Revving on its own. - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 07-08-2008, 12:49 AM   #1
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default Revving on its own.

With a ton of help from the_pipefather my MS is up and running. There is one problem we couldn't figure out. Sometimes I will start the car and it will rev from 1k-2k up and down up and down. Other times it will go about a 1/2 mile and start doing it. When it does that it drives normal and everything, it just revs up and down. So far there is no pattern it is just random. When it does it I can just turn off the car and restart and it is fine.

I did some research and found it could be a vacuum leak or a faulty TPS. I have double checked that it is not a vacuum leak, and if it was I think it would always happen. I'm still on the 5 speed on/off TPS. I will be putting in a VTPS as soon as I can get one.

This happens maybe 1 out of 5 starts, so it is pretty annoying. My IAT sensor is right before the throttle body, is that poor placement? Any ideas?
miataspeed1point6 is offline   Reply With Quote
Old 07-08-2008, 01:03 AM   #2
Senior Member
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

Run HR code.
wes65 is offline   Reply With Quote
Old 07-08-2008, 01:05 AM   #3
Senior Member
iTrader: (5)
 
Join Date: Nov 2007
Location: Troy, MI
Posts: 860
Total Cats: 13
Default

It IS running HR10g code. it can't be either of those because i'm running a different TPS and a different IAT, yet the same thing happens to my car.
The_Pipefather is offline   Reply With Quote
Old 07-08-2008, 01:12 AM   #4
Senior Member
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

Hmm.. interesting. Well tell me if you figure it out because actually mine does it to but it didnt on hr code. Now that i am back to low res, it does it.
wes65 is offline   Reply With Quote
Old 07-08-2008, 02:15 AM   #5
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

Mine did that when I had the Recovery Speeds in Idle Control Continued set too quick.
Joe Perez is offline   Reply With Quote
Old 07-08-2008, 07:45 AM   #6
Junior Member
 
Join Date: Sep 2007
Location: Brisbane, Australia
Posts: 112
Total Cats: 0
Default

Mine does it too when cold and sometimes when warm too, with it set to steady no less. Though mine has some other issues, including a nb manifold/idle valve and fairly lumpy cams...
zoomzoom is offline   Reply With Quote
Old 07-08-2008, 08:42 AM   #7
Senior Member
iTrader: (1)
 
Join Date: Sep 2007
Location: Trenton, NJ
Posts: 1,125
Total Cats: 0
Default

I had this problem too. It turned out to be the IAT sensor heat-soaking. Paul adjusted some settings for me and its been running perfect since.
ArtieParty is offline   Reply With Quote
Old 07-08-2008, 09:04 AM   #8
Junior Member
 
Join Date: Sep 2007
Location: Brisbane, Australia
Posts: 112
Total Cats: 0
Default

Quote:
Originally Posted by ArtieParty View Post
I had this problem too. It turned out to be the IAT sensor heat-soaking. Paul adjusted some settings for me and its been running perfect since.
Pretty sure thats not the case with mine, it is still N/A and IAT sensor is only in a bit of pvc pipe
zoomzoom is offline   Reply With Quote
Old 07-08-2008, 09:08 AM   #9
Senior Member
iTrader: (1)
 
Join Date: Sep 2007
Location: Trenton, NJ
Posts: 1,125
Total Cats: 0
Default

What are the intake temps when it does this? Do you have a WBO2? Have you noticed that when it does it, its going really lean?

My car is NA right now too... until Tim finishes the AbsurdFlow manifold.
ArtieParty is offline   Reply With Quote
Old 07-08-2008, 09:46 AM   #10
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,899
Total Cats: 1,792
Default

gotta be an idle valve thing.
Braineack is offline   Reply With Quote
Old 07-08-2008, 11:19 AM   #11
Junior Member
 
Join Date: May 2008
Location: So Cal
Posts: 47
Total Cats: 0
Default

OR TPS...my Link was doing the same thing and it turned out to be the TPS...tried cleaning, waiting to see how it works now...might need new one.
Lincoln Terns is offline   Reply With Quote
Old 07-08-2008, 12:28 PM   #12
Senior Member
iTrader: (5)
 
Join Date: Nov 2007
Location: Troy, MI
Posts: 860
Total Cats: 13
Default

is it possible for you to log this when it happens so we can change the recovery settings to match the rpm oscillations?

These are the settings we are using right now:

Deadband : 50 rpm

Upper limit: 280 rpm

Lower limit: 100 rpm

Fast recovery: 15

Slow Recovery: 100

Closure Speed: 2

Startup Delay: 2
The_Pipefather is offline   Reply With Quote
Old 07-08-2008, 04:09 PM   #13
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

Quote:
Originally Posted by ArtieParty View Post
What are the intake temps when it does this? Do you have a WBO2? Have you noticed that when it does it, its going really lean?

My car is NA right now too... until Tim finishes the AbsurdFlow manifold.
Not sure of intake temps, but AFR is normal for whatever rpm the engine is at(I have an LC1).

Quote:
Originally Posted by The_Pipefather View Post
is it possible for you to log this when it happens so we can change the recovery settings to match the rpm oscillations?
I can try getting my laptop to link up. It happened last night on my way home. The injector settings are working, it started right back up.
miataspeed1point6 is offline   Reply With Quote
Old 07-08-2008, 04:29 PM   #14
Elite Member
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default

I should try to adjust the recovery speed, I think thats what causeing mine.
cardriverx is offline   Reply With Quote
Old 07-08-2008, 04:37 PM   #15
Elite Member
iTrader: (7)
 
samnavy's Avatar
 
Join Date: Apr 2006
Location: VIRGINIA BEACH, VA
Posts: 6,020
Total Cats: 175
Default

Mine does the same idle-bouncing with MS as it did with the stock ECU. If messing with the idle recovery doesn't help, I can bet you it's the IAC going bad as it eventually does on almost every Miata.

Head over to m.net and search "idle droop" in the NA/NB forums. There's an easy way to clean the passages and test the voltages to see how healthy the unit is. A new one is like $350 or you can get one off a parts car for cheap... or you can just deal with it. Mine's done it for 30k miles and I don't even notice it anymore.

Additionally, how would one go about adjusting the IDLE RECOVERY settings. What does each one of those settings do?

Last edited by samnavy; 07-08-2008 at 04:38 PM. Reason: .
samnavy is offline   Reply With Quote
Old 07-08-2008, 04:45 PM   #16
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,899
Total Cats: 1,792
Default

maybe one of your screws on your butterfly valve is missing.... oh god i fail.
Braineack is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Car not starting any help appreciated bruss MEGAsquirt 1 08-31-2015 11:45 AM
Whats the highest revving production engine? Saml01 Insert BS here 23 02-25-2009 12:28 AM
Constant Revving at ~2000rpm... momo182 Engine Performance 3 12-06-2008 09:51 PM
turbo miata revvs at full throttle and doesn't accel. - seems to hold boost thought?! davechaletzky Prefabbed Turbo Kits 15 10-12-2007 12:57 AM


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 Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:36 AM.