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Discussion Starter · #1 ·
Sorry if this has been covered before, but can anyone tell me the how to check the MAF readings while on the move i.e. get the expected and actual figures?

My car is running pretty crappy at the moment - hunting idle when you roll up to a stop in neutral (amplified by the new engine mounts), and generally under performing (eddyh can vouch for that! [;)])

I suspect its the MAF....

TIA
 

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Yep, I can confirm that Tab's car is under performing but I won't embarass Tabs and tell people how I know.[:)]
 

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I ain't no effin padawan
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Tabs

It's one of the early blocks, you should see 140-150g/s max on your car. I'm in liverpool area monday afternoon. Give me a shout and I'll pop in and give you a helping hand.

Could swap the maf for mine to see if it sorts it.
 

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Hi m8

When you say performance is down, what do you mean? Is it smooth enough delivery, just not as much power as usual?
 

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Discussion Starter · #6 ·
Just not enough power as usual, and it seems to stuggle at high speeds - its almost stock performance.

Tried switching the chip (via the button) to stock then back again to program 3 and there is little difference between proggies!!
 

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I ain't no effin padawan
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Doesn't look that bad tabs. Are the readings smooth as you accelerate. Log them and graph them to see.

Have you cheked for boost leaks etc around your new IC? Does the standard program run smoothly?
 

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Discussion Starter · #11 ·
Yeah they were smooth, nothing peaking or suddenly falling - cant do the log tests as I dont have the full version of the software so will have to rely on my mates eyes [:D]

I've done a full check of all pipework from and to the IC. Cannot see any obvious signs of leakage, nor can I hear any while driving.... The only weak link I could think of would be the small hose connecting the lower turbo outlet pipe to the intercooler inlet - on mine I've had to stretch it accros to connect both systems together - could be worth getting a longer Samco replacement?

Program still runs smoothly, no surging, hessitation or anything of that ilk - just the car is deffers not performing as it should - EdyyH managed to keep up with me on Sunday on more than one occasion and his car is a stock AGU.

Is there any way to measure boost both before the intercooler and on the inlet manifold? Would like to compare to see if this is were the problem lies.
 

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On a related note, I think I've finally found the cause of my pinking problem. The MAF sensor's reading 2g/s at idle (with the A/C turned off, which it should be when checking values at idle), rather than 3-6g/s. Otherwise, it seems OK. The workshop manual suggests a "large amount of unmetered air between the sensor and the intake manifold" is a possible cause. Not only that, but the car runs worse with the MAF sensor unplugged, so I don't think the MAF sensor's the cause of the problem. So the problem really is some sort of vacuum leak.
 

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Further to my last post, have you tried running with the MAF sensor disconnected? If it runs worse, then, like me, you probably have a vacuum leak.

Strange you should mention 680RPM as the figure your revs drop to. That's what mine idles at, and while it's in spec (650-750RPM), I'm sure it should be higher, more like 720RPM. What does block 002 read at idle, with the A/C and other electrical consumers off? On the V5 it should be 3g/s or more. There's no reason why it should be any lower on the 1.8T.
 

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Sorry to be contrary to the logic, but my maf was failing, i unplugged it and it would've been quicker to get out and walk.

New maf and all OK after.

Maf failure gives 'grey' results, not 'black and white'
 

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Discussion Starter · #15 ·
Stevie, idle range on the 1.8T AGU is between 800rpm and 920rpm - mine settles at just on a smidge over 900rpm on block 002 then proceeds to bob between the low 700's and low 900's when rolling in nuetral.

Anyhow, tried disconnecting the MAF.... and blow me (not literaly), my blower stopped working! Yes folks, my turbo wouldnt spool and it was like driving the N/A 1.8 20v - plus there was a real bad smell of sulphur coming from the exhaust....

The idle problem was still evident so at least we've ruled out the MAF for causing that one....

So is it possible that the fault lies elsewhere? I think so bargain hunters, what do you think?
 

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Discussion Starter · #16 ·
Well this strange little fault is doing my head right in!!

Driving backfrom the NEC on Sunday I could just about get it to shift on the motorway in fourth gear - then all of a sudden, it sprung back into life. Then as quickly as the performance returned, it returned to the slugish performance i've been experiencing.

I'm gonna take your advice golfttish and check the hoses, and just so I can eliminate it, swap the SMIC back to the stock item.

Will keep you informed.
 

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Tabs,

I know on an S3 that had this problem. The hose to the intercooler was loose but not...

It only became apparent when it was taken apart. What was happenning was that the hose seemed ok, but it would sometimes come off the intercooler but slip back on again. THe clamp wasn't as tight as first thought.

Rich
 

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Tabs, I don't know much about what happens in an engine, but when I had a problem like this (REVO 1.8T) I reset the ECU by doing a battery disconnect for 30 mins. This worked wonders.
 

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I ain't no effin padawan
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Tabs

SAmco do a full kit for ic inlet, outlet, turbo outlet, and a couple of the DV pipes for about £100. But a simple piece of silicon hose of the right diameter would be under £10.
 
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