panzerman200

Hi guys,

got a 1986 Jeep Cherokee Pioneer, 2.5 TBI.

Died on the highway, towed it home. No "buzz" from fuel pump when turning the key. Threw a new fuel pump in. Still no "buzz."

Engine briefly starts when spraying engine starting fluid into throttle body. Pretty sure it's a problem with a relay or a fuze/bad ground.

I've done some looking and it looks like a lot of the late 80's jeeps have a set of four relays under the hood. Mine has two, with no cover. I tried switching them and still no luck.

I'm not great with electrical- so any kind of testing with an OHM meter is going to require some special explaining. Haha. Have to be honest...

Anyhow, could a bad ballast cause this? Is there a fusable link? Where can I check for grounds? The leads coming out of the tank go straight up into the tank. There are three wires, FYI.

Thanks in advance for any thoughts!

Pete

RTorrez1

Try by-passing the fuel pump resister. It is on the drivers side fender. It's the white ceramic piece with the two connectors. Give that a try and let us know if it works.

panzerman200

Thanks for the advice! I took a look for it and found no such thing. Could it be under the washer fluid bottle?

Also, might be a silly question... I bench tested the new pump. Works fine. Right now it is connected but not IN the fuel tank. Could that cause any issues? I just realized that there is a ground on the pump assembly... I imagine the assembly needs to be connected and in the tank to be properly grounded...?

Thanks again!

panzerman200

Searched high and low for the resistor. Could not find it. Could my model not have one? Could it be made from something else besides ceramic?

I've put the fuel pump into the tank, replaced both relays under the hood. Still no dice. The wiring looks like it goes straight up into the frame... Anyone chased wires from their pump before? Does it just run up into the plastic siding and then past the drivers seat somewhere? Just trying to know as much as possible before tearing everything apart...

panzerman200

Bump for the night crew.

Also, can anyone let me know where the fuel pump grounds to? I haven't been able to find it.

Thanks

Pete

panzerman200

Alright.

Cleaned every ground I could find (Oil Dipstick, weird braided wire at rear of head, large ground on block next to alternator, two small grounds; one on the left side of the engine compartment, one on the right) and one ground I found under the dash.

I tried jumping the fuel pump at the relay spot. Here's what happened.

Fuel pump spooled up. So I put the relay back in (all while the key was in the forward position, on.) and it started clicking.

Went and put the key back to off, then forward again. Heard it spool up. Jeep started right up! Let it run for a bit. Stopped it, tried to start it again. Did not hear the pump spool up. Jeep would not start.

Ran a ground from the pump to the -Terminal on the battery just in case it was a bad ground. No dice. Pump still spooled up if jumped at the relay. (30 to 87.)

Double checked the fuses under the dash. Nothing was burnt.

Tried putting starting fluid in the TBI, would not start like it did a few days ago. Pulled a plug, checked spark by setting plug against metal surface. No spark....

Replaced starter relay, ignition coil, and ICM (Ignition control module, under the coil, which tested bad at the store.)

Still no spark. Still no spool-up at the fuel pump when pushing key to forward position. Fuel pump will spool if jumped at relay, but jeep will not start of course (no spark.)

Replaced CPS. Still no dice.

I'm out of options here guys. If ANYONE has any idea what to try, I'm game.

So in all I've:

Cleaned as many grounds as I can find.
Jumped the fuel pump at the relay, and run a ground straight to the battery.
Replaced CPS, Ignition coil, ICM, checked fuses, replaced starter relay, replaced both box relays under the hood, and prayed over the Jeep.

Please help.

panzerman200

Well, I hate to post so many times in a row... But I'm hoping as time goes on someone will read this and have an idea of whats going on...

New development.

So there are two spots for relays. The one closer to the front, when jumped, powers the fuel pump.

The one closer to the back when jumped...the jeep starts and runs like a top! (30 to 87) (Funny enough I can't hear the fuel pump spool up, but the jeep runs that way...)

Tried putting a different relay in it- no dice.

So whatever is going on has to do with that relay spot...I think.

So I tried tracing wires. One goes the the starter relay. When unplugged the jeep doesn't run (when jumped) so I'm pretty sure it's not that wire.

Two others run, eventually splicing together, and ending up at a yellow cap above the cylinder head- (I think?) that almost seems to be a dead end.

The last one ends up somewhere under the dash... I think. Best I can tell

If it doesn't work... What I was thinking was running a wire from the 30 terminal inside the jeep to a switch, and then a wire back out to the 87 terminal with an inline fuse. Just switch it when I want the jeep to run and call it good...?