Testing the MAF - Boost issues

[nutttr]

So i've got a MK5 TDI 2.0L, recently had the turbo replaced (and manifold and actuator, etc, thank god for dealer warranty!), but after playing with Vagcom i've noticed that is quite obviously overboosting.

I had the Bluefin (superchips) map on it and the 'specified' boost matches the actual on soft acceleration, but full throttle from 1500-4000rpm in 3rd it goes beyond what Vagcom will measure. Ambient pressure was .989bar, boost specified was 2.5bar (this includes ambient) and actual was well above 2.6bar, while this doesn't sound like a big difference, it shouldn't be going beyond what the specified is, I believe...

What I want to do is test some things, like the MAF to see if anything is going bad and causing this issue. I do notice at idle (it's a manual) occasionally it feels like it may miss a beat. There's no error codes or anything from the ECU and on the stock map (what its on now) it seems to perform OK.
How do I test the MAF? Are there any other things I should test for? It also has a new EGR!

I don't know how to attach an excel spreadsheet here, but I can list out the data from a flat out 3rd gear run:

(Edit - Pasting it in and reformatting wasn't working, so simply take these values in the column and paste them beside each other into excel, will make a lot more sense then....)

TIME
STAMP

7.8
8.28
8.77
9.25
9.72
10.21
10.69
11.18
11.68
12.18
12.66
13.14
13.63
14.11
14.61
15.08

Group 9 - Field 0
Engine Speed - (G2
/min
1848
1848
1995
2184
2394
2625
2835
3045
3276
3465
3654
3801
3948
3885
3675
3213

Group 10 - Field 1
Atmospheric - Pressure
mbar
989.4

Group 10 - Field 2
Boost Pressure - (actual)
mbar
1611.6
1346.4
1642.2
2101.2
2601
2601
2590.8
2601
2601
2560.2
2478.6
2407.2
2335.8
2264.4
1713.6
1397.4

Group 11 - Field 1
Boost Pressure - (specified)
mbar
1040.4
2397
2468.4
2529.6
2529.6
2529.6
2499
2468.4
2448
2417.4
2386.8
2346
2295
1071
1060.8
1040.4

Group 11 - Field 3
Charge Pressure - Control Duty Cycle
%
70.9
74.1
68.5
45.4
25.1
38.3
33.1
28.7
25.5
23.9
22.7
19.9
17.5
44.2
44.6
46.6






Any analysis?

Thanks,
Aaron

[Transporter]

When it feels "ok" and there are no fault codes, then most likely - it is "ok"
The specified and actual don't have to match exactly.

You can upload the spreadsheet to Google documents and share link in here.
I have a program that when you enter data MAF, Boost, Engine speed, it tell what it really really should be.
Just post the link to the spreadsheet and I will check it for you.

Make sure you log MAF, Boost, Engine speed under right conditions.

[nutttr]

Excellent, will try and get it done soon.

My biggest concern was that I had a turbo go already while running a remap and the actual boost appears to be going quite a way beyond the specified. I didn't think it was supposed to?

I obviously don't want to replace a turbo . I also read that the turbos aren't the strongest of things on the pd140's...

Thanks,
Aaron

[Greg Roles]

If I had a PD140 I'd be VERY wary of blowing the turbo remapped. The 170 has a lot of changes to handle the extra power, especially the heat involved, and a 140 at similar levels is pushing the reliability envelope in my opinion. I'd be looking at everyway to help it handle the heat, from cold air inlets, wrapped, upping the intercooler ability, watersprays, ducts, etc, even to any way to help the turbo run cooler, increasing the oil cooling it receives, things like that. Even the EGR cooler on the 170 is massive compared to the 140. VW really thought it through.

There's been more than a few remapped 140'd pop turbo's now, and I've yet to hear of a remapped 170 doing the same, although it's very possible.

[nutttr]

OK, I've uploaded it to google docs! I have the 'cut down' spreadsheet here with a few 3rd gear WOT runs and the second link is the 'entire' set of data I collected over a few mins total.

http://spreadsheets.google.com/ccc?k...thkey=CNCJp4oM

Looks like as stock the car has boost spikes over 23psi... But even at WOT it seems to be up to 0.2bar above the 'specified', which isn't too much of an issue as stock, but with the remap, I can imagine it being an issue.

Here's the link with the whole series of data:
http://spreadsheets.google.com/ccc?k...thkey=CPnvrp4B

Looks to me like the MAF isn't well as it is reading 435 or so at idle, which according to vagcom should be more like 250???

Thanks for the help!

[parso_rex]

I just had a bit of a look at your logs and it seems on par with some of the MkV TDI's that we've done, they do spike a bit. I'll post up the logs of one of the stock cars on the dyno in a sec. Logged with a Hexcan cable so its bit faster i.e more samples. I spent a bit of time on this one a while ago so we logged everything. Its still running happily as far as I know although the intake flapper thingy did fail at one stage and was replaced under warranty. This is with stock everything
Log 1
Log 2

You might find the superchips map actually has better boost control than the stock one

[nutttr]

Excellent, thanks for that! It does look very similar to mine! After looking through it, i'm not 100% sure that i'm not overboosting, but it really doesn't look like it any more. Stock seems to overboost a fair bit! My MAF may still be an issue though as i'm starting to blow a bit more smoke at night. On the stock map i'm blowing more now than I was on the remap (which was smokier originally!). So i'm going to look into it. It could be a leaky pipe of vacuum lead somewhere. It's not helped by the fact that the engine bay has no room to get to the piping.

The 'intake flap thing' is the egr valve. Already had mine done, it failed!

I guess another thing to consider with remaps is that we get a lot hotter in summer than europe does, so the remaps probably don't take that into account!
Thanks!

[parso_rex]

Theres a smoke limiting map and when you accelerate hard it will check this to limit the amount of fuel being injected. If you set it too high then it will let in more fuel than the car needs (than it can consume) eg at low revs WOT accelerating hard and it will smoke a bit.Its particularly noticeable with out shyte fuel and its difficult to pre-determine if that makes sense. Greg could explain this better perhaps. There was thread here a while back about brand of fuel and the smoke emitted.

[nutttr]

Ah I see. I remember seeing a few values in Vagcom, but I haven't touched them. Currently it's on the stock map and at WOT at night it's not completely blacking out the street, but it's definately bit of a smoke stream. I rarely drive during the day, except weekends, so I don't generally see it (and it's gotten worse since i've had all the work done on the car!). I am assuming either the MAF went/is going bad and it's just unlucky, or the people that replaced the turbo left something off or disconnected! At low revs WOT it's not too smokey, it's when it hits about 3k rpm that you can see the trail (at night)!

[nutttr]

I got some 'MAF' cleaner on the weekend (just contact cleaner) and cleaned out the MAF. I'm now flowing the correct (I.e specified) amount at idle rather than a figure double it. It is quieter when cold now too.

It appears the maf is still over reading at WOT though as it is a bit smokey with the remap back on.

I cannot recommend superchips uk (bluefin) enough as I asked them to make me a new map with only 1.5 bar of boost and less fueling (reducing the EGT) and they mailed it to me a few hours later! Well impressed!

I would like to dyno it at some stage, but I need a new DMF first...