Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
Been looking for the common thing in the 4 modes that power is supplied to the pump. Going to throw an ign switch at it. Cheap only 14 bucks, so not out much if thats not it.
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fuel problem
- Thread starter Mike Mike
- Start date
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Well, probably not a BAD idea, or you could test the fuel pump relay socket for 12 volts with the key ON.
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
Whats the brown wire on the ign switch for? Barb on the switch for this one was cooked. Ran out of light going button it up tomorrow and see what happens
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
Have power at pin 30 on the fuel pump relay and a new relay. Power at the fuel pump wire on the stater relay.
something to think about. like I said, I went to troubleshoot one in an 87 the other day.
The connector at the fuel pump on mine was all nasty in the ground area, tons o resistance. I bypassed the connector and wired the ground straight wire to wire. That and a little knock on the tank with a 2x4 while providing 12V to the pump fixed it. Mine needed a knock because it had been sitting for a while, but the ground at the tank (tab on the fuel sending unit) and the ground at the plug were my culprit. I'd really look at the sending unit side because that tab is exposed, and in an area that catches a lot of road grime.
at this point I would probably hot wire the pump to 12V and ground at the socket to see if the pump is working. I use speaker wire, because it's got two conductors handily right together. Obviously this is only for troubleshooting in the driveway.
If the pump works hotwired to the battery for 12V and ground take away the hotwired ground and see what happens. If the pump dies wired straight to the 12V but using the factory ground then you've got a ground issue. If not, then you've got a 12V to the pump issue. If you get nothing with the hotwired pump you have a problem with the wiring in/at the fuel sender (you did check that ground tab right?) or a bad pump. If the ground tab is shot, or torn of as it was in my case, you can drill a small hole to the 10 o clock of the fuel output, and use a self tapping sheetmetal screw and a ring terminal to get a good ground bad. Cleanthe face of the sender before you drill the hole. I did this still instaled in the tank and didn't blow myself up, but take it out to be cautious
The connector at the fuel pump on mine was all nasty in the ground area, tons o resistance. I bypassed the connector and wired the ground straight wire to wire. That and a little knock on the tank with a 2x4 while providing 12V to the pump fixed it. Mine needed a knock because it had been sitting for a while, but the ground at the tank (tab on the fuel sending unit) and the ground at the plug were my culprit. I'd really look at the sending unit side because that tab is exposed, and in an area that catches a lot of road grime.
at this point I would probably hot wire the pump to 12V and ground at the socket to see if the pump is working. I use speaker wire, because it's got two conductors handily right together. Obviously this is only for troubleshooting in the driveway.
If the pump works hotwired to the battery for 12V and ground take away the hotwired ground and see what happens. If the pump dies wired straight to the 12V but using the factory ground then you've got a ground issue. If not, then you've got a 12V to the pump issue. If you get nothing with the hotwired pump you have a problem with the wiring in/at the fuel sender (you did check that ground tab right?) or a bad pump. If the ground tab is shot, or torn of as it was in my case, you can drill a small hole to the 10 o clock of the fuel output, and use a self tapping sheetmetal screw and a ring terminal to get a good ground bad. Cleanthe face of the sender before you drill the hole. I did this still instaled in the tank and didn't blow myself up, but take it out to be cautious
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Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
I checked with a meter at the plug by the gas tank and not getting power.
Every plug i've ever pulled apart on this jeep looked like new on the inside. It's been a southern Arizona jeep all it's life. So hardly an rain and no snow or salted roads. Even the rear upper shock bolts came right out when I did shocks.
Every plug i've ever pulled apart on this jeep looked like new on the inside. It's been a southern Arizona jeep all it's life. So hardly an rain and no snow or salted roads. Even the rear upper shock bolts came right out when I did shocks.
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
I used chassis ground. The pump is unused new mopar and powers up out of the tank. Jumpered the relay socket and nothing.
Now chasing wiring forward from pump.
Now chasing wiring forward from pump.
I say try hotwiring the pump and starting it up. Then you can start troubleshooting the wiring. A particular vulnerable spot is under the sill plate. If the XJ is like my MJ it runs under there, and all it takes it a little shift and it get's pinched or chafed by all of the constant in/out stepping. Whomever thought it was a good idea to run the fuel pump/tail light harness on the drivers side wasn't thinking clearly that day.
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
I chased the wire up to a 24 pin plug behind the left kick panel and still no power. Next week pulling washer bottle and starting on the other side of the firewall. I'm thinking it's going to be where the harness passes thru the firewall. Need to get this fixed it's my wifes DD and she hates driving my XJ. She's short and has to hop up to get in it and it don't ride nice like hers.
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
Is That what it's called! C101 connector. I'm going to probe the wire on the engine side of firewall. If theres power than I'll tackle the C101. Don't have time till Monday to mess with it.
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
The C101 connector was eliminated in 88 due to the many problems it caused. While your wife's 89 shouldn't have that connector, not all changes are at perfect cut-off points.
If you have a C101 connector, it is located right over the brake power booster, as in this photo from JP Magazine: http://www.jpmagazine.com/techarticles/154_1005_jeep_cherokee_xj_problems_and_fixes/photo_07.html
If you have the C101 connector the normal fix is to eliminate it by removing the wires and soldering them directly together, protected by heat-shrink tubing.
If you have a C101 connector, it is located right over the brake power booster, as in this photo from JP Magazine: http://www.jpmagazine.com/techarticles/154_1005_jeep_cherokee_xj_problems_and_fixes/photo_07.html
If you have the C101 connector the normal fix is to eliminate it by removing the wires and soldering them directly together, protected by heat-shrink tubing.
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
It doesn't have a C101 connector, wires come thru below master cylinder. Had to remove washer bottle to get at them.
Ran out of time and my disposition is going south. Headed to the shop on Monday. Only pay 1/2 labor rate and jobber on parts.
Ran out of time and my disposition is going south. Headed to the shop on Monday. Only pay 1/2 labor rate and jobber on parts.
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
I'll post up what they find for reference
Mike Mike
NAXJA Forum User
- Location
- Tucson Arizona
OK, Bad ECU
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
If you don't have to have that bad ECU for an exchange 5-90 would love to have it for figuring out the Renix ECU configuration.
- Location
- Rainy side of Washington
Wow, those aren't very common... glad you figured it out.
It is probably a pretty easy fix inside the ecu, I would bet on a smoked relay driver transistor. The renix ones aren't even waterproofed with hellish goop like the obd ones since they hide under the dash instead of in the engine compartment.
It is probably a pretty easy fix inside the ecu, I would bet on a smoked relay driver transistor. The renix ones aren't even waterproofed with hellish goop like the obd ones since they hide under the dash instead of in the engine compartment.
cruiser54
NAXJA Forum User
- Location
- Prescott, Az
I'd be curious as to what is found upon opening up the ECU.
My first thoughts are that it could be nothing and that the original problem might have been a poor connection at one or more of the pins at the ECU harness and the process of swapping ECUs just corrected the connection.
A good friend and excellent tech had a real bear of a problem on his Renix Jeep and after a few weeks of doing everything he could think of, he unplugged the ECU and used a small pick to tighten the connectors inside the harness plug. Sprayed it with contact cleaner and plugged it back in. No more problems.
Send the ECU to 5-90 if you could. It's like donating body parts to science, except you could get it back.
My first thoughts are that it could be nothing and that the original problem might have been a poor connection at one or more of the pins at the ECU harness and the process of swapping ECUs just corrected the connection.
A good friend and excellent tech had a real bear of a problem on his Renix Jeep and after a few weeks of doing everything he could think of, he unplugged the ECU and used a small pick to tighten the connectors inside the harness plug. Sprayed it with contact cleaner and plugged it back in. No more problems.
Send the ECU to 5-90 if you could. It's like donating body parts to science, except you could get it back.
5-90
NAXJA Forum User
- Location
- Hammerspace
The single most common issue with the RENIX ECU seems to be smoked fuel injector drivers.
Here you go - thought I had this somewhere: http://www.naxja.org/forum/showthread.php?t=953382
Here you go - thought I had this somewhere: http://www.naxja.org/forum/showthread.php?t=953382
