VDR

[Jim Warman]

In another thread, discussion turned to using the VDR... a stand alone "flight recorder" to the uninitiated.

 

There are some valid complaints, pretty much all pointing to noon-productive recording sessions - but we see a lot of those or similar as we drive and drive and drive with the IDS connected (you guys ARE making recordings rather than trying to watch data live, right?) and fail to gather any useful info.

 

A couple I have on the go right now. One involves several cars that seem to be doing the same thing but the subject vehicle is an 09 Edge with the 6F50 transaxle. This is a concern that I have yet been unable to reproduce, but has been experienced by several reliable sources.

 

Owner concern is a "bump" on driveaway from a rolling stop or near rolling stop. There were many fruitless recordings as we searched for the PIDs I needed. Finally, I get a set of recordings that shows a spike in TRAN_RAT just about the time it seems that the problem occurs (about three seconds before the recording is triggered). TRAN_RAT takes a brief stroll from 4:1 and heads towards 1:1 (usually making it to around 1.4 give or take).

 

Forgive me if I've already mentioned this one... The VSS graph shows nothing remarkable... but if we analyze it frame by frame just before and during the TRAN_RAT excursion, we see three VSS frames showing 317 mph... 650 mph... and 653 mph. The frames are not contiguous and (what is striking) they are in MPH when all the other readings are in kph.

 

These transmissions are known for concerns with the OSS so, when I take it apart to look for the needle in a haystack that hotline wants me to find, I will replace the sensor "just because".

 

Another involves an 06 6.0. After driving long distances the truck will start to miss on acceleration. Another one that we can't reproduce mostly because you can't predict when it will happen and we can't devote that kind of time to a road test. This man is a friend and runs a car in Quick Rod. The miss is actually EVERYTHING, including all the APPs, IPR, ICP, MAF, VGT... you name it surging... Somehow I missed VREF on the PID list but at least we now have a better idea of what we are looking for.

 

Your chances of having a VDR session reveal nothing are there.... your chances of having an air management test or EGR system test reveal nothing are also there.

 

Bottom line... if you don't look - you wont know.

[Shlep]

 

Owner concern is a "bump" on driveaway from a rolling stop or near rolling stop. There were many fruitless recordings as we searched for the PIDs I needed. Finally, I get a set of recordings that shows a spike in TRAN_RAT just about the time it seems that the problem occurs (about three seconds before the recording is triggered). TRAN_RAT takes a brief stroll from 4:1 and heads towards 1:1 (usually making it to around 1.4 give or take).

 

Forgive me if I've already mentioned this one... The VSS graph shows nothing remarkable... but if we analyze it frame by frame just before and during the TRAN_RAT excursion, we see three VSS frames showing 317 mph... 650 mph... and 653 mph. The frames are not contiguous and (what is striking) they are in MPH when all the other readings are in kph.

 

These transmissions are known for concerns with the OSS so, when I take it apart to look for the needle in a haystack that hotline wants me to find, I will replace the sensor "just because".

 

 

Funny you should bring this up Jim, I just finished explaining to the powers that be... the very importance of being willing and able to "capture" the live data with the proper equipment. Seems I've been chasing the exact same concern on the exact same model, with exactly the same description. Turns out, as you noted the OSS would spike just as you mentioned and my readings were pretty darn close to what you have here. Now numerous recordings were made and others found nothing out of the ordinary... now when reviewing each frame it was plain as day. This is after we had 2 very unhappy customers and 4 different techs involved.