Car Only Firing Two Injectors

[AWDBOB]

Hey R3V-

I just put an M20b25 back in my 1990 325iS after taking the car apart a little while back and the car wants to start and catches a bit, but won't fire. The car has good pressure at the rail and I tested the regulator and it's working well.

The car also has strong spark.

The odd part is, when I pull the plugs, only cylinder 3 and 5 have any fuel on them and they are soaked. I'm assuming cylinders 3 and 5 are the only ones grabbing which is giving the "I want to start but won't" condition.

I've swapped ECUs as well, and nothing so far has changed my condition. Grounds all checked, fuel verified at the rail, reg verified working, spark is strong, etc.

What would cause only two injectors to fire?

[skitzy777]

Check the little pins in the Connector to the injectors that wont fire, i remember my car would do what your describing and the connector part came out of mine and wouldnt let the car start. Sounds like its electrical.

Also check the injector connectors with a voltmeter to see if they are actually getting power.

[ForcedFirebird]

Do you have the round injector connector under the manifold/TB?

Just skimmed your build thread, too. :/

[AWDBOB]

Check the little pins in the Connector to the injectors that wont fire, i remember my car would do what your describing and the connector part came out of mine and wouldnt let the car start. Sounds like its electrical.

Also check the injector connectors with a voltmeter to see if they are actually getting power.

I will check the pins tonight and make sure they're getting power. I also have a spare set I'm going to throw in to test even though these are rebuilt.

Do you have the round injector connector under the manifold/TB?

Just skimmed your build thread, too. :/

Yes I do have the round connector for the injector harness- I pulled it apart last night and checked for any corrosion/damaged pins and it all checked out. I haven't checked the injector plugs yet though.

[AWDBOB]

For anyone reading this in the future, the injector harness was bad. Swapped it with a known good one and it fired right up.