CLT & TPS noise
 

So I have been experiencing some of the random RPM spike issues that have been seen by others. I have been researching and getting ready to do the Abe NB mod. Due to this thread:
https://www.miataturbo.net/megasquirt-18/misfiring-while-cruising-seems-get-worse-when-hot-46772/

I looked back at my log and found A LOT of noise in my CLT and TPS. I believe this is related. What is causing this noise and how can I fix it?

Attachment 195611

Try the cap on the boot jumper on the mail board mod. I helped me a lot.

-Raj

Yeah I would like specifics on that mod. I have MS1 and looking thru the info it seems like this is a MS2 fix. Does it install on the daughter board?

You know I was thinking thismorning. ... All 3 of t he signals I have noise on are the ones i am sharing with the stock ecu

...which all share the same ground.

Bingo! My iat has no noise but it is grounded locally I think

Solutions????

The cap is supposed to go across the boot jumper on the main board. I don't know if it will work for MS1.

What size?

try a .1uF, .22uF or .33uF

I'll give it a shot. How does putting a cap across the boot jumper help clean the signal? Won't that essentially short it out?

I put a .22uF. I also have a .22uF and a 3300uF across the 12V coming in.

electronics run on magic.

Good enough answer for me lol

I'm pretty sure they run on smoke.

Every time I let the smoke out of electronics they stop working.

Try grounding the sensors to the MS instead of the stock ECU; what's the stock ECU need an accurate reading for? :D

Haha. The grounds are currently all tied together in the harness. How should I separate them?

AN UPDATE:

-I tried installing Abes NB input mod...it didnt work. I looked over my circuit and it looks fine. I went back to my original circuit and the car started right up.

- Separated stock and MS grounds. Made a better connection... ms has 6awg wire all the way back to the battery ground.

- Installed .22uf cap across boot jumper

I am bumed out the nb circuit didnt work. IDK why. It wouldn't crank, oem tach didn't work, ms tach showed about half of the actual value.

The CAP seemed to work... sorda. I took it for a 5 minute drive getting on boost and bringing it into high rpm. It didnt break up or anything, but the log shows there was still SOME noise. Should I try a different size cap?
-

a larger 3300uF cap fro.m 12v to gnd might help too

Pics please? I'm intrigued by this but I'm a visual learner. :o

I'll post screen shots and pics later

Abe's input circuit will reverse the polarity of the signals. You should change the "Ignition input capture" setting to the inverse of what it is now.

-Raj

Ugh really? Oh well I don't feel like doing it any time soon... Maybe next weekend

does MS1 even allow you to invert the input in the software? I couldnt find it

I don't know if MS1 has that option. I am running a MS2 setup.

yes, you can change from rising to falling edge and vise versa. You should have looked at your composite log while cranking to see what it was looking like.

Me + anger + frustration = lack of patients

I plan on tearing back into it next weekend and I will spend more time diagnosing the issue.

I HAVE CLEAN SIGNALS!!
It is really freaking amazing.

My problem was the stock ECU. I was missing some grounds to it so it was feeding back noise through the MS. I ditched it and went to full standalone and id never look back :)