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Discussion Starter #1 (Edited)
I had a well known and highly regarded tuner (known to this forum) sell me a tuned PCM for my car. I only had one made to get the speedo to read correctly, and I kinda also wanted a spare sitting around. The one that was in the car works great - it just reads fast.

So I get the PCM from the vendor, and immediately notice the idle is 800-900 RPM's in park - hot. (The car is an A4) And 700 or so in gear. Both of these are high by 150-200 RPM's. The idle also was a little rough, and there were some pops in the exhaust, almost like a misfire/stumble. I drove it like this for a day, and it also got much worse MPG.

I got home and put my old PCM back in, and all of the problems instantly vanish.

I reached back out to the vendor and he tells me that the pops in the exhaust and the high idle are surely signs of a vacuum leak, and its not his tune. I tried to tell him that all the issues go away with the old PCM, so his response was: "put in your old PCM and I guess you'll be good, then"

Before I lose my stack with the vendor - I have to ask: is it possible for one PCM to react to a vacuum leak and the other one ignore it? I've checked the car with propane as well as a vac gauge and everything appears normal. To my knowledge, there's no leak. But I'll keep looking if you all think this is possible
 

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If your original pcm runs your car fine and a 2nd pcm does not, either the tune in the 2nd pcm is off, or the pcm itself has a problem.

Flash chips always have a chance of small parts of tune being corrupted. If you had tunercat obd 1 tuner, you could read the contents of both pcms to see what the differences are. Tunercat even has a compare mode to highlight the differences between 2 bin files.
 

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it would throw a code and not run if there was a checksum error. something is wrong. unless there is a part of the story we aren't hearing, i'd demand it's sent back and flashed with a virgin bin file matching the calibration ID stamped on your ecm, then having the speedo corrections done. any good tuner would be willing to do that just to set your mind at ease, it's a 2 minute job. also ensure the knock module in the ecm you were sent isn't a b-body one, if it gets a KS code, it'll just retard a ton of timing.
 

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Discussion Starter #4 (Edited)
Thanks for the input. I've asked the vendor to just take back the PCM and give me a refund, since this tune is not right. He told me that he will only refund my core deposit, and that I could pound sand for the rest - essentially swindling me out of a couple hundred bucks. Seems like a great racket- just send out whatever tune will run the car and tell the buyers to take a hike.
 

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Discussion Starter #8 (Edited)
my common sense says there's a part of this story we aren't hearing.
:craz28:

Your common sense isn't working. I can post the entire email chain if need be. What went down is EXACTLY as I presented it.

What about this is so hard to believe? Car ran great on orig. tune - speedo was off b/c of gear change by previous owner. Ordered a replacement PCM with the correct G/R tune from Keith. (I actually submitted the wrong ratio, so he re-tuned it for $20 and sent it back.) Installed his PCM, and it idled with a random stumble, and idled high. But speedo read correctly, so there's that...

Installed original PCM and the car idles at the correct RPM, with no pops in exhaust. Now running original PCM and sending back the PCMForLess one to Keith to get my core back. I'm not wealthy so I can't afford to just burn that money. Anything is better than getting back $0

Hell - I would LOVE for keith to pop in here and respond. He won't - because I've given all the info and he can add nothing to the scenario.
 
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