MSefi.com read only forum (Jan.15,2018)

Probing the coil drivers, ie the negative side of the coil you will see 300+ volts, all be it a very short spike but enough to kill your scope input if it can not handle the voltage. As state you will need to attenuate the signal first!

Duffy, how are you driving your tacho? If from the IDM (EDIS pin 2) did you notice your tacho drop to zero or any strange behaviour? I am wanting to know what can cause the IDM signal to go flat even when ignition events are still occurring. Thus I am wondering if a bad SAW signal would be reported ...

A 3 pole switch that could leave a port pin (if there are any spare) either open, grounded or tied to 5V could add or subtract a few degrees while driving along. You would need two inputs for that, then you could have four positions. The ECM will see and open and 5V input as the same thing with a ...

This is beginning to drive me mad. I replaced my EDIS-8 with a 'new' second hand unit and it has made it worse! I now get misfires from approx 4000 RPM on, under acceleration I now hear pops and bangs and the guy following me said he saw 2ft flames out the back! Also the tacho drops out as before ...

An Update:
Today I finally got around to retesting my ignition system, by re-scoping and this time monitoring both the IDM signal and the PIP signal directly off the EDIS-8 connector.

This time I have no doubt that it is an EDIS/coil pack issue, it can be clearly seen from the trace (see below ...

Hi Zoltan, that is a good point and a much easier signal to monitor. I could probe the ECU side along with the tacho wire to confirm, just need to do it all again. I take it you would still strongly suspect the speed signal side of things?

I have been running a small block Chevy V8, with MS-II, 2.883 s/w, using an EDIS-8 with twin Accel coil packs for just over 2 years now (that is with continual s/w upgrades). In all that time I have had a persistant problem that I am very slowly getting to the bottom of, I shall explain...

Any ...

I may have had a similar problem, my MAT sensor was mounted in my alloy filter tray that I fabricated. The problem was that after running and then doing a hot restart I would get a feeling of running very lean, confirmed by looking at the AFRs, this would last for a number of minutes. What I found ...

I had big problems with my original mounting. It was located below the filter in an ally filter tray on top of the throttle body. What happened was after running and then turning off the ally would heat soak and heat the air around the sensor. Then on a hot restart the IAT reported a very high ...