to ship you a pair

5 Year Member

Aug 25, 2016

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polk county florida

Jul 30, 2020

#2

• Jul 30, 2020

• #2

Is the pump running constantly when you turn the key on?

 

Blown88GT

Founding Member

Nov 13, 1999

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Palm Beach Gardens, FL

Jul 31, 2020

#3

• Jul 31, 2020

• #3

FPR?

 

africansnowowl

Active Member

Apr 29, 2020

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San Antonio

Jul 31, 2020

#4

• Jul 31, 2020

• #4

May sound stupid, but make sure it doesn’t have a kill switch you forgot about, or didn’t know about. I had this exact problem on mine. Replaced the pump, inertia switch, relay, an hour of tracing wires before i found out the previous owner neglected to mention the kill switch under the seat.

 

Blown88GT

Founding Member

Nov 13, 1999

2,283

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Palm Beach Gardens, FL

Aug 2, 2020

#5

• Aug 2, 2020

• #5

"Voltage at the pump" indicates the pump is running.
At the pump & at the connector to the tank are not the same.
How much voltage? It's won't provide pressure at <10V.
If the pump is running & there is no fuel pressure, it can only be a few things.
1. Fuel pump is bad (OP installed new pump).
2. Fuel filter is clogged (OP installed new filter).
3. Fuel supply line is blocked.
4. Fuel pressure regulator is bad. If you have 0 psi & the pump is running, you are pumping raw fuel into the intake through the vacuum line on the FPR.

 

96pushrod

I think they're a little easier to get off

5 Year Member

May 15, 2018

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Savannah

Aug 2, 2020

#6

• Aug 2, 2020

• #6

So you are for sure getting 12v at the pump with the key on? Can you hear the pump click on?

 

J

JDFoxbody91

Member

Jul 30, 2020

8

1

13

South Carolina

Aug 2, 2020

#7

• Aug 2, 2020

• #7

Bump for update.