Acceleration cutout?

[Zepboy]

Apologies if this has been brought up before. I searched, but couldnt find anything similar.
Me and at least 1 other person know have experienced this issue. It seems restricted to GT manuals. On hard acceleration, when changing gears I occasionally get what feels like a complete fuel cutout, so absolutely zero throttle responses for 1-3 seconds, and then it kicks in hard. For me it has happened 5-6 times in 4 months, most going from 2nd to 3rd and I think it occurs if I change gears whilst cornering. For my friend it apparently happens in all gears from time to time and in a straight line. The closest thing I can compare it to is turbo lag....but this is a stock GT
Has anyone experienced anything at all like this at all? Has anyone come across any forum posts on this anywhere that they could point me to?
Richard

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[Hornet]

Silly question but anything coming up on the dash when it happens?

Sounds like traction control kicking in and killing the throttle potentially

 

[Zepboy]

Silly question but anything coming up on the dash when it happens?

Sounds like traction control kicking in and killing the throttle potentially

Not that I've noticed, but that's a good idea. I'll look for hat specifically next time something happens....

 

[GT 550]

Richard sorry if this sounds too simplistic but you're not hitting the rev limiter are you?

 

[Aubrey]

What mode you driving in? Sounds like traction control. Maybe get it re-flashed by the dealer?

 

[Zepboy]

Richard sorry if this sounds too simplistic but you're not hitting the rev limiter are you?

Not that I know of. usually in the 3500-4500 rpm range....

 

[Burkey]

If you put the car into a high load, low revs situation, there’s a good chance that clutch protection will kick in. I’ve had it happen before when the car was stock.
It’s highly unlikely that it’s TC intervening in third gear on a stock GT unless your tyres are completely shagged or it’s raining.

 

[msweet]

Long left handers? Could be fuel starvation like a lot of us experience on the track

 

[Ben James]

I’ve had a similar issue one or twice with my 2018 GT with 10 speed auto. It seemed to be once the car got up into the taller gears (4th-5th-6th) under hard and prolonged acceleration.

I had a few runs on a long road and I could get it to happen 2 out of 5 runs as it changed gears (especially from 4th to fifth). I checked out the rear view and saw a bit of smoke coming out the back pipes when this was occurring.

When I researched the PCV system, I found that it was common for these newer breeds to pass a fair bit of crackcase fumes (particularly straight after momentary throttle off).

The right side PCV vents crankcase fumes through the intake straight after throttle off, and I noticed that it can take half a second or so for it to affect the intake into the engine, which I imagine when doing a prolonged acceleration run would vent quite a bit of oil fumes back into the engine.

I figured it was quite possible that the engine management system was detecting early detonation in the fuel/oil vapour and cutting power momentarily to compensate.

I got a JLT oil separator (catch can), fitted it, and I’ve had no problems with smoke out the back, cutting of power etc since.

To give an example of how much vapours pass back through the intake, I have measured roughly a teaspoon or more of oil in the separator per 1000km.

Hope this info helps

 

[ugstang17]

There are torque protection strategies at work in the factory tune. On hard acceleration right at shift point if you are feeling a slight nose down on the car caused by a hesitation this may be what you are experiencing. Ford was doing this on the 2011+ cars. This is not to be confused with the 1-4 shift lockout on 11-12 models only. This may be what you are experiencing under hard acceleration and quick shifting in "spirited driving mode".

My 2013 had this symptom which was present even with advanced trac off. This symptom became even more prominent when I added the Roush phase 1 package. The car would completely fall on its face at a 7000 RPM shift point (300+ RPM below rev limiter). IT was very annoying and effected the performance of the car quite a bit. I datalogged the issue and observed as much as 252 milliseconds (over 1/4 second) of throttle position actual delay over throttle commanded in the log. I sent this to Roush (datalogging was requested by them) and they told me it was clutch slip (head of engineering specifically). So I updated the clutch package and the problem remained the same. Further investigation of the symptom revealed that it was in fact suspected protection strategies at work both in the factory tune as well as Roush's POS tune that was creating the problem. A local tuner diagnosed it in theory after riding with me and driving the car and recommended VMP performance (tuning at that time) for a tune that would resolve it since at the time he was not tuning Coyotes yet, Justin's tune at VMP resolved the phenomenon and the car then ran like an FI car should.

Skeptics may say that this does not apply to S550's, however I disagree. The concern (at least until 2018) has been to protect the MT-82 Getrag that Ford cheaply diverted to as well as the inferior clutch components. The same Getrag MT-82 and very likely the same clutch is used through 17. Getrag/Ford reworked the MT-82 (rumored) and added a better clutch package in 2018. That however does not mean the protection strategy is not still there.

Some years ago while at the track a guy was making passes in his 15 Roush setup. His runs were terrible in spite of being on an 18" DR. I shared with him my experience and he told me he had read something about this and that there was a fuse in the BJB that he read could be pulled which would disable all nanny states (though the dash would light up like a Christmas tree). So he tried it and ran the best time of the day with a huge change in ET and driving experience. He soon took my advice and chose a tuner and resolved his disenchantment of these nanny protection strategies as well. Hope this helps.

 

[Aubrey]

Yes, same problem under hard acceleration using no lift shift - it feels like the rev limiter kicks in after the shift. I've asked Rob Herrod to speak with Ford Performance as I've read they did an update to the tune in the US. Failing this its a Lund Flexfuel tune.

 

[Aubrey]

I’ve had a similar issue one or twice with my 2018 GT with 10 speed auto. It seemed to be once the car got up into the taller gears (4th-5th-6th) under hard and prolonged acceleration.

I had a few runs on a long road and I could get it to happen 2 out of 5 runs as it changed gears (especially from 4th to fifth). I checked out the rear view and saw a bit of smoke coming out the back pipes when this was occurring.

When I researched the PCV system, I found that it was common for these newer breeds to pass a fair bit of crackcase fumes (particularly straight after momentary throttle off).

The right side PCV vents crankcase fumes through the intake straight after throttle off, and I noticed that it can take half a second or so for it to affect the intake into the engine, which I imagine when doing a prolonged acceleration run would vent quite a bit of oil fumes back into the engine.

I figured it was quite possible that the engine management system was detecting early detonation in the fuel/oil vapour and cutting power momentarily to compensate.

I got a JLT oil separator (catch can), fitted it, and I’ve had no problems with smoke out the back, cutting of power etc since.

To give an example of how much vapours pass back through the intake, I have measured roughly a teaspoon or more of oil in the separator per 1000km.

Hope this info helps

I'm using a separator and still had the hesitation power loss problem

 

[Ben James]

Hmm.. maybe something else is at play...

I’m still leaning towards the PCV system interrupting the fuel mixture though, which is causing an error in the calculation of the ignition timing /air-fuel ratio that the PCM has calculated (at WOT) in particular times when the engine is under load.

My theory is that the blow by that the cylinders experience in long WOT at load is great enough to cause the PCV system to vent excessive spent gasses back through the intake.

The intake manifold would experience a much larger volume of unusable gas entering in, which in turn would create a situation where the fuel mixture would not be able to effectively burn.

There had been times where my car has emitted a small flame out the back after WOT applications which would support this theory.

Oil separators would minimize this but you still have the problem of large volumes of used gas entering though the intake, and even the oil separator can’t take large volumes of oil/fuel vapours out completely... it would just kick the problem down the road a little so to speak.

I’ve watched a fair amount of dyno runs (on you tube) where you can visually see a short puff of smoke pumping out the back at about 5000-6000 rpm. This would tell me that at during the dyno run the engine sump becomes excessively pressurized by blow by, which defeates the PCV valve seal (a good thing rather than blowing an engine sump seal) and the spent gas gets dumped back through the intake manifold in an uncontrolled manner.

The PCV system is not supposed to open at this time, but it’s the only component I can think of which would cause such a particular puff of smoke out the back at that particular instance (on NA cars).

The ECU protocol may not account for this as it has no measurable way of knowing the EGR valve location (not 100% sure of this).

Dunno... Thoughts?

 

[Aubrey]

This is the feedback from Ford:

“No issue with the calibration. The issue is that the calibration has no lift shift. When they are shifting they are hanging their foot on the clutch activating it. Tell them to take their foot off the clutch completely when shifting.” I’m not so sure this stacks up.

I’ve now seen two before/after comparisons of the PP2 on 2017 GT, there is a minuscule improvement in overall power. One of them is mine and I’m no longer happy. I’ve requested an updated calibration file, but not expecting anything at this stage.

I think another tune is the solution.

 

[Burkey]

This is the feedback from Ford:

“No issue with the calibration. The issue is that the calibration has no lift shift. When they are shifting they are hanging their foot on the clutch activating it. Tell them to take their foot off the clutch completely when shifting.” I’m not so sure this stacks up.

I’ve now seen two before/after comparisons of the PP2 on 2017 GT, there is a minuscule improvement in overall power. One of them is mine and I’m no longer happy. I’ve requested an updated calibration file, but not expecting anything at this stage.

I think another tune is the solution.

I’m curious as to why Joe stopped the pulls so early? Roller speed?

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