4.0 into 2.9 question

[snoopdoggie]

Will there be any problem using a 4.0 and computer, Auto, from a donor '91 Explorer into a '90 BII 2.9 and retain the BII 5 speed. Will the puter in particular be okay without the A4LD?

 

[Rangermilitia]

seems fine to me

Just did a 93 explorer auto, 4.0. Into my 87 ranger manual... couple codes for the trans torque switch.. but everything else seems ok.

 

[AllanD]

When you check codes the Comuter will consistantly throw codes for
both the TCC (torque converter clutch) and the 3-4 shift solenoid, but they mean nothing.

BUT because of slightly different idle control strategy your 4.0 won't be
All it can be with the auto computer.

a MANUAL trans computer when confronted with a situation where the engine rpm is above 1500rpm and a closed throttle will turn off ALL the injectors after about 1500milliseconds of closed throttle operation and it will leave them turned off
until the idle drops to 1250rpm or so, then it will start firing them randomly

an auto computer keeps the engine rpm up to the transmission pump speed
otherwise the trans stops functioning and you lose whatever minimal engine
braking an auto trans provides.

In moderatly hilly country this can equate to as much as
2-2.5mpg depending on driving style and terrain.

you CAN get the engine running on the auto computer and switch to the
proper M/T computer later.

BTW, 1990-1992 4.0 engines have a physically different camshaft for the
manual and auto trans engines.

the manual transmission cams are advanced about 5degrees to make
the low end torque just a little "fatter" to make up for the lack of
Torque converter multiplication before TCC lockup.

This moves the engine's torque peak by around 150-200rpm
which may not seem like much. but...



AD

 

[Rangermilitia]

Hm... so for taking a 93 explorer motor automatic computer am I loosing power? Should u use a manual computer instead?