Hi,

Recently got my car remapped. Before the remap, there was a very smooth curve all the way to 5600rpm, and a very flat torque curve as a result.

After the remap, despite the remapper supplying maps from different sources, my car holds the torque till 4500rpm and then tails off. The maps have both in the past held torque till 5000rpm, then tailed off.

We checked the boost levels of the car (actual vs specified), and its boosting rather healthy for a K03s. I havent got around to checking timing corrections, but we did notice that at 5000rpm the engine's MAF it only was sucking in 155g/s at most, when it should be bringing in 180g/s+.

Is it normal for a MAF to degrade over time, or do they often fail outright? Only the dealers appear to have this MAF in stock, at an expensive £90+ vat considering the 1.8T's MAF can be had for £50+ vat. Are there any other measuring blocks in VCDS that are worth checking before I buy a new maf?

Thanks

Edited 28 June, 201015 yr by bluevrs3

I'd take the MAF out and clean it first with some electrical degreaser and see what happens? Also check the seal around the MAF if thats leaking?

I'd take the MAF out and clean it first with some electrical degreaser and see what happens? Also check the seal around the MAF if thats leaking?

I could give that a try, anything in particular or would some electrical cleaner do the job? The seal didnt appear to have weakened, and it seems strange that it was reporting fine before the remap.

hey mate good to bump into you on saturday. Worth checking to see whether you have am after market panel filter as there can lead to a build up of grease on the maf. This may prevent future problems if this is the cause. Could be worth trying to borrow someone elses maf to swap over for yours to see if it resolves the problem before investing o a new one.

Ive use brake parts cleaner on all my MAFs and never had any issues.

hey mate good to bump into you on saturday. Worth checking to see whether you have am after market panel filter as there can lead to a build up of grease on the maf. This may prevent future problems if this is the cause. Could be worth trying to borrow someone elses maf to swap over for yours to see if it resolves the problem before investing o a new one.

Good to see you - CR remap well in the end? There's a bog standard filter in the engine cover for sure, which wasnt that dirty to begin with unfortunately. Think i'll need to ask someone local as I cant return the MAF if its not the case.

Try cleaning with pure IPA (isopropyl alcohol). Be careful not to damage it

On the whole though, once they play up they have had it and cleaning, if it works at all, gives only a temporary cure.

Check very carefully that all vac hoses etc are properly connected and not split.

If you jump back to standard map does the fault go away? If so, then that would indicate some sort of mapping problem.

Try cleaning with pure IPA (isopropyl alcohol). Be careful not to damage it

On the whole though, once they play up they have had it and cleaning, if it works at all, gives only a temporary cure.

Check very carefully that all vac hoses etc are properly connected and not split.

If you jump back to standard map does the fault go away? If so, then that would indicate some sort of mapping problem.

In standard form it showed a perfect dyno curve berforehand (pretty much standard TFSi plot). The ECU doesnt raise it as a fault (i.e. not hitting any internal min/max thresholds), but would be worth trying at some point. The tailing showed up on both supplied maps (different suppliers), although the 2nd map's smoothness and torque delivery lower down the range (2 - 3.5k) was much improved.

We checked the boost levels of the car (actual vs specified), and its boosting rather healthy for a K03s. I havent got around to checking timing corrections, but we did notice that at 5000rpm the engine's MAF it only was sucking in 155g/s at most, when it should be bringing in 180g/s+.

just for comparison my MAF peaks at 204g/s on stage 1 software. If you have logs on yours which if i read correctly then they should be similar to mine in this thread

my graph and logs

like you say mine is bringing in 185g/S at 5k

Edited 28 June, 201015 yr by vRSy

What sort of boost pressure are you running at 5000rpm?

What sort of boost pressure are you running at 5000rpm?

presuming you mean bluvrs3

What sort of boost pressure are you running at 5000rpm?

Just about 2100mbar at 5k and 1950mbar at 5.5k. Looking at vrsy's link above, actual boost levels are on par.

Just about 2100mbar at 5k and 1950mbar at 5.5k. Looking at vrsy's link above, actual boost levels are on par.

Aye I meant blue Sy.

Yep your maf is very low, I presume you checked all connections from the maf to the turbo? Also make sure there are no blockages around the air filter. The fact you are hitting boost indicates air is drawing through the system well but it may be drawing from a leak pre turbo.

If all ok I would give the MAF a clean before forking out for another. I used to clean my Mk1 regularly and it always gave good readings all the way up to when I sold it @ 117k iirc.

My maf was 174 @ 5000rpm but my boost is only 1900 mbar on standard filter, roll on stage 2 lol.

Edited 28 June, 201015 yr by vRSMart

I havent checked all the piping as of yet, but that was in part due to the standard dyno result being spot, which suggested there were no leaks. I would have thought I would see a boost leak in standard map as well as remapped? When it does start tailing off from 4.5k, its very gradual all the way to 6.5k which suggests the ECU is reigning it in.

Just out of interest, does anyone know the peak reading of a standard tfsi?

I havent checked all the piping as of yet, but that was in part due to the standard dyno result being spot, which suggested there were no leaks. I would have thought I would see a boost leak in standard map as well as remapped? When it does start tailing off from 4.5k, its very gradual all the way to 6.5k which suggests the ECU is reigning it in.

Just out of interest, does anyone know the peak reading of a standard tfsi?

157g/s for stock car stock filter

Obviously you are pushing more boost remapped so leaks would show more, usually you should get a fault code when the maf is reading low.

It's been damn hot lately maybe the ecu is pulling the power back, you are running a lot of boost which does create a lot of heat and pushes up EGT.

I got 162g/s @ 6k standard do I get a prize

Edited 28 June, 201015 yr by vRSMart

Obviously you are pushing more boost remapped so leaks would show more, usually you should get a fault code when the maf is reading low.

It's been damn hot lately maybe the ecu is pulling the power back, you are running a lot of boost which does create a lot of heat and pushes up EGT.

I got 162g/s @ 6k standard do I get a prize

your prize is thatyou can take yesterday off

mart i right, if your map is pushing high EGTs, or pulling the timing back because of to much knock etc the ecu will pull back things.

can you post up your logs

can you post up your logs

Going to do some comprehensive logging on Thursday along with checking the pipes and trying the new MAF. Remapper suggests that given the readings we've taken so far, and the discussions had with the supplier of the map along with healthy boost levels detected is leaning towards the MAF now. Can always drop the MAF on the 'bay if it proves not to be the case.

Edited 28 June, 201015 yr by bluevrs3

Going to do some comprehensive logging on Thursday along with checking the pipes and trying the new MAF. Remapper suggests that given the readings we've taken so far, and the discussions had with the supplier of the map along with healthy boost levels detected is leaning towards the MAF now. Can always drop the MAF on the 'bay if it proves not to be the case.

do the logs from this page, very comprehensive and everything you would need

APR logging guide

do the logs from this page, very comprehensive and everything you would need

APR logging guide

Thanks for that. Just out of interest, should the MAF prove to be the problem (fitting it later today), would it take long for the ECU to adapt?

I'd reset the ECU to learn all new values when fitting a new MAF.