Code 1223 and surging idle/hard starting

[redfoxiii]

I've poked around and searched the forum, didn't see anything exactly like my issues.

This started very suddenly a couple days ago when I came to a stop sign mid-drive, on a warm engine. I had some low idle issues over the winter, which were chased off by a new-ish FPR and replacement CTS (an imports direct model).

I'm getting a wandering, surging idle, 750-1600rpm. Occasionally it will drop to 750 and idle normally. I have a check engine light and a stomp test gave 1223 (CTS). I also have hard warm starts. I had a cheapy CTS which I replaced with a new bosch, no dice. Here's what I've done so far and if it had an effect:

ICV vibrates and has been free moving for the past year whenever I check it. Unplugging it causes the idle to stop surging and drop to a very rough <500rpm.

I ran with the CTS unplugged for a day waiting for the replacement. Idle was a little low but did not surge. Cold starts were (understandably) really hard.

Unplugging the TPS stops the idle racing, but it surges from 600-800 in a sine wave until it's plugged back in, when it will stabilize and then start racing again.

The AFM vane moves freely, and reacts to the idle surging as normal. Unplugging the AFM causes an instant stall out.

I did a smoke test around a year ago and found nothing. Granted, that doesn't mean there isn't a vacuum leak, but my instincts tell me that would lead to a problem which steadily got worse rather than suddenly appearing.

I'm planning on removing the ICV to check for free play, but it seems like it's opening TOO much? I'm also going to check c191 for corrosion. Will update on what I find.

[tiger_e30]

I've poked around and searched the forum, didn't see anything exactly like my issues.

This started very suddenly a couple days ago when I came to a stop sign mid-drive, on a warm engine. I had some low idle issues over the winter, which were chased off by a new-ish FPR and replacement CTS (an imports direct model).

I'm getting a wandering, surging idle, 750-1600rpm. Occasionally it will drop to 750 and idle normally. I have a check engine light and a stomp test gave 1223 (CTS). I also have hard warm starts. I had a cheapy CTS which I replaced with a new bosch, no dice. Here's what I've done so far and if it had an effect:

ICV vibrates and has been free moving for the past year whenever I check it. Unplugging it causes the idle to stop surging and drop to a very rough <500rpm.

I ran with the CTS unplugged for a day waiting for the replacement. Idle was a little low but did not surge. Cold starts were (understandably) really hard.

Unplugging the TPS stops the idle racing, but it surges from 600-800 in a sine wave until it's plugged back in, when it will stabilize and then start racing again.

The AFM vane moves freely, and reacts to the idle surging as normal. Unplugging the AFM causes an instant stall out.

I did a smoke test around a year ago and found nothing. Granted, that doesn't mean there isn't a vacuum leak, but my instincts tell me that would lead to a problem which steadily got worse rather than suddenly appearing.

I'm planning on removing the ICV to check for free play, but it seems like it's opening TOO much? I'm also going to check c191 for corrosion. Will update on what I find.

Check my post but I had the same symptoms and it was c191

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[e30davie]

Have you confirmed that the idle switch in the throttle position sensor is working and activating when the throttle is returned to zero?

The idle switch is what tells the ecu to start managing the idle using the idle control valve.

[redfoxiii]

Checked c191 and found it was loose from it's bracket and missing the upper (male side) rubber boot. The upper ends of the pins were exposed, and showed some 'corrosion.' The female side showed some water intrusion and a little corrosion as well.


...Which reminded me that I had pressurized, spraying coolant leak from one of the throttle heater hoses a little bit ago that let out in that general direction


See, I get BMW blue coolant free from work, and when it dries it leaves a resdue very similar in color and texture to copper electrical corrosion.


I'm thinking what happened is that c191 got showered in coolant which just now worked it's way into the connector, casuing intermittent shorts between pins or something goofy. In any case, just fiddling with the connection stabilized the idle somewhat. I'm going to clean it out and tape up the connector so it isn't exposed anymore.

Have you confirmed that the idle switch in the throttle position sensor is working and activating when the throttle is returned to zero?

I have not, but see above. If cleaning up c191 doesn't fix it I'll add that to my list.


This is a 1990 325is, btw. Most of the fuel system and DME troubleshooting for my car is actually in the E34 BMW shop manuals.

[redfoxiii]

It was c191.


Once I peeled back the boot on the female side of the connector I found it and the bottom of the connector chock full of slimy sweet coolant residue. I cleaned it out, and then discovered that the male connector was actually all present - but it was broken:

The upper "collar" into which the "spacer," which keeps the exposed solder joints on the back of the pins from touching, was snapped off and pulled up the cable with the boot to hide under the manifold. This left just the connector below where it fixes into the metal mount, and the "spacer" floating above it. I'll probably get another male side connector housing from work and rebuild it eventually.


Anyway, with that joint cleaned out it ran just fine. Idle was totally normal (as normal as an m20 ever gets, anyway) and the CEL was gone.

EDIT: Just found that connector is only available as a unit with the injector plug wiring. Yeesh. 140+ for a broken connector >_<

[AWDBOB]

Bump for another confirmed fix for hard start rough idle + 1223 code fixed by the injector harness aka C191!

[jeffnhiscars]

This hits close to home...but I'm not aware of my 87 cabrio having the separate injector harness