No throttle response on heel-toe?
 

Guys,

I did a search but didn't find anything on this topic, so am asking a question that may well have been addressed already - sorry for the redundancy if so.

I was at the track last weekend (rainy conditions most of the weekend). On three occasions, I had no throttle response when heel-toe downshifting. In each case, I was clearly on the throttle, had been successfully getting a throttle response for several laps before, found I didn't get a throttle response for three or four turns, and then would get a throttle response back again. It felt as if the DME was rejecting the throttle input because I was on brake. Once I was through the turn and on power without brake, the throttle worked normally.

Is this the infamous ice mode (which I thought was no brake, not no throttle)? Has anyone else run into this?

Any insight appreciated.

Thanks,

Jim

Camber, that's not ice mode. You're correct, ice mode is "no brake", specifically braking in ABS mode; which can be very disconcerting. Don't know why you would get no throttle response when downshifting. Perhaps some one else will chime in.

John

PSM?

Porsche Stability Management kicking in.

No PSM on the 996 GT3

E-Gas.. nothing to do with "Ice mode".

Did you had the clutch in?

Were you trying to left foot brake?

In any case check for faults but note that the electronic gas doesn't interfere with heel and toe.

Near empty fuel tank? Mike

I've experienced this pre-autocross when doing some brake warming. Riding the brake pedal, and hitting the gas, the gas does nothing. Can lay into it 100%, but with the foot on the brake, the car just slows. The brake warming is quite different than heel-toe, and there could be a speed related issue, sort of like how the cruise control doesn't work under 25mph.

Follow up...
 

Thanks for the thoughts, guys.

This was not a PSM, fuel related, or left foot braking situation. I had the clutch in with my left foot, and was braking and throttle blipping with my right. I agree that this is very similar to the brake warming/brake break-in situation where if you have your foot on the gas and then apply the brake, then the throttle cuts back. If you then take your foot off the gas and reapply it, the throttle will work.

These events happened on corners with lots of slowing, e.g. braking from 140 to 50 MPH. I suppose it's possible that my right foot was pressing on throttle at the same time as, or before, the brake. That would take either an angled ankle at first brake application (which I doubt, but you never know I suppose), or the brake pressure was fast and hard enough that, from the DME's perspective, my foot hit the throttle at effectively the same time.

I'll pay attention to the timing of brake/throttle at my next track event and see if I can disprove or verify either of these theories.

Jim

maybe test it on a straight road (not at a race track) , no traffic, and just put it in neutral so you can bake left footed, and give gas with your right foot under braking

The eGas will definitely cut if you are on the brake for more a sec (WO clutch). The sensor might be off. The engine will also choke under heavy G-Load when you have a quarter tank or less. I kind of assume thats not the case unless you are coming in from high G's..

DME: Any chance that you jump started the car recently? The DME is very sensitive to crossed cables when you jump start. You can damage it in subtle ways that don't show up under normal circumstances (except the track), but you would usually get a check engine light.

This happens to me on occasion too.. All on the same turns too @ RA Turn 1 & Mid Oh after the long straight. Once it starts it does it every time.. I cannot figure it out either. Definitely under high G's but I haven't tied it to my fuel level yet..

Dan212,

In each of these corners, I would be on the brake for at least a second before pushing in the clutch. Of course, that would be true for the times the throttle works too. Interesting thought, though. The car has not been jump started, so no cross-connect instance in this case.

Jim

I have experianced the same issue but I'm having other throttle related issues as well. I have been trying to find a cure for an intermittent full throttle problem for two years now. I get an error code 1109 and have replaced the MAF and throttle body and still have the problem. don't know if there is any connection with these issues or not.

Do any of you guys have any dataloggers installed?

I do.