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87 Renix XJ No fuel, No brake lights, cranks fine

Ecomike

NAXJA# 2091
NAXJA Member
My 1987 Wagoner, new battery, cranks fine (Engine cranks, starter cranks), radio works, AC/Heat blower works, but does not start/run.
Also no brake lights or tail lights.

Got suspicious and found no Zero fuel at the fuel rail. I do not hear the fuel pump run when I turn the Ignition switch to run.


Been ages since I was an expert on the wiring, and going to dig into it tomorrow. Needs some quick ideas please.


I ran and drove fine when I parked it months ago.

Gotta be a common electrical issue, relay under the hood, or fuse under the dash. Ignition switch is not that old or overloaded like the old days..

Glad to see some folks kept the lights on here.
 
You can try swapping the relays around on the passenger inner fender and see if it's the fuel pump relay.

BTW, do you still have that fuel pump retaining ring tool I made and sent to you years ago?
 
You can try swapping the relays around on the passenger inner fender and see if it's the fuel pump relay.

BTW, do you still have that fuel pump retaining ring tool I made and sent to you years ago?

Thanks, I re-read the Renix manual last night, and plan to also test that Ballast resistor and the starter relay output to the
Ballast Resistor in the image below. Because I have no brake lights, or tail lights I suspect is not just a FP relay or ballast relay.
I never replaced the Starter relay below




image.png
 
BTW, do you still have that fuel pump retaining ring tool I made and sent to you years ago?

Since I never throw stuff away, it is likely here, somewhere.

But the 2017 Harvey Flood (foot of water in the house) made a mess of everything here, and the joint damage, etc, in my hands limits what and how much stuff I can do now days by myself.

This getting old and fight RA gets old fast.

Having the living room (my shop these days) ceiling fall in last year, did not help either. EF-3 Tornado got a wee bit too close

I will keep an eye out for it. :wave1:

Glad to see you are still alive and kicking.
 
Is there a chassis ground at the back which would be common to FP and tail lights?
 
Is there a chassis ground at the back which would be common to FP and tail lights?


That is what I am wondering.

I just ran some checks and head lights and tail light, running lights work.

There is no ballast on this 87 Wagoneer, never was it seems. My Renix Cherokees have them. Battery disconnected I checked the + Bat Clamp the Starter Relay + post and got .003 ohms resistance, there is not problem in + battery cable. Same for the battery Ground to the frame and about 6 locations I tested under the hood.

Going the test the FP relay next Swap), once the wind slows down. Feels like 70 MPH gusts outside today.



I need to rig up a remote Volt meter (long wires) to test for power getting to the relay while switching to run.

I do hear a click and about a 5 second later time out click under the hood, when I switch the Ignition switch from off to run.

My guess is that FP relay is switching on and times out off, but that is all.
 
Too windy to continue today. Windy gust nearly blew away the Jeep hood, them it fell.....
Never had that happen before. Good thing I was not under the hood.

Crazy, clear skies massive north to south wind gusts. Is the 89 Starter relay the same as the 87 ?
 
Is there a chassis ground at the back which would be common to FP and tail lights?


IIRC, on my '90, the ground for the rear (fuel pump and lights) is located behind the drivers side rear panel, behind the spare tire mount. Could it be the same on the '87?
 
Thanks gentlemen, The Fuel Pump relay is working. I got that far last night.

I will dig into the grounding....Thanks!!!


Edit: Is the dash gauge fuel level sensor on the same ground? I know the tank has plenty of gas (I would have seen and smelled a leak) so of the dash gauge

is not working that would be a huge clue? Ground? If it is working, the fuel pump may have died?
I now I fixed the ground on another 89 just by refreshing connector near the gas tank, down under about 14 years ago. But it is parked in the grass right now. Ugh...
 
OK, The "ground for the rear" tested as .001 ohms all the way several ground locations under the hood.

The relays under hood are good and working, the grounds under the hood are awesome.

In the run ignition switch position the only thing not working on the dash is the fuel level gauge.

This rig has no ballast resistor. Never did since before i bought 20 years ago. Unless I missed something on the wiring diagrams, the ground connection at the Fuel Pump assy, and or the hot wire to both are not making contact, because if it was just a bad fuel pump, the gas level gauge on the dash would be working.

Have I missed anything? Does the B+ Latch relay need to work for the fuel pump to get power? What does the B+ latch need to work for, to work?

I hear the FP relay turn on and off, and I swapped the B+ and I could still here it power on and off, when I move the Ignition from off to run. So both relays work, But I have found an easy test to verify the output of the B+ doing what ever it does (I thought it was a sort of fuel stop, early anti-roll over tech??, but I forget exactly what it does.



XJ-Body-Ground.jpg


IIRC, on my '90, the ground for the rear (fuel pump and lights) is located behind the drivers side rear panel, behind the spare tire mount. Could it be the same on the '87?

Yes, it is.


Cruiser54 , I have started looking for the tool, but there is a whole lot of stuff I need to move and dig through, and joint problems limit how much I can do now days, and no longer have any help. I will keep looking.
 
The B+ latch circuit goes from and back to the ECU, so it should have nothing to do with my problem.
 
To check fuel pump circuit. jumper the DLC 1, the small one and its the pin closest to the driver and firewall if you will. And the pin directly forward next to the 1st pin. Clear as mud I know.
 
To check fuel pump circuit. jumper the DLC 1, the small one and its the pin closest to the driver and firewall if you will. And the pin directly forward next to the 1st pin. Clear as mud I know.
Pin 6 when hot wired from the battery B+ engages the O2 sensor relay on the drivers side fire wall (Before that Pin 6 has 2 ohms of resistance to ground).

Pin 5 has infinite resistance and giving it 12+ Volts does nothing.

Ignition key on or off, makes no difference. 3-4 seconds after going from off to run (ignition switch), I hear one of 4 relays, like the Fuel Pump relay turn on for about 3-4 seconds, and then times out, but the fuel pump does not turn on.

1708813467153.png
 
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