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RENIX poll

Do you have a RENIX ECU?

  • Total voters
    96
A

AJPulley

NAXJA Forum User
Location
South-eastern MA
OK, this is a poll to see how many have an MJ or 87-90 xj with the RENIX system/ECU.

This is a public poll. PLEASE, no opinion bashing. I would like as many to participate as possible.
 
Last edited:
At the moment, my renix is pissing me off like none other . . .

I hate how it can't store trouble codes and subsequently you can't view them quickly and easily via a check engine light. If only i could cycle the ignition a few times and have a blinking light tell me whats broken . . . I've been batling an overcooling issue that i think is keeping the engine in open loop mode and giving about 10mpg. I'm just going to try to get the guy at autozone to run a good scan on it tommorow and hope that its just a coolant temperature sensor rather than the o2 sensor thats probobly going to end up being the problem knowing my luck . . .
 
The poll is missing the option "I have a Renix and like it, but still like the 91-95 Chrysler OBD better".

asheets934 said:
I'm just going to try to get the guy at autozone to run a good scan on it tommorow and hope that its just a coolant temperature sensor rather than the o2 sensor thats probobly going to end up being the problem knowing my luck . . .
Click to expand...

AutoZone can only scan 1996+ OBDII vehicles. They don't have the equipment to scan anything earlier.
 
anony91xj said:
The poll is missing the option "I have a Renix and like it, but still like the 91-95 Chrysler OBD better".
Click to expand...
Just looking for a yes or no. Not really concerned with the reason in a poll. You're welcome to explain in the threads if you'd like to however.
 
What about those of us that have two? ;)

I like Renix because it's easily tested with a multimeter, more accepting of strokers, and seems more forgiving when you have problems with sensors.
 
u don't have renix on a 96. Renix was a computer controled engine managment system that was developed jointly by RENault and bendIX. It was used on the early 4.0 Cherokees from 87-90, and also used on Renault vehicles and some winnebagos if I recall. It has no provisions to store codes as errors occur with the engine for later diagnosis, and its really hard to find a scan tool that will interface with it since it wasn't used very widely. That said alot of ppl like the Renix system because it was advanced for its time and it features a knock sensor, and for the reasons mentioned above.
 
RENIX was used 1984-1990 with the AMC engines - but the GM V6-60 2.8L was OBD-1 compliant. I don't know what controls the Renault 2.1L TD used, but Diesels are usually simpler than spark-discharge ignition setups.

Like RENIX? I've got five right now! I like the system because it doesn't diagnose itself, which allows me to figure out what's going on on my own. I don't care for "self-diagnosing" vehicles much - but I came up on points and condensers, and I don't care much for OBD anyhow. I find it overly complicates things to little effect.

5-90
 
Any chance you know how to "Kill the alive memory?
Click to expand...
To erase the "Keep Alive Memory", remove the negative battery cable and leave the door open for about 15 minutes. (Leaving the door open allows the ECU capacitors to discharge and erase the KAM.) Why do you want to do this anyway?

Please excuse the thread hijack.:piratefla

Back to topic: I loved the Renix system on my 89 except for one thing, the long cranking time required to start it. This irritated me so much that I traded for a 96 with OBD II.
 
I like my '88 and it's quirky Renix system. As may others have said, the Renix system is relatively easy to diagnose when problems come up. You can test most, if not all, of the system with a multimeter and a manual. My rig is almost 20 years old, so I have been replacing all the sensors over the last couple of years. Good Luck.

Woody
 
Runnin'OnEmpty said:
To erase the "Keep Alive Memory", remove the negative battery cable and leave the door open for about 15 minutes. (Leaving the door open allows the ECU capacitors to discharge and erase the KAM.) Why do you want to do this anyway?

Please excuse the thread hijack.:piratefla

Back to topic: I loved the Renix system on my 89 except for one thing, the long cranking time required to start it. This irritated me so much that I traded for a 96 with OBD II.
Click to expand...

It seems the "long crank time" is related to the aging OEM mains power leads - I've gotten reports from the field that upgrading battery cables (using mine or someone else's) shortens that, because more current can make it to the start motor, and the grounds are better as well.

Also, making sure your charging is up to scratch will help considerably - with my 1 gage power leads and my Red Top battery (and my SJG starter - also, check my website for those...) I kick over just about as fast as anyone else.

The RENIX is a little quirky on starting tho - from what I've found out and what I recall, the RENIX ECU looks for a 300RPM signal from the CPS, and it also wants a valid CPS signal AND a valid SYNC signal before it will start. (SYNC = Camshaft Position Sensor, in the distributor.)

RENIX will start and run without the SYNC signal, simply by "guessing" until it hits #1. However, it won't run as well as it could - operation would be analogous to "limp home" mode on OBD. Also, the SYNC doesn't have anything to do with timing per se, rather, it simply lets the ECU know when the #1 cylinder is coming up for operation, and the ECU then responds accordingly.

5-90
 
5-90 said:
It seems the "long crank time" is related to the aging OEM mains power leads - I've gotten reports from the field that upgrading battery cables (using mine or someone else's) shortens that, because more current can make it to the start motor, and the grounds are better as well.
5-90
Click to expand...

Reports are correct
My start time shortend when I replaced the terminals.
I thought this system was built to crank longer in order to sufficently lube the crankcase.
 
You know, I thought the same thing - to the point where I "remembered" reading it somewhere.

However, it seems to be somewhat apocryphal - I haven't been able to verify it.

Still, the reasoning behind it is entirely valid - and I can understand it. I used to set up pressurised pre-oilers for similar reasons - you pulled a cable (which opened a valve) and then turned the key. Before you shut the engine off, you pushed the cable back in, which trapped a supply of oil (about a quart) into a vessel with an air bladder that was compressed as a result. It wasn't a lot of pressure - probably 10 psig, tops, but it was enough to start circulating and have a comforting layer of oil on things. I just haven't bothered to do it with an XJ yet...

5-90
 
5-90, I think you're correct with the sync signal theory. My repair manual states that the ECU needs two valid signals from the cam sensor before it will fire the ignition and injectors. This equals 4 engine revolutions.

After replacing all the tuneup stuff, mine would always light up after about 4 revolutions.
 
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