Turbo Grand Prix 3500 swap

[Jonpro03]

i posted all the important bits already. what exactly are you looking for?

it's a waste-spark system that uses the PCM to control when the coils fire and the ICM just carries out those actions/commands. dwell is likely controlled via ECM pulse length as well.

Well, I can't find anything in megasquirt that reads long and short pulses that the lx9 reluctor puts out. I did however find lots of information about decoding crank signals and modifying them for the megasquirt to understand which is typically used in coil over plug setups.

I am just trying to figure out if i can use this system to read the two crank signals that the cps puts out and give the megasquirt a signal that's not long/short.


A local friend/mechanic had an idea to get the old distributor that was used on the motors and use the variable reluctor signal that was outputted by them.
Thoughts?

[robertisaar]

i posted all the important bits already. what exactly are you looking for?

it's a waste-spark system that uses the PCM to control when the coils fire and the ICM just carries out those actions/commands. dwell is likely controlled via ECM pulse length as well.

[Jonpro03]

Robert are you able to pull up information on the LX9's ignition system? I'll take any info you can find.

I think it's waste spark coil on plug setup, just obviously not cop

[Jonpro03]

There is a ray of hope:

From: http://www.msextra.com/doc/ms2extra/...l.htm#features

I found this

Coil on plug: As above, but additional code is required to decode the trigger wheel.

There is hope yet...

[Jonpro03]

Here is what I can find about compatible reluctor wheels.

http://megamanual.com/ms2/wheel.htm

http://www.megamanual.com/megatune.htm#si - the Ignition settings and the Trigger wheel setting sections


This is the section I was interested in

The trigger wheel settings are:

* Trigger Wheel Teeth (No_Teeth): is the nominal (include missing) teeth for wheel decoding. (0=no wheel decoding).
* Missing Teeth (No_Miss_Teeth): Number of consecutive missing teeth.
* Skip Teeth (No_Skip_Teeth): Number of teeth (between tach pulses) to be skipped. You must create the same number of 'tach' signals as you want ignition events. On a four cylinder four stroke engine, this is two per revolution. Suppose it has a 60-2 wheel. What you need to have happen is for MegaSquirt-II to 'skip' a certain number of teeth so the only the right number of teeth are counted as 'tach signals' per revolution. Since we have determined the number of tach signals we want is 2, we need to skip 60/2 = 30 teeth. For a eight cylinder 60-2, we need 4 ignition events per revolution, so we set skip teeth to 60/4 = 15. And for an eight cylinder 36-1 wheel, we would set skip teeth = 36/4 = 9.
* Delay Teeth (Delay_Teeth): Number of teeth to delay after 1st tooth after the missing teeth before 1st tach synch declared. You get synch as soon as you detect "first real tooth after the missing tooth". If that tooth is at TDC when it is detected, then there is 0 delay. If TDC doesn't occur until the next tooth is detected, then there is a delay of one tooth, and so forth.

[robertisaar]

jon, the 3400 ICMs(LA1 at least, i don't know if the last iteration of them used it or not) read the good old 7X reluctor that's been used in all of the 60V6 MPFI applications up until the 3500 came around and messed it all up.

then it sends a 3X signal to the ECM, which determines engine speed, which is all it needs for batch-fired injectors and waste-spark.

[bszopi]

Does anybody have a diagram of the lx9 trigger wheel? I have to figure out how to make megasquirt read the signal it's putting off. Does it have a notch every 6 degrees except for 2 to mark tdc or something like that?

Trying to find a picture of it, but you won't be able to use it with MS. It is a coded trigger, so each cylinder is a different pattern. Ok, here it is...



Here is a good thread discussing the trigger: http://60degreev6.com/forum/showthre...+crank+trigger

The ignition control module from a 3400 requires a 7x signal doesn't it?

Yes

[Jonpro03]

Does anybody have a diagram of the lx9 trigger wheel? I have to figure out how to make megasquirt read the signal it's putting off. Does it have a notch every 6 degrees except for 2 to mark tdc or something like that?

The ignition control module from a 3400 requires a 7x signal doesn't it?

[CNCguy]

The LX9 trigger wheel is unique and I don't know of anything that will work with it except the stock ECM. The good old DIS system with the 7x trigger is hard to beat. Simple and reliable.

A batch of trigger wheels where shipped to WOT-Tech yesterday for those in need.

Thanks for the plug John. The new internal wheels require removal of the crank but they can be installed by the owner without being sent here. The install procedure is to mark the crank with a center punch, remove the old rings, heat the new ring to 450 in your Easy Bake oven, drop in on the crank, align the marks and let it cool.

[Driver_10]

Mark at TCE just got through fitting my 3500 crank with an internal relucutor wheel. He made a run of about 15 wheels in all I think. You may want to consider sending your crank to him and get it fitted with a wheel also. Then you can use a 95 Camaro ICM and then be able to use the megasquirt.

Its a bit more expensive then using the external wheel because you will have to remove and send the crank to a shop unless you have a means of aligning the crank position prior to mounting (hence the reason I sent my crank off to TCE). It may be just as good to wait on the external trigger.

Its just an idea that Im tossing out there for concideration if you need options.

[Jonpro03]

Ya, I don't think megasquirt is going to run that.

[robertisaar]

whoa, new ICM is WAY different in terms of controls.... it looks like the crank position sensor is directly connected to the PCM, not through the ICM like the older ones... the newer PCM also individually controls the coil packs, instead of supplying a signal to the ICM for it to control them.

[robertisaar]

depends.... the way it worked with the old system was that the ICM read all 7 notches and sent a pulse to the ECM 3 out of the 7 times(once at the +1 notch(or was it at the normal notcth before/after it?) and then two other times when every other notch passed.

with the newer ones, i'm not sure what kind of signal they send... i may be able to look it up.

[Jonpro03]

Is it compatible with the old system?

Does it require a different set of inputs?

[robertisaar]

i believe the new style is a "quick sync" ICM. compared to when the old style had to rotate potentially 360* before there was a spark event(to find notch 7), the newer style does it in less than 120* IIRC thanks to the coded wheel.