sefippoly

has anyone upgraded thier computer system to a later model system, and would there be any benifit to doing this? staying OBD I, mine has the renix system as of now. i need to replace my engine and if its worth while i will upgrade the computer at the same time. will be easier with the engine out to mod than with it in. just researching all my options before i spend any $$$$.

opinions???!!!

kevin

Metmknice

The head for the HO is different, and the wiring is different as well.

matejcekautoworks

i would mainly just ubgrade the head and intake, the computer upgrade is alot of work

sefippoly

i will need a little exsplaining. changing wiring is not a problem. but what are the differences of HO, heads, and intakes. and what might you, matejcekautowerks, consider a lot of work? if its going to be a worth while mod, i will do it. heck i added fuel injection to my 66 charger, using a LT1 system.
http://66-67charger.com/v-web/galler...s-1966-Charger
this should be a lot easier. is there a site or thread that might exsplain the differences. i know alot more about the older mopars, but havent delt with jeeps much. just need to do my research before i decide.

kevin

sefippoly

ok, looking at wiring diagrams, it doesnt look that bad. lets say i go with a 91-93 engine, and computer. looks like staying with all the same sensors for that year, change the computer, and the connector to the computer. may be wire in a check engine light, and diagnostic connector. and keeping the same exhaust manifold for the 88. am i missing anything? is the air filter assembly different?


kevin

JeepDeepInIt

I am about to undergo the computer upgrade that you have been asking about. I have already installed the engine (dummy move!) anyhow, you are suggesting that the computer, the obd port, and all the harnesses to and from computer to engine. you omitted the fuse relay panel however? is this not necessary?

Abovetimberline

If you want to upgrade to a 91 or later system you will also need to change the motor and flexplate,nothing is the same.

Jamie57

Do you have a donor jeep the newer engine is coming from?
Personally I would grab the entire engine bay wiring harness. You may get lucky and it will just plug into the firewall plug.

Abovetimberline

it is not that the harness will not mount up and work,it is that the renix operating system cannot even connect to the connectors of the chrysler connectors,the renix and chrysler are not even the same shape. you would have to change everything including the dist,intake,flexplate,evrything was changed in 91.

Jamie57

I know you mean well Abovetimberline but why do people post things like don't bother never work etc.
Why not post Gee I've never heard of that. Or I remember a thread where so and so tried that. or try this thread someone was working on that.
Why are the people that post fastest ARE always the ones that say it can't be done.
! mean did anyone but me look at the outstanding work he did on his Charger?

The OP already said he's not afraid of a litle work. He will have engine out. I'm sure he will know or will quickly see that the parts are different between the two systems.

I say go for it. I would use as new a computer system as you can get your hands on. Remember that they got better each new generation. plus you get the benifit of using OBD II.
Heck I would try to put on 00 or 01 system on with the coil packs. Everything else is just parts.
As you do some more searching some guys have found the latest blocks to be the strongest. Watch out for heads with the 0331 casting as they are prone to cracking. The 99-01 intakes are considered the best for HP. There are also some tricks of using Mustang and Neon injectors with Higher pressure fuel regs.
After looking at your Charger project I want to see you Jeep as you work on it. It should be very interesting.


P.S. What ignition system did you use on the Charger? I've never seen anything like that before.

Abovetimberline

The reason I say it will not work is because it will not,the only way it will work is to replace all control points on the engine to the chrysler control system,trying to use the chrysler harness on a renix system is the same as square peg in a round hole,just not going to happen,yes I do mean well and that is why I point this out to save this man time,he will see once he looks a little closer.

Jamie57

Guess you missed reading post #5

Abovetimberline

Sir,I have read all the post,he has a renix system and is wanting to replace with a chrysler system,what I am saying is if he wants to do that he will also need to replace all engine controls to a chrysler system also. The renix and chrysler are not compatible,I have tried, But if he wants to swap the harness, and engine controls,that is fine.

5-90

Abovetimerline is correct - RENIX is pre-OBD, ChryCo is OBD-I or OBD-II (given a preference, I'd take OBD-II...) and the harnesses are not pin-for-pin compatible. Therefore, to swap to a later control setup (doable) would take a total transplant of the control setup and wiring - from at least the firewall forward.

It should also be noted that some gages were driven by the ECU in OBD-I, and were all driven by the CAN bus in OBD-II (leaving aside that the OBD-II panel is a different shape, unless you can get your paws on a 1996 IP.) This yields another headache.

It most certainly can be done - but will probably be even more "fun" than the fuelie conversion he's already done!

As far as mechanical conversion, the HO head did change (the intake ports were raised for 1991 to improve intake port flow. This moves the intake a bit higher, which can be difficult with adapting the later intakes to the earlier heads. Also, the throttle body and some sensors were changed - but ChryCo still used Delphi Weatherpacks for a good deal of their connexions.) And, the TPS - Throttle Position Sensor - works backwards going across the RENIX/HO division - again requiring either a rewire or an adaptation to use one sensor on the other throttle body.

The RENIX Knock sensor was deleted for 1991 - but that's no trouble, just remove the thing.

You can continue to use the RENIX short block (provided there's nothing wrong with it,) but you're better off using the later heads if you've got a choice (with the exception of the 1999-2001 #0331 head. If you want to use a #0331, use a 2002-up head - they'd resolved the cracking isseus by then.)

Considering my idealised stroker build - a truly mixed bag of a heavy-cast RENIX block (bored to 4.000",) an offset-ground crank (to right around 4.000",) a massaged #7120 cylinder head, a 1999-up "ram's horn" intake (if I don't end up fabricating something for the next bit...) and a Whipple laid on its side feeding about 1/2-atm into the engine, you can see there's a good deal of compatibility there - if I leave out the Whipple and go NA, the only "non-Jeep" part, or part that didn't start life intended for a Jeep engine, would be the SBChevvy slugs I'd use (their number is legion, and they're all ground for a 4.000" bore.) I may have to get custom rods done with that stroke, tho - but I'd prefer rods that took screws vice nuts and bolts anyhow.

If you've got specific questions about what you're trying to do, I'd be happy to help. I know it's been done, and I'm sure I could help you do it (pretty much the basic thrust of my second book - Swappology,) and I've no trouble doing what I can to help you do what you want to do. "Nothing is impossible - but some projects are damned expensive..."

Jamie57

See that wasn't so hard! Lots of info with which to make an informed decision with. And it's upbeat with a few caveats. And finally he has had the experience the OP is looking for.
Now this is a forum response I like to read!