no fuel prime

tunnelramefi · Post by **tunnelramefi** » Wed Aug 27, 2014 9:50 am

I have a MS-II 2.88 V3 running a SBC. After disconnecting the battery for a month to fix some unrelated items and reconnecting everything I now have no fuel prime. Checked relays, fuses and power to relay board all ok. Pump works when jumped to battery.
What's up, need to reload firmware?
Thanks Rich

Bernard Fife · Post by **Bernard Fife** » Wed Aug 27, 2014 11:36 am

Rich,

Does the fuel pump relay click closed?

Do you have a stim to test the fuel pump output?

Re-burning the code and your MSQ settings can't hurt. If it doesn't help, you might want to post your MSQ and a datalog.

Lance.

tunnelramefi · Post by **tunnelramefi** » Thu Aug 28, 2014 10:25 am

No click of the relay while installed in the board but test ok when removed and checked with a 12V source. Removed the MS and checked with the stim. Pump led on for few seconds then off. Increased rpm pot, pump led constant. Seems to checkout ok. I am lost.
Thanks Rich

Bernard Fife · Post by **Bernard Fife** » Thu Aug 28, 2014 3:57 pm

Rich,

Post your MSQ and a datalog of a power up, that will help us eliminate some possibilities.

But to eliminate one thing that trips people up on the fuel pump, the Megasquirt supplies a GROUND for the relay, not 12V. So can you verify tht you have 12V to one end of the relay coil, and MS's FPump pin is connect to the other end of the relay coil?

Lance.

tunnelramefi · Post by **tunnelramefi** » Fri Aug 29, 2014 10:28 am

I pulled out the MS and the relay board and applied 12v to the batt pin and grounded the ground pin. I then jumped the batt pin and the switched batt pin. No click of the power relay. I don't see any evidence of over heating or burns in the board traces.
Thanks Rich

tunnelramefi · Post by **tunnelramefi** » Tue Sep 02, 2014 12:24 pm

Lance,
I have checked all I know to check over the long weekend . Could the problem be the relay board circuit breakers?
Thanks Rich

Bernard Fife · Post by **Bernard Fife** » Wed Sep 03, 2014 7:20 am

Rich,

Post your MSQ and a datalog of a power up, that will help us eliminate some possibilities.

Lance.

tunnelramefi · Post by **tunnelramefi** » Wed Sep 03, 2014 10:54 am

Lance
How do I power up the MS? With the stim? These is no power thru the relay board. Did check the circuit breakers for continuity-they check ok.
Thanks Rich

trakkies · Post by **trakkies** » Wed Sep 03, 2014 2:53 pm

I'd remove the daughter board and apply 5v from the proto area to Pin 33 of the socket. Then power up the MS with everything plugged in. The fuel pump should now run. This tests the entire chain. If the pump runs, the problem is with the software or daughter board.

kjones6039 · Post by **kjones6039** » Wed Sep 03, 2014 3:04 pm

tunnelramefi wrote:With the stim?

Certainly.... If you have one! That would be the easiest way to accomplish trakkies suggestion also. (IMO of course)

Ken

tunnelramefi · Post by **tunnelramefi** » Thu Sep 04, 2014 8:33 am

Hey guys
Now I am really lost. I ran the MS with the stem connected and all the leds checked ok. I have no power at the relay sockets on the relay board. Does MS control incoming voltage?
Thanks Rich

kjones6039 · Post by **kjones6039** » Thu Sep 04, 2014 9:16 am

tunnelramefi wrote:Does MS control incoming voltage?

In a word.... no (if I understand your question correctly)

I have no power at the relay sockets on the relay board.

Some clarification here, might help. How are you testing for this voltage?

If the MS is working on the Stim, your issue is in the Relay Board itself. Did you assemble it yourself or buy it already built?

Did you follow trakkies suggestion above?

How are chances of posting pics of both sides of the board?

Ken

EDIT: Another reason why I prefer to not use the Relay Board.... but that's just me..........

tunnelramefi · Post by **tunnelramefi** » Thu Sep 04, 2014 9:53 am

Ken
I assembled the relay board, stem and the MS. I removed the relay board from the car and connected a small 12v battery to the 12v pin. I have 12v to one side of the main fuse but no voltage to any of the relay sockets. The 25a fuse shows continuity. All was working before I pulled the heads to fix an oil leak.
Rich

kjones6039 · Post by **kjones6039** » Thu Sep 04, 2014 10:08 am

I removed the relay board from the car and connected a small 12v battery to the 12v pin.

And you connected the other side of the battery, where?

I have 12v to one side of the main fuse but no voltage to any of the relay sockets.

Measured from what point?

Not trying to be a smart a$$, Rich. Just checking for the obvious things first!

Ken

tunnelramefi · Post by **tunnelramefi** » Thu Sep 04, 2014 10:49 am

Ken
To the ground post on the relay board. Checking with my volt meter, black lead on the ground post, there is no voltage at any of the relay sockets. Perhaps to expedite this, please call me at 915-549-3813
Rich

kjones6039 · Post by **kjones6039** » Thu Sep 04, 2014 4:27 pm

I will have to dig out an old relay board tonight and refresh my memory.

On the other hand, there are any number of guys here that can do this off the top of their heads. I will get back to you if one of them doesn't chime in soon.

Ken

tunnelramefi · Post by **tunnelramefi** » Fri Sep 05, 2014 9:58 am

Ken
Any luck finding a relay board? I still can't get any of the relays to click when installed in the board. I am sure there is some procedure to follow to check the board.
Rich

trakkies · Post by **trakkies** » Fri Sep 05, 2014 10:24 am

tunnelramefi wrote:Ken
Any luck finding a relay board? I still can't get any of the relays to click when installed in the board. I am sure there is some procedure to follow to check the board.
Rich

Using the schematic, check continuity between all grounds. And between the +12v feed to all points it shows in the diagram. It's pretty straightforward device.

tunnelramefi · Post by **tunnelramefi** » Sat Sep 06, 2014 8:54 pm

Trakkies, Lance, Ken, and
all those that have responded to my relay problem please accept my thanks and take note. I checked all grounds for continuity (underside of the board). All checked ok. All power feeds (top of the board) check out except one of the main power relay sockets. The trace from this one socket goes right to the 12v switched pad and feeds all the other relays. Checked ok for continuity where the pin sticks out of the bottom of the board but not on top where the relay blade fits the base. Break out the cheaters and magnifying glass. There is a break in the trace under the relay socket base. I think trying to unsolder the socket base and repair this is more trouble than its worth. Did not know it was quite that fragile. It's mounted under the seat and the car might have 5 miles on it. I guess I will replace it and hope for fuel prime. I may be back asking novice questions.
Thanks for the help
Rich

trakkies · Post by **trakkies** » Sun Sep 07, 2014 12:46 am

If there's a break in a PCB track that you've proved and seen, not too difficult to fix. Get some tinned single strand copper wire. Fuse wire can be an easy source of this. Scrape the solder resist off the track for about 1/2in either side of the break and solder the wire across the break. If the break is close to where the relay pin sticks out of the PCB, wrap it round the pin one turn. Use fuse wire of at least the rating of the maximum load on the circuit.

Is the track burnt? If so, it sounds like you had a short somewhere. Might be worth adding a suitable fuse on the input to the unit to prevent it happening again.

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