No power to the main relay

toon1 · Post by **toon1** » Tue Feb 21, 2017 9:39 pm

Hi guy's, MS1 V3.0

I'm having an issue with what I thought was the relay board but now I don't think so. I turn the key on and there is no activation of the main power relay on the relay board.

I thought I had a bad trace on the relay board but after close inspection, it looks ok. I now think it's a problem with the MS board. IIRC, at power up, MS tells the power relay to engage and that powers up the board and the FP.

any help to start trouble shooting is greatly appreciated

Thanks

kjones6039 · Post by **kjones6039** » Tue Feb 21, 2017 9:55 pm

toon1 wrote:IIRC, at power up, MS tells the power relay to engage and that powers up the board and the FP.

Not exactly, if I understand you question correctly.. The power relay is controlled by the ignition switch (or other switch for that purpose).
MS controls the fuel pump via the fp relay after the MS is powered up by the power relay.

Do you have a multi meter available to test voltage and resistance?

Ken

toon1 · Post by **toon1** » Tue Feb 21, 2017 10:44 pm

I do have a multi meter.

maybe it is the FP switch transistor. I have power to the relay but it's not activating the FP

I put MS on the stim board a while back and it looked like the FP relay was activating. The FP LED light was going on and then off after 3 seconds.

Thanks again

DaveEFI · Post by **DaveEFI** » Wed Feb 22, 2017 3:14 am

toon1 wrote:I do have a multi meter.

maybe it is the FP switch transistor. I have power to the relay but it's not activating the FP

I put MS on the stim board a while back and it looked like the FP relay was activating. The FP LED light was going on and then off after 3 seconds.

Thanks again

Nothing will work if the main relay isn't making. If it is, the pump relay is only made when MS sees a tach signal. Although it should make for a couple of seconds or so when you switch on.

WillExoIX · Post by **WillExoIX** » Wed Feb 22, 2017 7:36 am

Need to make sure the signal wire to the main relay is actually being triggered. If it's not, then just trace that wire/trace to find the break/problem.

At this point you know the voltage is getting to the relay, now you just need to figure out why it's not triggering.

I personally didn't use the relay board but I would imagine it's design is simple enough to troubleshoot.

Make sure you also don't have the boot jumper in there.
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kjones6039 · Post by **kjones6039** » Wed Feb 22, 2017 8:13 am

I think I would put the MS back on the Stim. That will help eliminate the relay board and may tend to shorten up the troubleshooting process.

As a side note....... I am very distrustful of the MS relay board! I used one on my very first MS project and found it to just create another, unneeded level of complexity. I eventually threw it in the spare parts bin and never looked back. If your MS checks out on the Stim you might even consider ditching it also.

Ken

WillExoIX · Post by **WillExoIX** » Wed Feb 22, 2017 9:25 am

kjones6039 wrote:I think I would put the MS back on the Stim. That will help eliminate the relay board and may tend to shorten up the troubleshooting process.

As a side note....... I am very distrustful of the MS relay board! I used one on my very first MS project and found it to just create another, unneeded level of complexity. I eventually threw it in the spare parts bin and never looked back. If your MS checks out on the Stim you might even consider ditching it also.

Ken

If the entire harness is being rebuilt from scratch the relay board makes perfect sense. Or if the original harness is too destroyed to recover. If not I say use what came with the vehicle/project relay wise.

I just reimplemented what GM designed and added my own extras in the Camaro.

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toon1 · Post by **toon1** » Wed Feb 22, 2017 7:21 pm

Thanks guy's.....I didnt want to add too much info.

The car had been running perfectly on MS for long time. One morning I went to fire it up and noticed the fuel pump didnt turn on. I looked at the relay board and noticed that there must have been something on it because there was a little melting on the top of the relay mount. so there was a short of some sort that happened.After doing some checks I thought I had a bad relay, swapped in a good one and no change.

All the fuses are good( first thing I checked)

Relays are good and swapped them around to verify

If I turn the key switch ON I get 12v through to the relay pole closest to the incoming relay board power. I also get 12v to the top pole of the relay socket that the 12V SW power goes to.

If I jumper from 12Vpower to FP, it runs.

I've put the MS board on the stim and the FP led light will light at power up and then turn off after 3 sec.

Hope this is info helps, I'm stumped

DaveEFI · Post by **DaveEFI** » Thu Feb 23, 2017 2:41 am

I've not used the relay board, but if there were signs of something melting, I'd remove it and check every single track for continuity. You'll find a schematic for it on the MSefi site.

WillExoIX · Post by **WillExoIX** » Sat Feb 25, 2017 8:35 am

DaveEFI wrote:I've not used the relay board, but if there were signs of something melting, I'd remove it and check every single track for continuity. You'll find a schematic for it on the MSefi site.

I concur. If the relay shorted internally or melted via another influence, the 12v could have shorted the FP relay wiring/traces.

Time to trace.

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toon1 · Post by **toon1** » Sat Feb 25, 2017 9:30 pm

WillExoIX wrote:
DaveEFI wrote:I've not used the relay board, but if there were signs of something melting, I'd remove it and check every single track for continuity. You'll find a schematic for it on the MSefi site.

I concur. If the relay shorted internally or melted via another influence, the 12v could have shorted the FP relay wiring/traces.

Time to trace.

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Thanks guy's

A burnt trace is what I initially thought, and still may be the case. After looking at the traces on the RB I can't seem to find anything. There may be a burnt trace that is hidden.

WillExoIX · Post by **WillExoIX** » Sun Feb 26, 2017 5:26 am

A continuity check with your DMM can show you broken traces you can't see.

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toyotaspeed90 · Post by **toyotaspeed90** » Sun Mar 26, 2017 5:43 pm

Late response, but....

It has been a long time since I wired a relay board - but you should note that MS doesn't supply power for a fuel pump and not even a voltage signal. It supplies a ground signal to activate a relay.

So, if you aren't getting 12v at the FP on the RB then the issue could be MS or it could be the relay board.... if you throw the MS on a stim board you can check the fuel pump signal and rule whether it's an MS or relay issue.

Once you know, then you can move forward. My guess is that it isn't MS....

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