why do the mpfi and spfi have different distributors? my mpfi has two vaccume solenoids, and the spfi has none. im guessing i cant switch the two. on the mpfi one, it has four wires coming out(two on one side, and two on the other) are two for ignition and two for tachometer? thanks

What years are you talking about.. I ran an 87 SPFI dizzy just fine in my 87 turbowagon.. plugged right in

the one with the four wires, is off an 85 multi point xt with the flapper door. and the one with no vaccum hoses is off an 89 spfi.

so does anybody know why one needs vaccum hoses and one doesnt?

sorry i cant help with the vacuum but i had a question relating. In the Hayne's manual it says that all turbo's have an air gap in the distributor. But a spfi or n/a mpfi does not have an air gap. i was wondering what the air gap is, and how you can still run an spfi 2wd on a turbo 4wd?

its not a difference related to mpfi vs spfi. Its because one is from an 85, which uses vacuum advance, and on is from an 89 which uses a CAS/optical setup. 85-86 have vacuum advance. 87-up do not(with the possible exception of 87 carb models.. don't know.. never had one).

The other 2 wires are turbo/knock sensor related. Retards timing under hard acc. for pinging & knocking. If you want to know if your sensor is working, hook up a timing light, and lightly tap with a hammer around the area of the sensor.

Kerry/Roo-Builders