Intermittent malfunction

[lekman]

My ms1v3, MSnS, does sometimes stop working. The engine stops running (firing) for about one up to two - three seconds. It happened today, the longer time (three seconds) and I noticed that the tach-signal disappeared for that period of time. (I have a separate output for tach) I was planning to pull over when the engine started running again. I will solder in a bulb onto the power supply on the ms-box, so I can determinate if Im loosing the power to the box, but if that's not the problem.... Is this a common phenomena?. I can have the TS attached as much as possible, and do dataloggings....
/Lars

[lekman]

How quickly can the system restart (Reboot) if I actually have short failures in Power feed? Some of the blackouts have been very short....
/Lars

[Matt Cramer]

A data log will give a lot more to go on.

[lekman]

the problem is so rare. I have driven the car now for several days without this phenomena... I have to wait and see....

[Matt Cramer]

You can check for some sorts of noise issues - for example, make sure the MS is solidly grounded to the engine block or cylinder head.

[lekman]

Hello
I have found that the ms doesn’t not re-boot when this happens, but it seem that it fails to pull the fuel pump relay (an as a consequence I don’t get power feed to my hall sensor, hence no tach-signal). Last time I had a total stop, and I managed to start up again, by just forcing the pump relay with my finger. As I see it, I have a poor wire for the pump relay, or that the ms is failing pulling it. Could a poor hall sensor be the cause of that?

/Lars

[slow_hemi6]

You do not supply your hall sensor from the fuel pump relay. It is supplied from the main relay like the MS itself.
See http://www.msextra.com/doc/general/ms2external.html

[lekman]

Im using the stock cable routing for the feed of the hall sensor, since these cables already were there. Im looking at the schematics for the car, and, no, it seems that the pump relay is not involved in the feed for the hall sensor. Perhaps I have a faulty hall sensor then, I suppose that ms don’t pull the pump, if not getting a tach signal? But, its so intermittent. I can drive the car for days, without any problems, and then it can stop suddenly.

/Lars

[lekman]

My intermittent function was caused by the hall sensor giving up. The car ended up being totally dead and a new hall sensor solved the problem.
/Lars