Megasquirt problem

stevieturbo · Post by **stevieturbo** » Mon Oct 05, 2015 9:21 am

Any time you change a map, always save a new one. Easiest way is just to add incremental numbers to the name file.

eg 001, 002, 003..and so on.

richardpope50 · Post by **richardpope50** » Mon Oct 05, 2015 11:18 am

.... and backup the files off your computer in both above posts.

Can you use TunerStudio's automatic map mode to get to at least a good map?

DaveEFI · Post by **DaveEFI** » Mon Oct 05, 2015 12:30 pm

kusanagi wrote:I have managed sort the problem with the Megasquirt it turned out to be the cam position sensor being a sod, the sensor would work fine on a bench and would work fine when being tested on the car but would stop working every time you tried to start the car. So I have replaced the optical unit I was using with a hall sensor and modified the trigger to match and the car now runs.
I now have got to redo all my fuel maps and cold start settings as I messed them up when trying to fault find this problem. I have also gone coil near plug using 2 VW 4 cylinder logic level coil packs.

Sounds like you were running the sensor from 12V, so it was failing when the starter motor dropped the volts? But this happens on every car, so was it a sensor designed for this use?

But it does also show to do a full range of logs before ripping things apart. They are designed to show the most likely problems.

kusanagi · Post by **kusanagi** » Tue Oct 06, 2015 9:16 pm

The sensor was a luminition optronic sensor which was running of the 5v ref ( as used by the tps ), I only remembered during changing the sensor that I had intermittent problems with the luminition unit before in a previous installation.
I pulled all the wiring because I found one or two wiring mistakes in my loom and decided to put the Megasquirt under my dash instead of in my boot ( this has helped with more stable Map readings due to a shorter vacuum pipe run ) and I decided to totally re do my fuse panel.
I decided to use a totally new fuel map as my old ones where all over the place because of inconsistent vacuum readings, already my new fuel map is a lot better than the old one only after a week where as my old map took a couple of months as was never right as the vacuum was never stable and kept bouncing all over the place due to the long length of the vacuum pipe.