darek_u

So I've done so far 500 km with A-Tune. I must say it's a pleasure to drive it around the town now - car feels much more responsive, power is delivered smoother. However I have noticed few issues:

- idle - before install car was idling at approx. 900 rpm, little fluctuating due to small air leak. Now when I set up idle with pins shortened it shows 850 rpm, as soon as I remove bridge idle rises to approx. 1100 rpm, no matter how many times and how accurate I set the screw. I borrowed a meter with rpm reading and hooked it up to coil to read rpms directly from the ignition rather than tacho but the difference between meter and tacho reading was 200 rpm (lower on meter). Hmmm, little bit too much I think, I would rather trust tacho than Chinese meter. Is it normal with A-Tune or I should look further?

- car jerks when I let go the gas pedal at approx. 2100 rpm, each gear, most noticeable on 2nd and 3rd gear. This issue drives me crazy as it looks like I lift off my foot from the pedal at this rpm range most often for some reason... If I let go higher or lower - no issues at all, just slow drop in rpms and car rolls nicely. I have no idea what causes it, injectors kicking in at this point? Is there a way to get rid of it?

- max boost - well, this is a little strange. Before I had (I think, I'm not sure, there were no stickers or other information) Authority chips or something different - definitely chipped car, 270 hp at the dyno. When I depressed the accelerator pedal to the floor on 2, 3, 4 and 5th gear boost gauge pegged ALWAYS to almost 2 bar and stayed there for the whole time. maybe little less on 2nd gear but this is obvious. Now when I floor it sometimes it rises to 1.85 at the first blast (like up to 4000 rpm) and than drops to 1,6 and stays there till the red line. Sometimes it pumps up only to 1.6 bar and stays flat until red line. Just like K26/6???? I have never driven a car that was not chipped so I do not have a good reference point, however as per manual Turbo S should produce 1,85 bar on the gauge and stay flat until red line. Besides A-Tune and one 0.8mm wastegate shim car is bone stock. Tomorrow I'll check it at the dyno to compare with my previous results.

Anyone had similar experience with A-Tune or it is just me? Any thoughts are much appreciated.

eman930

Sounds like a vac leak to me

dillon410021

yes for the injectors kicking on josh set it like that for cars with a light flywheel so they wouldnt stall. I agree on it being annoying.

Rogue_Ant

No, this is not normal. The A-Tune standard idle is set for the same rpm as factory. The idle with A/C on is a little higher than factory.

A few things could be the issue: TPS, vacuum leak, sticking AFM, bad AC switch, bad/sticking ISV, etc.

This is also not normal for the A-Tune. Most likely the high idle issue and this are tied via the same culprit...

There is no reason that boost should change because of the A-Tune. Though this could also be tied to your other issues, via a boost leak or other issue.

Definitely check thoroughly. Refer to this excellent guide by Van:


No, the added drop-throttle assist is M-Tune only. The A-Tune has no such facility.

darek_u

Thanks for your replies. I know I have a little vacuum leak through AOS top cap oring. I presurrized system several times looking for leaks and this is the last one I cannot get rid of. As you know to remove AOS I need to remove turbo but I don't want to deal with it now - I just spent too much time reassembling the car from bare frame after paint job....
Anyway, leak is small and starts to be noticeable when I pressurize the intake over 8-9 psi. I agree it can affect idle but I don't think it would affect boost - it is before turbo? Correct me if I'm wrong here. I have covered all other suspects when it comes to high idle - TPS checked as per Clarks, AFM cleaned and refurbished as per Wilk page, AC is currently down, ISV was cleaned and checked however it is not new, DME temp sensor new and reading ok.
The only thing that makes me wonder is that before A-Tune all of this was not present or just less noticeable. I was just wondering if the tune makes a car more sensible or something similar and all leaks have much more impact on the car's behavior,don't get me wrong - i do not blame it at all, I just try to find a right direction for troubleshooting.

darek_u

OK, picture says it all. What is going on? Where to look now? I have hooked up stock DME and KLR (unmolested never opened) and I'm heading back to dyno tomorrow again. I'm going to check power with stock chips and again with my original ones (unknown tune, 270 hp). To explain the graph: higher values are with unknown tune (both DME and KLR), lower with A-Tune loaded inside the same DME and my spare unmolested KLR, 3 bar FPR.

Rogue_Ant

You swapped KLRs between the runs? The A-Tune can run with any KLR/KLR-chip.

It looks like the boost pressure is different between runs. Try not changing the KLR.

darek_u

I have already swapped the FPRs. It will be difficult to swap them again between the runs. Can A-Tune run with 2.5 bar FPR?
I swapped them because I was not sure what settings are programmed in the chipped KLR. Do you think this can be the issue? What do you suggest to do tomorrow - I will have dyno for and hour for me.

User 52121

KLR controls boost so long as your wastegate is still connected to the CV.

DME controls fueling. A-Tune is set up for a 3.0 FPR. If you put the stock 2.5 FPR in, and run the A-Tune, you will run lean at WOT. Put the 3.0 back in before you dyno with the A-Tune.

And as Joshua stated - DME should have 0 effect on boost levels. If you swapped KLR's at the same time, then that would explain the varied boost level. One KLR has a different chip (or is just malfunctioning) compared to the other KLR.

black944 turbo

You should never be pressurizing your AOS. That is always under vacuum and should be blocked when boost testing at your intake boot, for that matter all lines preturbo are only under vacuum.

darek_u

I followed Van's video when I did it for the first time. I hope I didn't break it myself...

darek_u

I pressurized the system once or twice with this line blocked off - no leaks.

joker2cv

I run A-tune with 2,5bar FPR (11,5 afr at wot) because with 3bar was too rich at wot 10,7.
No leaks all around

darek_u

10.7 is too rich?

fejjj

Yes.

11.7 is a good target.