Thread: Intermittent Loss of Power

Had a guy I know in the UK who's running a VNT and 3.5Bar sensor give the MAF mod a bit of a stress test. He's running just under 29psi boost, and managed to push the MAF into limiting at somewhere around 855kg/Hr without too much trouble. The MAF seems to limit at around 26psi boost with his VNT.

Comparing logs with one done a few months ago the relationship between the MAP and MAF readings are the same but the are a lot more data points at high flows and far few at zero on the MAF axis.

cheers
Paul

Excellent work Paul..... you've really torn this ECU to pieces!!!

Just for understanding (depends on my poor english...):


The MAF is not the limiting factor?
Changing the MAP, adjusting the ECU for this and then the original MAF will work with more amount of air flow?

Originally Posted by Werdenfelser

Just for understanding (depends on my poor english...):

The MAF is not the limiting factor?
Changing the MAP, adjusting the ECU for this and then the original MAF will work with more amount of air flow?

You need to also change the ECU setting for the MAF.

I've altered both the stock curve, and the ADC parameters to make it work. These ideas are not new - this sort of manipulation is quite common on other engines. It's simply that lack of information made it impossible on the Td5 in the past.

The original MAF has usable range above the 710kgHr specified in the engine maps. It's outside the calibrated range but the readings seem to maintain the same slope vs the MAP as below 710 so it appears to be accurate enough.

The limitations are that the ADC converts a maximum value of 5V and the further above 710 you go the more uncertain the accuracy becomes. 850kgHr looks to be as far as you can meter with this method. In theory you could set the limiter slightly higher than 5V and let the ADC saturate the reading at 5V//870kgHr - effectively a soft clamp on the MAF.

These levels of airflow are way beyond the safe capacity of the stock turbo btw.


cheers
Paul

Originally Posted by Tombie

Excellent work Paul..... you've really torn this ECU to pieces!!!

Thanks.

I've actually started to post what will end up being a guide to remapping and modding the Td5 ECU. I should have written more before I started posting because I've got bogged down talking about it here and on D2BC.

Td5 Tuning - a "new school" approach | DiscoTD5.com

There is a bit of info about Airmass and nanocom logs at the moment. It's a bit patchy so needs to be cleaned up and I'll be adding something on the smoke maps when I get a chance.

Originally Posted by wobba79

Hi Gang,

Been getting intermittent Power Loss on acceleration every now and then (bloody scary when it happens pulling into traffic with a Semi bearing down on you. Lol) .

Anyway, today it happened while driving along. Got the revs back up to over 2k slowly & then off she went again. Thoughts or ideas?

(MAF has been checked with multimeter but have ordered a new one to test it's not failing. Anything else to check? Also getting intermittent considerable Black smoke upon acceleration. Guys at work joke I'm driving a 007 car dropping smoke bomb & disappearing before the car behind me makes its way out of the smoke.)

Had this on mine. Looking like throttle pedal potentiometer.

Wobbles problem sounds like the old Delaminating hose issue

Hi Lara,
I went down the track with the throttle pedal potentiometer issue, with the amount of redundancy built into the throttle pedal I doubt that the pedal will be the problem. If you know it is fine, if you are looking for something to blame that is a challenge to remove check and put back you have found it.

I would suspect a lot of other things before I went looking at the throttle pedal.

Cheers Marty