91 fj80 wont start no power to fuel pump

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kingslender

10 Year
Joined
Apr 27, 2013
Threads
1
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Hey Guys new to ih8mud so please go easy.

As the title says i have a 91 cruiser that I cant get to start. I have read several helpful posts on here but still cant find the answer. Back story, I bought this last year drove it home about 100 miles, ran fine. Ran it around town the next day getting insurance and stuff. On the way home pulling on to interstate it would not get to full speed/power. After about 5 miles pulled off interstate, took foot off gas and enginie died never to start again.

Here's what I know for sure. I have no power going to fuel pump. Engine still has comperssion. No antifreeze in the oil or vice versa. Engine is getting spark. Testing 12.5V at fuseable link and at efi fuse see attachment 2013-04-20 13.38.43.webp. No cel light on, but a/t temp light is on.

Items replaces so far.
Fuel pump (tested good)
coil
distributer cap
rotor button
plugs and wires
EFI relay

Any help is welcome, if you have any answers please explain in detail. I have the mechnical ability, but soft on the electrical side.

Or if in the Huntsville Alabama and willing to help out a fellow cruiser let me know.

2013-04-20 13.38.43.webp
 
You can jump the B+ to FP connector on the PS firewall to send power to the fuel pump. Truck should start and run with the two connectors jumped if you haven't been getting power to fuel pump. The Circuit Opening Relay is what turns on the fuel pump. It is located in the driver's inside kick panel to the left of the foot rest. It is the bottom right relay. It can be removed and tested as well. Detailed information can be found in the FSM on page FI-71. Here's a link for the FSM. It takes a while to load so be patient. http://tlc.cnlson.com/3FE REPAIR MANUAL.pdf

AND A BIG WELCOME TO IH8MUD!
 
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OK so the fp to B+ worked to get fuel pump working. So I have fuel in the cylinders I rechecked and have spark, I have compression, but I have no cel, and still no start. Would a new COR fix this problem? Should I be looking in another direction?
 
Hey guys I'm at the end of my rope. Just replaced the fusible links and still no change. No cel, have spark have compression, the only way to get the fuel pump on is to jump pin B+ and fp. The only thing I can think of is the security system. Could that be shutting down the cor and ecu preventing the cel and ignition in cylinders? :bang:
 
Have you called the seller? After market alarm or kill switch?

Replace the fuel pump relay since jumping the relay via B+ FP gave power to the pump. Drivers side next to the hood shock IIRC.

Just some thoughts.
 
Let's back up a bit here.
You say your CEL is OFF and you have spark??
If that's the case, then I would say your CEL is burnt out or has been removed to mask another problem.

Please verify if the CEL is working or not by jumping pins 6 and 3 on the CHECK CONNECTOR by the firewall. With the 2 pins shorted and the key in the ON position, the CEL should blink in a pattern. If the CEL is not illuminating at all, then the bulb is out.

Assuming the bulb is good, this motor will NOT start if the CEL is off when the key is in the ON position. No need to even crank it over. If the CEL is off, then the EFI circuit is dead.
 
Tried to jump the pins and still no cel, must be the light. Replaced the EFI circuit already. The alarm is called a steal stopper.

Thanks for all the help so far guys, love this site and look forward to the day when i get this thing running
 
Without a CEL, you can't see error codes that are stored in the ECU and we can only ASSUME that the EFI circuit has been energized by the ECU.
The fact that you're getting spark is telling me that it is in fact energized, but fix the light so you know what's going on with the sensors and the ECU.

The fuel pump relay (circuit opening relay) has 2 coils. The primary coil is fired by the starter circuit, the secondary coil is fired by the flap in the AFM when the motor catches.

The fuel pump shouldn't run with the key simply in the ON position unless pins 1/8 are shorted on the check connector.
 
Ok bad bulb in cel. Removed old security system. Jumpped the pin to get code and cel just continued to flash, no pauses (flash---flash---flash, just like a heart beat). Now what????
Thanks
 
So now the cel is on solid, no flashing. I took out the fuse to reseet it now it stays on. Still no start, still need to jump Fp and B+ to get the fuel pump to kick on.
 
kingslender said:
So now the cel is on solid, no flashing. I took out the fuse to reseet it now it stays on. Still no start, still need to jump Fp and B+ to get the fuel pump to kick on.
Click to expand...

So with the fuel pump jumped to always on, does the truck start normally and run OK?
If yes, then it's just fuel pump logic. I would verify the following:

pin 6 of the COR is ground
Pin 3 of the COR is +12 when the starter is cranking.
Pin 2 of the COR is +12 when the key is ON
Pin 4 of the COR has continuity to pin 2 of the AFM
Pin 1 of the AFM is ground
 
silly question...could it be a bad fuel pump? given that it won't start with the fuel pump jumped to be always on?

I feel for you...I had some fuel pump related issues with my rig...all electrical and thankfully all resolved eventually with input from fellow forum members.
unfortunately for you, I don't have a 3FE in my rig, so I can't be much help.

having said this, did you check the wiring from the fusible link to the fuel pump (assuming the fuel pump is in the same location for your model year as it is for later years). On my 94, the wiring harness had melted and the wire was shorting out on the firewall.
 
PCM is supposed to fire the injectors if you have fuel pressure. if you have spark, and know that the fuel pump is giving off pressure, then i would triple check your ECM main relay and make sure your injector is actually sending out the fuel.
 
kingslender said:
no truck dosen't start
Click to expand...

OK, so you've said you're getting spark and getting fuel but the truck doesn't run?

How are you checking for spark and how are you checking for fuel?

Spark should be checked at the plugs.
Fuel should be checked first at the cold start injector banjo fitting. This will tell you if the fuel pump is pumping fuel.
Next, you should check the FPR banjo fitting. This will tell you if the fuel rail is pressurized.
Next you should check the plugs after cranking to see if they're wet with fuel.
 
BlackLS1 said:
PCM is supposed to fire the injectors if you have fuel pressure. if you have spark, and know that the fuel pump is giving off pressure, then i would triple check your ECM main relay and make sure your injector is actually sending out the fuel.
Click to expand...

The 3FE ECU has no sensor for fuel pressure. It regulates fuel pressure by switching a VSV that controls the FPR, but there's no direct feedback to the ECU. The FPR VSV is activated from feedback of the water temperature sensor and some others I can't remember.
 
Checked spark by removing one and grounding it against the motor. Checked spark plug and it was wet with fuel. Could the timing be off that much not to be firing at corect time?
 
I had similar issue, then replaced the MAF with a rebuilt one. Ofcourse, I'm not sure if this would help you. L.B.
 
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