B7 3.0tdi Quat s line.....engine advice needed please

C

caddymandean

Registered User
Joined
Mar 27, 2014
Messages
12
Reaction score
1
Points
1
Location
Chorleywood, Herts
Hi all,

I have a 3.0tdi B7 s line quat the 204bhp. I bought it knowing it had some sort of turbo lag issue. So I got a deal :drool:

Turbo wasnt kicking in until about 2100rpm. Under that car was very sluggish and would sometime thow itself into limp mode. Mate of mine stuck the VCDS on it and found fault code J724 013128 Which all pointed towards the actuator unit.

When looking at the actuator we saw the clip at the top was broken. So i ordered a new one from TPS another mate borrowed his VAS tool from work and we fitted it and calibrated it correctly.Its 100% working fine.

Anyway this has not resolved the problem! This is where it gets interesting. If i disconnect the MAF it drives fine (maybe a little underpowered, but hardly noticable) turbo comes in nice and early and pulls well throughout the rev range.

So where to go next? Ive done some searching and im getting different opinions. Could this be a clogged EGR? What else is controlled/sensed by the MAF?

If its the EGR, I was, once running right going to get it remapped and the EGR mapped out. Rather than take hours taking it out to clean....looks like a pig of a job on the 3.0tdi! Can I still get it mapped with the MAF disconnected?

Anyone have any similar experiences to mine with anything further to suggest?

Thanks,
Dean.
 
You're a brave man buying a car that knowingly has a fault causing it to go into limp mode...

From memory (before mine was mapped) the turbo is supposed to kick in about 2000-2100rpm, so that lag is normal without a remap.

Running with the MAF disconnected will mean the ECU doesn't know how much air is getting into the engine and the fuel/air mixture will be more than likely be incorrect. The car will run (usually), but MPG and performance won't be as good as it should be. No reputable tuning company will map a car with a known fault, the first thing they should do is scan your car for fault codes, as mapping can easily make minor issues worse as the engine is being pushed harder. Keeping the car mechanically top-notch is important when running a remap of any kind.

Someone who is a VAGCOM expert may be able to help you with the code itself... unfortunately that someone isn't me!

Initial thoughts would be to get a part-used MAF and see if that curse your problem...

Hope you get it sorted!

NB: The 3.0tdi with a map (when in full working order) is a dream to drive and a force to be reconned with on the motorway :thumbsup:
 
Thanks for the reply.

Lol. Well when I went and test drove it i could tell there was a lag problem. Used it to knock the price down £1500! Happy days. Well except for the problem. lol

Turbo coming in at 2-2.1krpm sounds rather late. I suppose it depends on how it drives below that. Mine literally was so sluggish! Then of course it would sometime throw it into limp mode. Quick flick on and off of the ignition and that would clear. Above 2.1krpm once turbo was on bosst it goes like stink.

Now with the MAF disconnected it drives much nicer under 2krpm but there is also a very slight pick up from then on. I understand regarding the extra fuel consumption. Actually driving the car with the MAF disconnected has put eml light on. New MAF in and fitted EML light was still on. Does this just need a reset? If so could the reset tell the car a new MAF has been connected and potentially cure the problem?

I am massively confused now. Even more so! lol No need on the part used MAF..ive just fitted a brand new one and still getting the same problem.

I have read threads suggesting rough running/lag can be down to EGR/throttle all clogged up with crap. Maybe i'll take the half day to strip down and give it all a good clean up. See if that cures the issue.

Does anyone else have an idea what rev range the rubo should kick in? I would've thought 1500rpm is more apt?
 
From personal experience (2.5tdi V6 and 3.0tdi V6) without a map it kicks in about 2000rpm, with a map it's more like 1500rpm...

That's my favourite part of the map!

I would be very weary of 'flicking on/off' the ignition to get the car out of limp mode... there could be something seriously wrong which is not being attended to and you could be making it worse by driving it! I've been bitten by that before and had a £3k repair bill... kept stalling... in the end it was the HPFP (high pressure fuel pump) which went.

You can map out the EGR, clean it, or blank it off (also needs mapping out). Cleaning would probably be your cheapest option but it may require some elbow grease!
 
  • Like
Reactions: caddymandean
Cheers. Going to catch up with my mate who's got VCDS see if we can find any other fault codes.

Only other thing thats of notice: MAF connected, slugish and turbo at 2.1krpm and a big old puff of black smoke.
MAF disconnected turbo seems to come in around 1500rpm with an extra pick up about 2100rpm but no big puff of smoke.

Not worried about getting my hands dirty on the cleaning bit. Spoke to the guy I want to remap it and he said no way until its running right. EGR clean and another plug in lets see if that helps!
 
sounds like your MAF is knackered mate, if it runs better when it's disconnected but ****e when reconnected I'd say you have a dodgy MAF. When disconnected it uses default settings so won't run optimum.
 
madmike01uk said:
sounds like your MAF is knackered mate, if it runs better when it's disconnected but ****e when reconnected I'd say you have a dodgy MAF. When disconnected it uses default settings so won't run optimum.
Click to expand...

I just changed it with a brand new one. Now a cheapie either. Denso, which is apparently what is provided from factory. Still the problem persists. What does the MAF control/affect? Anyway I can find out?

Thanks.
 
I'd look at the oxygen sensors on the cats as well.
My current ride, a venerable 1.2 Corsa, had two dodgy sensors, before the cat and after and it was running like a pig. They did show up in the fault codes tho... Changed them out and it's much much better but we still think it needs a MAF as well. However, no fault codes to confirm.
 
Have you check all the simple stuff ie air filter and the very important and often forgotten mesh hidden in the air ducting trunking thats always blocked, wifes was so badly blocked I was amazed it actually ran!
Why not get a cheap code reader preferably one with live data read out, that way you can see what all the sensors etc are doing.
Oil and filter last changed etc etc all simple and not expensive at all, dont believe the service book!
 
  • Like
Reactions: jdp1962
lynallbel said:
Have you check all the simple stuff ie air filter and the very important and often forgotten mesh hidden in the air ducting trunking thats always blocked, wifes was so badly blocked I was amazed it actually ran!
Why not get a cheap code reader preferably one with live data read out, that way you can see what all the sensors etc are doing.
Oil and filter last changed etc etc all simple and not expensive at all, dont believe the service book!
Click to expand...
Yess, dammit! Don't forget that second air filter.
 
lynallbel said:
Have you check all the simple stuff ie air filter and the very important and often forgotten mesh hidden in the air ducting trunking thats always blocked, wifes was so badly blocked I was amazed it actually ran!
Why not get a cheap code reader preferably one with live data read out, that way you can see what all the sensors etc are doing.
Oil and filter last changed etc etc all simple and not expensive at all, dont believe the service book!
Click to expand...

Checked that funny shaped air filter bit and cleaned it all out. Also done full service when I bought it.
Guess its gonna be a case of digging a little further. A cheap code reader is a good shout as my mate with VCDS is always busy! lol.

I plugged the MAF back in yesterday and thought I would take it for a couple of decent runs (both motorway and town) drives fine when cold only starts driving like poo under 2k rpm when it gets hot. Thats why it would be good to know what the MAF controls.....any temperature sensors that could be playing up??
 
Iirc the maf = mass air flow, so measures the amount of air being drawn in and probably also the air temp
Early mafs were called air flow meters and were swinging flaps that moved causing a track to register their position back to the ecu, later current ones send a current down the element and measure how much air is flowing in by how much power it takes to keep the wire at a certain temperature, again all from memory.
Theres also the MAP sensor = manifold absolute pressure, not sure if audi uses one, but again measures temp and boost pressure in the manifold.
A lot of cars use 2 coolant temp sensors, 1 for the dash display and the other for the ecu

The cheapo code reader I have is off ebay U581
Pm me otherwise I will forget and I will test it on wifes car tomorrow and report back.
 
You must log in or register to reply here.

Similar threads

S
need b7 s line engine
Replies
7
Views
1K
chrisa4quat
chrisa4quat
piglet14
Paddleshift question (3.0Tdi s-line)
Replies
3
Views
584
SteveMcB
SteveMcB
Chrisb7a4
B7 3.0tdi tuning advise needed.
Replies
8
Views
6K
Chrisb7a4
Chrisb7a4
R
3.0tdi Cab S-Line Quattro.To buy or not to buy???? Advise please
Replies
11
Views
2K
RacDave
R
M
Help needed re B7 S-line cabrio rear springs please.
Replies
9
Views
4K
dimitar.tuntov.5
dimitar.tuntov.5
Top
Back