Megasquirt failure: LEDs flashing, fuel pump relay clicking

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Megasquirt failure: LEDs flashing, fuel pump relay clicking

Postby MargarineOfError » Mon Sep 26, 2016 5:39 pm

Hi everyone,

It seems my Megasquirt has gone bonkers. If anyone can provide some insight as to what failed, I would greatly appreciate it. All opinions are welcome.

Specs:
Pushrod OHV V8 with 4-pin HEI and a 454 TBI unit, Megasquirt II v3 board, controlling fuel only, EGO feedback disabled (monitor only).

Some background:

I built this unit myself in 2008 and it only has around 5,000 miles on it. Everything was working great until about 2 years ago.

Over the past two years or so, there have been problems with the unit once the car warms up. Originally, the signs would manifest 15-20 minutes after the engine reached operating temperature (195*), but that window progressively shortened. During the first year, I dismissed this as a lack of proper tuning or components getting hot on ninety degree days. I didn't think there was a problem.

When started when cold, everything runs fine, but then as soon as the engine warms up, the fuel mixture would get richer and richer until the AFR was 10:1 and the engine could barely idle. It would also stumble and rich misfire. Sometimes turning the car off and on would fix things, sometimes it wouldn't.

I checked the injectors, and they were not leaking.

I then reflashed the firmware, and thought the problem was solved because everything worked fine for a few driving cycles that lasted an hour each. No issues whatsoever.

However, a couple of days ago, I started up the car and let it warm up. This time, the engine started idling rough and the AFRs richened up much sooner than usual - around 180*. I was hitting 9.6 to 10:1 at idle, when I should normally be around 12.8:1 (my cam needs a fairly rich idle)...

What the Megasquirt is doing:
I then turned off the engine, and then turned the key back on to the "run" position and this happenend (please excuse the vertical video - I was in a rush to capture this just in case the problem was intermittent):

https://www.youtube.com/watch?v=X29_9wExqPI

Turn up your volume: that clicking noise you hear is the fuel pump relay - the injectors and injector relay are not making any noise.

I cannot capture a datalog because the Megasquirt will not connect to my laptop.

Also, notice that the clicking slows down the longer the key stays in the run position.

Many thanks for any insight you can provide.
MargarineOfError
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Re: Megasquirt failure: LEDs flashing, fuel pump relay click

Postby Matt Cramer » Wed Sep 28, 2016 6:31 am

OK, with no laptop connectivity, this will be nearly impossible to diagnose. So we should get that fixed first. Are you using a USB adapter or a direct serial connection?
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Re: Megasquirt failure: LEDs flashing, fuel pump relay click

Postby DaveEFI » Wed Sep 28, 2016 6:45 am

Tuner Studio has a logging function. Which shows pretty well everything going on with MS. So as Matt says, you need to get connectivity fixed so you can do a log of the problem.
Rover SD1 3.5 EFI
MS2 V3
EDIS
Tech Edge O2
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Re: Megasquirt failure: LEDs flashing, fuel pump relay click

Postby MargarineOfError » Sun Nov 26, 2017 11:01 pm

Just wanted to post an update.

After many months of diagnosing and tinkering, I was able to solve this issue. It seems that there may be a fundamental design flaw inside the MS box, and NO AMOUNT OF DATALOGGING or connectivity could have possibly caught it or been relevant/helpful in any way whatsoever.

So glad I was able to figure out what was going on and get this sorted out! :yeah!:
MargarineOfError
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Re: Megasquirt failure: LEDs flashing, fuel pump relay click

Postby prof315 » Mon Nov 27, 2017 6:00 am

So what was wrong?
Linfert Performance: Come run up front
92 Corrado 2.0L ABA and Borg Warner EFR 6258 on MS3Pro.
94 Ranger 2.3 Twin Plug on MS2
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Re: Megasquirt failure: LEDs flashing, fuel pump relay click

Postby DaveEFI » Mon Nov 27, 2017 6:57 am

prof315 wrote:So what was wrong?


Be interesting to find out what non of us knew after some 10 years of production? :D
Rover SD1 3.5 EFI
MS2 V3
EDIS
Tech Edge O2
London UK.
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Re: Megasquirt failure: LEDs flashing, fuel pump relay click

Postby prof315 » Mon Nov 27, 2017 12:57 pm

DaveEFI wrote:
prof315 wrote:So what was wrong?


Be interesting to find out what non of us knew after some 10 years of production? :D


Wouldn't it though 8)
Linfert Performance: Come run up front
92 Corrado 2.0L ABA and Borg Warner EFR 6258 on MS3Pro.
94 Ranger 2.3 Twin Plug on MS2
Support the developers!
prof315
Super MS/Extra'er
 
Posts: 2487
Joined: Sun Jan 18, 2009 3:13 am
Location: Melbourne, FL


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