After having an annoying problem with the headlights (HID's) stalling the engine i went through lots of testing of wiring, replacement of ballast and installation of an uprated headlight loom.
I fixed the relays using an existing hole on the strut housing. And spliced into the existing headlight wiring that runs along the front panel.
This improved the lights but made no difference to the headlight fault, so moved onto testing alternator, as battery was replaced recently. Alternator was tested at the battery as 13.3v. I realised this wasn't good so tried to clean connections.
This turned out to be a bad idea because the nut siezed and caused the stud to spin in the alternator, forcing me to find a replacement.
The alternator was replaced and the cabling was upgraded with some 4awg cable and gold terminals had in the garage, as the original cable looked a bit old and brittle.
After that the voltage at the battery terminals was 14.4v -14.6v.
But...... The headlight problem got worse. The engine would now completly stall at idle and would need to be revved to keep it going as the lights were switched on.
So, It got me thinking about the MS, as this controls the FPR and its that that switches off and turns of injectors, wideband etc. It seems that when the lights are switched on, there is a surge or dip in voltage and the MS resets. This was confirmed with the laptop connected and in megatune.
Did some research and found this. Taken from here on the post from W113
http://www.msextra.com/forums/viewtopic.php?p=149614#149614My understanding is that you have defined the "surges" as the cause of the hesitation and that the resets come at WOT .
The processor resets that I have experienced in MS1 have all been in connection with either disturbances in the power supply or radiated/conducted disturbances finding their way to pin 6 RSTinv.
I would try the following ( observing the + 5V on a scope would be a great help)
Power supply/ injectors
Make sure that + and ground leads are of decent size and that no major ground loops exists. (There was a recent post which got rid of disturbances by electricaly isolating the MS box from the firewall !)
Arrange so that the flyback + feed is separated from the +12V in feed to the MS(several posts exists on this )
Try out a LC filter in the +lead
CPU
Install 100nF mylar caps directly between pins 1/2 , 19/20 and 31/32.
Solder the caps irectly on the socket pins. This could help the +5V
Install a 100nF cap between pin 6(RSTinv) and a ground very close by .
Pin 6 is quite sensitive to disturbances. Even a scope probe of 50Mohms/8pF which is touched to pin 6 will cause a reset.
With the 100nF cap added the RSTinv (pin6) becomes quite insensitive.
I did this mod after buying some capacitors and I have turned the lights on and off repeatedly with no stuttering or stalling. Also did it again this morning as i had my doubts, but it was rock solid. Hopefully any random misfires i was getting on the odd occasion under load will stop too.
I have also found that since doing this, it also reduces the stumble you get when you "burn to ECU".
