jimijoe

I'm replacing my fuel filter and I'm trying to depressurize the fuel line by removing the fuel pump fuse and running the car till its dies from fuel starvation. The fuse is out, the cars been running for 7 mins... Is this correct. How long should it take?

thanks

scorp508

About 10 seconds if that. You sure you got the right fuse? :crazy:

jimijoe

Yea. I'm sure. Its clearly labled on both the fuse block and the fuse cover. Its a yellow 20A fuse in between the EGM fuse and the ABS/ASR fuse, 2nd from the end. The fuse has been out for 15 mins and I just shut the car off. Not sure what to do. Any ideas?

John Row

Did you remove the gas cap? The tank will retain a pressure.

jimijoe

Yes the gas cap was off during the procedure. Should the cap be on or off while while the car is running??

jimijoe

Update. With the engine running and the fuel pump fuse removed I measure 12V to GND on BOTH sides of the fuse terminal (where the fuel pump fuse would be if it was installed). Is this correct. It seems to be that with the engine on and the fuse removed you would only have 12V to GND on one side of the terminal. What gives??

:confused:

tommelton

The fuel pump gets a secondary voltage from the oil pressure sender. Even if the fuse blows, the pump will run, if you have adequate oil pressure.

Tom Melton
82 CE
86 Z51 Coupe

jimijoe

Oh well. That would explain things. So why do people, and some repair manuals, say that you can depressurize the fuel line by removing the fuel pump fuse and running the engine till it dies?? maybe I should drain the oil 1st. Just kidding :D . Do you have any reccomendations to depressureize the fuel line before changing the filter??

thanks

PeteL

Not true on my 89. Fuse is after both the pump relay and oil pressure switch. Pump should not run with the fuse out!

Of course this is a 94 in question, so I don't know.

VetBoy89

It should die without the fuse, but can't you just unplug the pump itself. It's only like 4 or so bolts to pull the cover by the filler neck then just unplug the electrical connector there.

The other option is: make sure the car is completely COOL, then get a rag, wrap it around the Schrader (sp?) valve on the fuel rail and push the needle. Gas will come out but with a cool engine and a rag you shouldn't make to much of a mess.

Just my .02 :smash:


[Modified by VetBoy89, 12:17 PM 12/23/2002]

lead foot 85 vet

I went through the same thing with my 85, you can't turn off the fuel pump easlly....so remove tank gas cap and then just deal with the gas pressure as you open the system..............of course if your opening the line below the gas tank it's going to drain out ether way. :chevy

JCAIRE2

Pulled the fuse here. Ran for ~10 sec, started chugging and died. Cranked for an additional 10 sec. and only got about 8oz. of gas out of the lines.

Good luck. Hope you get it figured out.

J

Rich_01659

sounds like some 'after market wireing" has been done. Check for wires that have been added.

kittmaster

:iagree:

STL94LT1

My 94 has two 10 amp fuses labeled for the fuel pump.

F.P.1 & F.P.2

Goody

My 93 is the same way.

VetteTech81

Also you coud let it sit over night and open the shrader valve you shouldn;t get much out anyway... I do alot of fuel filters and various cars includeing my 95 LT1 and rarley depressureize the system first.. usually don't get much pressure inthere anyway after it's been off for a minute or 2.. but I suppose it's still a good Idea to depressureize it..
-Rick :chevy


[Modified by VetteTech81, 4:32 AM 12/25/2002]

jimijoe

Thanks for the help. I am trying to replace the fuel filter and was hoping to follow a procedure from a to z. However, my wiring appears to be correct and I am removeing the one and only fuel pump fuse. I'm just gona go back to old school style and open the line, let any fuel in the line drain, and replace the filter. When all else fails.. Just do it.


Happy Holidays.
-James

jimijoe

Final update.
I removed the fuel filter with out depressurizing the fuel line by loosining the input line to the fuel filter and placing a catch pan undernieth the fuel line. The fuel trickled down to one point and dripped into the pan from there. I'd say about 12oz was caugth another 3-4 leaked on to the driveway.

Also to remove the filter, aside from removing the frame X brace (an extra chore for verts), I wound up removing the passenger side Cat. The outlet side was too tight for me to Reliablely break with out possibly rounding off the fitting.

Another thing... My filter did not come with new orings. My local Parts store was able to find some to fit, but I can't imagin why the new filter did not come with new ones . Any ideas? :confused:

lone73

Just replaced it on my '96 lt4. Don't recall seeing any o-rings at all. Maybe I wasn't paying attention. It isn't leaking though.
dr