My Computer Hates Me and My New Old Engine :(

[willhf1011]

I have bad news on that front as well. Allegedly the cam and crank sensors both get different signals on the 2 different motors which will keep the computer unhappy. I don't have any news on the SKIM setup though. I think they we could find a way to make the sensors work if we can work around that SKIM deal.

I'm not giving up, but my first reference said something to the effect of, "have fun with that"

edit:after some more reading, you definitely should swap your cam sensor over from the old motor. Which head are you running Matt?

[Matt612]

I will text Stables and tell him that..strange that the different year sensors give off different signals. To answer your question he is running the head of the 2003 motor because of the coil pack set up that bolts to the head.

[willhf1011]

To answer your question he is running the head of the 2003 motor because of the coil pack set up that bolts to the head.

That is what I thought. That was another of the issues that kept popping up in peoples responses so I figured he must have swapped it over.

[zach119]

I will text Stables and tell him that..strange that the different year sensors give off different signals. To answer your question he is running the head of the 2003 motor because of the coil pack set up that bolts to the head.

Do you know if Matt still has the head from his donor motor?

[willhf1011]

I will text Stables and tell him that..strange that the different year sensors give off different signals. To answer your question he is running the head of the 2003 motor because of the coil pack set up that bolts to the head.

Do you know if Matt still has the head from his donor motor?

He does

[MtnManMatt]

As some of you may know, I threw a rod through the block of my good ole reliable 4.0 and have been in the process of replacing it with a very similar 4.0 from a 96 Cherokee...

GOOD NEWS: I've got the engine in, all hooked up, and learned a lot in the process.'

BAD NEWS: My computer hates me and won't start the new engine

I may post more detail up here later, but currently the suspects are the PCM (Powertrain Control Module) and the SKIM (Sentry Key Immobilizer Module), so if anybody is an expert on these, you're assistance would be much appreciated!!!

Also, if somebody has a 97 TJ or other TJ without a SKIM that I could borrow or buy the PCM out of to see if it will run my engine, I'd greatly appreciate that as well!

[TerryD]

Have you double checked all your wiring harnesses? Checked the crank position sensor? Checked to see that the distributor is set correctly and not 180* out? Do you have fuel and spark?

If your SKIM and PCM were good before the engine died, there is no reason to doubt them at this point. I would go back over everything with a fine tooth comb and re-check my double checks. It's easy to leave a wire unhooked or for something to get re-installed wrong to cause this kind of problem.

[MtnManMatt]

Let's see if I can answer everything...


As far as what I'm running:

From the 96 Cherokee - Block and Block Internals, Accesories

From 03 Wrangler - Head, Coil Packs/Rail, Camshaft Position Sensor (Replaces Distributor), Fuel Injectors, Engine Wiring Harness, Crankshaft Position Sensor, Manifolds and manifold sensors, Throttle body and sensors, and some other non electrical stuff...

Basically all the electrical stuff and sensors are the same with the same wiring. That's why it just doesn't make sense

Also, I can't figure out why the PCM won't communicate with the scanner... It seems like the computer just flat out isn't working and I can't figure out why that condition would have changed from before the swap

Apparently the PCM doesn't have anything to do with just cranking the engine, so jus cause it cranks doesn't mean the PCM isn't bad...

To Will, as far as changing the camshaft position sensor, wouldn't that mean I'd have to go back to a distributor? And then the computer wouldn't have any idea at all what is goin on? And even if that would fix the no-spark problem, the computer also controls the injectors, right? And on the crankshaft position sensor, I don't have the 86 one cause it was on the transmission, and even if I did, it seems like this one should work since it's the same computer, same wiring harness, same sensor, and same flywheel...

Also to Will, I don't suppose Advance would let me return a PCM if I bought one and it didn't work, would they?

To Zach, I messaged ya back.

To Terry, ye, I know how often electrical problems are connection problems, but I'm pretty darn plum sure I've got everything connected up well. And it doesn't appear I have fuel or spark (both of which are controlled by the PCM)...


It jus seems no matter how ya switch the sensors and everything around, you should still be able to communicate with the PCM, which is makin me think either it's bad or not getting power. I'm definitely gonna pull it out and take another look when I get home this evening.
I wish I could get my hands on a PCM to test it before I go and buy one

Please let me know if anyones got any other ideas.

[willhf1011]

I agree. The lack of communication through the OBDII port is confusing. Correct and the camshaft sensor I think, I was just passing on information I was told. You should have all of the ignition components squared away.

The flywheels ought to be the same between the two so if you are running your 03 CPS that shouldn't cause any issues. The SKIM setup should not prevent the computer from feeding out the OBD port, so I would agree that at this point it is looking like a computer issue. The lack of gauges as well should not be caused by the SKIM malfunctioning, although it does have a role in the communication between the PCM and the BCM. A new matching computer would be a decent place to start, though you will have to have it programmed for your key/ignition/SKIM/BCM setup.

[jstables]

Well the computer is toast one of the bigger square chips has one pin melted off out of the 40+ going into it and it has a large chunk missing... Pic coming soon...

[willhf1011]

Well that certainly would pose a problem..haha

[MtnManMatt]

Well that certainly would pose a problem..haha

Yeeeeup. I'm gonna try to electrical tape it back together

[willhf1011]

Well that certainly would pose a problem..haha

Yeeeeup. I'm gonna try to electrical tape it back together

You would.

[BadAssEddie]

Well that certainly would pose a problem..haha

Yeeeeup. I'm gonna try to electrical tape it back together

Don't.

I will excommunicate you if you bastardize this TJ anymore...

[MtnManMatt]

Any techno fellers out there who can tell me for sure if this microprocessor is dead? Besides the chip in it, there's a wire that's burned through on the lower right...

And what might have caused this so I don't do it again?

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