Volkswagen Bora 1.9 pd tdi 115 HP MK IV - 1.9 pd tdi 115HP Bora MKIV lagging...

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Fri 7 Mar 2014 22:17
Volkswagen Bora 1.9 pd tdi 115 HP MK IV - 1.9 pd tdi 115HP Bora MKIV lagging... - roypaci

Hi guys,


I have recognized few weeks ago my car is lagging at high speed, around 110-140 km/h.
It was hesitating for a second, then for another, and went well again....
At higher speed it is more noticable.
Feels like when you run out of fuel for seconds.
Then run 200 km without problems.

Today I started the car after 5 days rest time(I do not use the car too often).
The engine started but it was shaking, and when I pushed the throtle it was lagging and shaking even more, with much more smoke all around my garage then ususally.
I left the car for about fifteen minutes in neutral idling, and all gone.
No more lags, and shakes, and smoke was normal.

Vag-Com does not shows any error codes, neither the Auto Scan option, but I moticed some wierd things at measuring block 3:

When the engine was on for about 5 mins:
MAF specified: 250
MAF actual: 1950




When all the symptons gone after 15 mins it looked like this:
MAF specified: 250
MAF actual: 248


Do you have an idea what could cause that?

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Sat 8 Mar 2014 10:23
Volkswagen Bora 1.9 pd tdi 115 HP MK IV - 1.9 pd tdi 115HP Bora MKIV lagging... - craig-pd130

The MAF sensors can and do fail, but before you replace it, try cleaning the electrical connector to the MAF, as the pins can get corroded over time, which affects the signal from the MAF.

Use electrical contact cleaner (NOT WD40) to spray on the pins and into the connector plug, leave for a few minutes, then plug in the connector, then remove it again, re-connect, remove etc etc a few times to 'wipe' the contacts clean. Then give it another spray and repeat.

See if that works!

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Sat 8 Mar 2014 17:09
Volkswagen Bora 1.9 pd tdi 115 HP MK IV - 1.9 pd tdi 115HP Bora MKIV lagging... - roypaci

Thanks for your advise :) !

Today morning I have re-tryed, and it was laggy again.

So unplugged the connector of the MAF, started the engine, and all symptons have gone!

Fourtanetly I had a used one, as I was sturggling also with the turbo, and changed the MAF before the turbo has been taken a part.

So replaced the current with the old MAF, and no more lags

An other question about:

Could this faukty MAF caused any damage in other parts of the car?

The top of the EGR valve looks pretty smutty.

Shall I do anything with?

Clean the EGR inside?

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Sat 8 Mar 2014 17:38
Volkswagen Bora 1.9 pd tdi 115 HP MK IV - 1.9 pd tdi 115HP Bora MKIV lagging... - craig-pd130

The faulty MAF will not cause problems elsewhere in the car.

The EGR valve will be dirty inside -- it is possible to remove and clean it but it is a VERY dirty job, lots of hard carbon and oily crud.

Here's how to remove it: www.youtube.com/watch?v=l_aL3xciHZI

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