Unable to Dyno FWD Leon FR?

[TripleBob]

So I took my MY18 Leon FR 184 tdi DSG for a rolling road custom remap session today - and long story short the guys running the dyno could not get my car to play ball.

No matter what they tried the car would not change out of 1st gear on the rollers... they tried Drive, Sport and Manual, traction control disabled, all the different drive modes - car in dyno mode or in stock form - it just wont change out of 1st gear. Paddles dont do anything in manual on the rollers either.
As soon as its backed off the rollers and all 4 wheels are rolling it works perfectly - so they've refunded me and sent me on my way - apparently I need to find a linked 4WD dyno so that all 4 wheels are in motion during the run?

Has anyone else dyno'd their 2wd DSG Leon without issues? Or am I best giving up and just getting a generic revo flash done and hope the results are anything like claimed? I usually try and get proven gains, rather than take a figure plucked out of the air (like those DTUK tuning boxes that are clearly BS figures)

 

[Mr Pig]

Why did he need to get it out of first gear?

 

[East Yorkshire Retrofits]

If they aren't capable of putting the car into Dyno mode, I highly doubt they're capable of carrying out a decent remap on it...

If they actually had it in Dyno mode, they shouldn't be having these issues

 

[TripleBob]

Why did he need to get it out of first gear?

They said they needed it in 4th gear to do the Dyno runs?

 

[TripleBob]

If they aren't capable of putting the car into Dyno mode, I highly doubt they're capable of carrying out a decent remap on it...

If they actually had it in Dyno mode, they shouldn't be having these issues

I'll be honest I was surprised, as they get excellent reviews and map far more serious machinery than my Leon - looking at their Facebook page they'd only just done someone's Cupra 290 with no issues.

They definitely had it in Dyno mode (activated with hazards + 5 press accelerator, DIS shows traction control off etc).

Tbh I've never had anything automatic or VAG before, so had to take what they said at face value

 

[BigJase88]

Why did he need to get it out of first gear?

Yeah dyno runs are done in 4th

 

[adam davies]

I'll be honest I was surprised, as they get excellent reviews and map far more serious machinery than my Leon - looking at their Facebook page they'd only just done someone's Cupra 290 with no issues.

They definitely had it in Dyno mode (activated with hazards + 5 press accelerator, DIS shows traction control off etc).

Tbh I've never had anything automatic or VAG before, so had to take what they said at face value

Traction control normally has to be deactivated in vcds. It doesnt fully do it using in car switch or headunit.

 

[Rusty2k]

Yeah dyno runs are done in 4th

It should be the gear that's closest to 1:1 ratio (ignoring final drive). On my Mk2 Leon CR170 DSG that's 5th not 4th, yet on the equivalent manual transmission model it is 4th.

Any tuner worth their salt will check if they don't know but far too many these days will just assume it's 4th without bothering to check.

 

[UnworthyBean]

I had the same problem with mine, took them a day of faffing to find a solution.

Not sure if it's the official solution but if you disconnect the rear wheel speed sensor, you'll be able to Dyno it properly.

Obviously some sort of safety measure as it thinks the rear wheels are dragging or something.

 

[TripleBob]

I had the same problem with mine, took them a day of faffing to find a solution.

Not sure if it's the official solution but if you disconnect the rear wheel speed sensor, you'll be able to Dyno it properly.

Obviously some sort of safety measure as it thinks the rear wheels are dragging or something.

Brilliant, thanks for this - yeah the guys said they'd had some diesel Audi's in the past that did the same thing, go into Dyno mode but won't change gear without the rear wheels turning - and again they'd spent hours trying to disable it.
Whereas they'd literally just done a golf R, which went into dyno mode perfectly fine and ran in fwd mode with zero issues?

 

[mcspook]

They definitely had it in Dyno mode (activated with hazards + 5 press accelerator, DIS shows traction control off etc).

I'm not sure that it's necessary in FWD cars. If I remember correctly my dyno session, he just kept the accelerator pushed with the traction control light flashing for a moment and then the rpm climbed and he told me that now he is in dyno mode (mine is a manual). But I'm sure that my hazards was off and he kept a steady rpm for a moment!

 

[TripleBob]

I'm not sure that it's necessary in FWD cars. If I remember correctly my dyno session, he just kept the accelerator pushed with the traction control light flashing for a moment and then the rpm climbed and he told me that now he is in dyno mode (mine is a manual). But I'm sure that my hazards was off and he kept a steady rpm for a moment!

They also tried just driving it up onto the rollers, disabling traction control, and accelerating as normal - would hit the red line in 1st and just bounce off it, wouldn't change up. That's in drive, sport or manual

 

[TripleBob]

As an update - now booked in for a rolling road session at more-bhp in Crewe. They've got a 4wd dyno, so will see how they handle it!

 

[adam davies]

As an update - now booked in for a rolling road session at more-bhp in Crewe. They've got a 4wd dyno, so will see how they handle it!

Im betting the rear wheels dont even need to move. Update us though will be interesting to find out.

 

[martin j.]

Could they manually change up to 3rd or 4th then floor it and let it do it’s stuff to red line, as you would in a manual?

 

[TripleBob]

Could they manually change up to 3rd or 4th then floor it and let it do it’s stuff to red line, as you would in a manual?

The original company couldn't, it wouldn't change up in manual once it was on the rollers. To be fair I watched them do it - put car in manual, drive slowly up onto rollers, then floor it - car wouldn't change gear at all. Not using paddles or when it hit redline (when it would normally change up regardless)

Will see how more-bhp get on tomorrow now, they have a proper 4wd dyno and seem to have a lot more experience with VAG cars. Certainly their pre-sales support has been great thus far

 

[TripleBob]

Im betting the rear wheels dont even need to move. Update us though will be interesting to find out.

Lads at More-BHP absolutely nailed it - zero issues
And no, no the back wheels didn't need to be rolling - absolute nonsense from the original company. Clearly didn't know wtf they were doing - dodged a bullet there I think!

 

[adam davies]

Nice stuff dude, a proper company

 

[Chris Bartram]

I had the same problem with mine, took them a day of faffing to find a solution.

Not sure if it's the official solution but if you disconnect the rear wheel speed sensor, you'll be able to Dyno it properly.

Obviously some sort of safety measure as it thinks the rear wheels are dragging or something.

Maybe relevant: My Mk2 Leon DSG developed a reluctance to change up automatically that eventually turned out to be a rear wheel sensor. The gearbox ECU uses the wheel sensors to detect when you're cornering to avoid a change mid-corner, so it's entirely possible if it sees vastly different speeds between the front and back wheels it might throw a wobbly too. It eventually went back to normal once the ABS sensor failed enough to flag a code, at which point I got ABS/ESP error lamps but at least got gearchanges back.

 

[adam davies]

Maybe relevant: My Mk2 Leon DSG developed a reluctance to change up automatically that eventually turned out to be a rear wheel sensor. The gearbox ECU uses the wheel sensors to detect when you're cornering to avoid a change mid-corner, so it's entirely possible if it sees vastly different speeds between the front and back wheels it might throw a wobbly too. It eventually went back to normal once the ABS sensor failed enough to flag a code, at which point I got ABS/ESP error lamps but at least got gearchanges back.

The issue was resolved with a company that knew how to tune and use a dyno.