Notices
MEGAsquirt A place to collectively sort out this megasquirt gizmo

Cranking/startup questions (log and msq included)

Old Dec 29, 2011 | 04:34 AM
  #1  
one-niner's Avatar
Thread Starter
Junior Member
 
Joined: Sep 2010
Posts: 80
Total Cats: 1
From: Denmark
Default Cranking/startup questions (log and msq included)

Hi guys.

I actually meant to include a cold start as well but I accidentally did an overwrite of that log. Oh, well - it'll come later, so lets start with the warm startup:

Looking at the log, the thing that worries me the most is dwell. It's set to be 2.5ms both cranking and running (per TSE instructions) but is logged as 5.1 - 5.7ms during cranking and then settles at 2.5 when the engine is running. What's going on? Is there any danger of frying my coils?

Cranking RPM is set to 300 but only logs at around 180. It starts ok'ish when warm but rather reluctantly when cold (I'll do a log later). During cranking, the DIYPNP logs the voltage as dropping to around 9V, which I believe is too low. However, a voltmeter on the battery during cranking says something like 10.5V, which sounds more like it. Any ideas for improving the cranking RPM? Should I consider a new battery?

Cheers,
- Tom
Attached Files
File Type: msl
2011-12-29_08.34.18wamstart.msl (73.1 KB, 140 views)
File Type: msq
Old Dec 29, 2011 | 11:08 AM
  #2  
hornetball's Avatar
Elite Member
iTrader: (4)
 
Joined: Mar 2008
Posts: 6,301
Total Cats: 697
From: Granbury, TX
Default

A fresh battery is important, but also take a critical look at your battery cables. They are long, thin and have a tendency to fray.
Old Dec 29, 2011 | 11:18 AM
  #3  
Braineack's Avatar
Boost Czar
iTrader: (62)
 
Joined: May 2005
Posts: 80,552
Total Cats: 4,368
From: Chantilly, VA
Default

set cranking dwell to 5ms. the dwell increases as battery voltage drops.

but thats not the issue.
Old Dec 30, 2011 | 03:58 AM
  #4  
one-niner's Avatar
Thread Starter
Junior Member
 
Joined: Sep 2010
Posts: 80
Total Cats: 1
From: Denmark
Default

Originally Posted by Braineack
set cranking dwell to 5ms. the dwell increases as battery voltage drops.
I have the TSE kit with the Toyota COP's. The instruction from TSE was to set them at 2.5ms for both cranking and running. Why would I want to set their dwell time even higher at cranking? I'm worried that the increased dwell at startup will damage them. But then again, it makes sense that they charge for longer when the voltage drops - but that long?

I've attached a cold start (4°C / 40°F). Of course it started up no worse than warm on the day I had the PC ready set up to log. Oh, well. I'll attach another when I log a more typical cold start. Either way, the logged cranking voltage and RPM are even lower - around 8 V and 110 - 140 RPM - and dwell time is even higher at around 6 - 7 ms.

- Tom
Attached Files
File Type: msl
Old Dec 30, 2011 | 04:05 AM
  #5  
Reverant's Avatar
Elite Member
iTrader: (10)
 
Joined: Jun 2006
Posts: 6,020
Total Cats: 369
From: Athens, Greece
Default

140rpm does seem a bit low. I would expect around 180rpm on a cold day.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
StratoBlue1109
Miata parts for sale/trade
21
Sep 30, 2018 01:09 PM
Quinn
Cars for sale/trade
6
Oct 23, 2016 07:58 AM
chris101
Miata parts for sale/trade
2
Oct 9, 2015 09:08 AM
The Gleas
MEGAsquirt
3
Oct 1, 2015 09:30 AM


Thread Tools
Search this Thread

All times are GMT -4. The time now is 11:28 AM.