durangorider

I have a fully built evo VIII. I was running sparktech coils with my AEM EMS. Was running 32psi on 110 the other day and it worked great all day. The next day whenever I would go above 4000rpm the the engine broke up. I figured it was an ignition problem and since aem said if the ems went bad it wouldn't run at all. So I decided to put the AEM cdi box and coils on instead of the sparktech, in case they went bad. We wired them up directly to the EMS and bypassed the OEM ignition box. I triple checked the wiring but I still cant get it to fire up. It just back fires every several cranks. In the AEM I changed the dwell setting to the CDI setting. Then turned off coils 6 & 7 which were being used with the sparktech. And then turned on coils 3 & 4. which were empty ports in the engine harness. I also changed the ignition parameters so it matches the firing order. Any Ideas? Please help.

project_skyline

iTrader: (30)

So the car was running on the sparktech and you switched to the AEM and now it won't even fire up?

What fuel are you using?
Plug gap?
AFR at problem area?
Did you check the plugs or swap them?

Also I'm confused when you say turned off coils 6 and 7... in the AEM there is only 4 coil outputs. That could be your problem. I however don't have experience with the AEM twin fire so if that is the problem I can't help ya there.

I see your in durango, nice place but haven't been there is 7 years I'd say.

TheBoz

iTrader: (9)

did you change the 10 dollar plugs that were in the car first.

Is your aem twinfire blowing fuses? If so you have a bad AEM TwinFire box. If not then try to wire it up using the stock ignitor. get that to work first before you try to bypass the ignitor.

I also have a TwinFire and mine was DOA from the factory. The replacement I got worked pretty good however I removed it and just opted to run the COP and stock ignitor.

durangorider

The first thing I did was change the plugs and tryed it again, no luck. I figured I would bypass the stock ignitor in case that was the original problem and also since I needed 4 coil outputs and the stock harness only has 2, I would just go off the aem. Im not sure why the sparktech's used coils 6 & 7.

project_skyline

iTrader: (30)

Stock has 2 coil outputs which is all it needs because its a wasted spark system.

When you wire up the twin fire you use the other two inputs on the AEM, pin 16 and pin 52 IIRC which are coil 3 and 4.

It doesn't sound like your AEM was bad in the first place and it still isn't probably. Blowout has numerous causes.

browningderek

iTrader: (7)

you unpluged the stock ignitor? i thought the ignitior was built in the coils?

durangorider

And those are the pin locations we used. We had a sparktch COP on when it went bad. I dont think the AEM is bad because we get spark on all the coils. So either Im missing something in the EMS or there is a physical problem in the EMS. It seems Like timing now. Im thinking maybe the timing bet jumped a tooth when we were getting on it.

project_skyline

iTrader: (30)

Even if it had jumped a tooth the car would still run. I guess first thing to do would be verify timing and if possible swap either one or both of the CAS's.

Are you tuning your AEM or are you using someone else?

DarksideZ

iTrader: (1)

Reload the firmware first and see if the problem persists. Make sure you save your tune and reload the firmware with a clean firmware, not the one you are using currently. This usually solves most problems related to spark/ignition failures on the AEM. Let me know if this works for you, if not I got a couple more ideas.

durangorider

So I think I slipped a tooth or two when I line up the cam gears the mark on the crank shaft is at BTDC. Is that were its supposed to be or at the T mark? Here is a pic. Let me know what you think.

project_skyline

iTrader: (30)

You mean TDC? If it was BTDC it would be 180 off. I can't really tell by the picture.

DarksideZ

iTrader: (1)

It does look a tooth off. Are you getting a static sync?

DynoDude55

iTrader: (20)

After you verify cam/crank timing upload the old tune (sparktech tune) and try a new cam sensor if you have one. After reading your first post it sounds like you cam sensor may have gone bad due to excessive heat from an aftermarket header.

If you need any help feel free to call us, we are one of very few AEM certified shops in CO that specialize with Evo's.

-Lucas