need Megasquirt MSQ file speed density

rfuerst911sc · 10-23-2006, 03:50 AM

I have been running Megasquirt II for about 10 months now but I have been running in Alpha mode. In that 10 month time I have used up two TPS sensors for what ever reason, the most recent this morning

. So I want to convert over to speed density so I can eliminate the TPS for good. Rather than reinvent the wheel does anyone have a MSQ file they can share to get me close? Stock 3.0 with 46mm ITB's is what I'm running. I am running MSII version 3.0 with Megatune version 2.25. The fault I am seeing with the TPS sensors is out of the blue at cranking rpm they are showing a throttle position of 80-90% which makes the ECU think the throttle is nearly floored and it won't start. Also for you guys running speed density is it best to get the vacumn from the throttle body or below the throttle body on the manifold? Thanks

ronin · 12-26-2006, 09:15 AM

I'll share if you share. are you still working on this problem?

rfuerst911sc · 12-26-2006, 11:37 AM

Yes I am still working on this issue. I have switched to speed density and I have a running driveable engine but I'm running rich and I have some surging at aprox. 2300 to 2500 rpm's. I can't get my wideband O2 to read any leaner than aprox. 12.5 to 1 in Megasquirt. If I go leaner via tuning she runs like crap. Unfortunatley I am at the end of my knowledge on this system and don't know where to turn. I have tried posting on the Megasquirt forum but the replies are full of technical jargon that just confuses me. What do you have going on your side?

smdubovsky · 12-27-2006, 05:06 AM

You'll still need a TPS even in speed-density to run an accel pump function. Why are you eating them up? They should outlast the car. Maybe thats something you should look into. Are you running them into the stops, have a misalignment, or some sort of axial thrust load, miswired? Something must be wrong.

rfuerst911sc · 12-27-2006, 08:14 AM

Don't know what the problem is with the TPS sensors. I am running TWM throttle bodies and useing the supplied TPS sensor. The problem I occasionally get is the TPS at closed position will say it's at 90 % open when in fact it is closed. So when trying to start the car it is flooding and won't start. I have tried 2 different sensors and this happens to both. Not all the time but randomly. I was told I didn't need a sensor for speed density is that not correct? Yes I have it wired correctly per the install directions and the feedback I get from the megatune software. I also agree that there is something wrong but I haven't been able to figure it out. I had a local MS guru lined up to help me but I think the aliens got him because he seems to have vanished.It's very frustrating to be this close and not be able to get it done.

john70t · 12-27-2006, 10:09 AM

I've no experience with the setup, but perhaps that TPS has a seperate connector for closed throttle whick is wired into the potentiometer/sweep circuit by mistake.
This might give the CPU too much voltage, thus a false reading at closed throttle.

One thing to check is to take the TPS off and make sure it has a consistently accending(I think) resistance across it's entire path. They sometimes have carbon tracking(?) which will short at certain points and create flat spots in acceleration.