gearheadette

on any magnetic relay 86 and 85 are the secondary circut, 87 an 35 are the primary to jump it just go from 86 to 85

5-90

1) Throttle body spacers are supposed to help increase the plenum vollume and help with low-end torque. I'm not sure how well they work - I've not tried them. You'll generally find them for 1991-up AMC242 (irrespective of ignition, it's the throttle body mount and bore that are important,) and the 1987-1990 242ci used a three-screw throttle body mount (NB: For 1991-up 242ci, you can usually use a Ford 5.0L throttle body for a quick "bored" version. A bored throttle body doesn't really help performance tho - it just makes part-throttle response more crisp.)

2) RENIX (1987-1990) has three individual coolant temperature sensors:
A) Driver's side radiator tank (thermal fan switch, triggers the electric fan relay.)
B) Driver's side of cylinder head at rear (drives IP gage/warning lamp)
C) Driver's side of engine block, below exhaust manifold (reports to ECU.)

If your temperature gage is way off, replace its sensor (you'll need a 7/16" deep socket, and be careful! It really sucks when you snap the head off of that thing...)
If the E-fan isn't responding to temp, it's likely the TFS. The ECM doesn't have anything to do with triggering the E-fan due to temperature - the only time the ECM sends a signal to the E-fan relay is when it gets an "A/C Req" signal.
The engine runs just fine without the EGR valve - and cleaner besides (per CA smog tests, oddly enough.)

You have the correct thermostat housing for your RENIX. You may install a later (1991-up) version if you like, which will gain you a 3/8" NPT port for adding a sensor, but you should really only bother if you plan to do something with it. Otherwise, you're fine.

3) Oil pressure sensor. Don't break it. Standard GM part.

Anything else?

gearheadette

why does everyone say Renix? is that my engine? why is it called that?

5-90

RENIX = 1987-1990 w/AMC engine.

RENIX is the control system, also the generation of cylinder head (the intake ports were raised and changed for the 1991 model year to improve breathing - the three revisions of that head are collectively known as "HO". Later controls are either ChryCo OBD-I, ChryCo OBD-II, or ChryCo OBD-II DIS/COP.)

RENIX comes from the designer (Renault) and the integrator (Bendix/King) - RENault + bendIX/king = RENIX.

The RENIX system is actually pretty damned tough - I've only heard of three controller failures (I have two of them - one came to me all the way from South Africa. The third one was in Czechoslovakia, and got used to develop a repair...) and all three were due to a blown injector driver - same cylinder, I think. This is mainly due to the builders - Bendix/King also does avionics.

The RENIX systems is "pre-OBD," so conventional scan tools won't work. You'll need the Chrysler DRB-II, Snap-On MT2500, or something similar to access the computer directly. However, being pre-OBD, RENIX does not "store" or "throw" codes, and just about all troubleshooting can be done with a DMM.

Given a choice, I prefer RENIX over OBD. I also prefer OBD-II over OBD-I, but that's because OBD-I was specified by CARB, and OBD-II was taken over and unified by SAE. But, I still prefer RENIX overall - I'm used to doing my own thinking, and I like it that way (besides, I've run into cases where OBD was just plain wrong. OBD-II is better about that.)

There's nothing at all wrong with the RENIX setup - I've owned five RENIX XJ's to date!

BlueXJ

X2 on the Renix system being very tough. I have had (still own) 2 and a third was under my supervision for much of it's life. They are easy to diagnose and I would rather figure out a problem than have a computer tell me the solution, which in the case of OBDI may or may not be correct.
The sensors are well thought out and also well placed for their intended purposes.
Long live the Renix.

gearheadette

blue, i have been waiting for you to chime in, what do you think about my sensor issue? i think from the disscusion that i need to replace the one behind the head and the one under the exhaust to start. whats your opinion?

whowey

Thanks for the pick-up Jon. I completely forgot that the Renix uses the thermal switch for the fan.

And I would certainly be x3 on my preference for Renix XJ/MJs. Easier to diagnose..easier to work on. Tough as nails.

5-90

The one on the back of the head, as I said, drives the gage - so if your gage is screwed up that is the one to replace.

I'd only worry about the one under the exhaust if you were having fuel economy issues, and none of the usual suspects panned out. What trouble are you having again? Detailed symptoms, please.

Apart from the very occasional fuel injector driver blowing out (rare, as I said,) I'd say that the RENIX control setup is Mk-1 Mod-0 simple, and about as reliable as the average brick. It rewards a mechanic who can do his own thinking - which is why to-day's "techs" can't work on it properly (I was taking courses to become a "certified" wrench when I got clobbered, and they were all OBD-II driven. Nothing on OBD-I, nothing on points/condenser setups. Gawd - I cut my teeth on a set of points!)

losingxinsight

Not to hijack the thread...but

Renix is pre 90 from what you guys are saying?

Now what years do OBD-I and OBD-II fall into that?

whowey

Renix is 87-90
91-95 OBD-I
96-onwards OBD-II

losingxinsight

Thanks man!

5-90

And OBD-II can be further divided - the 0630 head (1996-1999 XJ, 1996-1998 other models) got the 0630 head with a conventional distributor ignition, and the 0331 head (2000-2001 XJ, 1999-2007 other models) got COP/DIS. The 0331 may be readily identified by the presence of drilled and tapped bosses for mounting the coil rail.

The 1999-2002.5 0331 heads have about a fifty/fifty shot at punching your ticket into the "0331 club" - if/when they crack on top between the #3 and #4 cylinders (usually visible from the oil fill.) Replace with a 2002.5-2007 0331 head for the easiest swap (and if you're near San Jose when you get your ticket punched, let me know - I'm still trying to score a pair of 0331 heads for research purposes. I don't care if they're cracked - in fact, I'd prefer it.)