TheSamba.com :: View topic - Throttle switch question

Sat Feb 25, 2006 4:22 pm

I've been troubleshooting some odd starter and poor running issues for the last 2 weeks or so. I noticed at one point that the plug to my throttle switch was undone and hanging loose so I plugged it back in. When I started it up after that it ran very oddly. It was like a rhythmic pulsing as if I was gently revving the engine, from a normal idle to a very low idle, almost stalling. I unplug it and it seems to run fine, but I still can't seem to get it out of 3rd gear (automatic transmission). I'm getting a lot of lurching when shifting into reverse or into first and the idle seems high.

Does this indicate that I need to replace my throttle switch? Could it be contributing to the transmission issues?

Sat Feb 25, 2006 6:10 pm

Check for vacuum leaks, especially in the hose that runs to the modulator valve on the transmission.

Sat Feb 25, 2006 6:31 pm

That would be the hose coming from under the intake hoses down under the car into the silver valve thingy on the AT pan? Sorry for being so knowledgeable but I'm new to this greasy hands thing. I knocked that hose off while I was changing out my starter, while undoing the bolt in the engine compartment and it started running poorly right after that. I will check that as soon as I can. Thanks for your help.

Sat Feb 25, 2006 6:41 pm

auto_rex wrote: That would be the hose coming from under the intake hoses down under the car into the silver valve thingy on the AT pan?
Yes that is the one. Also, the valve could be defective as well. The Bentley manual has a good chapter on auto transmissions in it.

Sat Feb 25, 2006 6:44 pm

I'm going to hope it's just the hose, 'cos that's an easy fix. I'm going to just swap out a new hose and clamp in the morning. The connection to the modulator valve on the pan doesn't have a clamp on it, does it?

Sat Feb 25, 2006 7:26 pm

The vacuum line doesn't have clamps on it. If it needs a clamp, it's time for a new hose.

Sun Feb 26, 2006 3:47 pm

When I pulled the old hose off of the vacuum modulator, I noticed a thick black viscuous material, like really thick oil coming out of the hose. Is this normal?

Sun Feb 26, 2006 3:54 pm

It is kinda. As long as it is not red. If it is red, then you have a bad modulator valve.
Black crap is usually just condensed oil from the air cleaner. That hose is at the lowest point of the air intake collector box.

Sun Feb 26, 2006 5:31 pm

Thanks Russ. It's definitely not red. I decided to do an ATF change while I was under there and I'm now fully aware of exactly what AT fluid looks and feels like. Yum. I hope it's good for the hair.