MS2 cranking PW curve? - 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 11-25-2010, 10:20 AM   #1
Junior Member
Thread Starter
 
Join Date: Oct 2008
Location: Manchester, UK
Posts: 274
Total Cats: 0
Default MS2 cranking PW curve?

Regardless of the injectors you're running, surely everyone who has their settings nailed at all temp ranges will have the same looking curve or very similar.

I'd be interested in seeing peoples curves and also what prime pulse figures you guys are running. My hot-start is 100% OEM and although I have no issues with cold starting (even at 0*C) it can sometimes take a little longer to fire up.

I'm using a prime pulse figure of 1ms for all temp ranges. Is anyone using upwards of 1ms as the temps drop off?

Here are my settings, good for 0-96*C starts but starts more quickly when hot. (425cc injectors)

Name:  MS2crankingsettings.png
Views: 25
Size:  31.8 KB
CRAIGO is offline   Reply With Quote
Old 11-25-2010, 10:37 AM   #2
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,441
Total Cats: 199
Default

The problem is 100% syncing and sequential. When the engine is hot, its turning faster, and therefor syncs faster. It takes 3-4 engine turns to sync.
Reverant is offline   Reply With Quote
Old 11-25-2010, 10:44 AM   #3
Elite Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,658
Total Cats: 39
Default

Dunno if this is relevant, but mine takes a lot longer to catch when hot, and when it does it's weak till the idle valve icks in and raises the revs. It's like it's on the cusp of starting, so you keey the starter engaged, but as soon as you 'give up' the car does actually start.

As it does always start I've never been arsed to fix it.

I have asked in the past for batch fire when starting to improve the sync - and thus starting - time but didn't get much of a response.
richyvrlimited is offline   Reply With Quote
Old 11-25-2010, 11:01 AM   #4
Junior Member
Thread Starter
 
Join Date: Oct 2008
Location: Manchester, UK
Posts: 274
Total Cats: 0
Default

aah that makes sense. It also explains why my logs show cranking events without the injectors firing for about a second.

FWIW, I have a similar issue to you Rich, but when cold. The engine starts every single time when cold but does run lumpy after it catches at around 700rpm and then the idle valve kicks in a second later and the revs are pulled up.
CRAIGO is offline   Reply With Quote
Old 11-25-2010, 11:18 AM   #5
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,441
Total Cats: 199
Default

Quote:
Originally Posted by CRAIGO View Post
aah that makes sense. It also explains why my logs show cranking events without the injectors firing for about a second.

FWIW, I have a similar issue to you Rich, but when cold. The engine starts every single time when cold but does run lumpy after it catches at around 700rpm and then the idle valve kicks in a second later and the revs are pulled up.
Issue #2: Notice - when cold - how much % PWM duty you need to sustain your idle. Ie you may need 38% to get 1300rpm at 20C. Go to PWM Idle cranking duty, and set the cranking duty 2-3% higher than the duty you need to retain your RPM. If yu need 38% to retain 1300rpm at 20C, set the cranking duty at 20C to 40-41%C.
Reverant is offline   Reply With Quote
Old 11-25-2010, 12:27 PM   #6
Junior Member
Thread Starter
 
Join Date: Oct 2008
Location: Manchester, UK
Posts: 274
Total Cats: 0
Default

Good stuff Reverant.

I'm just going through the extraEFI idle page too.
CRAIGO is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Another Cast Manifold Corky Bell Prefabbed Turbo Kits 18 11-22-2016 10:01 PM
Need help - Stock Balancer and Fastforward overlay pulleys Frank_and_Beans Supercharger Discussion 13 09-12-2016 09:17 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Got bad Crank Angle Sensor and Random Misfire codes, but runs fine. Greasyman General Miata Chat 2 09-28-2015 11:44 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 09:04 AM.