abusamra

Dear All
I'm new to the forum and to jeep.
I bought mine "1995 4.l manual transmission"for a month now and I'm very happy with it. It has 238000 km,

In my country"Egypt", It's registered as a 1996 model,But after searching the internet I found out it's a 1995 model "sci connector".
It's rare to find 4.l manual trans in my country

Everything is running perfectly Except "check engine" It doesn't light when I turn the ignition on,Would it be possible that the check engine bulb or diode needs to change ?

So I can not read the fault codes of the engine.

I found out also the difficulty to buy a code reader for obd1
Would it be easy to upgrade it to obd2 ?
thank in advance for any input.
abusamra

abusamra

i would like to refresh my question about

upgrading the pcm for a 4.l manual trans 95 to the newer 96+ and keeping
the same block?

cheers

5-90

1) Check/replace the bulb first, since it's likely gone out on you.

2) 1996 was the "official" first year for OBD-II, but it was also a "changeover" year - I've run across some /very/ late 1995s that had OBD-II, and some /very/ early 1996 vehicles that had OBD-I (not specificially Jeeps, either.) But, Jeep being Jeep, it's possible that you might have the "wrong" control system for your model year - stranger things have happened.

3) To switch to OBD-II would require a compatible control unit (4.0L/242ci w/manual transmission, sounds like) from 1996 and a wiring harness. Lookup to see what sensors, if any, changed between OBD-I and OBD-II as well - I don't recall offhand, and that notebook isnt' handy for me at the moment. You'd be in for a fair amount of work, and you'd really be better off if you had the entire donor vehicle to hand while you were working (and FSMs - Factory Service Manuals - for 1995 and 1996 model years.)

"Upgrading" your current PCM isn't really an option - not only is the PROM different (Programmable Read-Only Memory chip, the bit that stores all of your vehicle's information) in its programming, but the PCM logic and control bus are also different, making it rather different internally. The CAN Bus (Controller Area Network - how OBD-II runs information back and forth) is also not present in OBD-I, which means wiring changes as well. And, the instrument cluster is (I think) different - as OBD-II IPs (Instrument Panels) are driven by the CAN Bus instead of discrete individual sensor signals.

Yeah - it's going to be a fair amount of work. Not impossible, merely difficult.

abusamra

I could find a complete 4.l engine 96+ but only automatic !

would it be possible to with my manual tranny without the pcm causing me troubles?

5-90

It isn't the engine that makes it OBD-II - it's the control system. In theory, I could put an OBD-II control system on a 1950's Small Block Chevrolet - I haven't tried it, but I'm sure it could be done.

The main reason why I tell you you'll want to have the entire donor vehicle to hand (if possible) is because when you're doing a major conversion like this, there is always something-or-other that you find out you needed but didn't get - and you downcheck your project for a month while you're trying to find it. You can always get the entire donor, do the swap, and then sell the donor for parts or salvage later.

Again, if you swap an OBD-II engine into an OBD-I vehicle, you still have an OBD-I vehicle. If you put OBD-II controls on an OBD-I engine, you have an OBD-II vehicle - it's all in the electronics.

abusamra

It's not that easy to get used parts for xj where I live.but It's possible to get a complete used auto trans engines.
I love my manual tranny,It's like new !!
Jeep has an assembly plant in my country from the late 70s.they produced many cars but only auto tranny xj.
I would love to keep my manual tranny and have an engine with the next obd2 pcm
Thanks for reply

4.3L XJ

Changing over to OBDII would be a nightmare really. You would have to have all the sensors from the intake manifold, and the manifold, wiring harness, fuel tank (it is pressurized) ECM and exhaust pipe. It would just be easier to get a code reader for the OBDI system. I have an Auto Xray reader that does both.

Jesse Weaver

It would be better off to buy a obd2 xj and swap your tranny into it!