Engine swap, now no start

[Hawaii87]

I swaped an 89 m20b25 into my 87 325i, and not I cannot get the motor to start. I will crank, has fuel, but no spark. Everything worked fine in the car we pulled the motor from.

What all could cause no spark?

Thanks!

[jlevie]

A lack of spark and injector firing will be caused by; no timing reference data, no power to the DME, wiring fault, or bad DME.

Since you've just done an engine swap, the first thing to check is to see if timing reference data can reach the DME. That's best done by checking resistance on the two pins of the DME connector that feed the CPS signal to the DME. About 500ohms is correct and the resistance should change if you bring a ferrous object to the sensor end of the CPS.

The next check would be to see if power is reaching the DME.

[kenika65]

did you use the 89i or the 87i wire harness and dme?

[Hawaii87]

Thanks I'll check the CPS.

I used the DME and harness from the 87, but we tried a DME from a friends 89 and that did not work either.

Since everything worked when the motor was in the 89, i'm just trying to figure out what would make it not work in the 87. Maybe the coil pack? That's about the only thing that stayed from the 87.

[Hawaii87]

I got it to start. Stupid me crossed the CPS plug with the other one (Engine Speed Sensor, I think). It's always the small stuff that kicks your a$$....

[norwood e30]

check the crank sensor same shit happen to me last year turning with spark.