Another reset problem..

[mkehler]

I went through all the 'reset' posts... haven't solved mine yet though. I get a lot of resets at low rpms/low speeds (every 5 to 10 seconds). Once I get up to speed..they don't happen as often (once every 30 seconds or minute). They DON'T happen at all when the car is not moving...I can rev the engine up and down as much as I want, no resets. Only when its driving / under load.

All the posts on this have me kind of confused...where should I start?

- ms1 pcb3, new install
- Extra code 29s (was running 29q2, went to 29s but didn't make a difference)
- 1 vb921 driving MSD Blaster II coil. Cranking dwell 4.0, running 3.2, discharge .1
- VR sensor checked for polarity. using factory shielded cable
- re-did MS grounds, all going to common point. Redid power as well.
- using (new) resistor plugs

I'll attach my msq and datalog. Note due to all the resets it only has a few minutes of tuning/tweaking on it. If anyone can point me in the right direction for troubleshooting this.... well...I'd be gratefull

BTW, for some reason the datalog file reads '029q'. Not sure why..but its definitely 029s. The msns-extra.ini 029s file still has its signature as 029q... well, I guess thats why then!

thanks!
Matt

[mkehler]

Tried playing with the running dwell, no success. Any ideas on where to start?

thanks
Matt

[Kev]

I'm not going to help much I'm afaraid, I'm having a similar problem that's causing me great frustration.

I was advised to try moving the earth return from the coils away from the other earths. This may have helped a bit but it didn't cure it om mine.

The fact that yours only does it under load suggests an HT issue, AFAIK you need more energy to drive the spark under load hence a higher HT voltage is seen just before it sparks. Therefore make sure you've got really good earth strap(s) from the block or even better the heads to the frame.

On mine I got an improvement by reversing the signal wires from the VR sensor and also by getting the gap as small as possible.

hope this helps but I think there may be a fundamental problem with this design that so many people are having the same issue.

Kev

[shaodome]

Where is the VB921 pin 3 ground at? Stock MS groundplane?

[mkehler]

Yep, vb921 ground is stock as per instructions.

And I know I'm gonna feel stupid once someone tells me...but what is "HT"?

I'll have another chance to work on it tommorow a bit hopefully...just gotta figure out a plan of attack to make the most of my time. Any help?

thanks
Matt

[jsmcortina]

HT is "high tension" as in the 30kV in the spark plug leads.

Make sure you have the 330R resistor installed between the CPU and the VB921. Possibly try increasing it to say 1k (like MS2 uses.)

Try fitting a "stereo" filter or big capacitor on the power input to the Megasquirt.

James

[mkehler]

Thanks James. Yep, I have the resistor in place. I can just add a 2nd 330 inline as well for testing purposes correct? I don't think I have any 1k ones lying around.

I'll dig up a stereo filter as well. Hopefully that does it and I can take the car out for a drive this weekend.

thanks
Matt

[hobieboy]

Are you using resister plugs? Maybe that would help too...

[mkehler]

Success!

Just an update, I ran a 22uf cap off the coil, and the resets have all but stopped (22uf is all the local electronics place had). So since that seems to have done it, I'll go find the more weather resistant unit from a Ford and should be good to go.

My o2 sensor reading seems to totally disapear once in a while, and I still get the occasional "reset", which I think is actually power related; I think its a bad connection somewhere, as it only happens over *hard* bumps (the car has coilovers with short harsh springs, and the driveway off our shop looks like a minefield for 2 blocks

Does anyone have the Ford 25uf cap part number from the EDIS units? I can get it for cost, and it would save me a trip to the far-off junkyards.

thanks guys
Matt