Megasquirt Support Forum (MSEXTRA)

Hi All, I seem to have an very intermittent issue where sometimes as I'm driving along, the MS2 just seems to reboot/lose sync, it happens so fast it's very hard to see what's happening other than I think I can tell it's restarted as ASE kicks in again like I've just started the car. When this happens the car just stumbles for a second and then goes rich while ASE is active, after that it's back to normal.

It doesn't happen very often but I'd just like to know if there's any common causes for this and what I should be looking for? Doesn't seem a massive issue but obviously don't want it to happen when I'm at WOT at high rpm!

Unfortunately I don't have a log, it's that intermittent that it never seems to happen when I am logging! Just my luck! Doh!

Ecu is MS2 V3 running ms2extra 3.3.0b gslender v2.4.3 firmware. Car is a '90 MX5 1600 with ITB's running on the standard coil pack igntion with igniter.

Any suggestions would be great but if logs are needed I'll try and log each drive until it happens again.

Thanks

Managed to get a log of the issue earlier today by change. You can see it at about 758s in the log. If anyone could take a look and let me know what they think would be great.

Thanks very much.

Managed to get a log of the issue earlier today by change. You can see it at about 758s in the log. If anyone could take a look and let me know what they think would be great.

Thanks very much.

I noticed there's substantial noise on the battery voltage trace. This may be causing noise elsewhere. Where is the MS getting power and ground?

Thanks for the reply Matt, it's just connected to the standard loom via a 64 pin loom adapter, so is using the 12V and grounds from the original loom. So it should be the same as a PnP setup?

Are you running low-Z injectors by any chance?

Matt Cramer wrote:Are you running low-Z injectors by any chance?

No High Z, I'm running the red 260/265cc injectors from a MK2 99+ MX5/Miata.

Do you think if I've got something configured wrong it could be causing it if maybe my injector settings aren't correct?
My MSQ file is in this postif it helps?

It happened again at lunchtime today, just stumbled for a split second, ASE kicked in for all of a few seconds and then it carries on merrily on it's way!

Check the CAS connector and wiring. I've seen cars where the harness was falling apart at the connector - quite often, in fact.

Thanks very much, will do and I'll post up the results. I'm pretty sure it's ok as I was looking around there the other day but I'll double-check.

Don't suppose you know the correct injector settings for those injectors do you by chance?

Matt Cramer wrote:Check the CAS connector and wiring. I've seen cars where the harness was falling apart at the connector - quite often, in fact.

Checked the CAS wiring and can't see any issues there, car was running fine before fitting the MS so assume its something to do with the MS setup. Any other ideas please?

robd wrote:Managed to get a log of the issue earlier today by change. You can see it at about 758s in the log. If anyone could take a look and let me know what they think would be great.

Thanks very much.

I've had a look at your logs.

The ECU isn't rebooting or restarting. It is loosing sync. The MAP and various other inputs are still logging with correct values when the sync loss occurs.

There is something wrong with the input from the CAS and like Matt said, it could be related to that.

G

Thanks for the reply, ok, do you think it could be interference on the wires from the MS to the stock loom that I wired in? Or is it more likely a damaged wire or a faulty CAS? If it could be interference, is there any recommendation for wire thickness or insulated wire for the CAS sensor? I've used 16/0.2 wire for everthing on the MS loom which I believe it equivalent to 20g US wire.

Hopefully it's not the CAS itself and I imagine I'd be getting other issues or it would be losing sync more often if the CAS itself was faulty?

Thanks again. Apologies if the above are stupid questions, I'm still very new to all this and learning as I go!

You will need to figure out how to make it reliably reoccur. Until then it is close to impossible to diagnose.

Didn't you use the stock connector? Is it wired into the harness or via a plug?

G

Be sure you can pass this test:

if you unplug MS box and measure resistance from any sensor's (MAT, CLT, TPS) ground to car/engine ground , you should not have continuity.

Oddly it seems to fix a lot of installs

gslender wrote:You will need to figure out how to make it reliably reoccur. Until then it is close to impossible to diagnose.

Didn't you use the stock connector? Is it wired into the harness or via a plug?

G

Ok, that's fair enough but thanks for the reply. I've connected the MS to the stock loom via a short loom and 64 pin plug, so yeah it plugs straight into the stock loom. The only sensors outside the stock loom is the IAT sensor and TPS sensor. So I was wondering if my wiring from the MS to the stock loom could be the issue maybe if I hadn't used the correct grade wire or something silly I'd done!

Peter Florance wrote:Be sure you can pass this test:

if you unplug MS box and measure resistance from any sensor's (MAT, CLT, TPS) ground to car/engine ground , you should not have continuity.

Oddly it seems to fix a lot of installs

Thanks I'll try that and see what results I get.

Matt Cramer wrote:I noticed there's substantial noise on the battery voltage trace. This may be causing noise elsewhere. Where is the MS getting power and ground?

Just a question on this, how I can check for noise on the battery voltage? Is it just a case of checking my logs or could I look for voltage fluctuation at the battery with the car running and at different loads?

Many voltmeters won't respond fast enough - this is in the battery voltage trace on the data log.

Matt Cramer wrote:Many voltmeters won't respond fast enough - this is in the battery voltage trace on the data log.

Thanks, I've added that now and can see its fluctuating between about 13.7 to 14.3 on average. I'll try doing some tests as mentioned previously and see what I find.

Just a stab in the dark, but could a duff alternator or battery cause this?

robd wrote:

Matt Cramer wrote:Many voltmeters won't respond fast enough - this is in the battery voltage trace on the data log.

Thanks, I've added that now and can see its fluctuating between about 13.7 to 14.3 on average. I'll try doing some tests as mentioned previously and see what I find.

Just a stab in the dark, but could a duff alternator or battery cause this?

Maybe, but usually when I see it, it's from bad grounding on harness. Did you make the check I asked?

Peter Florance wrote: Maybe, but usually when I see it, it's from bad grounding on harness. Did you make the check I asked?

Not yet but its on my list to do. Will update with results once I've done it.