2001 XJ auto to manual swap ; no start

Ok a friend did a tranny swap in a 2001 XJ, donor tranny was from a 94. After the swap it will not start up, it cranks over but no spark. Haven't tried swapping in a new CPS and the ECM is still the one for the automatic. Suggestions on where to start the diagnostics?

Did you bypass the NSS as outlined in post #6 in this thread? http://www.jeepforum.com/forum/f11/automatic-manual-swap-thread-258497/

cpefy3 said:

Did you bypass the NSS as outlined in post #6 in this thread? http://www.jeepforum.com/forum/f11/automatic-manual-swap-thread-258497/

Click to expand...

That's what I was going to suggest at first but wouldn't you get nothing, no crank at all much like when your NSS goes out on an auto?

ECU will let it start, my guess is you smashed the CPS while installing the tranny. Did you bolt it to the bellhousing before mounting the transmission to the engine? That's the easiest way to smash a CPS that there is.

... learned that one the wrong way... well, I tore the cable off it because I forgot to unscrew the cable clamp from the fuel rail mounting bolt, but same issue. Always pull the CPS before installing/removing a transmission.

I would suggest testing to see if the fuel injectors are receiving input to "fire." You can do this numerous ways. If they aren't back track from there, if they are you know that your problem is not related to electrical miscommunication and is more mechanical.

Be advised here. The programming of the PCM is different between the manual and automatic transmissions. A replacement PCM will need to be sourced or, your existing PCM will need to be reflashed to reflect the transmission change.

It is not a simple "bypass the NSS" situation. There are significant changes in the PCM. Ignition timing being just least of them. Plus, the PCM will be looking for the TCM and will. most likely, fault into "limp home" mode if it can not find it.

For any given model year, Jeep had 6 versions of the PCM.

AUTOMATIC TRANSMISSION
49 State Emission
Low Emission (California)
Export emission

MANUAL TRANSMISSION
49 State Emission
Low Emission (California)
Export emission

When you source the replacement PCM, the VIN will need to be flashed into the replacement. Keeps both the Feds and your local Emission Inspectors happy...

Multiple people have had no real issues (aside from the check engine light being on for codes indicating transmission control system failures) just leaving it disconnected and using an auto ECU, where did that info come from?

The failure here though seems more like something actually wrong since it ran before and doesn't run now. Just a matter of figuring out what failed... check your fuses, maybe you shorted out the dark green wire with an orange stripe that powers everything on the engine as well as (at least on some years) the O2 sensor heaters. If that fuse blows you lose everything instantly, engine shuts off.

It also wouldn't be a bad idea to check the status of the ground that is attached to the block near the oil dipstick, since this is the ground that grounds the TCU.