So after a transmission swap, im having late shifting issues when up to temp on my 1990 renix XJ.

Fluid is topped off, adjusted TV cable, went to go back probe the connectors on the TPS and BAM... Splices... As far as the eye can see.

They are done pretty well though. So well that i would have to cut shrink wrap to be able to probe wires. Furthermore, i only have the slightest hint as to whats what.

I found a thread with a similar issue but his was only spliced on the ECU side so the responses focused on that. Furthermore, my bundle does not appear to have one of the colors mentioned (Blue with Black tracer)

I think my best bet would be to try to go pull a Junkyard TPS with the associated harness and splice it back in.

 

Probably had rot in the connector and didn't bother to redo to near factory. Your idea sounds good.

 

i found a yard with a candidate. Ill run out there tomorrow. Hopefully its in good shape. Super frustrating. Its one step forward two steps back with this thing.

 

I suggest proper soldering as a splice rather than crimping. for best long term trouble free results.

but your solder technique should be good. old oily corroded wires dont always solder well. so make sure they is clean.

 

Good news everybody! I havent rigorously tested it, but the pigtail transplant appears to be a success! I also installed a new TPS while i was there.

Unfortunately i wasnt able to extensively test it due to multiple other show stopping issues, but the truck responded very well and even had the high idle response. Which was predictable since the old one was probably way out of whack. It shifted very well through all the gears.

 

You ever visited my website?

 

you mean the legendary "cruiser's mostly renix tips"? Many times over the last few months. I very much appreciate your information and im honored that your directly responding to my thread.

I bought a 90 renix XJ that had been sitting for a long time for pretty cheap. But its got ALOT of show stopping issues. And TBH im kinda regretting buying it.

#1 a shorted/loose wire to the ECU that creates an intermittent no start. (Going to pull the ECU down tomorrow morning and try to solve that).

#2 possible overheating. Flushed and replaced the radiator with a NICE new unit and it still boiled over the other day. Once i get the ecu wiring issue sorted ill move onto this.

Once i get these two show stoppers sorted, i plan on moving onto your other tips (already did the grounds).

 

Explain in more detail about the ECU wire.

Overheating. Still have the closed system with the pressure bottle on the passenger side firewall?

 

Short version- if i pull/shake the main loom for the ECU the jeep will Die then not start. If i push/shake the loom, it will start. This is repeatable/reliable. I am 99.9% sure theres a problem with a wire/pushed pin/corrosion. I am so so so happy i found the cause of this issue, its been haunting me for 3 months.

I wont be able to update you with the cause until tomorrow as i am at work.


​​​​long version
when i bought the vehicle, it wouldnt start. Replaced injectors, CPS, bypassed the ceramic resistor, shook all kinds of wires, nothing seemed to be a confirmed fix... Never could put my finger on a fix. But i found if i disconnected the battery and discharged it, and did all those things, like a rain dance, i could get it to start.

Today when i went to go drive it after adjusting the new TPS the no start got REALLY bad. Like way worse than before. Could barely get 1/8th mile down the road. I did three rain dances and then i started to really suspect the loom. I shook the loom while holding the starter. I was able to duplicate the issue reliably. Thank jeepus.

Whats weird is i had shook the loom before but didnt get results. I guess the wire got bad enough that i became more apparent.

 

That is real progress!!

 

[Overheating. Still have the closed system with the pressure bottle on the passenger side firewall?[/QUOTE]


Short version

Its the original system with the expansion tank.

​​​​​​*New dual row HD aluminum radiator
*Aftermarket aluminum surge tank
*Heater core bypass
*No thermostat installed
*Hoses have all been removed and cleaned out
*Clutch feels good
*Electric fan works

Longer version
​​​​​​The expansion tank was full of THICK RUSTY SLUDGY "water". it looked like a chocolate milkshake. The hoses were CRUNCHY they had so much scale that you could pinch them and feel the scale break off the inner walls. I flushed and flushed, let it sit for weeks with radiator cleaner in it, cleaned the hoses out.

Took it for its maiden voyage on the highway and made it 15 minutes before it departed 210F. From there the temp skyrocketed. I watched it climb 3/4 up the gauge in 15 seconds. I can only assume the pressure released and the water boiled over prematurely.

My list of things im going to try
​​​​​​*bleed the system better

*Try to confirm good flow

*Try to borrow a pressure tester to see if combustion gasses are entering cooling system

*Replace the cap

*Replace the water pump


​​​​Hopefully this isnt a head gasket issue​​​​

 

Aluminum surge tank. Like a Mac's?

I'd be suspicious the blades in the water pump are rusted off.

 

Yes, i believe it is a macks. I installed the shiny new radiator after the flush BTW. And yeah. You are probably right. Someone else mentioned that too. I should just change it straight away since this is going to be a mud toy. Rather than wasting time and distilled water. Pump and cap. Right after i sort the wire issue.

 

I have plenty of times over the past two years, it's a huge help!

 

Pulled the ecu this morning. Tried pulling on individual wires but i couldnt get it narrowed down. Thought it may have been the connector on the ecu its self, so i swapped one in the PO gave me. No help.

Heres a video i took this morning. It shows all the symptoms.


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