Stalling under heavy braking?

Hi all,

This has happened 2-3 times now, I thought it was just a one off, but after the repeat episodes... has anybody had this before? What causes it?

Fingers crossed it's an easy fix!

(TT manual)

Auto or manual?

Is it only under heavy braking or does moderate braking result in the same issue?

The obvious thing to check is the battery contacts. Something is shifting weight and causing your stall, that would be my first port of call.

Manual, checked that and it all seems secure, but I'll re-jig it anyway!

had this on a car years ago turned out to be the air idle control valve

Idle control valve or possibly the O2 sensor making the engine run rich in closed loop.

Idle control valve or possibly the O2 sensor making the engine run rich in closed loop.

Would that not happen on every WOT let off though? Rather than just heavy breaking?

Having said that, the op hasn't answered the heavy vs moderate question

It may be a WOT let off issue rather than a braking one.

You're not forgetting to put the clutch down are you

You're not forgetting to put the clutch down are you

That was my first thought, hence the subtle "auto or manual" comment

is it single?

My mates single when running high boost 2.1 bar used to stall because of no BOV

is it single?

My mates single when running high boost 2.1 bar used to stall because of no BOV

Orginal post says it's a TT

Orginal post says it's a TT

opps didn't see that

Had that on my sold NA AT and now got it with the TT AT. Only under heavy braking, when a light turn red and you're just too fast to brake moderate. Just when the car stops it stalls.

Would that not happen on every WOT let off though? Rather than just heavy breaking?

Nope, as WOT means you're out of closed loop, so the O2 sensor can't cock it up. You have to haul the revs down to near idle and then dip the clutch to catch it out and stall it. Most people can't describe a problem for toffee so I fill in the blanks Braking isn't connected to the engine in the slightest, and any wiring loose enough to be affected by braking would also be all over the place under normal driving conditions, bumps in the road etc.. That'd probably be reported as a misfire. Ergo, it's not a braking issue but really a difficulty when the car goes to idle.

Braking isn't connected to the engine in the slightest............................

The brake servo is connected to the plenum.

I've never delved into the Supra setup but a spit in the hose on the servos side of a faulty NRV may cause some issues.

Christ, lots of replies. I'm definitely remembering the clutch, don't worry I got it again last night as I was approaching a roundabout, which would now lead me on to say 'moderate' braking as described above. Good thing I have a spare ICV knocking about, might have to swap it over tonight.

Thanks guys.

Oil level ok?

Christ, lots of replies. I'm definitely remembering the clutch, don't worry I got it again last night as I was approaching a roundabout, which would now lead me on to say 'moderate' braking as described above. Good thing I have a spare ICV knocking about, might have to swap it over tonight.

 

Thanks guys.

Is it stalling as you dip the clutch or does it do it with the clutch still engaged?

My guess is it's doing it just as you dip the clutch due to a faulty ICV, can the idle be a bit erratic sometimes?

I've had this a few times too and can be linked to a faulty or incorrectly wired speedo converter

Interesting that you say that Keron, as the dash has read the speed incorrectly since the TT swap. I'm popping an Auto dash in and checking everything while it's out in a few days anyway. Thanks

I'll update this thread when I discover the source, for anybody else with this in the future!

sounds like the problem then hopefully...i experienced them stalling under heavy breaking or comming up to some traffic lights etc... just cuts out...

found it had those cheap ebay converters that went wrong... try taking the converter out, putting the wires back to oem, then test it...make sure all the wires on the speedo plugs and odo plug and pink wire on the ecu are not uncut etc

Mine has done this and it's an auto TT. changed icv and O2 sensor and it still does it sometimes. No idea what it is.

sounds like the problem then hopefully...i experienced them stalling under heavy breaking or comming up to some traffic lights etc... just cuts out...

 

found it had those cheap ebay converters that went wrong... try taking the converter out, putting the wires back to oem, then test it...make sure all the wires on the speedo plugs and odo plug and pink wire on the ecu are not uncut etc

I'll give it a try. I wouldn't imagine it would be a cheap and/or bad unit as the rest of the 'import' work was done so well, but you never know. I'll be driving quite a distance on Friday, so I'll try and re-create it to narrow it down then!

The most dangerous part is the fact it cuts PAS, especially when you're just braking for a roundabout!

The most dangerous part is the fact it cuts PAS, especially when you're just braking for a roundabout!

Just heel and toe to keep the revs up .

Well, dash came out, re-wired the speedo converter (as it was a new dashboard) and I'm still getting it, although it's less common. It's only when I'm braking from shall we say, higher speeds that it happens. I'm sticking to just not doing higher speeds at the minute just in case.