Transmission problem after MAF conversion
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Mountain Pass
Joined: Aug 2005
Posts: 140
Likes: 1
From: Seattle
Transmission problem after MAF conversion
I just replaced my 94 F150 5.8L computer and wire harness with one from a 5.8L 95 MAF. I swapped a few wires according to what I saw in the Chilton PCM wire diagrams and I may have read to much into it. The truck starts up just fine and idles well. My O2 sensor in the cab shows the computer making adjustsments to the sensor it is wired to so things were looking good. I put the truck in drive and a got no where fast. The truck was driving in low gear. When I put it in 2nd it drove off just happy as can be. I think I know what the problem is but I want to get a second or third opinion on this. Both the 94 and 95 computer are setup for E4OD transmission and they use the same wires so no need to change anything. But, always a but. The 94 PCM uses pin 12 for the 4x4 High Low switch. On the 95 MAF California PCM it calls out pin 12 going to the transfer case and for Fuel Injector 6. Doh! Also, it calls out for Pin 42 to go to both the transmission and the 4x4 indicator switch. Hmm, so what did I do? Well, I decided to map pins 12 and 42 on the 94 PCM side to pin 42 on the 95 PCM side. But, it not working...at least not well. So, what the heck is going on? I'm sure I need to map the High Low switch to some where but where? Any ideas this one? With so many people making this swap someone surely has come across this small delima?
Thanks,
Scott
Thanks,
Scott
Laughing Gas
Joined: Jul 2003
Posts: 893
Likes: 8
From: Lincoln, Nebraska
Thread Starter
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Mountain Pass
Joined: Aug 2005
Posts: 140
Likes: 1
From: Seattle
Hey, thanks for the link! Nice find. Didn't know it was out there. I got a copy of the wiring diagram for the 95 Mass Air ECU and discovered some of the things that I had wrong. The Chilton diagrams were close, but not entirely correct. Some things you can get away with using horse shoes and hand grenades, but on this you have to be exactly right. I think I should be in good shape with just a couple of switches here and there. Again, thanks for the help.
