fuel pump?
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fuel pump?
So after six weeks of lying dormant i justed finished rebuilding the top end in my 2.9L as well as fixing the ignition system. the truck was running decent at idle and i just timed it at 10 deg before tdc. i managed to pull the truck out of the garage a grand total of twenty feet when it died. it will start and sputter but i can no longer hear the fuel pump. when i turn the ignition on i can hear a brief click from inside the gas tank followed by depressing silence. this problem sounds like a dead fuel pump to me but before i drop the tank and shell out even more money, do you all have any thoughts or suggestions. thanks
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From: UT
Before I assumed the fuel pump was bad, and undertook to drop the tank and replace, I would verify that the fuel pump is gettting power and has a good ground. Also, you don't say what year BII you have. Some years had two pumps: low pressure "lift" pump in the tank and high pressure in line pump mounted to the frame. Others only had one high pressure pump in the tank.
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From: YORK S.C.
i would check to make sure the pump is getting 12 volts and check and or clean the ground connections. if no power then your problem is likely to be a bad relay,etc.. try hooking the pump up to straight 12 volts to see if it comes on,if it doesn't then pump is bad
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i crawled under the truck today and as far as i can see all grounds and wires are soundly in place. the truck went from being totally dead yesterday to idling fine today. the pump only seems to quit when i try to accelerate in first. i'm checking my haynes manual for fuel pump relay location but the book doesn't have much info. could someone point me in the right direction and tell me how to bypass relay. also the timing on this truck is off, could this have any bearing on my problem as in the ecm is stopping the truck before i can do any damage?
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Joined: Dec 2001
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From: UT
On this engine, the ECM doesn't put that much thought into controlling the fuel pump relay. If the PIP/TACH signal dissappears, the computer would deicde to shut the pump off, thinking the engine was shut off, but it should otherwise be on.
Fuel pump relay should be under the hood on the passenger side fender, along with a couple other relays. Inertia switch is just to the right of the tranny hump under the carpet.
Fuel pump relay should be under the hood on the passenger side fender, along with a couple other relays. Inertia switch is just to the right of the tranny hump under the carpet.
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checked all relays on pass side of fender and they all appear to be working correctly. Now can anybody tell me if this 88 has 1 or 2 fuel pumps. if 2 then where is the location of the inline. is it on the drivers side by the door?
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ok i found that the truck does infact have 2 pumps. does the low pressure pump need to work before the high pressure kicks in. what is the best way to test these pumps to see which is bad. do you have to drop the tank just to test the low pressure. Again my pump does not appear to be totally dead. it will intermittenly start the car, but once the car is started it cannot sustain fuel for very long. i have yet to be able to drive the truck off of my driveway before it dies and i have to push it home.
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From: Yokosuka, Honshu, Japan
There is a test procedure on www.autozone.com in the repair guides section. Just choose the vehicle model, make, year (I forget which order you pick in) and then go to the repair guides section, then fuel system, fuel injection. You may also have a bad fuel pressure regulator. If you pull the vacuum line and it's wet with fuel, then it needs replacing. The high pressure pump may not be holding pressure, or the in-tank booster pump might be bad. Also, as funny as it may sound, you may also need a new gas cap.
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From: UT
The two pumps are wired in parallel, I believe, so they should both operate together. Most of the time, the high pressure pump isn't capable of drawing gas out of the tank by itself, though, so both have to work to get the correct fuel pressure at the rail.
You are correct, the FPR doesn't effect whether or not the pumps come on.
Assuming it's the same diagnostic chart I'm thinking of, the fuel pump diagnostic chart in the repair guides at autozone.com are actually quite useful.
You are correct, the FPR doesn't effect whether or not the pumps come on.
Assuming it's the same diagnostic chart I'm thinking of, the fuel pump diagnostic chart in the repair guides at autozone.com are actually quite useful.
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Joined: Sep 2004
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From: Yokosuka, Honshu, Japan
Yes, both pumps are in parallel: http://www.autozone.com/images/cds/gif/large/0900823d800f947a.gif
You can check the wiring diagrams (select year) on autozone.com http://www.autozone.com/servlet/UiBr...3d800f9461.jsp and troubleshoot the wiring. If you have 12v output to the high-pressure in-line pump and the connection is good, you -should- have 12v at the in-tank pump, unless there is a break in the wire / connection to the in-tank pump. If voltage is present and you're still not meeting pressure specs as per the test procedure previously mentioned, then more than likely one or both pumps may need replacement, however, you should probably check to see if your in-line filter is clogged or dirty as well as check the FPR to see if the diaphragm is blown (vacuum line wet with fuel). If the FPR is bad, pressure will be lower than required, if the in-line filter under the driver's side frame rail is clogged or dirty, the pressure and fuel delivery will be affected, and if the pumps are worn or wearing out, fuel delivery / pressure will be affected. You may also be having issues with one or more injectors leaking by, which may also affect fuel rail pressure. Hope this further explains things and helps fix your problem
You can check the wiring diagrams (select year) on autozone.com http://www.autozone.com/servlet/UiBr...3d800f9461.jsp and troubleshoot the wiring. If you have 12v output to the high-pressure in-line pump and the connection is good, you -should- have 12v at the in-tank pump, unless there is a break in the wire / connection to the in-tank pump. If voltage is present and you're still not meeting pressure specs as per the test procedure previously mentioned, then more than likely one or both pumps may need replacement, however, you should probably check to see if your in-line filter is clogged or dirty as well as check the FPR to see if the diaphragm is blown (vacuum line wet with fuel). If the FPR is bad, pressure will be lower than required, if the in-line filter under the driver's side frame rail is clogged or dirty, the pressure and fuel delivery will be affected, and if the pumps are worn or wearing out, fuel delivery / pressure will be affected. You may also be having issues with one or more injectors leaking by, which may also affect fuel rail pressure. Hope this further explains things and helps fix your problem
