'91 vs '94, engine/trans changes??

[04sd]

Can anyone give me a brief rundown on what the changes were between '91 and '94 on the engines, A4LD, wiring harness, computer, etc? I've got one of each as donors for a powertrain swap into an old Ranger and want to find out what to watch out for mixing between the two. The '94 engine is being used but will it work with the '91 harness/computer without issues. Thanks.

 

[Turdle]

You'll need to use the 91 upper intake and exhuast manifolds ( egr on 94-non in 91) and just ignore the 94 cam sensor-there is no plug for it on the 91 harness. Just leave it unplugged.

 

[SuRrEaLNJ]

Its actually pretty straightforward. Turdle covered pretty much all you needed to know

need to keep the 91 y- pipe as it only has the one 02 sensor

theres a couple of internal changes in the 93-94 a4ld, they both swap right over but there was a bearing change somewhere. makes it a little bit more desirable to have

 

[jwv3]

I have a 92 explorer and swapped in an engine from a 94. Here is some of the differences I found between 92 and 94. (91 should be pretty much the same as 92 I believe)

The 94 has an EGR system. I just used the upper manifold from and driver side exhaust manifold from my 92 for non EGR operation. The 94 had two oxygen sensors vs just one on my 92 so I think the year of the computer will determine if you need one or two O2 sensors.

I have a manual transmission so I can't tell you any difference the auto tranny may have.

(Looks like the same info already cover by the previous two posts)

 

[04sd]

Sounds like the '91/'92 setup is the simpler way to go w/out the egr. I actually have a '92 for parts also (left over from my BII swap a few years ago) which is more reason to stick with the '91 harness.
That said, would there be any advantage to using the egr and/or dual O2 sensor setup? Until now I've only had '91/'92 trucks.

 

[SuRrEaLNJ]

only if you want to swich the computer and all the wireing asociated with it to make it complient with the obd transition years.

stick with the 91 emisions

 

[04sd]

stick with the 91 emisions

A very good idea.