renix no start no fuel prime

Anyone care to help me diagnose my renix no start this xmas eve?

I've seen this covered many times and it seems to often pan out to something simple like a bad ground, but I'm hoping I can provide some clues, and renix folk might be able to point me in the right direction to find the culprit more efficiently. Also after all the threads to this end with no conclusion I promise to post my solution lol.

SO, 89 xj 4.0 auto 155k miles. I have had a no start twice, ONCE a few weeks ago after changing my exhaust manifold, put everything back together, and it would turn over but not catch. Left it in the sun for a day and it fired up fine, no problems since.

THIS time I reinstalled a t-case drop after installing a new tcase with an sye and forgot about needing to adjust pinion angles, so I put the drop back on on a cold drizzly morning: Ran fine after the new tcase, no start after just lowing the crossmember and reinstalling case drop. Didn't even open the hood.



Diagnostics.

1) CPS seems okay, I had a fairly new one when it wouldn't start. I switched in my NAPA spare, still no start. I have what appears to be a weak? yellow spark at the plugs. I swapped ICM with another and it had no effect. Dist, cap, rotor, wires and plugs are pretty new and indexed correctly a la cruiser54 tips.

2) Fuel pump is not priming. But it's running fine during cranking, no pressure at the schrader valve at prime, but there is pressure after a failed crank.

3) Tachometer has almost no movement and the battery gauge is inaccurate.



From reading other posts this seems to point to the b-latch relay or some ground. I have tried switching it around with other relays and I have't been able to get a fuel prime. The ground at the dipstick has been cleaned. I haven't yet checked for power at the b-latch relay to the ECU. Block to frame ground is looking kinda mucky.

I'm hoping someone can point me in a direction with specific targets to test. Where to start? Proper way to test relays? Any specific fuses I should look at and their locations? I have an multimeter and can report voltages/resistances.

Replaced block to frame ground with 4 gauge wire no difference, so that's ruled out my grounds should be good.

check for 12v at the pump.

check the fuel pump ground in the cargo area behind the drivers side panel. its really obvious 2 black wires on a ring terminal. just clean it up and see. mine was metal to paint.

also try bypassing the fuel pump ballast resistor under the hood driver side fender next to the air box. its a white thing with 2 orange wires. i just hooked the wires together. one less failure point

You might try checking the D-1 diagnostic connector (small connector), pin 6, should pulse when you turn the key to run. Checks the fuel pump relay and some of the associated wiring.

And the D-2 diagnostics connector (larger connector) pin 5 when you turn the key to run, it should pulse. Checks B+ latch relay function.

Check your voltage at the larger yellow wire at the ignition module when you turn the key to run. Lower than 10 volts with a full battery (over 12 volts) and you have a problem. Check the voltage at the gauge fuse with the key in run, same circuit as the ignition module, different spot.

8Mud said:

You might try checking the D-1 diagnostic connector (small connector), pin 6, should pulse when you turn the key to run. Checks the fuel pump relay and some of the associated wiring.

And the D-2 diagnostics connector (larger connector) pin 5 when you turn the key to run, it should pulse. Checks B+ latch relay function.

Check your voltage at the larger yellow wire at the ignition module when you turn the key to run. Lower than 10 volts with a full battery (over 12 volts) and you have a problem. Check the voltage at the gauge fuse with the key in run, same circuit as the ignition module, different spot.

Click to expand...

full battery
the b-latch relay was getting 12 volts to 86 and 30. And so was the relay adjacent to it (third from battery)

yellow power cord to the ICM is only getting 3 volts
D1 is getting no pulse
D2 is getting no pulse

Any ideas?

DMS3XJ said:

full battery
the b-latch relay was getting 12 volts to 86 and 30. And so was the relay adjacent to it (third from battery)

yellow power cord to the ICM is only getting 3 volts
D1 is getting no pulse
D2 is getting no pulse

Any ideas?

Click to expand...

Make sure you are testing the correct power wire (yellow) to the ignition module, the larger diameter yellow wire. Then do a volt test at the gauges fuse in the fuse block, same circuit but closer to the ignition switch. Then check the same yellow wire circuit at the ignition switch. Then the red wire at the ignition switch.

Best guess would be a bad ignition switch, a serious short in the yellow wire circuit, a bad connector in the yellow wire circuit, a bad fusible link and you are back feeding some voltage into the yellow wire circuit, but not enough.

I periodically drive through a swamp, sometimes when enough connections in that yellow wire circuit get wet, the voltage drain through the water and mud can cause low voltage.

I've had mixed result testing at the D-1 and D-2 so I really don't consider them reliable. Worth a shot, but IMO not definitive.

When volt testing make sure you test to a good ground, don't be fooled.

8Mud said:

Make sure you are testing the correct power wire (yellow) to the ignition module, the larger diameter yellow wire. Then do a volt test at the gauges fuse in the fuse block, same circuit but closer to the ignition switch. Then check the same yellow wire circuit at the ignition switch. Then the red wire at the ignition switch.

Best guess would be a bad ignition switch, a serious short in the yellow wire circuit, a bad connector in the yellow wire circuit, a bad fusible link and you are back feeding some voltage into the yellow wire circuit, but not enough.

I periodically drive through a swamp, sometimes when enough connections in that yellow wire circuit get wet, the voltage drain through the water and mud can cause low voltage.

I've had mixed result testing at the D-1 and D-2 so I really don't consider them reliable. Worth a shot, but IMO not definitive.

When volt testing make sure you test to a good ground, don't be fooled.

Click to expand...

Thanks mud, when testing these I used the dipstick ground for reference. I'm pretty unfamiliar with the electrical system. The yellow wire I tested was on the two prong connector going into the ICM and had one prong that was unused.

Is the gauges fuse located in the fuse box under the drive side dash? And just to clarify the ignition switch is located at the base of the steering column and requires removing the driver side lower dash?

DMS3XJ said:

Thanks mud, when testing these I used the dipstick ground for reference. I'm pretty unfamiliar with the electrical system. The yellow wire I tested was on the two prong connector going into the ICM and had one prong that was unused.

Is the gauges fuse located in the fuse box under the drive side dash? And just to clarify the ignition switch is located at the base of the steering column and requires removing the driver side lower dash?

Click to expand...

You want to test the larger yellow wire at the "A" pin. The smaller yellow wire going to the "B" pin is the ignition module trigger wire and rarely an issue.



Yes the gauges fuse in the fuse box by your left foot (lower firewall) when you are sitting in the drivers seat. If it checks out OK your problem is downstream, maybe a splice. If it doesn't check out OK your problem is upstream, likely the ignition switch, maybe the ignition switch connector or maybe something in the red wire main power feed to the ignition switch.

I can get to my ignition switch (the back side) without removing the lower dash. It is tight and cramped but doable. While you are down there inspect the wiring where it exits the connector for scorching. Pretty common for the brown wire to overheat and even get hot enough to partially melt the connector.

My method is divide and conquer, so I keep quartering a circuit until I've got it narrowed down.

I may be on the wrong track, just working a hunch here.

I use the battery negative terminal when voltage testing in the engine bay.

Have you run a test to see if the injectors are getting power to fire them? Any signs of fuel getting the plugs on a no start. Flooded?

Ecomike said:

Have you run a test to see if the injectors are getting power to fire them? Any signs of fuel getting the plugs on a no start. Flooded?

Click to expand...

I put this on hold for a while, I haven't checked for power to the injectors, but after cranking I can smell fuel on the plugs and there is some fuel in the rail. But there is no prime so pressure is never established for it to fire I believe. Going to see if I can find a bad fuse now

Okay, I had this issue on my 89 MJ and it stumped me for a few minutes.

I did not read every post but if the pump is not new or you haven't had it out you might have a deteriorated hose between the pump and bung. My MJ was pumping but the gas was just squirting out everywhere at that small peice of hose.

After fixing that I lost all power to the pump! I jumped a wire from the battery to the pump connection and limped home only to find that the bulkhead connector was the issue. You loose connection there if it loose/corroded. I also lost the radio at the same time?

I jumped the bulkhead connection that had a faulty pin and life has been good for 4 years

xjtrailrider said:

Okay, I had this issue on my 89 MJ and it stumped me for a few minutes.

I did not read every post but if the pump is not new or you haven't had it out you might have a deteriorated hose between the pump and bung. My MJ was pumping but the gas was just squirting out everywhere at that small peice of hose.

After fixing that I lost all power to the pump! I jumped a wire from the battery to the pump connection and limped home only to find that the bulkhead connector was the issue. You loose connection there if it loose/corroded. I also lost the radio at the same time?

I jumped the bulkhead connection that had a faulty pin and life has been good for 4 years

Click to expand...

fuses all looked good. I'm not sure what the ignition switch looks like so I haven't verified that yet

Hmm, It seems like the bulkhead could be the culprit since this started after raising and lowering the tranny a few inches, maybe the bulkhead got stressed. I will break it apart and spray the connections and push the wires in better to see if that might make any difference.

Thanks!

Cleaned the bulkhead this morning, there was a bit of grim between it and the frame. Sprayed it out with electronic cleaner and then added dielectric grease, and guess what.. It fired right up!

:worship:

The electric renix gods are happy once again thanks everyone for helping me figure this out.

http://cruiser54.com/

Time to start going through Cruiser's steps!

MT Mike said:

http://cruiser54.com/

Time to start going through Cruiser's steps!

Click to expand...

I have been a cruiser renix tip disciple for sometime now, the bulkhead is the one man electrical connection I missed due to not knowing how to open it... Should have spent the time to get in there earlier

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