Any else having problems with AEM CDI unit?
 

I purchased and installed the AEM Twin Fire CDI and have had failure after failure.
Has anyone else used this module and had better luck. Failure is completely random and there seams to be no correlating factors in play.
Any thoughts?:(

How do you have her wired? I have seen it best done by running a stand alone power straight from the battery for these spark units. I usually go from the starter post battery + and get the constant 12 volts from there. What did you use for an ignition source? AEM makes a pretty good product I am supprised that it is giving you as many problems as it is.

My ignition is bosche individual coil packs. ECU is AEM universal unit.
I'm so frustrated. I have gone through five of these things. The failure seams to be random. The car will run great for a couple weeks, no issues and then for no appearent reason, the unite melts down and I'm stranded somewhere.
AEM is building me a beefed up unit but I'm still going to be nervous.

Also, the unit does have constant 12 volt power but I'm not sure if it is coming direct from the battery. I guess I could route a wire direct and se what that does.
What's frustrating is the time it takes AEM to do anything. If word starts getting outt that these things don't work and AEM is slow to repair, thier toast.

try wiring it that way- now are you twin plug and are the bosch coil packs a "waste spark" set up? If so, how do you have the ignition wires routed to each cyl. If it is single plug, never mind.

I know this is an old thread but I wanted to see how this turned out. I am considering the AEM unit for my build. I will be running twin plugs and may consider the AEM Coil-On-Plug coils.

Bill

Hi, AEM completely redesigned their cdi's, no problem whatsoever on their new units.,for the price you can't go wrong with them.,cheers.
ps/ For twin coil on plug set up you will need two units.

Mamut, do you have first-hand experience with this? IOW, do you know they are really re-designed, or is that just what you were told by AEM on the phone?

We routinely use their EMS computers (Series 2 are fantastic), but were burned numerous times on the CDIs. If one worked, it tended to be fine for a long time, but too often one failed in minutes, if not seconds.
On UtahRuf's car we ended up switching to M&W CDIs -- a lot more money, but goodbye, problems.

I was in a technical training just the last week on their new series 2 ecu's and their new software for these units, I ask about this very issue(CDI's) to their vice president and his answer was that they were completely redesigned, new boards,etc., they haven't had not a single glitch with the new units.,for the price I might try them. By the way, their new software is something to behold simply amazing (and this is coming from a Motec guy!),cheers.
PS/ Nothing beats those M&W's been using them on cop's builds they are indeed bulletproof.

Chris,

Would I be able to fire two channels at the same time (using 2 6 channel boxes) for twin plug setup with a Motec M600?

Is this what was used in Tom's build?

Good to know, thanks!
And yes, the new software is great! The difference in drivability on the last 930 we did, compared to the older software and Series 1 EMS, was night-and-day. Despite big cams and a really lumpy idle, you could reach through the window and crank it over, no touching the throttle, and it fired up perfectly and idled perfectly, cold or warm. Perfectly smooth through 7,000rpm, no issues anywhere. Perfectly stable boost control at all rpms, no spikes or waviness. I can't say that for the last Motec M600 or M800 we did!

Tom's engine has 2x M&W 3-channel CDI boxes and 2x Bosch triple coil packs (3x2 wasted spark). TurboKraft usually stocks both these items, plus the plug wires.
From there you can wire it 2 ways:

(1) Use 6 channels out of the M600, full sequential ignition. Wire them in the firing order, both to alternating CDIs and coil packs. Cylinders 1 - 2 - 3 are CDI#1 and coil pack #1; cylinders 6 - 4 - 5 (firing order) are CDI#2 and coil pack #2. Coil 1 (both terminals) on pack #1 go to cylinder 1, coil 2 to cylinder 2, etc. etc. Basically, each cylinder gets its own coil.
You can also use their larger 6-channel CDI for this configuration.

(2) Use 3 channels out of the ECU and wire it up like a pair of standard wasted spark systems in parallel -- one for the upper bank of plugs, one for the lower. Each channel out of the M600 triggers both CDIs simultaneously. Yes, not the most efficient configuration -- I get that. But it also supports over 600rwhp, so it's not like it's inefficient either.
The advantage here is redundancy: loose a coil or CDI, and you can still drive the car home. We like to do this for street cars for obvious reasons.

AEM -- don't know about their new C2DIs, but their old ones said they could fire both capacitors (2x/box, thus the name C2DI). You should have been able to use 1x 8-ch C2DI to run both 6-pack (2x3) coils like above. But... In reality, they couldn't do this. Ask both caps to fire at once and they usually melted on you. Call the engineers up and they'll tell you it can't work that way, just "wire it up like the Supra guys" (show me a twin-plug Supra, please).
I'm hoping their new C2DIs are the real deal.
We'll test one on a forthcoming twin plug built 3.3L 930 (head work, SC cams, GT35R, RarlyL8 headers, TurboKraft intercooler, TK AEM system) and post the results.
We're still going to build the wiring harness to accept either the AEM or M&W CDIs, just in case...

Chris,

Thanks for the info. My plan was to run 2 6 channel M&W units in parellel and individual coil near plug. I know, thats a lot of coils. But I was really looking at redundancy as well. I am an IT guy so redundancy keeps me employed :-). I also like the idea of having the ability to turn off the top or bottom plus to make sure everything is firing under normal driving conditions. The AEM interested me due to the price point though. Lets face it, M&W is the ticket when it comes to reliability though. I was also toying with the possibility of running COP's. I just have not really seen any real data on our engines as of yet. Have you done any research on them? They make for a really clean setup when using 12 coils.

Doing an 800rwhp race engine right now with CDI coil-near-plug, tiny 2-tower coils, one per cylinder. Similar setup as the factory GT2LM engine.

I don't see fitting 12 individual coils plus 2 of the big 6-channel CDIs -- that's a lot of real estate used up!

We've also got another engine job lined up a few weeks after this that will be 12x coils-on-plugs. We'll test back-to-back against 6x 2-tower coils.

BTW -- current landed cost on the 2x 3-ch CDIs is about $1200, and 6x of the small CDI 2-tower coils is $450.

Yes I can agree with you 100% on the software, amazing, not to detract from the Motec stuff(software) which it is more geared for the pro sports.,on the hardware side I think that Motec is still ahead,(quality of materials,testing before releasing a unit (burn time),etc.,cheers.