I'm dense. Someone please explain how to calculate triggers

Post by **jsmcortina** » Wed Jun 28, 2006 5:47 am

The triggers spreadsheet has your numbers in it.
If you are getting kickback from the starter during cranking then you are too advanced.

I find on first startup it is easier to run timebased cranking as you have only one series of numbers to play with.

So make sure trigger return A,B,C are all zero and you have timebased cranking set.

Start with those numbers and a 60deg trigger. If you get kickback then try 65deg trigger (+Burn) then 70, etc. up to 85.

If/when you get it started then use your strobe to confirm the timing and set the correct trigger angle. e.g. set the "fixed angle" to 15 and adjust the trigger angle until the strobe shows 15deg. Then reset the fixed to -10.

James

Jon k · Post by **Jon k** » Wed Jun 28, 2006 5:51 am

jsmcortina wrote:The triggers spreadsheet has your numbers in it.
If you are getting kickback from the starter during cranking then you are too advanced.

I find on first startup it is easier to run timebased cranking as you have only one series of numbers to play with.

So make sure trigger return A,B,C are all zero and you have timebased cranking set.

Start with those numbers and a 60deg trigger. If you get kickback then try 65deg trigger (+Burn) then 70, etc. up to 85.

If/when you get it started then use your strobe to confirm the timing and set the correct trigger angle. e.g. set the "fixed angle" to 15 and adjust the trigger angle until the strobe shows 15deg. Then reset the fixed to -10.

James

Thanks james - I guess I need a more confident approach. Can you explain the difference between timebased as opposed to having return values? What do those return values even do?

The part about setting fixed angle to 15 and adjusting trigger angle until strobe shows 15, that means I need an adjustable light, correct?

Peter Florance · Post by **Peter Florance** » Wed Jun 28, 2006 5:53 am

Yes, that's pretty much it.

It helps to have a lot of older car experience where timing was always adjustable and needed to be set.

Right, James?

Peter Florance
First Fives.Org - The E12 Registry
1981 Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
1981 US BMW 528i "Repo Car"
http://www.firstfives.org
mailto:peter@firstfives.org (peter@firstfives.org)
ssr# 284

From: jsmcortina [mailto:jsm@jsm-net.demon.co.uk]
Sent: Wednesday, June 28, 2006 8:48 AM
To: megasquirt-mss@msefi.com
Subject: I'm dense. Someone please explain how to calculate triggers

The triggers spreadsheet has your numbers in it.
If you are getting kickback from the starter during cranking then you are too advanced.

I find on first startup it is easier to run timebased cranking as you have only one series of numbers to play with.

So make sure trigger return A,B,C are all zero and you have timebased cranking set.

Start with those numbers and a 60deg trigger. If you get kickback then try 65deg trigger (+Burn) then 70, etc. up to 85.

If/when you get it started then use your strobe to confirm the timing and set the correct trigger angle. e.g. set the "fixed angle" to 15 and adjust the trigger angle until the strobe shows 15deg. Then reset the fixed to -10.

James

My Success story http://www.msefi.com/viewtopic.php?t=8008
MS1/Extra at: http://megasquirt.sourceforge.net/extra

This post is at: http://www.msefi.com/viewtopic.php?p=128020#128020

Posted by email.

Post by **jsmcortina** » Wed Jun 28, 2006 6:01 am

No need for an adjustable light, a cheap and cheerful one is fine. If you do get a fancy light you need to ensure it is compatible with wasted spark.

James

Jon k · Post by **Jon k** » Wed Jun 28, 2006 6:03 am

jsmcortina wrote:No need for an adjustable light, a cheap and cheerful one is fine. If you do get a fancy light you need to ensure it is compatible with wasted spark.

James

Are "cheap and cheerful" lights intrinsically compatible with wasted spark? So cheap and cheerful implies no advance?

Peter Florance · Post by **Peter Florance** » Wed Jun 28, 2006 6:09 am

If he uses a standard light, he'll need a known angled reference spot on his harmonic balancer, won't he?
Years ago I had 0-20 degrees marked on mine.

Maybe he can just paint a known tooth (12 or 18 degrees) and strobe against timing cover pointer

Peter Florance
First Fives.Org - The E12 Registry
1981 Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
1981 US BMW 528i "Repo Car"
http://www.firstfives.org
mailto:peter@firstfives.org (peter@firstfives.org)
ssr# 284

From: jsmcortina [mailto:jsm@jsm-net.demon.co.uk]
Sent: Wednesday, June 28, 2006 9:02 AM
To: megasquirt-mss@msefi.com
Subject: I'm dense. Someone please explain how to calculate triggers

No need for an adjustable light, a cheap and cheerful one is fine. If you do get a fancy light you need to ensure it is compatible with wasted spark.

James

My Success story http://www.msefi.com/viewtopic.php?t=8008
MS1/Extra at: http://megasquirt.sourceforge.net/extra

This post is at: http://www.msefi.com/viewtopic.php?p=128029#128029

Posted by email.

Post by **jsmcortina** » Wed Jun 28, 2006 6:11 am

My el-cheapo light has a voltage supply and Xenon tube with a bit of spark plug wire wrapped around it. No clever gauges or knobs.

An inductive type would be nicer but you must ensure it is wasted spark compatible.

How did you check the timing when running wasted COP?

James

Post by **muythaibxr** » Wed Jun 28, 2006 6:12 am

a cheap light just flashes whenever there's a spark...

An adjustable one has some logic in it to delay the flash based on what you have the dial set to.... I think usually those types of lights expect the spark to happen lest often (every 720 degrees on a 4 cyl)... but wasted spark fires 2x more often, so the timing light will change the time when it flashes accordingly, but wrongly.

Just get the cheap light, the adjustable one doesn't really help.

ptegler · Post by **ptegler** » Wed Jun 28, 2006 9:22 am

just add a second crank position sensor to place the MS
sensor exactly where needed for best results.

ptegler

On Wed, 28 Jun 2006 05:10:41 -0700
"Jon k" <jkensy@comcast.net> wrote:
> Guys - what should I do here?
>
> The thing that troubles me is that AEM EMS, Tec3-R,
>etc., all are able to run on the stock crank wheel and
>stock CPS position - am I not going to be able to do this
>with MS? Please help I really want to get this car
>finished... here is why:
>
>
> _________________________________________________________
> This post is at:
> http://www.msefi.com/viewtopic.php?p=128009#128009

Paul Tegler
ptegler@cablespeed.com
Posted by email.

ptegler · Post by **ptegler** » Wed Jun 28, 2006 9:26 am

he starter kick back is telling me you simply have the
settings wrong and a plug is firing too early or not where
you think it is.

A wasted spark, and a cop setup should/can be wired almost
identially. Dwell settings needed arebased on the coil
itself and almost nothing else.

ptegler

On Wed, 28 Jun 2006 05:36:38 -0700
"Jon k" <jkensy@comcast.net> wrote:
>
> jsmcortina wrote:
> Could you explain why the wasted COP didn't work (in
>detail) and why you think you need different trigger
>settings for wasted COP compared to wasted spark.
>
> You had working trigger settings didn't you ? so just
>use them - the SAME ones because you are still running
>wasted spark.
>
> The wheel and sensor do NOT need moving. Plenty of
>people have got oem 60-2 working just fine and nobody has
>moved their wheel.
>
> James
> (end of quote)
>
>
> The coil on plug didn't work, I believe because not only
>was the dwell probably not right (i changed it around a
>lot!) but it seems like I was getting bad starter
>kickback. I want to run the GM coil pack for now so I
>can at least eliminate variables caused by the COPs. I
>guess I will just try those numbers again, but it made
>for some nasty noises when I cranked the car last time.
> _________________________________________________________
> This post is at:
> http://www.msefi.com/viewtopic.php?p=128015#128015

Paul Tegler
ptegler@cablespeed.com
Posted by email.

Post by **jsmcortina** » Wed Jun 28, 2006 9:30 am

ptegler wrote:just add a second crank position sensor to place the MS
sensor exactly where needed for best results.

The crank sensor DOES NOT NEED MOVING.

Jon needs to buy a timing light and find out what is actually happening.

James

ptegler · Post by **ptegler** » Wed Jun 28, 2006 9:48 am

Jon K startd this thread with me via the private messaging
system on this board. He originally was asking me about my
GM coil setup with the VB921's mounted in the bottom of
the assembly. I suggested he move the conversation to the
main board...(where we are now)

I didn't realize the background of what he was doing as it
was never brought up. Just Q's about the coil setup I was
using.

Correct...and I agree totally with James. Whatever
trigger positons you were using before should still work.
The MT prog is flexible enough to let you fire it almost
anywhere needed. I was under the impression from the post
that you could not get the 'stock' postion stuff to work
with the GM coil setup. That config vs a cop config, can
be wired up identically. you'd simply be firing two cop
coils at the same time.

As already mentioned.... any old timing like works just
fine. The inductive pick up type is best...not the type
you need to put in line with the plug and wire. Yes...
you'll get two strobes per cyle with the wasted spark, as
compared to normal, but it doesn't make it any harder to
see a timing mark on the crank. I have my TDC as well as
the original normal idle (non ms - oem setup) timing marks
painted onto the crank to make them easy to see. I've
since added two more marks around the pulley. I can now
quite literally put my timing light on ANY lpug wire and
see the timing postiion.

I too was geting a kick back...until I finally got the
right coils firing in the right order, at the right crank
angle. now its rock solid and right where expected.

ptegler

It's all a matter of knowing where your marks are compared
to when the spark being fired.

ptegler

On Wed, 28 Jun 2006 09:30:19 -0700
"jsmcortina" <jsm@jsm-net.demon.co.uk> wrote:
>
> ptegler wrote:
> just add a second crank position sensor to place the MS
> sensor exactly where needed for best results.
> (end of quote)
>
> The crank sensor DOES NOT NEED MOVING.
>
> Jon needs to buy a timing light and find out what is
>actually happening.
>
> JamesMy Success story
>http://www.msefi.com/viewtopic.php?t=8008
> MS1/Extra at: http://megasquirt.sourceforge.net/extra
> _________________________________________________________
> This post is at:
> http://www.msefi.com/viewtopic.php?p=128073#128073

Paul Tegler
ptegler@cablespeed.com
Posted by email.

Jon k · Post by **Jon k** » Sat Jul 01, 2006 9:27 am

Ok guys - I cut my spark plug wires, crimped, all set. I went out and bought a timing light from autozone, its an Actron (i think is the name) with advance. It is the inductive type. I had a gift card so I figured I'd get one with advance for future projects. Sound good?

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