FAST cam sync signal?

[KendallF]

Can anybody tell me exactly what a FAST ECM needs to sync the #1 cylinder, as far as signal? I know the base angle is adjustable...I am building a custom front cover for my motor, and was thinking it'd be nice to eliminate the cam sensor entirely. The 3800 gets a cam sync signal from a magnet on the cam timing gear; I was wondering if I could make that work.

Any input?

 

[bruce]

Why not look at the Fast-Start dampner?.
Uses the 3x24 set of rings on the dampner, and use the dual element crank sensor. The pinout I looked at had the same module wiring as a GN module.

It seems like a even cleaner deal.

 

[Craig Smith]

Kendall, are you using a bank to bank system or a sequential system? A B2B system will not need a cam sensor input.

If you can tell me the part number of your ECU, I'll tell you exactly what you need and how to get it.

 

[KendallF]

Craig, I have the B/B, wideband...but it still needs a cam sensor input to sync the module, as somebody pointed out in another thread recently. Bruce, I like your idea...would this screw up the ESC signal to the ECM?

 

[Craig Smith]

So much for my bold claim... I'm not sure how the cam sensor and the ignition module work together. Sorry.

 

[bruce]

Originally posted by KendallF
Craig, I have the B/B, wideband...but it still needs a cam sensor input to sync the module, as somebody pointed out in another thread recently. Bruce, I like your idea...would this screw up the ESC signal to the ECM?

ESC?, no effect at all.
EST?.
From what I've looked at thinks look fine.
I have a junk dampner (3x24), and I was thinking of using it till I went with the eDIST.

The S/C 3800s tend to knock the rubber out of them, so they are free for the asking at some shops. I was thinking of drilling out the rivets on it and then fastening the rings onto a GN dampner.

Some where someone has mentioned using a later ecm on a Gn and I think they used the 3x24, but I never found out who it was.

 

[TurboTR]

I don't think that crank pattern will work with the FAST. It wants the stock GN pattern.

Sorry Kendall, the GN coil module has to have the cam signal. The problem is that with the stock GN crank pattern there's just no way for a computer to identify any individual cyl pairs.

BUT! Where there's a will there's a way. For example, one option might be to switch to the Ford edis6 ignition system. It has a module, coil pack, different crank sensor setup. All in the boneyards or at the dealership. Then I believe you could can the stock GN cam sensor forever in your front cover case Email me if you wanna talk about it.

TurboTR

 

[TurboBob]

I think you can sync the ign module with a 1x signal off the crank in place of the cam.
There is a diagram in the red-white-blue power source book of this exact thing.

You may be able to find old Power-Source components to do the job.

Bob

 

[HighPSI]

Bob,
I was thinking the same thing. Could a magnet on the crank be used as a cam signal? With the GN "waste-spark" arrangement, it might be possible. Or is there some downside to the ignition getting "re-sinked" every crank rotation. Then again, it's getting late and I am probably overlooking something.

 

[bruce]

Originally posted by HighPSI
Bob,
I was thinking the same thing. Could a magnet on the crank be used as a cam signal? With the GN "waste-spark" arrangement, it might be possible. Or is there some downside to the ignition getting "re-sinked" every crank rotation. Then again, it's getting late and I am probably overlooking something.

As long as your DIS and Batch fire that is fine.
For the GN ignition module you can use a flip-flop to kill every other cam synch.

Isn't there a 3x1 ring used on one of the racing V6s (ie Indy car).

 

[RealFastV6]

(Attached diagram of Buick Power Source ignition Balancer with 3x1 ring)

 

[TurboBob]

That's it

Cal: I'm sure it would be fine. Taken to the other extreme, the ign module will run fine
with only one cam pulse...... (Caspers ign tester only gives one cam pulse)

You could sync on any cylinder and juggle spark plug wires......

I believe there are trigger pieces from MSD that could be used (flying magnet)

Bruce, if you run an ign module on your bench you can set that Camslator
for 3x1x (it's 6x1x / stock GN currently) and try it....

So, Kendall, I think that a magnet on either the cam gear or the balancer
or a hole in the flywheel (or a crank counterweight.... )

For simplicity, keep it phased the same as stock, falling edge of cam signal
somewhere near 25* ATDC.

Bob

 

[TurboTR]

Well let's see, the stock setup gives one cam pulse every 6 crank edges, and you are saying it will also work with one cam pulse every 3 crank edges? Hmm.

TurboTR

 

[TurboBob]

I believe so, but haven't tested it......

i.e. put a target on the balancer and use it to sync the ign module...

B

 

[TurboBob]

Another idea

You could also cut a second notch in the cam sensor trigger 'wheel'

This would make the ign module sync more quickly......


TurboBob

 

[RealFastV6]

Re: Another idea

I dont understand how the module would react to getting a sync signal on number 6 and number 3 firing, as it would if you were to use a 3x1 ring. Normally it looks for it on #6 right?

The cam sensor only really needs to sync once anyways. Once the motor is running, dont need it anymore. Any way to have it just pick it up once on cold crank and then ignore further input?

 

[TurboBob]

If you run without the cam sensor there is no way to recover from an 'unsync'
Automatic disconnection of the cam sensor after the engine fires is possible
but probably not worth the effort.

The ign module is really a 3 cylinder beast running waste spark. It should run fine
with a 3x1x signal. I'd be willing to bet there is an oem application that runs this way.
Is there an 80's GM V6 running DIS that's not sequential? (Bruce...?)

Bob

 

[KendallF]

Wow...looks like my topic ran away without me while I was over on the Gulf Coast!

Now you have me thinking...which is a bad thing, a very bad thing. Anybody got a Stage motor balancer with the two-pickup rings for sale?

 

[bruce]

Originally posted by TurboBob
If you run without the cam sensor there is no way to recover from an 'unsync'
Automatic disconnection of the cam sensor after the engine fires is possible
but probably not worth the effort.

The ign module is really a 3 cylinder beast running waste spark. It should run fine
with a 3x1x signal. I'd be willing to bet there is an oem application that runs this way.
Is there an 80's GM V6 running DIS that's not sequential? (Bruce...?)
Bob

The only ones I can think of use the 7 notch crank sensor setup.

Might just be easier to use the original idea, copy the measurements off of a FWD timing cover, and be done with it.

 

[TurboBob]

The power source ignition stuff is usually around in the swap-n-swindle at
BG. Beyond that, I'll ask around....

Seems to me that ATI can put a stock trigger on an SFI balancer,
maybe they have some other tricks.


Bob