Manual trans swap from automatic.

[Brent L.]

I have a question, I recently swaped a manual tranny into my 94 explorer, it started out being an automatic but it blew up and i wanted a manual. I transfered the flywheel/clutch, tranny, and clutch pedals and master cylinder linkage it runs fine except one thing. When I am driving my explorer hits a RPM limiter at 4000 RPM. But if im stopped and just hit wide open throttle it will rev to 5000RPM like normal. I have yet to figure out why if anyone has run across this before.

 

[Freshmeat]

Did you swap the ECM?

 

[rileyrs]

yeah, if it was auto originally, and you swapped to manual, you need an engine computer from a manual

 

[Brent L.]

ok i havent switched the ecm yet the doner truck is still at the junk yard. Will i need the wiring harness too or is it just plug n play?? I believe the ecm is behind the pass side lower kick panle is this correct?

 

[Maniak]

I can't think of any reason why the computer would do that. I'm running a 700r4 transmission which means the ECU can't see anything about the transmission. It doesn't limit the rpms and different than it did when we had the a4ld and I am still using an auto ECU and Auto trans wiring harness.

I used 23 ohm resistors so the ECU thinks it still sees the shift solenoids, but you can just wire in the solenoids (take them out of the tranmission) and wire tie them to the wire harness. Now the computer will still think you have the a4ld and won't throw solenoid codes when you do a KOEO test.

Also, I have our neutral safety switch wired shut (jumped the two wires together) so our X always thinks we are in neutral which has no ill affects other than I can start the truck in gear.

What I'm trying to say is the ECU shouldn't be lower the rev limiter because of the transmission change.

 

[Brent L.]

I couldn't think of a reason it would stop reving eighter. There are no wires running to my 5 speed, every thing works normally maybe a fuel problem?? its like at 4000rpm i get way lean and loose power like a rev limiter. I also found that there is two signal wires i had to jump for it to start and go into 4low I jumped the starter wires at the atuo trans connecter and also found at the same connecter u have to ground a wire to make 4low engage (dont remember color) and i have that wire hooked to a switch so i can operate 4 low and also cut it off from working at speed. The other two wires on the auto connecter are a + positive and a wire leading to the reverse lights, i have yet to hook that to a switch. Im kinda stumped, and at idle u hit WOT and it will rev up to 5000rpm and stop. . .

 

[Freshmeat]

Maniak, how high does it rev with the 700R4? It's possible that it's just shifting sooner so you're not noticing.

Brent- I'd say swap the ECM with the one from the junk yard (it's plug and play- grab the harness to the transmission, too- you can trace it to the driver's side inner fender- it'll have the oil level and pressure switches on it, too) and see if that does the job.

 

[Maniak]

It depends.. If I'm in 2wd high range and I let it shift on its own, its around 4200-4400 (depending on the gear)

If I put it in low range (2wd or 4wd) and let it shift it will actually bounces off the rev limiter at the 3-4 shift which is right around 5000 rpms.

~Mark