Parts I plan to use for DIS on a 7730/7727:

-eDIST (purchased and on the way)
-MSD Cam Synch/ Dist Plug
-MSD Crank wheel kit (Have not checked for sure yet)
-LS1 coil packs and wiring

Whether it is an MSD or not I know the crank trigger need to be 4X.

now the question verification needed is on the wiring:

EST from the ECM goes to the eDIST.
Cam synch and Coils packs wire to the eDIST

the main question is the Crank sensor I know it needs to connect to the ECM, but does it need to go through the current Ignition Module to get the signal conditioned correctly for the ECM? or do I just feed the Crank sensor direct tot he ECM.

Also do I retain the current ignition module in the distributor for anything? I am guessing yes to keep the ECM happy but I honestly don't know for sure

 

During crank the engine runs on the ign module, then as the rpm goes over ~375 RPM, the ecm takes over. So you need to either lower that threshold, or use the oem ignition module.

Be sure to double check your timing at low and high rpm once you get it running.

Wiring looks right, thou, double check it with the instructions.

Remember the cylinder offset when you wire it up, you'll see what I mean when you get the instructions.

 

What are you using to spin the oil pump?


I think I'm gonna call FAST today..

-- Joe

 

the Distributor plug/ Cam Synch from MSD will spin the pump.

When I had emailed FAST tech dept. they said the eDIST will only work with the FAST system. So since Grump has used it with a GM ECM, I figured I would give it a shot..




Grumpy,

Thanks for the info, I think I will just use the OEM ignition module to start with..

 

Jeff, Can you post the part numbers for the parts you used?

Thanks!

-- Joe

 

Joe,

I certainly can when I get all of them together.
only thing I have bought is the eDIST (got it used)

The plan is to use:

-MSD PN 8514 (Chevy V8, w/Slip Collar) for cam sync/oil drive

-MSD Crank sensor if it will work or any 4x Crank sensor

-LS1 coil packs and harnesses

 

wow.

so eDist: $300
Cam sync: $140
Crank sensor: $260
LS1 Coils: $200

$900 for an ignition? Nah.. Think i'll look at the northstar stuff again.

-- Joe

 

Yeah, well..

I got the eDIST for ~$200 ( 3mo old)
Cam Synch at $140 is not too bad
Cranks sensor I have thought of the Vortec truck stuff, not sure yet

LS1 coils, I will get from a wrecked Vette, I don't expect to pay that much

 

The effects of the best ignition you can get, PRICELESS.

 

The edist itself seems reasonable. The other stuff? no way. I'll go junkyard hunting for OEM gm stuff first.

-- Joe

 

You could get the distributor from a Vortec. They have a cam sensor in them and there is a cover available from GM for it. The cover was under $10 last time I checked. The cover is for a 2001 Chevy c6500 with a 7.4l. The used distributors aren't to expensive on eBay.

 

Can an edist work just off a cam sensor?

-- Joe

 

yes it needs a 4notch cranks for engine speed and a single output signla to determine cyl#1 tdc. a gm vortec distributor is actually ideal for this. it is however a hall effect design.

 

So the signal is wrong.. Whats edist looking for, for a signal?


-- Joe

 

I forgot to mention that the vortec crank sensor should work to and is under a $100 for the sensor, reluctor and timing cover.

 

this is another option. I think the eDIST allows for the hall effect, but I understood that the cam synch goes to the eDISt and the Crank signal goes to the ECM.

I will know more when I get the eDIST

 

The vortec crank sensor is a hall effect, if that matters to the e-dist.

 

You should be able to feed the crank signal from the Vortec sensor to the computer on the ref high wire and connect the est wire to the eDist. You will have to lower the RPM that est is enabled in the bin.

 

So does that Vortec Distributor just have a cam sensor? or both cam and Crank in it?

After seeing Doctor J's post when I was searching on this it looks like tot use the Vortec crank sensor I will ned to replace my double roller chain, which is fine, but by the time I am done it will close to the cost of an aftermarket wheel.

 

the vortec distributor is a hall effect like others have said. it is strictly a cam position sensor, that is 50 % duty cycle, so for one half of the revolution(180 degrees), its low, and for the other half its high. It has three wires, power, ground and signal out which goes from 0-12V.

 

both the cam and crank sensor are hall effect. I don't think the ECM would know what to do with that crank signal as is, but it would be cool if it did, or if there was an easy way to make it work since I already have the right wheel and cover on my car! May get me to change my mind on the N* stuff (doubt it though, I'm in a bit far now!)

 

So. The vortec dizzy found in the 5.7 liter trucks, is a hall effect CAM position sensor, and can be used with edist ?

I was under the impression that, if you didnt use the crank sensor, it would just take longer to fire. No?

Or does the '730/'749 ecm NEED the crank sensor input?

-- Joe

 

To my knowledge and understanding you are correct..

but the ECM needs the Crank sensor input for timing control I believe

 

Timing control has nothing to do with the crank sensor. On most setups, the crank sensor works with the ignition module exclusively. The crank sensors sends a signal to the ignition module to trigger the coils. There is only two wires that feed to the ignition module from ECM. One wire is a 5 volt bypass. The ecm will feed 5 volts onces the rpms reach a certain amount. This wire switches the circut(inside the module) from the mechanical 'base timing' (that is set into the dist/reluctor wheel) to ECM controlled timing. This is done through the other 'feed wire' to the ignition module from ECM know as the EST. The main functions of the ignition module are to fire the coils and send a reference signal to the ECM for injector firing. Most cam/crank sensors will not directly work with the ECM. Some produce 150+ volts. So think twice before hooking up a crank sensor directly to the ECM...

EDIT: ecms that have crank sensors directly hooked up(like the ls1 PCM) has the ignition module built into the PCM.

 

Bump... just wondering what it's looking for... shouldn't be that hard to built a conversion box.

Something like this:

http://www.fuelairspark.com/Technica...structions.pdf

 

Thanks that helps..

I was planningon feeding the crank sensor through an ignition module before going to the ECM, but it sounds like the hall effect sensor will not work with the OEM ignition module

 

you could use 2 op amps and bring the hall effect signal in and get a differential signal out of the op amps, and drive the ignition module. On my test bench, I'm using a 555 timer to trigger a factory module, with a +5v to gnd output(hmm, through a capacitor) and using both outputs, so you could do something similar. so yeah, you would need to build a small module, but nothing major, probably something about the size of a box of matches. i can give you more details/schematics if you want.

 

Yes that would help..

I also found out that the eDIST I bought has no instructions.. I hope i can get a set from FAST

 

I'm trying to go DIS with factory parts. Have read quite a bit about ignition modules......here is something you might find interest in.....


http://www.fortunecity.com/silversto.../10/ddis1.html
http://www.fortunecity.com/silversto.../10/ddis2.html

 

I have the full instructions for the eDist if you want them. I'll be happy to try to email them to you. The eDist will work with either a Hall effect or inductive pickup on the cam sync signal. You need to get a standard 4 pulse per crank revolution signal into the ECM, whether it comes from a trigger wheel or a distributor pickup. The EST signal from the ECM will go into the EST input on the eDist. It will also drive either "smart" coils or regular ignition coils. Man, I gotta get my eDist going.................

 

Thanks for the offer but I got it from FAST today VIA email

Also thanks for the info

 

looking at the MSD crank trigger it looks like I could possibly connect it firectly to my OEM ignition module

the signal looks the same as the reluctor on the Distrib.

 

Jeff:

I haven't had time to get my eDist going yet, but I believe you could just send the trigger output directly into the ECM via the REF HI input and tie the REF LO to ground. Then just send the EST line into the eDist and tape the BYPASS wire up. Don't see why you'd need the module at all. That's what I'm gonna try whenever I get around to it. As Grumpy said, you'll need to change the RPM at which the bypass lifts to a very low number and it should work without the module.

You've got me "fired" up about the eDist again and maybe that'll motivate me to get mine running.

Larry

 

I know what you mean.. I will not try it until later this year. since it is geting close to spring I want to drive my for a while. Besides I still need to gather all of the parts. I think I will use the MSD trigger..

all I have is the eDIST.. I need everything else