PaulD_944S2

Check the throttle body to see if it is stuck open, or if the throttle cable is stuck holding it open.

Your engine could not do that if the DME was bad.

Otto Mechanic

I'm sort of thinking the throttle is stuck open. I've pulled on the cable a couple times to see if I can get it unstuck, nothing just "snapped back". If I can't find something obvious this morning I'll take off the intake and see what I can see...

Otto Mechanic

My thinking too, it has to be mechanical. First thing I thought was the carpet had slipped over the gas peddle but that's not it. Last night I did fiddle with the cable a bit but nothing obvious happened. I'll probably pull off the intake next.

Otto Mechanic

It truly amazes me all the stuff that can happen to these cars when you let them sit in the shop a couple of years.

I'll probably find a dead mouse in the throttle body or something.

Otto Mechanic

Tiger, I can assure you I have a deeply ingrained morbid fear of gasoline. I begin shaking when I smell gas. I vacate the area for hours after opening all the doors and windows. I take off all my clothes and run them through the wash (not to be confused with running naked through the front yard), which entertains my neighbors and the dog...

I'm very paranoid about gas.

Otto Mechanic

Well, maybe I'll do some further thinking before pulling the intake. Seems I was a bit cavalier with that one. Taking the intake off a 928 so you can get to the throttle is a cinch, only takes a few minutes. It looks like a major operation on a 944S2.

Jfrahm

I recall the throttle body is easy enough to get to, not sure what would be gained by pulling the intake. Careful of the hoses to the bottom of the intake boot.

Otto Mechanic

I actually read your discussion on the subject earlier today, unfortunately all the photos have aged out of existence, I think the thread was started in 2005?

There was a debate about whether it was harder to get the throttle out without taking off the intake than it was to just take off the intake?

Arominus

the throttle body is right up front, no need to pull the intake. That's only on the 944S

Otto Mechanic

OK. I see it now, just aft of the AFM.

I have a question about vacuum lines that may be related. During the pre-start inspection a few weeks ago I found a disconnected vacuum line coming from what looks like a diaphragm of some sort just under the driver's side window (picture #1).

I leads to a connector on the throttle body (picture #2) but was disconnected at the time of inspection (photo #3). I reconnected it (photo #4) before starting.

On the off chance I got this connection wrong, I disconnected it again this morning and tried starting; no progress. The engine immediately red lined again. Reconnected vacuum line, no change.

Comments? Could this somehow be related? Anyone know what that line does?

Otto Mechanic

Update: It turns out to be both simple and mystifying. If I just unhook the throttle cable (photo #1) the car starts and idles fine. With the cable connected (photo #2) it red lines on start.

The mystery would be what caused the cable between the peddle and throttle body to get short? Is it just a matter of lengthening the cable? Something tells me there's an underlying problem I'm missing here?

jderimig

Cruise control?

Arominus

That runs the Evap system, the vac opens the valve when the car wants to cycle the system.

951and944S

Did you jack the engine really high to put the mounts on...?

Something is wrong with the cable.

Look at where it passes through the firewall near the pedal.

T

Otto Mechanic

I don't know about "really high", but I did jack it up, maybe an inch? Good suggestion and I'll check that.