Replacing plug wires - impulse generator wire

[claylake]

I am replacing my ignition wires. Is there a connector between the senor and the #6 wire or did I get the wrong wire set? The connector on my wire set (12121720529) is a flat plug. The one on the sensor near the harmonic balancer is round. Am I unable to see a male and female connector on a bracket? It's night and hard to see. Great if somone has a pic but any direction would be appreciated.

[nando]

what motor do you have?

[jlevie]

The Cylinder ID and the CPS connectors are under the intake manifold at about where the dipstick and diagnostic plug is.

[claylake]

Sorry, I have an M20 1990 325i but the engine was replaced and I do not remember what year the donor was, 1987 maybe?

[claylake]

The Cylinder ID and the CPS connectors are under the intake manifold at about where the dipstick and diagnostic plug is.

So do I access from the drivers side? Are there two types of Impulse Generator connectors?

[jlevie]

Yes, you reach the connection from the driver's side of the engine bay. I'm not aware of any differences in the ignition wire sets for different production dates for an M20B25. In fact the engine in my Spec E30 is a mix-n-match now. The engine came out of a 1990 525i, the harness from a 91 E30 vert and I'm using the new ignition wires I installed on the original 87 engine. After a couple of mods to the wiring harness to adapt it to the earlier production car, everything mated up and worked perfectly.

[claylake]

Light of day

Yes, you reach the connection from the driver's side of the engine bay. I'm not aware of any differences in the ignition wire sets for different production dates for an M20B25. In fact the engine in my Spec E30 is a mix-n-match now. The engine came out of a 1990 525i, the harness from a 91 E30 vert and I'm using the new ignition wires I installed on the original 87 engine. After a couple of mods to the wiring harness to adapt it to the earlier production car, everything mated up and worked perfectly.

Thanks, perhaps in the light of day it will appear more obvious. I have been struggling with a no spark issue and the only thing left after plug wires, cap, and rotor is the pulse generator.

[jlevie]

If you have no spark out of the coil the candidates are:

1) Bad coil or no power to the coil
2) Bad CPS
3) Bad Main relay
4) Bad DME
5) Bad fusible link

A further diagnostic is to check for firing pulses at the injectors while cranking over the engine. If there aren't any (2)-(5) become the possibilities.

[claylake]

Thanks

Thanks for the help guys. New ignition wires fixed it. Replacing the pulse wire was aggravating. The fan is always in the way. Another reason to consider fan delete with a SPAL.

[jlevie]

The fan isn't that big a deal. It is easy to remove and as long as the clutch is good works very well, thank you.

If you delete the fan and replace it with an electric one. Use a fan rated for at least 1800cfm and do not, repeat do not, mount it directly to the radiator. The push through the radiator mounts will eat a hole in the radiator before long. I'll leave it as an exercise for the reader to figure out how I know that. And an electric replacement for the engine driven fan needs an 81-82C thermo switch and relay for control. All in all, several times the price of a fan and clutch.

[Atreus]

necro bump.

i was searching for this today, and it appears that i have two old spark plug wire sets, and they both have the impulse plug, however the original one on my 89 cirrusblau 325i didn't have any. and the two plugs under the connectors were for, the CPS, and some unknown other one.

why are they different? all the wire sets were from 325i motors, various years of course.

93 - vert
91 - vert
89 - coupe

[jlevie]

All M20B25 engines use an ignition wire set that has the Cylinder ID Sensor. If the wire set on you 89 didn't have that, the wrong wire set was swapped in at some point in the past.

[Atreus]

okay, however underneath the diagnostic plug by my oil dipstick, there is a plug for my CPS, and some other plug that goes into a larger harness that runs along the block by the starter.... what is that then?

[jlevie]

That could be the connector for the Cylinder ID signal, oil level sensor, evap valve, or TPS. All of those are three wire connectors. If all but the Cylinder ID connectors are attached to their sensors, you know by process of elimination what that connector is for.

[Atreus]

weird. i do not have any missing plugs. everything is plugged in. and it runs fine. it ran fine with the previous ignition wire set, which didn't include a pulse generator..