No SAW or Tach

dlh98370 · Post by **dlh98370** » Mon Jul 20, 2009 1:31 am

So I'm converting from ESC (Ford stand alone ignition module) to EDIS4 + megajolt on my Zetec. Megajolt starts and gets connected to my PC and no issues with loading and reading files. Aux sensor works as well as the MAP sensor. PIP goes in and no SAW to the EDIS4. No TACH indication on the configurator. Coil signal is driving the external tach but is imaterial for this problem. Engine stars and runs, but the EDSI4 module is in limp home mode with spark fixed at 10 degrees. Harness has beeen double checked. Any ideas?

dlh98370 · Post by **dlh98370** » Mon Jul 20, 2009 5:21 pm

All,
I connected a signal generator to the PIP connection of the megajolt. 12v square wave at 50Hz. It goes onto the MAX232 chip but does not come out the otherside. I removed both the microcontroller and the line driver and now I have a signal coming out of the max232. I plugged the line driver back in and it still works and I have a output on the line driver. As soon as I plug the micro back in, it quits like the port on the micro is grounded.

Will this happen if the port on the micro is not configured for input?
dlh98370

Post by **brentp** » Mon Jul 20, 2009 5:35 pm

Hello,

Tell us a bit more info. V3 or V4 MJLJ- I presume V4 due to the comment about the Aux sensor? Was it working properly before, but now failed, or is this the first time testing?

dlh98370 · Post by **dlh98370** » Mon Jul 20, 2009 5:50 pm

Brent,
Version4 and it has not ever worked. What I mean when I say that is I can see the micro communicating with the PC. The MAP sensor reads correctly as well as the temp sensor, so its difficult to say the micro is bad. If I had another max232 laying about I would put it in and try that. I did remove the line driver an left the micro in to see if it was some kind of loading problem, but no luck there. Should I try flashing the firmware on the micro?
dlh98370

Post by **brentp** » Mon Jul 20, 2009 6:04 pm

Hi,

Flashing the micro again won't affect this issue- the fact that you're communicating with the unit shows the unit is basically 'alive' and has an active firmware image. Do check all of the solder joints- if no luck we'll discuss further.

Thanks,

dlh98370 · Post by **dlh98370** » Wed Jul 22, 2009 8:16 pm

Replaced the MAX232 this morning and it seems to be working

dlh98370

Post by **brentp** » Wed Jul 22, 2009 8:34 pm

And there you go! Clearly one of the more unusual problems we've seen.

dlh98370 · Post by **dlh98370** » Thu Jul 23, 2009 2:31 am

Installed it this afternoon and it seems to be working fine. I was going to go the local rolling road and try to do some comparison of different maps and the ESC module. Depends on how much they charge, otherwise a steep hill and a stopwatch

dlh98370