Stumble w/Throttle - fixed; was MAF

[Kenneth]

So I swapped in a different MAF sensor and the stumbling I was having seems 
to be gone now.  I can now accelerate smoothly and it seems to be alright. 
I'll have to drive it more regularly now and see how it goes.  I have to 
tackle the a/c, so it doesn't take much for me to drive something else.

When it started stumbling I had for a while been running a cone filter on 
the end of the MAF that quit working, no airbox.  The sensor wire looked 
intact and I couldn't tell anything was wrong with the MAF, except maybe for 
a crack or two inside the housing on the stem for the little "bubble blower 
wand looking thing" that looks like it samples the air in the middle of the 
housing.  Perhaps that crack is part of what is wrong with it.  Or, of 
course perhaps I damaged it with my cone filter, which is the oiled type but 
did not appear to be not over-oiled.

This time, I put the airbox back in.  I lost the loud APR R1 bypass valve 
noise and intake sounds, which I rather enjoyed.  I prefer those noises up 
front to go with the Stromung song out back, even if I was maybe sucking in 
warmer air than with the airbox, so I may try it again with a oil-less cone 
filter like the AEM Dryflow.

I only drove it for a bit, but it might be the first time I've driven it 
without something messed up since putting the RS2 turbo/EM and 7A cams in. 
It doesn't really wake up until almost 4k and then it scoots pretty good.

I couldn't find the new MFTS that I have laying around somewhere, so I 
swapped in another old one, 3-pin version, that was in the loose coolant 
manifold from a donor motor I have.  I didn't know if it was bad or not, but 
I still don't have a coolant gauge.  I did have the cluster apart to put in 
some urS4 gauge faces, but I seem to recall the coolant gauge wasn't working 
even before that I think I tried both my original and the urS4 actual gauge 
with neither working.  I'll have to find that MFTS or get another piece of 
crap one that will only work for a little while... Unless there's been any 
improvements on them since I last heard?

Speaking of the urS4 gauge faces, they are noticeably dimmer at night than 
my originals.  I think brighter bulbs may be in order.  Do you folks know if 
the urS4/6's had brighter gauge backlight bulbs than 200's did?

Thanks,

Kenneth

-----Original Message----- 
From: Kenneth
Sent: Sunday, September 21, 2014 10:45 PM
To: 200q20v at audifans.com
Subject: Re: Stumble w/Throttle

Thanks for the replies.  I unplugged the MFTS and while the behavior seemed
better somehow, some stumbling was still there.  It needs replacing, again,
anyway.

I'll try a different MAF sensor next and see if that does anything.

Kenneth

-----Original Message----- 
From: Phil Rose

Sounds similar to symptom my '91 200q had all this summer. It finally threw
a code indicating a problem with the MAF sensor. I checked all sensor
connections and finally removed the sensor and saw a broken wire. I replaced
with a used MAF sensor and problem solved.

The temp gauge issue is possibly our old nemisis, the MFTS. That would also
affect engine running, but not a stumble problem, AFAIK.

-----Original Message----- 
From: Kneale Brownson

Disconnect the multifunction sensor hanging below the coolant manifold. May
be a bad sensor.