EDIS reliability under extreme conditions?

[MadMax78]

Hi everyone,

I'm converting my type 4 aircooled engine on my 1978 VW type 2 bus to run with MS instead of the stock Bosch L-jetronic system. I first planned on only converting the FI system but now the EDIS system is getting more and more tempting. There are two things which are hugely important for me, being reliability and fuel economy.

I'm using this bus for overland rally driving and last year I drove it from Amsterdam to Beijing 10.000 miles. The injection system worked ok, but needed tuning often, mainly due to altitude differences (and we had an AFM fail). Also the fuel economy is something that could use some improvement. We will be driving this car from Amsterdam to Capetown in summer 2010 so it will meet major dust and possibly deep mud/water.

The ignition system worked fine, I have a mallory unilite dizzy installed but it is giving me some spark scatter and in general I'm just not that happy with it. I really like the idea of being able to just set a completely custom advance curve.

Anyway, if I convert to EDIS I'll probably make a connector in my wiring harness so I could effectively just swap from dizzy ignition to EDIS in case EDIS would give me trouble. But I was just wondering how reliable you guys think this system is, is it prone to damage from dusty conditions? What about the VR sensor? How does it cope with heavy dust or other contamination?

I'd like to get your take on this, since a lot of you guys probably have years of experience with this.

[FixItAgainTony]

MadMax -
EDIS has a bit more fail over than other systems. In the unlikely event the MS fails to provide the SAW signal, the limp home mode will keep it working at a fixed timing (usually 10 degrees - depends on how the Vr sensor / 36-1 wheel are mounted). The system has one coil for every two cylinders, if one fails, the other coils can still operate - not pretty, but on a V-8, that would keep you running. On a 4 cylinder engine, probably a little rougher.
If relaibilty is a concern, I would mount the EDIS module in a cool location and possibly add a heat sink to it, but as it is already designed for under hood operation, this is probably overkill. Alternatively, carrying and extra module / Vr sensor / adding additional coil drivers on the MS board (microsquirt can drive two coils) is a possbility. It is a pretty roubust, simple system - works really well with MS. The ability to increase the engine advance at partial load conditions helps improve milage. After seeing the difference between crank based ignition timing and distributor based timing, I would not go back to a distributor.

- Charles.

[msoultan]

I would think that EDIS is just providing more potential for failure - more hardware, more wires, more things to go wrong! Why not just let the MS control spark and use the distributor for doing just that.. distributing spark and that's it. Works great on my bus and swapping over to the MS is just a matter of removing the stock negative trigger and connecting the MS coil control wire. That's it! If you wanna switch back to your stock ignition, unplug the MS from the negative terminal and reconnect your points or whatever distributor trigger that you're using. No external modules and your timing curve is taken care of in software and is rock-steady. You don't need to lock your distributor and you don't need to touch it in any way. Can't get much easier than that.

Mike

[FixItAgainTony]

Mike,
You raise a good point. One could go to a crank based tach input using a Vr sensor and missing tooth wheel and then let MS control the coil without locking out the distributor. This would eliminate the spark "scatter". If there was ever a failure, change the trigger input to the coil and then let MS run fuel only. This set up would give the advantages of a simple crank based ignition set up + solid fail over. If memory serves several of the sand rail guys are using EDIS - that is a pretty harsh environment. EDIS eliminates all moving parts and delivers a strong spark - there is probably a trade off of mechanical distributor failure / rotor / distributor contact wear versus electrical wiring / electronic failure. I usually travel with hiking boots and water.

How are you getting your tach signal without a locked distributor?

- Charles.

[msoultan]

If memory serves several of the sand rail guys are using EDIS - that is a pretty harsh environment. EDIS eliminates all moving parts and delivers a strong spark - there is probably a trade off of mechanical distributor failure / rotor / distributor contact wear versus electrical wiring / electronic failure. I usually travel with hiking boots and water.

Yeah, that's a good point as there are no moving parts - but I've never heard of a distributor that stopped spinning - but I'm sure it can happen.

How are you getting your tach signal without a locked distributor?

trigger wheel on the crank:

http://www.shoptalkforums.com/viewtopic.php?t=125397

[MadMax78]

I would think that EDIS is just providing more potential for failure - more hardware, more wires, more things to go wrong! Why not just let the MS control spark and use the distributor for doing just that.. distributing spark and that's it.

Yea that is a good point, maybe I got a bit carried away with the EDIS stuff. I think staying with the dizzy for distributing the MS controlled spark is the best option. Besides that the dizzy obviously wears out at some point, but I don't think that will happen anytime soon, mostly wear affects the timing, not the dizzy from rotating . Besides that we carried a spare dizzy on our last trip so we'll probably do so again, just in case.

I'll be installing my VR/trigger just like yours mike, I really like the look of that setup. I'll probably add a connector in my wiring harness so I can unlpug the VR and plug in the coil in case I would need to switch ignition systems on the fly.

PS Mike, could you maybe send me your build log again? I don't have acces to my outlook for the next two weeks, only webmail. And I forgot to save it as a separate file.

[Matt Cramer]

While that can represent one more failure point, the odds of an EDIS module failing are very low. I've had customers report that EDIS modules work quite well when they bolted the MS to the underside of the roof of their Land Rovers because that was the only place they could keep dry while fording rivers, and that it really helped when they were worried that a distributor might get underwater and stall the engine. I can't recall if the EDIS module was bolted to the roof or in the engine compartment, but that should give you an idea of just how extreme the conditions can get and the EDIS module keeps running.

[msoultan]

I'll be installing my VR/trigger just like yours mike, I really like the look of that setup. I'll probably add a connector in my wiring harness so I can unlpug the VR and plug in the coil in case I would need to switch ignition systems on the fly.

Just make sure it's shielded! If you don't, you *will* get false triggers.

PS Mike, could you maybe send me your build log again? I don't have acces to my outlook for the next two weeks, only webmail. And I forgot to save it as a separate file.

PMed and emailed.

[Minami Kotaro]

Going to EDIS is a "don't even think about it" upgrade. As in, don't even think about it -- just do it.

EDIS has every advantage over a distributor. You eliminate moving parts, get more accurate spark control, infinitely better tunability, more reliability, I picked up some milage.

I can't even imagine using a distributor again after having EDIS. It really is that amazing.

[msoultan]

EDIS has every advantage over a distributor. You eliminate moving parts, get more accurate spark control, infinitely better tunability, more reliability, I picked up some milage.

The only advantage I could see is that you don't have moving parts so you might have more reliability. How would you get more accurate spark control, better tunability and more milage? Also, are you comparing this to a distributor controlling timing, or comparing it to the MS controlling timing and using a distributor just to deliver spark?

[Matt Cramer]

Well, EDIS modules seem to hold up better than caps and rotors from my experience. Some of the other benefits would not apply if you are crank triggering a distributor, though.

[msoultan]

Well, EDIS modules seem to hold up better than caps and rotors from my experience. Some of the other benefits would not apply if you are crank triggering a distributor, though.

Yeah, I think from a mechanical standpoint, yes, there is a big advantage. However, to be able to swap back to the stock system by just unplugging the MS coil wire and hooking the points wire back up to the coil as a failsafe is a big advantage. Granted, he could leave the distributor setup in there and then run EDIS, but that would get messy.

Btw, if you do take out the distributor and run edis, make sure you take out the distributor drive gear and everything below it!!! Otherwise you'll chew the brass gear up in no time!

[Minami Kotaro]

How would you get more accurate spark control, better tunability and more milage?

I'm comparing it to the distributor controlling timing. I had MegaSquirt controlling my distributor at one time and EDIS completely blows that out of the water, too. More accuracy comes from no spark scatter due to mechanical play in the distributor. More milage comes from more tunability.

It's not as if the EDIS will be any less reliable than the MegaSquirt itself, so that's not even a concern. If you're worried about the EDIS failing, carry a spare coil and module.

If you go to EDIS, I suggest getting an Accel or MSD coil rather than using a factory Ford one.

[msoultan]

I had MegaSquirt controlling my distributor at one time and EDIS completely blows that out of the water, too.

Why's that? (assuming that the distributor is only distributing spark)

[FixItAgainTony]

My experiences mirror Minami Kotaro's
If the distributor is distributing the spark, there is only one coil, an additional wire, connector and air gap across rotor / post back to another connector to the plug. All of those steps involve loss.

EDIS - coil ends go directly to the plugs. Exhaust cycle plug serves as ground (exhuast gasses ionized => low resistance path). => Coil wire to center post, post to rotor and rotor to cylinder post connections are all eliminated. Less opportunity for electrical loss / moisture effects / rotor & post degradation. As the vacuum advance / mechanical advance changes the gap that the spark has to jump (rotor to post) can change depending on the rotor design. Last one I had always burned the rotor on one side. Light sanding on the rotor / posts improved performance.

EDIS has 2 (or more) coils => dwell time becomes less of a concern over a single coil setup. The coils are used half as often and can have twice as long to charge - dwell is handled by the module, so the user does not have to worry about it => less chance for user configuration errors. The spark from these things is pretty impressive. There was a thread showing some data on this, but it looks like it is no longer available.

Both set ups have pros / cons, it probably comes down to what a person is most comfortable with and what kinds of spares / tools one like to carry. If it did not offer some substantial advantages (performance / cost / reliability), I doubt Ford would have never put it into their cars.

On my set up I looked into to milling down an unused pulley to add the EDIS wheel similar to what msoultan did, but I found that there was enough room for the sensor to allow the notches to be put in the pulley itself. This made things a little simpler for my set up.

- Charles.

[msoultan]

Both set ups have pros / cons, it probably comes down to what a person is most comfortable with and what kinds of spares / tools one like to carry. If it did not offer some substantial advantages (performance / cost / reliability), I doubt Ford would have never put it into their cars.

Yeah, I can see how there are some definite pluses. It would be interesting to see how much of a performance improvement I'd get on my bus if I ran EDIS, but I do like to be able to swap back very easily to the stock setup should there be a problem. Maybe one of these days I'll make the swap...

On my set up I looked into to milling down an unused pulley to add the EDIS wheel similar to what msoultan did, but I found that there was enough room for the sensor to allow the notches to be put in the pulley itself. This made things a little simpler for my set up.

That's an interesting idea. Do you have pictures?

[Heribert]

EDIS is an extremely well designed and manufactured ignition unit, that also has the advantage of serving rock steady IRQ pulses to the MS unit.
A lot has been said about the reliability of a low parts count distributor setup, and how it never fails. I certaily want to challenge that, ater having fooled around with cars for soon 50 years. All kinds from real clunkers to real top class.
The best that I can say about a distributor set up ( kettering )is that it is ALWAYS easy and fast to troubleshoot and repair. Fortunately
It certaainly has an abundant amount of failure modes, from "o, not again" worn out points, rotors and caps to " Well , that´s it, I´ll walk home" instants when the gear drive on ( mostly hot chevy big block) engines have developed such monumental wear that the engine conks out. And , everything in between. And that is quite a lot.
Now to EDIS
As long as the VR sensor is well mounted and the wiring of the EDIS plug is well done I very much doubt that it has any well known failure modes.
And a spare module is snapped in in 2 minutes.

Using the functionality in MS1 V3 for trigger conditioning and driving coils is of course a worthy alternative, but judging from the forum posting volume on trigger questions, resets and blown coil drivers, there is a pretty big difference in complication for many of us less well experienced squirters.

EDIS, to me, is "Plug and Play"

Heribert

[Minami Kotaro]

Why's that? (assuming that the distributor is only distributing spark)

It's hard to explain unless you've experienced it yourself. Once EDIS was on, it didn't run like a Volkswagen anymore, it ran like a modern engine. I figured the biggest benefit the EDIS would have would be better adjustability but literally everything about the engine was better. I think a hidden benefit of the EDIS was that it was delivering a far cleaner ignition pulse to the MS, which made it also work better than it ever did with the distributor. The green dot on my VE and ignition tables was a lot steadier with EDIS.

I don't want to oversell EDIS. Maybe I just never had a good distributor. I don't care. EDIS was what finally made my MS project come together and work beautifully. I'll never have a distributor again, on any vehicle.

The posts from Heribert and FixItAgainTony have already stated many other reasons why I think EDIS is better than a distributor.

[msoultan]

It's hard to explain unless you've experienced it yourself. Once EDIS was on, it didn't run like a Volkswagen anymore, it ran like a modern engine. I figured the biggest benefit the EDIS would have would be better adjustability but literally everything about the engine was better. I think a hidden benefit of the EDIS was that it was delivering a far cleaner ignition pulse to the MS, which made it also work better than it ever did with the distributor. The green dot on my VE and ignition tables was a lot steadier with EDIS.

I don't doubt that it's a huge improvement over the standard stock setup, but did you go straight from a distributor setup to EDIS, or did you go to MS controlling spark through the distributor (with a trigger wheel) and then to EDIS. I did notice a huge improvement, just like you describe, when I converted over to the trigger wheel and allowed the MS to control spark through the distributor. It was amazing how smooth the engine runs compared to the distributor controlling the ignition pulses. It would be neat to have a comparison... I'll let you know when I eventually switch over to EDIS ;)

[FixItAgainTony]

Here is a picture of the drilled pulley wheel I used. Nothing fancy, but it works great.

Trigger_Wheel_a.JPG

Here is link showing another way of doing the same thing:

viewtopic.php?f=89&t=35544

- Charles.