Wonky Idle, Changes When Using Electricals

[91vert]

Hi all,

I'm a long time lurker that finally found an e30. I just purchased a '91 325i automatic. On the drive home, I noticed the engine temp would creep towards the red zone. It would also shift around when pushing the brake, widow switches, lights, etc. (anything electrical). I figured it was a bad gauge. Got it home and started measuring the engine temp with an infrared gun.

Results:
145 around the thermostat housing
185 at the top of the radiator
205 at the coolant temp sensor
150 and the auxiliary fan switch.

I tested the aux fan buy jumping the terminals and it worked in both speeds and never came on by itself. This put my overheating worries to rest.

Now I get back in the car and notice the engine idle is behaving weirdly. The same electricals that were causing the temp guage to shift are causing the idle to surge and fluctuate. At this point the engine is idling high, right around 1100. I turn the lights and highbeams on and it drops and almost stalls. After a little bit it comes back up. I pushed the AC button and the rpms shot up to 2000 and stayed there. All while the temp guage is all over the place. I monitored the temperature throughout all of this and it shifted about 10 degrees, the above being the maximum it reached.

I noticed the check engine light flashed a few times. I then checked the codes and got 1222, which could be a variety of things relating the air/fuel mixture. I started it back up and it ran fine for a bit, then started acting up again.

I'm guessing the temp guage and idle issues are separate issues.

Thanks

[jlevie]

Turning on the headlights or setting the HVAC blower to max is a significant increase in the load on the alternator which is a load on the engine. Turning on the AC is also significant increase in the engine load. That, the idle issues, and the 1222 code suggests that there are intake leaks. A smoke test is the only way to find all of them.

[91vert]

Thanks.

Just an update. I drove it about 80 miles today averaging 70mph. It runs extremely rough. I noticed that if I turned the heater on, highbeams, basically anything other than the headlights, it would begin to miss and hesitate badly. The entire car would shake and power would cut. Once I turned those things off, it would smooth out.

As well, it would periodically begin missing/hesitating on its own. If I turned the heat (or windows, high beams, etc.) on for a second and then off, it would even out for a bit.

Alternator? Battery seems to be charging fine.
Voltage regulator?
Bad battery?
One of the above in conjunction with a really bad vacuum leak?

[dnguyen1963]

Look, you have gotten code 1222. Fix the vacuum leaks before doing anything else.