random , occasional sync errors

[x-faktory]

Greetings. I am new to this forum and this is my 1st post.. Several years back I installed/tuned a Independent t'body injection setup, 60-2 flywheel crank trigger with Hall sensor and also a cam/hall sensor for full sequential.... COPs, with common plenum, etc. this is installed on a Porsche 911 w/3.8RS engine. It is a beast and runs fantastic.....95+% of the time and then, occasionally it will get a sync error and either shut down or run funky until it re-syncs. The Cam/Crank capture looks pretty good to me.....sensors have been checked, renewed, gaps set/reset...grounds checked, changed.....The tune has been config has been reviewed and.....I cannot find the source of this sync error

I would like to attach a copy of the tune, a log file and a cam/crank sensor capture..... but I do not see how this is accomplished. can anyone provide me with directions for attaching these files?

Once i overcome that hurdle....Please review and provide me with your findings, recommendations , wild ass guess, etc.

[Simonsta]

Hi, I am also new here and joined to try and get info on how to setup cold start / idle on my Delta integrale. I saw your post and it rang a bell as I had a similar sounding issue on my car which has since been resolved.

Please forgive the layman's explanation but hopefully you can make some sense of it.

On my previous ECU (a Marelli which is standard for the car, but mine had been modified to be programmable) I was having random cut-outs with the car going into limp mode for a short period each time. That ECU was unable to identify the issue other than reporting a sync error. After several months of living with the issue (the car isn't used every day), and assuming that the problem would have to be either the loom or the ECU, I decided to change the both and went with an M84 and custom loom. After fitting these and doing a preliminary mapping session on the dyno the issue was still there.

The chap that did my mapping delved deeper into the problem and (with the aid of an oscilliscope I think) discovered that there was a point at which the reference signal from the cam sensor and the signal from the crank sensor would sometimes occur at exactly the same moment and cause the ECU to trigger the cut-outs. To fix the problem he changed the point on the square wave that the ECU takes as a trigger from the 'up' turn of the square wave to the 'down' turn. I think it was the crank sensor that he changed. That has resolved the problem and the car is now running pefectly (apart from the cold start).

I hope that helps.

[Stephen Dean]

Hi,

You can attach files to posts now.

As Simonsta said, it may be that there is an edge swapping which forces a recalculation of the engine position leading to the misfire.