Is this my fuel pump? (1 Viewer)

Joined
Jun 1, 2012
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309
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GA.
Hey guys I've got a 91 3fe that will start and idle fine. When you drive for awhile it starts to loose power. If I feather the gas it will slowly go as long as your not going uphill but if you push the gas at all it just drops off like its out of gas. I opened the cold start and its getting fuel but it doesn't seem to be the 37 to 46 psi the fsm indicates. I haven't figured out how to hook up my pressure guage yet for a good reading just looking for input. Thanks in advance
 
Joined
Jul 22, 2012
Messages
2,009
Location
Ann Arbor, MI
Could be any of the following:
1. Fuel Pump "sock" filter
2. Fuel Filter
3. Charcoal Canister
4. Fuel Pump

If you have not "baselined" your truck, I would go through each of those in order.
 
Joined
Jul 20, 2014
Messages
445
Pull the back seats out, pull the carpet back, remove the 3 screws and remove hatch. Go to Autozone and borrow (pay the $150 and get it back when you are done) the fuel pressure test kit. Hook up the 12mm banjo bolt to the outlet line coming out of your gas tank and check your fuel pressure before you do anything else. It sounds exactly what my truck started doing when I had the pump itself get dislodged from the housing and the hose was leaking at the fitting. I'm not saying that is what yours is doing, but it sounds like a fuel delivery issue. If I would have done this first it would have saved me tons of time (a few hours a day for a week to be exact) There are new copper crush washers in the kit which the manager at my Autozone said I could keep. Yours may be different so you can buy them at your local Toy dealer for probably $1 or $2 a piece. You'll need 2.

If it gets worse as your fuel level drops I can almost guarantee it's a fuel delivery issue. If you have pressure within spec at the fuel pump, next step is to change the fuel filter. Then the fun begins if that doesn't fix it! :bounce:
 
Joined
Dec 13, 2008
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N. West CT.
If you don't know about the status of the fuel filter I would start there. pretty easy install. If not then go to the fuel pump.
 
Joined
Jun 1, 2012
Messages
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Location
GA.
The filter was replaced about 2 years ago as well as the pump. The filter was oem but the pump was an AutoZone special so I'm thinking that's my problem. If I remember I didn't really like the fitment of it when it went on
 

Hornd

SILVER Star
Joined
Dec 18, 2013
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2,595
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Toledo, OH
Pull the back seats out, pull the carpet back, remove the 3 screws and remove hatch. Go to Autozone and borrow (pay the $150 and get it back when you are done) the fuel pressure test kit. Hook up the 12mm banjo bolt to the outlet line coming out of your gas tank and check your fuel pressure before you do anything else. It sounds exactly what my truck started doing when I had the pump itself get dislodged from the housing and the hose was leaking at the fitting. I'm not saying that is what yours is doing, but it sounds like a fuel delivery issue. If I would have done this first it would have saved me tons of time (a few hours a day for a week to be exact) There are new copper crush washers in the kit which the manager at my Autozone said I could keep. Yours may be different so you can buy them at your local Toy dealer for probably $1 or $2 a piece. You'll need 2.

If it gets worse as your fuel level drops I can almost guarantee it's a fuel delivery issue. If you have pressure within spec at the fuel pump, next step is to change the fuel filter. Then the fun begins if that doesn't fix it! :bounce:

I just had the back seats out and took a look under 3 screws and top was corroded, so I sprayed whole top with lithium grease and put cover back on (it stinks). That will help with the corrosion in future. Just a thought...
 
Joined
Jul 20, 2014
Messages
445
The filter was replaced about 2 years ago as well as the pump. The filter was oem but the pump was an AutoZone special so I'm thinking that's my problem. If I remember I didn't really like the fitment of it when it went on


From what I've read 2 years from the Autozone specials is actually really good.

Go get the test kit and get ready to order your new Denso pump

Here's a good write up:

http://www.copperstatecruisers.com/fj80-fuel-pump-troubleshooting-and-replacement.html
 
Joined
Mar 6, 2010
Messages
128
Location
Montrose, CO
And I might add it intermittently
Mine was doing almost the exact same thing and was driving me crazy. It kept throwing a PO code(can't remember the number) something about being lean some of the things were O2 sensors, MAF, fuel filter, etc. Finally pulled the pump to replace the spotless sock and noticed that someone had replaced the pump but hadn't used fuel proof hose in the tank and the pump was starting to detach. This left a small gap that would leak pressure when heading uphill. It also got progressively harder to start after driving it awhile then shutting it off( going into store). Hot start runs max fuel pressure so it would also leak off the extra pressure. I did change out the pump, sock and hose since I didn't want to worry about it for awhile. Cured the problem(at least till the HG blew)
 
Joined
Jun 1, 2012
Messages
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GA.
So no symptoms for a couple of days. I'm curious about the charcoal canister idea
 

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