After changing the ignition leads, i started the engine and had some major tracking in the engine bay, traced it to a rubber boot not over the end of the lead properly at the coil pack. I had some nice big sparks jumping around the engine bay.....
However i went for a run last night and noticed that he Tacho was not working (i am running the tacho from the PIP signal.) the car ran quite well, I have just connected the lap top to the MJLT and i have no reading on the RPM gauge of the software and still no tacho. everything else works, the load gauge and the outputs, except those driven by RPM limits.
I have removed the MJLT an visually inspected the circuit board and there is no signs of any damage.
It looks like i have lost the PIP signal from the EDIS module, Is this possible?
What tests can i do to check or shall i just get another module?
No PIP signal
Moderators: JeffC, rdoherty, stieg, brentp
Just tested the voltage output from the PIP signal an there is 0 volts with or without the engine running, so it looks like i have damaged the EDIS module somehow
It looks like i will be visiting the scrap yards to find another (it's getting harder to find them now too many MLJT users
)
I will let you know what happens.
Thanks
It looks like i will be visiting the scrap yards to find another (it's getting harder to find them now too many MLJT users
)I will let you know what happens.
Thanks
I have now plugged in a new EDIS module and it still does not work, however if i unplug the MJLT i get 12 volts on the PIP signal. (i cant run the engine to check the Tacho with the engine running as the power to the coil runs through the MJLT connector as the rev limiter is in the unit)
It looks like the MJLT could be dragging down the signal.
Any ideas on where to look next?
It looks like the MJLT could be dragging down the signal.
Any ideas on where to look next?
I have disconnected the tacho and with the MJLT connected there is no 12 on the PIP wire.
As soon as i unplug the MJLT i get 12 volts on the PIP.
I will try to make a jumper for the molex plug so that i can run the car on the EDIS alone, however i thing that it is the MJLT pulling the PIP signal down.
Is there any tests i can do on the MJLT to prove this?
As soon as i unplug the MJLT i get 12 volts on the PIP.
I will try to make a jumper for the molex plug so that i can run the car on the EDIS alone, however i thing that it is the MJLT pulling the PIP signal down.
Is there any tests i can do on the MJLT to prove this?
Would like to see the results from you bypassing the rev-limiter- we need to see if you can measure a 5-6v signal on the PIP line with the engine running and the MJLJ bypassed.
Going back to your original event, you described that sparks were tracking around the engine bay- how extensive was this? I'm wondering if any HV got injected back into the MJLJ
The PIP is fed straight into pin 8 on U2 - which conditions the signal and presents it to the CPU out on pin 9. See:
http://www.autosportlabs.net/asl_dist/m ... v3_sch.png
If U2 was damaged by a high voltage signal it would've taken the fall, protecting the processor. Yet, U2 is also used for RS232 communications between the MJLJ and your PC- and that part is still working, which is interesting.
You may want to check the solder joints on U2, also look for any burning or tracing around that area.
Furthermore, if you can measure and report back the resistance between pin 8 on U2 and MJLJ ground that will be useful. I will measure the same on a known good MJLJ V3 and we can compare numbers.
Going back to your original event, you described that sparks were tracking around the engine bay- how extensive was this? I'm wondering if any HV got injected back into the MJLJ
The PIP is fed straight into pin 8 on U2 - which conditions the signal and presents it to the CPU out on pin 9. See:
http://www.autosportlabs.net/asl_dist/m ... v3_sch.png
If U2 was damaged by a high voltage signal it would've taken the fall, protecting the processor. Yet, U2 is also used for RS232 communications between the MJLJ and your PC- and that part is still working, which is interesting.
You may want to check the solder joints on U2, also look for any burning or tracing around that area.
Furthermore, if you can measure and report back the resistance between pin 8 on U2 and MJLJ ground that will be useful. I will measure the same on a known good MJLJ V3 and we can compare numbers.
OK Progress so far. the tacho works perfectly with the MJLT removed, there is 5-6V with the engine running.brentp wrote:Would like to see the results from you bypassing the rev-limiter- we need to see if you can measure a 5-6v signal on the PIP line with the engine running and the MJLJ bypassed.
Going back to your original event, you described that sparks were tracking around the engine bay- how extensive was this? I'm wondering if any HV got injected back into the MJLJ
The PIP is fed straight into pin 8 on U2 - which conditions the signal and presents it to the CPU out on pin 9. See:
http://www.autosportlabs.net/asl_dist/m ... v3_sch.png
If U2 was damaged by a high voltage signal it would've taken the fall, protecting the processor. Yet, U2 is also used for RS232 communications between the MJLJ and your PC- and that part is still working, which is interesting.
You may want to check the solder joints on U2, also look for any burning or tracing around that area.
Furthermore, if you can measure and report back the resistance between pin 8 on U2 and MJLJ ground that will be useful. I will measure the same on a known good MJLJ V3 and we can compare numbers.
The tracking was extensive, the car is fiberglass and the engine bay is coated in heat/flame resistant foil cloth, the HT voltage was jumping to a section of this cloth then sparking across joins around the engine bay. The MJLT and EDIS is situated outside the engine bay and the only connections into the engine bay are 1. Coil wires x 3
2. VR sensor fully screened and earthed at the EDIS end
3. An output wire to an Amal valve (boost Valve)
All the rest of the wiring is outside the engine bay
I tend to agree with you that if U2 had been damaged by HT then maybe some signs of tracking, but there are none, the MJLT communicates fine with the PC except for the RPM gauge. (I Still experience problems changing output settings on MAP 1)
The resistance reading between pin8 and 0Volt is 8.1 ohms Seems a bit low to me, what did you get?
Update...
Its all fixed, Spot on again Brent thanks.
U2 was damaged,
i have replaced u2 (and now mounted it in a DIL socket) it all got a bit messy without a de soldering bench and the board doesn't look quite a pretty as it did before, but electrically it is all sound (i think).
Fitted it back on the car and powered up, communications ok, so unplugged the Tacho and started up, every thing worked ok so i reconnected the Tacho and everything works.
I only have one more question, I could only get a MAX232C and not a MAX232A. Is this likely to have much affect on the running parameters?
Its all fixed, Spot on again Brent thanks.
U2 was damaged,
i have replaced u2 (and now mounted it in a DIL socket) it all got a bit messy without a de soldering bench and the board doesn't look quite a pretty as it did before, but electrically it is all sound (i think).Fitted it back on the car and powered up, communications ok, so unplugged the Tacho and started up, every thing worked ok so i reconnected the Tacho and everything works.
I only have one more question, I could only get a MAX232C and not a MAX232A. Is this likely to have much affect on the running parameters?
Great you have it working again. I was about to suggest swapping out U2- good you had access to a replacement chip.
You're in the clear as long as you can communicate with the unit. I haven't waded through the MAX232 datasheet on the differences with the MAX232C, but if you have problems in the future you can certainly swap it out now.
You're in the clear as long as you can communicate with the unit. I haven't waded through the MAX232 datasheet on the differences with the MAX232C, but if you have problems in the future you can certainly swap it out now.