Help! Broke down in Winnipeg!

[Dan McNarry]

Hi,

I broke down last week in Winnipeg. Still there

(I am running MS II with spark advance)

I figured it was my relay board which is 9 years old now. Also worried about my home made ECU cable. Got new ones which arrived today. I installed the new relay board and cable but now I hear my relay board clicking like a turn signal flasher. I ran a new switched power source wire to separate it from the feed to my new accessory buss. Car is a 62 Cadillac. I pulled all the relays off the relay board and the clicking stopped. I could put the two nearer the 37 pin plug back in but the one near the power feeds and ground starts the clicking again.

I left that out then undid each wire on the board one at a time then put the relay back in. Still clicked each and everytime. I then unplugged the ECU cable from the relay board and the clicking stopped. I plugged it in again then unplugged at the ECU. Still clicking. I then took the ECU out of the case and looked at it. Doesn't appear to have released the "magic smoke" anywhere. I unplugged the Processor daughter board and voila, no clicking.

I am travelling and only have my laptop and null modem cable with me. No stim. Any input would be greatly appreciated. I am stuck and several days overdue on my return home. Oh, to make matters worse, the car is at my sister in law's in West Winnipeg and I am staying at my mother in law's up in the North end.

[Dan McNarry]

There is a typo in the above message. " I plugged it in again then unplugged at the ECU. Still clicking", should read "I plugged it in again then unplugged at the ECU. No clicking as expected. "

[Matt Cramer]

Which relay is clicking?

[Dan McNarry]

Hi Matt,

The ECU relay is the one clicking. My car and me are in two different locations in Winnipeg. I was going to go over and do some testing of the power circuit today when I get a chance. Marc P suggested that I test the power legs for 5 and 12 volts then check for 5 volts on pin 19 of the socket. I don't have a stim with me. If I unplug the the fuses on the relay board would it be possible to use the ECU cable in the car as a stim for testing or is this risky?

[Dan McNarry]

It seems weird that the daughter board can trip the ECU relay. When I can get back over to the car I will check to see if anything on the daughter board is getting hot when power is on and the clicking is happening. Do you know if the relay board ECU relay is providing protection as inacting as a auto reset breaker as well?

It seems like strange behaviour for sure.

[trakkies]

If the main relay isn't controlled by MS - but by your ignition switch. Or rather it should be.

[Dan McNarry]

I have been running the switched power on the relay board from my ignition switch for years. As part of the troubleshooting, I have isolated it by moving to switched power from the cars fuse block. Further to that, I have made that a connection I can take apart for testing and have tried "manually" switching power to the board using a test lead to battery positive. Just trying to eliminate the cars ignition switch as a source of the problem.

[trakkies]

Don't forget the grounds when testing things.

It's often easier to measure the voltage drop in a circuit before running in new ones etc. Do this by measuring from the battery positive to the relay positive, using say the 2 volts scale on your DVM. With the circuit switched on (under load). Do the same from battery negative to relay ground. If the total of these two measurements is more than about 0.5v, you can then do some more fault finding.

[Dan McNarry]

Looks like I found the problem. I was running switched power to a bus. The switched power came from just off the cars original fuse block. I had tapped into the wire there with a soldered joint. Measuring voltage there while cranking the car showed the voltage drop off drastically. It looks like the problem is actually in the 60 year old ignition switch. I am going to run a new source of switches and fused power to the bus and leave the ignition switch out of it for now. That should get me back home. I will do something about the ignition switch later.

Thanks for your help!

[Dan McNarry]

Quick question, I bought a spare daughter board just in case the current one was fried. Any time that I upgraded the image on the processor I would use my stim. I don't have a stim with me. Is it okay to upgrade the image in the car using power from the relay board? The instructions say to use the stim and that is what I have always done.

[trakkies]

Quick question, I bought a spare daughter board just in case the current one was fried. Any time that I upgraded the image on the processor I would use my stim. I don't have a stim with me. Is it okay to upgrade the image in the car using power from the relay board? The instructions say to use the stim and that is what I have always done.

Absolutely no problems doing this - but unplug the coil(s) and injector feeds so there's no danger of the engine starting, or those parts being damaged.

[Dan McNarry]

Thanks! I don't want to do anything that will further extend my already extended visit to Winnipeg.