HELP! 93 PCM in a 94? Egr problems...

[tan94ex]

Hi everybody- This site has helped me greatly, so I thought I'd join.
I own a 94 4.0 4x4 explorer. It needed an engine swap, so I just put a 91 engine in it (My dad wrecked his 91 with a good engine, so it was the only one available). The 94 had EGR but the 91 didn't, and now I'm pulling an EGR Circuit Failure code and it's running rough. I have searched about reflashes and engine swaps, but no one seems to have the same problem. Can I just get a used 91-93 PCM w/o EGR? Also, I just called the dealer and he said a reflash won't help. I'm lost!! Any help would be greatly appreciated.

BTW: The 94 PCM is VET1. Thanks!

 

[Cobraguy]

If you use an earlier PCM, you will no longer be emissions legal. I don't know how that will affect you in Denver...or if they can even tell.

Can't you swap the components from your 94 over to the 91 engine so you can be compliant? Sounds like the best plan of attack to me.

 

[MrShorty]

'91-'94 used the exact same block, so you should just be able to transfer the EGR system over to the '91 engine.

One thought about swapping PCM's, I expect you'd also end up swapping part or all of the wiring harness, too -- there are other differences in engine management beyond EGR/noEGR.

 

[tan94ex]

Thanks Cobraguy and MrShorty; I followed your advice and just swapped the 94 exhaust manifold onto the 91 engine. Much less hassle than computer swapping. After poking around quite a bit with the EGR system, I found out that my EVR was missing, so I just now popped a new one on and it runs perfectly. No check engine light and just a 111 System PASS code. Thanks alot!

 

[Cobraguy]

Well, a happy camper! How 'bout that!!