COILS???

[ian@ue]

Has anybody ever had their coils blow up on an F4i engine or any other engine running a Motec computer. This is my first posting so I don't really know what I am doing and I don't know what happened to our coils. If you have anyinformation please email me at im11@evansville.edu

[ian@ue]

Has anybody ever had their coils blow up on an F4i engine or any other engine running a Motec computer. This is my first posting so I don't really know what I am doing and I don't know what happened to our coils. If you have anyinformation please email me at im11@evansville.edu

[VFR750R]

The general opinion I get from talking to my old boss (motorcycle mechanic) and various other ethusiasts is that coils often get blamed and are rarely at fault. Make sure they are wired correctly and if you are not using the direct coil on plug style coils keep them away from sources of heat (headers). I would have to believe you are either missing a ground or not triggering the coils at all...especailly if all 4 aren't working.

I have not had direct contact with Motec before, but my roomate from NC state has nothing but good things to say about them and how helpful they are, so try calling them directly with wiring questions and they should be able to give you some advice.

[ian@ue]

Thanks. Yeah we are trying to wire it up differently right now, but it was running quite well until it blew up the coils (and it literally blew them up). No I don't think that the coils were bad. The only things that we could figure were that maybe we cracked them while putting them back on, or we could have gotten them too hot because the way that we had them wired they were receiving power any time that the computer was on, which was like 4 hours, but they didn't feel hot and they should have had time to discharge because we had the engine running for like 30-45 seconds and then smoke started to role!!!(from the coils) I am open to any more advice because I don't want to do the same thing to the new coils that we had to drive 2 hours to get today.

Thanks,
Ian
Brakes/Wheels and tires
and now everything else

[BryanH]

In main setup make sure "ignition type" is set to 1 and a figure between 1 and 2 is entered in the "dwell" field.

[Jarrod]

we are running Denso coil on plug units, I'm pretty sure they are F4i, off a Motec, using the Bosch module recommended by Motec. One of the parameters that needs to be set is the coil dwell time, as Halfast has suggested, named dELL in the ignition setup dialog. The correct way to set it up is to get a current clamp, (it loops around the wire and uses magnetic fields to measure current in the wire), plug that into a CRO, and determine the coil saturation time. The current should ramp up, peak, then fall. You need to set the dwell time to just when the current starts to peak. We found it to be about 2 milliseconds from memory(maybe 2.2).If the current is being sent to the coil for too long it will damage it.

[B Lewis @ PE Engine Management]

Ian,

You described the exact symptoms (literarly blowing them up and cracking the cases) of coils that have been overheated due to too much dwell time. 2 ms sounds about right for the saturation time for those coils. I would start to look at that first.

If you guys are still having trouble give us a call. I am familiar with the problem and maybe I can help. I have been manning the phones this weekend since we have so many teams using our stuff next week.

[Colin]

We blew up a set of coil on plug coils becuase i left the ignition on for two long without the engine running (1/2 hour) after i did that i found out that motec has a function that allows you to set one of the digital output to turn on power to the ignition system and fuel pump only when it detects the engine spinning. it's a good little function and i recomend using it