ok, I have a msI v3.0. I have built the 2nd vr off the sticky in the forum. I have double and triple checked the built in vr input for correct set up. Here is where I am different and may be having a problem. Instead of building a new harness or installing a pre-built harness I have spliced in to the stock s5 wiring harness. I have all my inputs but no rpm signal. I have double checked my wires to the cas. My car was running fine before, so I don't suspect a bad cas. I have turned the pots all the way to the left, and still no rpm. Please any suggestions would be appreciated.
P.S. the stock wiring to the cas is shielded.

 

I should clarify I have no rpm in megatune and no start/fuel/spark.

 

Thought, I couldn't find a 18ohm resistor for my 2nd vr circuit input so I used a 22ohm instead. Think that could be my problem?

 

Your resistor shouldn't matter. An 18 ohm resistor can be around 22 ohms anyway if it is a 20% tolerance.

But more to the point, you mean 18K, right? There is no 18 ohm used in the VR circuit.

Did you pin the CAS connector all the way back to the Megasquirt to make sure you are running the proper wires back? As I recall, S5 CAS wiring changes colour from the CAS to the other end of the wire. Also, the shield gets grounded at the ECU end only.

Are the jumpers correct on the board? TACHSELECT to VRIN and TSEL to VRININV?

Are your trigger settings correct on the ECU?







Do you have any troubleshooting equipment available like a scope?

 

Yes Aaron I meant 18k and 22k. I followed your write up for my settings. Yes my TACHSELECT is jumped to VRIN and TSEL to VRININV. I have verified the the wires twice. I may be able to get a scope. That was going to be my next step. I haven't had much time to look into it, I had to fix my other car and work two jobs. But I hope to look into it more in the next couple days.

 

Are the pots fully counter clockwise?

Ken

 

yes. i'm going to play with it tomorrow a little

 

aaron where do i find those settings in tunerstudio?? i cant seem to find them

 

No idea about TunerStudio. I still use Megatune, and will only stop using it when it is ripped from my cold, dead fingers.

Or at least until I use an MSIII.

 

Those settings will be in the same place in TS as MT. They both use the same ini file for ms1.

Ken

 

i had some prob getting RPM as well we found **** loads of noise on from my cas, i used a scope prob free from the webs and used my mic in jack with a cheap dollar store head phone wire
i think megatune comes with a scope software now no?? i had to download 5 different free once until we found one that worked great we also found that we made a mistake once on the vr2 witch fried the main chip on the VR2.

 

Ok. so I did some testing and found the lm1815 timer power and ground circuits were open. So I fixed the solder joints and rechecked. Still no rpm signal. I think I fried the lm1815 any thoughts? My cranking graph.

 

Leaving those open shouldn't have fried it.

Do you have a scope? You'll need some way of checking both the LM1815 circuit and the built in VR conditioner.

 

I'm working on getting a scope. My hookup that had one hawked it for bail. I'm working other avenues for a scope. I am running new twisted pairs shielded wires to the cas. Has anyone used the windows scope that comes with the diy software bundle?

 

ok got a scope and I do not have any signal on either sensor. I have run new shielded wires between the cas and squirt. and still no signal. This squirt was running an fc when I got it but he was using a modded cas. I'm getting frustrated. thanks all for the help.

 

You need to start at the beginning. First, check for signal at the CAS itself. Then at the end of the wire where it connects to the DB37. Then the input of the VR conditioner circuits. Then midway through the circuit, etc. etc.