Quick BEW limp like pointers

[jptbay]

Went into limp like state right away after starting when I left to drive home this morning after nightshift. Tried a dozen or so restarts on the way home, but would not resolve.

Was acting similarly this spring and I deleted the EGR by going to PD150 intake manifold and retaining the ASV. Seemed to resolve issue and have had no trouble for 6 months.

No codes. Checked vnt operation with VCDS, all good. Changed fuel filter, went for a ride and back to normal, full power. There are no boost leaks. Have doggie collar, vnt17 and upgraded intercooler. Went to bed.

Left for work tonight, car had full power. Was snowing so I was driving easy. Went into limp like state again sometime while I was putting around on a city street. Stopped at a light and was limped out.

Some ideas for things to check?

No codes is annoying. Thinking fuel. New VW lift pump last winter, seems to be working good. Car has about 335ooo km. Still on original tandem pump, but I have a new one on hand. Put in new Bosch MAF this spring too when I did the manifold.

 

[jptbay]

Thinking about it more, I checked and forgot that BEW and ALH MAF's are different. Been working fine until now, but maybe with colder weather it is out of range.

I'm going to try unplugging it in the morning and see what happens with a default value.

 

[jptbay]

Well that was a slow ride home...

Unplugged the MAF and no improvement. I ordered a new one so it would be correct. Going to have to dig some more when I have time.

 

[JB05]

Does no boost leaks include the IC connections down under?

 

[jptbay]

Does no boost leaks include the IC connections down under?

Yes. Took a good look. I changed the oil when I changed the fuel filter and had the car up in the air with the skid plate off. When I installed the upgraded SMIC I swapped all the lower boost pipes to ALH ones.

Further, if there where boost leaks I would expect a code for deviation from requested.

Been reading a lot of old threads and there seem to be a few things to look at. I am going to more thoroughly check the N75 and turbo, as well as change the tandem pump that I have been meaning to get to for a while because of a leak.

Welcome other avenues look at too. Don't be shy, throw out your ideas please.

Don't think it could be the cat plugged, due to the intermittent nature of this issue.

 

[jptbay]

So it wasn't the tandem pump. At least it won't be leaking any more.

Will look at it more tonight.

 

[wonneber]

Further, if there where boost leaks I would expect a code for deviation from requested.

If it looses power while you are driving (limp mode) you have to scan for the code before you shut the car off.
It self resets when the ignition shuts off.

 

[P2B]

If it looses power while you are driving (limp mode) you have to scan for the code before you shut the car off.
It self resets when the ignition shuts off.

No, you don't. Limp mode resets when the ignition is cycled but any stored code remains until cleared with a scan tool.

Simon

 

[jptbay]

No time tonight unfortunately to look at it, but appreciate any brainstorming ideas.

 

[jptbay]

Checked a bunch of things this morning and it looks like my three bar map is the issue.
Click on thumbnails for larger picture.
In measuring blocks in VCDS, both idling and engine off, boost is showing 2196 mbar. When engine off specified is supposed to be 192. Idling specified is just over 1000.
Also group 22 shows charge pressure system malfunction.
Funny how no fault codes were logged.
Ignore the MAF readings. It's not working because as I previously mentioned it's the wrong one, and clearly not working, so a new proper BEW one is on it's way.
Going to order up a new map and see what happens.

 

[jptbay]

MAP sensor ended up being faulty.

Pretty happy car again. Got some love with the proper MAF finally, no more leaking tandem pump, and got the winter tires on.

 

[wonneber]

Glad you resolved it and posted the fix.
It may help others down the road.

 

[jptbay]

Well almost 2 years to the day and looks like another 3 bar map is shot.

Same symptoms, same VCDS readings.

I bought a Bosch PN 281002401 last time. Looks like there is a supersession to newer 3 bar map Bosch PN 0281002976. Hopefully it has better longevity.