Oil in throttle body? (fairly long)

[BAYEMVAY]

Couldn't get the 'stomp' test to work. After finding out that the WOT contact in the TPS is used to activate the electronics, I decided to investigate the TPS.

Took off the ICV first and found oil inside. Because it's positioned so that the connector end is pointing downwards, oil must be collecting at the electronics' end too. I manually rotated the ICV cylinder to 'open', applied voltage, it buzzes, but it rotates to the 'closed' position. It doesn't 'open' after the voltage is removed. It looks like I need a new one.

Moved on to the TPS. Didn't get any closed contacts at WOT or idle position on the TPS. Decided to remove it for a better look. It's full of oil too. It hangs directly under the throttle body on the M20 engine. It looks like oil from inside the throttle body seaps down the air plenum shaft into the TPS. I tried to get as much of out of the TPS as I could and actually found that the idle position contacts worked which means it wasn't adjusted properly. But I get nothing at the WOT position. I'm wondering if the oil did something bad inside the TPS. While I wait for a new ICV and TPS, I'm going to take the old TPS apart. I'll let you know what I find inside.

I also found a broken gasket between the throttle body and intake manifold, but I know the oil is not getting in that way.

As for all the oil I found, can anybody give me an idea where it's coming from and why?

Hank - Can't believe it took me until my 40's to find out how much I enjoyed working on cars.

[Messerschmitt]

Don't know about the oil sounds like a PCV issue though.


Messerschmitt

[winfred]

the oil is normal and is drawn through the tube from the valve cover, the icv is not spring loaded on the m20 and will move quite easyly,spray it out with carb cleaner and it'll probably be fine, the oil cruds over the open contacts of the wot switch, the idle switch is a closed microswitch and hardly ever dies, it will run and drive without the wot switch but not at full power

[Karl]

More oil will be drawn from the vavle cover if you have a vacuum leak someplace. Check the usual suspects.

[BAYEMVAY]

... found out that the inside of an M20 TPS is a mirror image of the photo posted in one of the other threads. I believe the posted photo is from a 535i.

I used a thin hobby (razor) saw to along the joint line between the top cover and base, being careful not to cut through the four tabs that lock the top cover to the base. I used an X-acto blade to cut the joint right up to the tabs. Then I went around to each of the tabs and used a small thin screwdriver blade to lift the tab and a wood chisel as a wedge between cover and base. Working slowly I was able to remove the cover and have three tabs still intact. Note - the top cover fits over a lip on the the base, which means you don't have to stick the wedge in more than 1/16". Let me just say thanks to the first person to cut one of these open, because knowing what's inside makes the job way easier.

Inside I found more oily residue that didn't come out when I tried cleaning the TPS from the outside. The microswitch and relay style contacts were intact. I gave the inside a liberal shot of electrical contact cleaner, let everything dry out and checked for operation. The idle microswitch was working. The WOT relay contacts were not working. I wondered if the relay contacts were still dirty so I pushed the terminals together between two fingers and I finally got the contacts working, but they were intermittant. I checked for continuity between the connector pins and each relay contact and found a bad solder joint. I re-soldered all four pins inside the TPS and now it works like new. It took about an hour, but I learned a little more and saved another $50 too.

Can hardly wait until tonight to get this all back together to see how it affects the idle and performance, because in reality, I've been running without a TPS since I got the car.

I should also finally get to try the stomp test too. I'll let you all know later.

Thanks again to everyone that posted explanations and tips on troubleshooting these idle systems.

Hank