TPS Noise spikes. Not what you expect. Help me! - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to   Members

ECUs and Tuning Discuss Engine Management, Tuning, & Programming

LinkBack Thread Tools Search this Thread
Old 09-16-2011, 10:26 AM   #1  
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
y8s's Avatar
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,050
Total Cats: 441
Default TPS Noise spikes. Not what you expect. Help me!

I have a most idiotic problem.

On my MS3x, I have very VERY brief spikes in my TPS that are significant enough to trigger accel enrichments without touching the throttle.

Essentially the TPS value will go from 0.0 to 0.3 and back to 0 over a very short duration. The actual magnitude could be higher but not caught by the relatively slow datalog. My SDCard logs aren't reliably working right now. I did get some scaled-up screen shots of some logs that show the problem.

If it were constant noise that looked like a sawtooth I could probably fix it more easily. But since it's very infrequent and subtle, it's harder to nail down.

I have already tried decreasing the lowpass filter just before the CPU input for TPS from 700-something Hz to 70-something Hz and it had no effect. I guess a single transient spike doesn't really get filtered out there.

There are no aberrations in the other sensor inputs on the same 5V and GND (CLT, MAT) so that's also odd... and makes me suspect that the spikes are external to the Megasquirt enclosure. I plan to unplug the TPS connector and see if they persist just for funsies.

I have purloined some 3-conductor shielded wire from work in case I need it but I hate to re-wire the factory setup.

Any suggestions on where there might be noise generated or received would be AWESOME. Remember, it's not constant like the patsmx5 thread so I doubt his solution will help me. But maybe it will.

Attached Thumbnails
TPS Noise spikes.  Not what you expect.  Help me!-pw_spikes.png   TPS Noise spikes.  Not what you expect.  Help me!-pw_spikes2.png  
y8s is offline   Reply With Quote
Old 09-16-2011, 12:27 PM   #2  
Supporting Vendor
iTrader: (10)
Reverant's Avatar
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,461
Total Cats: 213

Do you have a datalog where the car is idling?
Reverant is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
1.8 TB/TPS for use with 1.6 wiring Elfering MEGAsquirt 17 12-16-2016 06:44 PM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 12:15 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 10:28 PM
Another Alternator thread ihiryu General Miata Chat 9 09-28-2015 10:22 AM
BMW TPS / P&P TPS for Megasquirt albumleaf WTB 0 09-10-2015 09:28 AM

accel enrichments, megasquirt, noise, tps

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 05:20 AM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.