89 xj emmissions

alright im new to this forum so i thought id give it a try postin a question ive got an see what you all come up with. I have an 89 cherokee laredo 4 door with the 4.0 an auto tranny in indiana where im at we dont have that emmisions/smog tests to pass an this is a trail rig only im tryin to figure out what of the emmsions system i can do away with an not affect the way the engine runs does any body have any idea what it takes to keep the motor happy i would really like to get rid of all the junk under the hood cause half of it dont work anyway well i would really like to hear what you all got on this one.

Indiana XJ said:

alright im new to this forum so i thought id give it a try postin a question ive got an see what you all come up with. I have an 89 cherokee laredo 4 door with the 4.0 an auto tranny in indiana where im at we dont have that emmisions/smog tests to pass an this is a trail rig only im tryin to figure out what of the emmsions system i can do away with an not affect the way the engine runs does any body have any idea what it takes to keep the motor happy i would really like to get rid of all the junk under the hood cause half of it dont work anyway well i would really like to hear what you all got on this one.

Click to expand...

How are you sure that half of "all the junk... don't work anyway" and yet are not aware of what can and can't go?

How much do you really think can go without affecting how that engine and ECM run? It's actually not a bad setup as it is.

Your time might be better spent learning how that combination works and you will find some tricks to squeeze a little more power out of it. That and a real quality tune up should be on your list.

Perhaps others might disagree, but learn the Renix system. It's worth the time.

Definitely learn the RENIX system - I prefer it over OBD, because I find it more flexible, and I think it uses more standard (read: GM) parts.

The only system I can think of that you could easily do away with would be blocking the EGR (at the exhaust and intake manifolds,) since most emissions systems also are critical to engine management. Be glad you don't have to deal with an air pump as well!

5-90

okay let me clarify a lil here i had a 78 cj-7 until last fall when it finally met the big junkyard in the sky thanks to a brake failure on a hill an rollin bout 100 feet down a hill backwards haulin balls an hittin a tree square on. it broke the fram off in front of the rear axle spring hangers an pulled the axle/frame/fuel tank a foot an a half back an cocked the the right so i sold it for parts an came across this cheorkee for cheap with 188,000 on it my problem is like u said im new to the whole fuel injected/smog systems since the old amc 304 had next to nothin in the emmisions dept left by the time i got ahold of it(previous owner had pretty much stripped everything off when i got it) so why im sayin half of it dont work is the exhaust manifold is cracked big time on each side of the O2 sensor (I think?) an its throwin an emiss maintinece light (havent had it checked so not sure yet on that) but i would really like to get rid of everything i dont have to absouletley have an clear out some room inside the engine compartment sorry if i was a lil vauge earlier oh an i have already done plugs/cap/rotor/coil/soleniod an replaced the rearmain seal an water pump an radiator i guess im just not familiar enough with the renix system to know what exactly it requires to function an was lookin for some info/help

Slow down... Take a breath...

Working with fuel injection, most emissions systems are also heavily related to fuel metering and efficient function - the sensors are dual-purpose. Therefore, you can't pull much.

If you go to the "strokers" group (groups.yahoo.com/group/strokers) and join, you should still be able to download the RENIX FI manual (as a .pdf file) and thumb through it. That will help you learn - because it does a fairly good job of explaining how it all works.

Your 78 CJ-7 probably didn't even have a feedback carburettor on it, so you've probably not seen all these control systems before. The good news is that RENIX is pre-OBD, which allows you to modify it (if you live outside California, that is.) OBD - OnBoard Diagnostic - systems are rather less forgiving.

You'll still be able to modify and tune, but most of the system should be left alone until you better understand it (download that manual!) The EGR setup can be pulled, since there's no feedback involved. However, you really should leave everything else alone - at least for now. Figure out how to tweak it later.

5-90

alright thanks for the link sure appreciate it ive worked some with OBD II on later fords so i know where ur coming from on that i just have never dealt with chrysler EFI before an i aint as sure how exactly it works compared to the others im a big fan of KISS (Keep It Simple Stupid) so thanks again for the info an link ill see if i cant get that downloaded

Just breathe...

RENIX isn't actually Chrysler - nor is it AMC. It was largely designed (and exclusively built) but Bendix under contract to Renault - therefore, RENIX.

Considering it was built by the Bendix/King Aviation Division of Bendix, it's no wonder that it's been pretty damn solid, nearly bombproof, and easy to adapt to things. I'd like to see more OBD systems like that.

The only thing that drives people nuts is troubleshooting it - it's pre-OBD. For "old mechanics" like us, who actually know how to troubleshoot a system, it's no trouble. However, for OBD junkies, the lack of codes is frustrating, at least.

RENIX is actually quite a bit simpler than most OBD-I systems, and nearly all OBD-II systems. It just takes some getting used to...

5-90

I am in complete concurrence with 5-90. The Renix system is dependable and works well. It can be diagnosed with not much more than a quality digital meter and some good troubleshooting skills. It does not have OBD capability (no DTC/check engine light) other than an emissions reminder module and light. Really, take the time to learn the system.

Unlike carbs, FI requires the inputs/outputs to run. I could understand if you had a Varijet, for example, which can function without some of the ECM components. You can block off the EGR valve, or just disconnect and plug the right vacuum line preventing it from opening and also preventing a vacuum leak when the solenoid is open. You need your O² sensor, but you can replace the manifold with a header (I have Borla's). There are MAP adjusters you can buy, or build.

Learn the system first!