megasquirt glitch or spike? - Miata Turbo Forum -Boost cars, acquire cats.

Welcome to   Members

MEGAsquirt A place to collectively sort out this megasquirt gizmo

LinkBack Thread Tools
Old 05-01-2010, 10:44 PM   #1
Thread Starter
Join Date: Oct 2009
Posts: 32
Total Cats: 0
Default megasquirt glitch or spike?

OK so I have a megasquirt 1 version 3 that was made and installed by a member on this forum. I keep having this glitch of some sort and my car bucks when this happens while driving. It does it randomly and I can not figure out what is triggering it. I'll be driving at WOT and then randomly it will miss and go crazy for a second then be ok. It is currently tuned map-based because we could not get the TPS to work properly. It is indeed working well now and I am waiting untill I figure this issue out before I get it re-tuned TPS based for more boost.
Setup :
95 1.8 with a turbo setup, dsm 450's with acura resistor box and modded flyback circuit. Toyota COP's.
The following is wired directly to the MS bypassing the factory harness completely:
TPS, Coolant temp, intake temp, & the CAS
the only things still on the factory wiring are the injectors and the coil packs.

Any advice, questions or concerns are welcome and appreciated:

more pics of the datalog are available if need for further analysis.

Last edited by silvertn350; 05-01-2010 at 11:42 PM.
silvertn350 is offline   Reply With Quote
Old 05-01-2010, 11:12 PM   #2
Senior Member
iTrader: (14)
Join Date: Aug 2008
Location: Tinley Park, IL
Posts: 1,488
Total Cats: 0

Are all your grounds clean, tight and all where they're supposed to be? does it have a solid power supply?
lordrigamus is offline   Reply With Quote
Old 05-01-2010, 11:36 PM   #3
Thread Starter
Join Date: Oct 2009
Posts: 32
Total Cats: 0

all 6 grounds from the megasquirt are going to the same point on the chasis. I sanded off the paint and made sure they were clean. Its getting its power from the white/red wire I used this diagram:

All of the grounds in the engine bay seem to be in order. I even supplied an extra from the engine to the chasis. I've been contemplating on adding a few grounds to see if it would clear up the issue.
Maybe something like this:
chasis point that the megasquirt is using to the engine itself
maybe one from the negative of the battery to that same point?

CAS is getting its own ground from the valve cover. Shielded wiring was used from the CAS straight to the MS and the copper inside is getting its ground from the same grounding point on the valve cover. TPS is getting its own ground from the OE grounding point at the front next to the throttle body. Coolant temp is getting its ground from the valve cover as well.
silvertn350 is offline   Reply With Quote
Old 05-03-2010, 01:03 PM   #4
Supporting Vendor
Matt Cramer's Avatar
Join Date: Sep 2006
Posts: 2,143
Total Cats: 41

Looks like a communications glitch, but if you could post the whole log I will be more certain.
Matt Cramer is offline   Reply With Quote
Old 05-03-2010, 04:10 PM   #5
Junior Member
iTrader: (1)
Join Date: Oct 2007
Location: Bay Area, CA
Posts: 105
Total Cats: 0

Both your MAT and your MAP spiked up, what's weird.
Latch is offline   Reply With Quote
Old 05-04-2010, 08:46 AM   #6
Junior Member
Join Date: Jan 2008
Location: Toronto, Ontario, Canada
Posts: 74
Total Cats: -4

Check the connector & harness that the sensors are connected to. It looks like everything was unplugged then there are a couple of spots where a wiggle briefly made a reconnection.
StarGehzer is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 12:25 PM
Any pnp megasquirt for 2001 Big_gumby WTB 0 09-30-2015 03:34 PM
1996 Turbo Build Goldwar DIY Turbo Discussion 2 09-29-2015 09:20 AM
First gen (white) megasquirt pnp 90-93 Miata firmware reflash Johnny Tater MSPNP 1 09-27-2015 12:38 AM
Megasquirt died mid operation psyber_0ptix MEGAsquirt 4 09-22-2015 09:35 AM

glitch, issue, megasquirt, spike, turbo

Thread Tools

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 On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 09:56 PM.