Hello,
I am repairing my 91 GTA L98 350. I want to replace the stock ECM with a FAST XFI, Acell DFI or AEM ECU. FAST XFI system seems to be the easiest. Anyway, I intend to create a coil per cylinder, distributorless crank triggered ignition system.
I need to eliminate the stock distributor as my new custom manifolds and plenum will not allow it.
Correct me if I am wrong PLEASE.
I believe the HEI distributor preforms three functions other than spark distribition:
1. Provides the Tachometer signal ???
2. Drives the oil pump ???
3. Hole in distributor shaft lubricates the rear of the camshaft ???

Problem: If I eliminate the stock HEI Distributor;
1. How do I generate a signal to run the Tachometer ?
2. How do I lubricate the engine properly at any RPM ?
3. Not sure how necessary this is since no distributor gear to lubricate.

Please reply directly to
Firebirdjim@hotmail.com

Need some helpful advice.

Firebirdjim@hotmail.com
Firebirdjim@hotmail.com

 

1. Use a crank trigger. You need more than just something to run the tach; you need something to tell the plugs when to fire, and the injectors when to fire. The pulses from the dist provide the trigger for all of that.

2. Use the little mock distrubutor thing that comes in the LT1.

3. There is no such hole... the rear cam bearing is the very first component that the pressurized oil reaches, before it even gets to the dsitributor. Rather, there's a passage around the dist housing that completes the front-to-rear passage through the block, that carries oil to the pass side lifters.

 

Another way is to leave the dizzy in, and convert the signals.
The dizzy is essentially a cam sensor. A pulse multiplier will give a crank sensor signal.

This post I think is better off in the ECM board so I'm sending it there.

-- Joe

 

The FAST System has a device called E-dist.
It is an Electronic disrtibutor and is controlled by the XFI ECU.


What exactly is this LT1 Mock distributor thing you spoke of ?
Got a part number or picture ???

Thanks for the advice.

 

Do a search on DIS.
Also eDist will turn up some stuff also.

I believe the eDist gets a timing signal(when to fire) from the ecm.
The edist determines which coil to fire.
I believe you need a crank signal and a cam signal.
There are dist that will do both. Accel dual sync is one.
You can also go to a crank trigger and use various dist to get your cam signal. The factory LT1 ignition stuff won't fit your motor.
I'm sure FAST could answer all your questions since your using all of their stuff.

 

http://shbox.com/ci/oil_pump_drive.jpg

 

Hello Z69,
So far the Tech service people at FAST has been not been very helpful. They do not seem very knowledgeable about their own product and very lacking in the application of their product. This worries me. It is the biggest drawback to the FAST / E-Dist system.
I'm hoping to find someone who has installed the system.
Several people have suggested the LT1 Oil pump drive solution. You say it will not fit ? Why
It it too big ? Wrong diameter ??? In what manner will it not fit ?
A LT1 block is still a small block like a L98 block isn't it ?

thanks

 

An L98 won't have the boss to bolt the LT1 drive too.
You'll have a nice hole at the back of the intake unless you swap to LT1 intake also. You need a cam sync signal to run 8 coils unless you go to a waste spark 8 coil setup.

Look through the XFI and eDist documentation.
One or both books should address what kind of dist signal they will accept. Then you just need a crank signal. This can be done with a crank trigger setup or a dist. setup to provides both signals.
I know of at least one person running a stock 1980's ecm and an eDist on a v6. So you should have no problems doing it. Provided you determine the correct parts to buy. There are only a few types of common trigger sensors, so it's not as difficult as it might first seem. I didn't like the price for an eDist so I'm persuing a factory based setup like some others are. Do the searchs I suggested above on the DIY Prom board and you'll get more info to help figure this out. You might try an email to FAST with very specific questions. What type of signals does an eDist need to run 8 coils. What distributor and or crank trigger/Dist can I use. Hopefully it will get forwarded to someone that knows.
I'm pretty sure the XFI can be set to use about anything, so that's just a matter of reading the book that comes with it.

The way I think it works, and I'm not 100% on this but..

You need a 4 pulse per crank revolution signal and a 1 pulse per 2 crank revolution signal (cam sync). An msd crank trigger setup will provide this as well as a 98 or so sbc vortec trigger wheel, timing chain, timing chain cover, and sensor set. Then you need a distributor that will provide a 1 per 2 crank rev signal(1 per dist rev). An msd dist with 7 of the teeth ground off will do this.
The eDist either provides a 4x signal to the XFI or the XFI is piggy backed onto the same signal. And the XFI provides the timing signal back to the eDist. You may see these listed as 4x, 1/2x, and EST signals.

 

If you are going DIS then you'd need a crank signal like earlier explained from crank trigger and cam synch and also controller to relay information for timing and firing order. For the distributor there isn't a hole that provides oiling there is the grooved area the oiling goes through. A nice way to take care of this would be MSD sync distributor plug
http://www.msdignition.com/ignition_..._8506_8521.htm

 

Well there you go.
And thanks for the (Ford) link.
Been meaning to dig around for that thing.
First one I saw was on a stang.

 

Yeah Ford and GM listed. lol. even fords are on the leading edge of cool stuff

 

To hell with Fords their almost as bad as Chrystler products.
But even I have to admit the Ford GT and Shelby GT do LOOK cool.
The only edge ford has is due to a lack of GM competition.

Now back to our originall scheduled topic. DIS Systems.
I need the help. Too many decisions. I know I want true sequencial system not the fake batch fire mode.
I want to control each cylinder with my laptop.
So far FAST and Electromotive info has been scarce.

Experienced DIS users encuraged to reply.