I have an interesting problem on my hands here. I just got the engine (S4 TII) rebuilt and dropped back in the car, and then got everything else back together and set up the past few weeks (waiting on parts). Tonight, after a bit of fiddling with settings, pots, and reloading 029w (it stopped communicating with my laptop), she was ready to start.

I cranked it a few times before connecting the plug wires to the plugs in order to fill the oiling system and make sure everything was properly lubricated, and then reconnected the plugs. On the first bit of cranking, she started to catch, and a little bit of gas maintained it. Rich as hell, but started with almost no effort on the first try! (on a rebuild?) I look down at the computer screen to see the afr, and notice that what feels like a low, lumpy idle is actually reading around 2000 rpm on the screen. Sure enough, the tach was reading the same. Very odd. I killed the engine and tried to restart it, and it did restart, but I noticed that during cranking both tachs were reading 1200 to 1500 rpm. What could be causing this? its got me confused. I know that the stock tach is triggered from the trailing coil, so I guess the MS is firing the coils as if the engine were running that fast? Why would it be reading such a blatantly incorrect speed?


Summary: Tach and megatune display showing 1500 rpm while cranking, moreso while running (very poorly). Why?

The attached file has my .msq along with a short datalog

Thanks!

 

It sounds like you have the wrong number of teeth configured, or you have stim-for-wheel turned on.

I'll check your settings when I get home from work.

Ken

 

hmm, stim for wheel may be turned on, i dont remember. the teeth configuration is 1,3,7,9 for a 12 tooth wheel, rising, 2nd trigger enabled (+1). what page in the msq file is it located on?

 

I don't remember, I'll have to look when I get home... It's probably in "Advanced" or "Spark"

Ken

 

stim for wheel is on in that msq ...

 

well hopefully thats what the problem is then. I was looking thru the msq in notepad here at work but wasnt sure where in the file that variable was located (or even what it was called). Thanks for checking that for me!

 

Thanks for checking, I don't have megatune here at work, and didn't really have time to be digging through a raw msq.

Ken

 

yea, that was the problem. (that and a mis-stabbed CAS). Now, for some reason, its not catching anymore, altho it may just be that I need to get the cranking PW's correct. Another day to play with it...