fuel pump control

[asu4runner]

hey guys. looking for a little guidance on testing the fuel pump control P/N 89570-60140. im having a fuel delivery issue on my 2000 lx470 and i think i have narrowed it down to the module or possible the wiring between the pump and the module. a few weeks of troubleshooting, to include the efi relay kit from medtro, and going through the fsm testing the inertia switch and pump. i replaced the pump with a new oem unit with new oem filter on a hunch that maybe it had a wiring problem inside the tank, and i wasnt going to pull the original one out without putting a new one back it, truck has 337k miles on it. anyways, i get 12v at the fuel pump control plug but i only get 10.2v at the fuel pump. pump wont turn on. if i hot wire it, it kicks on fine. i cant seem to find the values to test the module in my service manual, although im sure they exist. can anyone help point me in the right direction?

 

[hoser]

98-02

 

[asu4runner]

98-02

thanks hoser. what im taking from this is that with engine off and key in the ON position, i should be seeing 12v at the pump from the ECM, correct? and once started and in idle, it should drop to 8.5v? i am not getting any fuel what so ever to the engine bay. while cranking.

can anyone confirm for me, with a faulty CPS, will the engine try and crank or no? i have no CEL but i understand they dont always throw a light when going out. i have a CPS ordered but the hell of it.

 

[hoser]

Did you check the Fuel Pump Control (FPC) voltage at the Fuel Pump ECU, at starting? Should be 3.8V.

 

[asu4runner]

Did you check the Fuel Pump Control (FPC) voltage at the Fuel Pump ECU, at starting? Should be 3.8V.

i think i am a little mixed up, i apologize. so there should be a constant 12v and also a 3.8v coming IN to the ECM, i just need to check the FPC terminal on the plug end and see if i have 3.8v there while cranking correct? lets assume i find tonight that i am getting 12v to the ECM B+ terminal, but i am not getting 3.8v to the FPC terminal. i am not sure where i would need to back track to before that for more troubleshooting.

 

[hoser]

Yes, if not getting 3.8v (or any voltage), the problem is upstream. I'd check the CPS and wiring... since it's a common issue.

 

[asu4runner]

Yes, if not getting 3.8v (or any voltage), the problem is upstream. I'd check the CPS and wiring... since it's a common issue.

a denso CPS is in the mail, i looked at the wiring last night behind the belt

Yes, if not getting 3.8v (or any voltage), the problem is upstream. I'd check the CPS and wiring... since it's a common issue.

Yes, if not getting 3.8v (or any voltage), the problem is upstream. I'd check the CPS and wiring... since it's a common issue.

Ok testing AT the fuel pump ECM, I have 12v on the B+ terminal, but I have zero on the FCP terminal. I understand this to mean that the ECM has full 12v power coming in but isn’t sending anything out to the fuel pump? I do however have 12v on the FP+ terminal, on the ECM. Testing the other end of that wire at the pump it shows 10.8v. Got confirmation that the CPS shipped today, maybe if the CPS goes out it can tell the fuel pump ECM to kill the pump?

 

[asu4runner]

Well I thought for certain after pulling this CPS that it would be the issue, but back to the drawing boards. I have a hard fuel pump ecm in the mail.

 

[SteveH]

Check this thread - I had a wiring problem under truck that gave me your exact symptoms. I would find that harness and unwrap, inspect, etc. and check continuity of all wires between the EFI controller (at the pillar in the rear) and the pump.

Fuel pump wiring failure - and the fix

The breakdown: Having just completed a 2200 mile trip to Indianapolis, IN and back, my 100 was running great, until the next day. On that day, I drove north of town (in a blizzard and salt/slop storm) and I heard a faint 'click' while driving and the engine died at 55 mph. I peeled over to the...

forum.ih8mud.com

 

[asu4runner]

Check this thread - I had a wiring problem under truck that gave me your exact symptoms. I would find that harness and unwrap, inspect, etc. and check continuity of all wires between the EFI controller (at the pillar in the rear) and the pump.

Fuel pump wiring failure - and the fix

The breakdown: Having just completed a 2200 mile trip to Indianapolis, IN and back, my 100 was running great, until the next day. On that day, I drove north of town (in a blizzard and salt/slop storm) and I heard a faint 'click' while driving and the engine died at 55 mph. I peeled over to the...

forum.ih8mud.com

i actually found this thread last week and it got my attention. i checked the wiring at the plastic elbow by the tank, and at the fuel pump ecm. i will say, i did not check continuity between the pump and the harness, i just did a visual inspection and my harness looked fantastic, but if the new fuel pump ecm doesnt do anything i will be tackling this next, thanks for th tip!

 

[asu4runner]

Guys. We have ignition. Played around with bypassing the Fuel pump ecm but jumping the B+ to FP+ and E to FP-, she fired right up. I ordered a used FP ecm on eBay.

 

[asu4runner]

Back to the drawing boards! New fuel pump ECU did not let the truck start. I jumped the fuel pump again at the FP ECU and the truck starts fine. This leads me to believe there is an issue with the FP control circuit? Driving into more wiring diagrams today. I won’t try ti describe the tantrum I threw in my shop this morning.

 

[asu4runner]

Per the FSM, I checked voltage across terminal 5 and 8 on the fuel pump and ecm. I should show 3.4-4.4 volts, I get nothing. At least I know kind of where the issue is now. Next step is checking for opens/shorts on the ECU according to the book.

 

[2001LC]

Have you checked the fuel safety cut-off. I've only read about resetting it, in passing. So I'll not be of much help today. But I understand in above drives foot, under dash. Search mud for where and how to reset.

 

[kevgentile]

You can check the wiring/connector at the bottom side of the truck under the left door area. Harness that goes into the cab.
But probably not an issue since it starts with a jumper, which would indicate that there is no problems in the harness.
Possibly a signal issue in the main ecm or an unlucky faulty new pump ecu

 

[asu4runner]

Problem solved. Although the inertia switch was one of the first things I checked, it had been tripped somehow. Discovered this AFTER I yanked the carpet out to check the wiring between the fuel pump ECm and the ecu. My guess is, it was the fuel pump ecm that was initially bad, but somehow while I was checking things I must have tripped the fuel cutoff and not noticed. I narrowed it down to the FOC wire by jumping from the fpc terminal at the ECU over to the fpc terminal on the FP ecm. Ran fine. Traced out the wire and found no issues, eventually came back to the inertia sensor and bam.

 

[asu4runner]

Have you checked the fuel safety cut-off. I've only read about resetting it, in passing. So I'll not be of much help today. But I understand in above drives foot, under dash. Search mud for where and how to reset.

It’s a small yellow push tab on the bottom of the sensor.

 

[Donquijote]

Have you checked the fuel safety cut-off. I've only read about resetting it, in passing. So I'll not be of much help today. But I understand in above drives foot, under dash. Search mud for where and how to reset.

Hello , I have same problem , where is the safety cut off ? Any picture ? Thanks

 

[Donquijote]

Have you checked the fuel safety cut-off. I've only read about resetting it, in passing. So I'll not be of much help today. But I understand in above drives foot, under dash. Search mud for where and how to reset.

Where is locate ?

 

[asu4runner]

Where is locate ?

under the dash by the fuel pedal, at your right foot.