'87 325 w/ '89 m20b25 motor MISFIRE AT IDLE, rough

[mbonanni]

The harness is actually in fact from a manual.

I have my bets on the i.jectors not firing.

[lcoleman]

^Wouldn't the neutral safety switch lock out the starter altogether? I don't think a crank no start would be a wiring issue, especially since he has fuel and spark.

Swapping coils is a good suggestion.

[noid]

The 173 ECU is fine, it is interchangeable with the 153.

If the harness was meant for an automatic car, you may need to by pass the neutral safety switch:

http://www.e30tech.com/forum/showpost.php?p=894253&postcount=12

[F34R]

Tells the relay to open and shut to the starter.

But the thing is I swapped a SETA into my 87 ETA. The SETA uses the SAME harness as the b25. All I had to do was splice the automatic relay selection switch bypass.

So in theory you should not have to do the above since I did not do it to mine. We have the same car besides mine was automatic from factory.

I went and read the first post...lol

Do you know if the coil is known working order? If not change it out for one that is. I was getting spark on my old ETA and it would not fire, changed the coil and it worked. since you're changing to the b25...did you put the correct ECU in? 173 not the 153.

[F34R]

Tells the relay to open and shut to the starter.

But the thing is I swapped a SETA into my 87 ETA. The SETA uses the SAME harness as the b25. All I had to do was splice the automatic relay selection switch bypass.

So in theory you should not have to do the above since I did not do it to mine. We have the same car besides mine was automatic from factory.

[mbonanni]

I'm confused as to what exactly this will do for me.

It cranks/turns over, gets fuel, gets spark.

[F34R]

This is the wiring for the starter from swapping a b25 into a b27 spec e30(my sister's). Motronic uses 3 wires for the starter apposed to the jetronics 2. What I did was run a female connector from the c101 to the k7 relay and on the 85 prong I removed it and spliced the new lead into the relay.

[mbonanni]

The car was not an auto, but the '89 motor came from an auto, and the harness is unknown at the moment.

[F34R]

The K7 relay to pin 14 on the c101 fixes the starter for the newer jetronic firing of the solenoid retraction. Tells it when to stop firing after it kicks over the starter to turn over the engine.

The 325ic 87 harness is the same since it is using the b25 engine.

[mbonanni]

Guys,

Is using a 173 ecu okay with this setup? From my understanding by using this '87 harness everything is kept motronic 1.1, and the 173 ecu is 1.3?

If this is not the right ecu tell me which one is!

Thank you

[mbonanni]

I bet the timing is fine, we just redid the TB. So it is fresh.

I will double check the spark wires and the order.

I know that we have spark, and fuel getting to the rail. I do NOT know if there is fuel getting into the cylinders, so I need to check to see if the injectors are firing as well as in correct order.

Then I will check compression, because I will need to borrow one.

Thank you!

[noid]

The wire numbers are labeled on the distributor right where the plugs plug into the cap. I think it starts with number 2 up top and ends with 5 at the bottom.



If the wires themselves arent numbered then just take a volt meter and check for continuity on both ends of the wire.

As for the timing marks, just make sure they line up at these two points:




Checking the timing is jumping a bit ahead of yourself if you haven't just completed a timing belt job. Check the aforementioned stuff.

Any engine needs three things, fuel, spark and compression, make sure you have all three.

[mbonanni]

Okay thanks. before I could check compression my dad started to take it apart to check all the timing.

Can anyone tell my the wiring configuration for the distributor cap is?

My dad is also asking me what the timing marks are for the first firing cylinder? (sorry if this does not make sense, he is sort of illiterate ;)

Thanks guys. Will double chekc the fuel lines, but I am pretty sure they are correct.

[jlevie]

The hose that hose to the rail (not the FPR) is the one that should deliver fuel when cranking. Since the engine has spark and fuel delivery when cranking, the next checks should be to see what the rail pressure is, whether the injectors are firing (using a noid light), whether the cam is correctly timed, and whether the ignition wires are correct. Also make sure that there isn't a major intake leak.

[noid]

Fuel, spark, and compression is all you need. Have you checked compression in the cylinders and power at the fuel injector connectors? Made sure all the wires are in the correct order on the distributor cap?