Renix, pre-91 era XJ jeep tech differences

[Ecomike]

Most annoying and hardest to find water leak I ever had was from the back seat door windows, with manual window cranks. Stuff on the back seat floor would hit the crank and turn it just enough that the window looked closed and windy rain would blow the rain in. They it would run to the front seat floor and pile up there and make the leak look like a front dash-windshield-firewall or front window leak.

 

[87manche]

I could never get the factory sun roof to remain sealed, and the gaskets are long since obsolete.

 

[Ecomike]

You could not pay me to take any vehicle with a sun roof. Had new 76 Dodge Charger with one. What a mistake. Dealer service dept forket it up. One of the need to DIY :banghead: lessons I got long ago.

 

[87manche]

Agreed, but I'm somewhat annoyed by a lot of the stuff on a RENIX now that I own one. The internally regulated alternator's a minor annoyance (I'm a picky EE, most people probably won't care), the throttle body design and intake hose annoy me, the TPS and CPS are FAR more susceptible to failure and water issues than I'm used to from owning a 91, a 96, and a 98, and the wiring harness is minimally waterproofed and not thought out very well. A lot of this can be chalked up to it being an 80s design - things have progressed significantly since then - but I never understood why a lot of RENIX owners say "it's always the CPS", replace TPSes every time they go mudding, and swear by cleaning connectors and packing them with dielectric grease. I've never had to do any of that on an HO. My 88 MJ sat for a couple years in my yard and I couldn't figure out why it was unable to start until I threw an oscilloscope on the CPS... sure enough it was dead. Worked fine when parked :dunno: then after that it would barely run right and would stall if you dropped the throttle, which turned out to be a completely dead TPS, which again worked fine when parked. I might be just a little bitter about that :confused1

I have owned 4 renix jeeps.
I have never replaced a CPS or TPS.
and the 87 ran for years with the CPS wires wirenutted to the body harness.
it kept running like a top, I didn't mess with it.
it also sat for so long that the friction disc was literally frozen to the flywheel. I had to fire it up and wait 30 minutes before the clutch worked in sub zero weather.
but it did fire after sitting for two years, get driven onto a trailer and then get wheeled for a summer before it broke in half, with 0 maintenance effort.

So maybe they just hate you.

RIP uglytruck.

 

[kastein]

My brand new TPS just bit the dust after a cooling system boil-over and I get to buy another new one or live with it driving like garbage again now.

Yeah, still annoyed. My 91 has gotten soaked any number of times including the upper radiator hose exploding at 280 degrees with the hood shut and blasting the entire engine bay with high pressure steam and flash boiling coolant. Never ate a TPS, still has the factory one in it far as I know. Because they seal to the TB somewhat instead of being the garbage "lets make a lever move a lever for no reason" design that Renault/Bendix came up with.

Some people might have luck with these things... they are welcome to the parts pile when I strip this thing bare in a year or so and swap it over with all the HO parts off my rotten parts beater.

 

[cruiser54]

My brand new TPS just bit the dust after a cooling system boil-over and I get to buy another new one or live with it driving like garbage again now.

Yeah, still annoyed. My 91 has gotten soaked any number of times including the upper radiator hose exploding at 280 degrees with the hood shut and blasting the entire engine bay with high pressure steam and flash boiling coolant. Never ate a TPS, still has the factory one in it far as I know. Because they seal to the TB somewhat instead of being the garbage "lets make a lever move a lever for no reason" design that Renault/Bendix came up with.

Some people might have luck with these things... they are welcome to the parts pile when I strip this thing bare in a year or so and swap it over with all the HO parts off my rotten parts beater.

Take it back under warranty.

Many folks with later non-Renix Jeeps have experienced TPS failure from water.

 

[kastein]

Many have, but I haven't. Maybe I just got lucky.

I've considered taking it back for warranty but not sure I feel right doing so, seeing as it getting blasted with coolant was my fault.

BTW, thanks for setting up your website. It's been invaluable getting this thing running again after it sat for years. I knew nothing about renix diagnosis, only HO, so I was really scratching my head on some of the issues.

 

[cruiser54]

Many have, but I haven't. Maybe I just got lucky.

I've considered taking it back for warranty but not sure I feel right doing so, seeing as it getting blasted with coolant was my fault.

BTW, thanks for setting up your website. It's been invaluable getting this thing running again after it sat for years. I knew nothing about renix diagnosis, only HO, so I was really scratching my head on some of the issues.

Glad the site helped.

What brand TPS did you purchase?

 

[kastein]

I can't remember. It was in stock at the oreilly 10mi from work so I jumped on it. BWD maybe? I've had alright luck with them before.

Worked great till it got a non-consensual coolant bath

 

[cruiser54]

I can't remember. It was in stock at the oreilly 10mi from work so I jumped on it. BWD maybe? I've had alright luck with them before.

Worked great till it got a non-consensual coolant bath

I'd warranty it.

 

[Ecomike]

I can't remember. It was in stock at the oreilly 10mi from work so I jumped on it. BWD maybe? I've had alright luck with them before.

Worked great till it got a non-consensual coolant bath

I have never had a chance to try it, but I have always felt that distilled/DI water triple dip and soak rinses and a trip in an oven at 225 F would fix the Wet-Renix-TPS syndrome.

 

[kastein]

I suspect it would as well, though I am going to substitute denatured alcohol since it should evaporate far faster and is non conductive.

 

[Ecomike]

I suspect it would as well, though I am going to substitute denatured alcohol since it should evaporate far faster and is non conductive.

DeIonized (DI) or Distilled water is also non conductive, and will dissolve and draw out the ions from the coolant (salts of sodium metasilicate for one used in the antifreeze formula that are the cause of the TPS errors) better that denatured or IsoPropyl Alcohol (IPA) (which is denatured on the pharmacy and grocery store shelves) at dissolving and drawing out the salts in the first 2 rinses. A final rinse with alcohol, or two is a great idea!!!!

70% Denatured IPA (rubbing alcohol) is 30% DI water, and is also available at 90% (10% DI water). So it may work fine, and faster, but I would go with pure water the first time. I my case I manage water treatment, lab equipment so I can test the used DI water after soaking a TPS sensor with a TDS (Total Dissolved solids) test meter to see how the cleaning is going

The alcohol will dissolve the ethylene glycol, so will the water, but Alcohol is a poor solvent for sodium or silicate ions.

 

[kastein]

Very true. I was mostly thinking of it since ethyl or IPA is a great way to cure swimmers ear since it dilutes and carries off the water and then the remainder evaporates. Didn't consider what coolant chemicals it would dissolve and carry away, thanks! (This is why I am an amateur chemist at best and a professional EE...)

 

[Ecomike]

We can't be a pro at everything, no matter how hard we try. :sunshine:

But YOU do a damn fine job of coming close when it comes to anything XJ-Jeep.

I just happen to have decades of cleaning equipment and cleaning chemistry formulation experience that covers all manufacturing and re-manufacturing cleaning. Not your every day topic. One of the reasons I never toss anything out, I spent 45 years around rebuilders....selling to them and later doing consulting...Wish to hell I had a few years of EE education. I grew up with a father and an older brother that were EEs and ham radio operators.....among other things, so I got a lot of hands on experience, but I never got as deep into theory as I wanted to. Still have all their old WWII ham radio, Army Air Corp gear Talk about energy hogs.

 

[Ecomike]

Rediscovered a great old sight on XJ OEM tech differences over the years, Yuccamans site which I learned a lot from 10 years ago and forget about. Found it again today to nail down the specs on 1989, 4 banger XJs for a new troubleshooting thread here, and I thought they were MPI by 1989, but no they stayed TBI until 1991 it seems per Yuccaman ( a pretty good authority as I recall )

http://www.yuccaman.com/jeep/history.html

 

[old_man]

I haven't seen Jim in a long time. I remember him coming over and working together on his heap in my driveway when he was just starting. That really brings back memories.

 

[sjx40250]

Ecomike - thanks for that reference! Its been a few years for me, but there was another site that was really informative from a guy who was in the middle east. Do you or old_man remember or have that site?

I use to have it in favorites but with all the OS updates, I lost it.

 

[Ecomike]

Ecomike - thanks for that reference! Its been a few years for me, but there was another site that was really informative from a guy who was in the middle east. Do you or old_man remember or have that site?

I use to have it in favorites but with all the OS updates, I lost it.

I think I remember him, he was big on engine rebuild details parts wise, but no I do not have it or recall much of it. Have not seen him here since about 2006-07?

 

[kastein]

That sounds like DrDyno. Google that plus stroker and you will probably find his site