I need a real expert on this one.

[Karl]

I have a v3 board with MSnS 024 and megatune 2.25.

The car is a Mitsubishi Eclipes GST with the 4g63t engine. When the car was running the stock computer a power transistor burnt out on the car. This thing is basically Mitsubishi's equivelant to the vb921 circuits.
I replaced it with a used power transistor. About three weeks later that transistor went out. At that time I checked the coil packs according to the manual and they checked out ok.

Fast foward.

I have been running the Mega Squirt for about 3 or 4 days, not much driving just short tuning trips. While in my driveway while the car was warming up to operating temperature. It died and I restarted it. It died again and wouldn't start. While cranking it I smelled the aroma of an electrical fire. I quickly turned off the igntion and traced the smell to the Mega Squirt. I had not installed the cover to it yet so I had quick access. The whole thing was warm exspecially the heat sink. The vb921 mounted to the heat sink was smoking hot. So hot it had melted the nylon nut holding it and it sizzled spit easily. I also noticed the relay that I had installed to power the coil packs was very warm, warmer than the identical relay used for other things on the Mega Squirt.


On the stim the Mega Squirt still works and doesn't get hot.

I believe some thing is wrong with these coil packs. Does this make sense?

Also, since I don't live in Eclipse mecca, It's hard to find junkyard parts around here for them. What coil packs can I use? I assume I can use any as long as I know the dwell for them. Is this right? What other Mitsubishi cars use these coil packs? Also how about you neon guys. Could I easily use your coilpacks on this? There are tons of those in the junkyard. What dwell settings would I use?

What would you reccomend I do to try to fix of trouble shoot this?


Thank you

Karl

[Karl]

Some how my dwell control got turned off. I know it was turned on previously, maybe I loaded a save .msq wrong or maybe it's because I use two different computers to play with the megasquirt. Anyway could this have caused my problem.

Also, the car will not start at all now. The Megasqurit appears to work correctly on the stim. The two led's driving the coils are flashing correctly. However, on the car I can't get them to flash at all. One will come on and stay on for a long time but no flashing. Also, while cranking sometimes I get a 300 rpm reading in megatune and sometimes it says 0.

Why is this now working on the stim and not on the car?

[bluetrepidation]

At this point I'd be mad enough to get some new coils. Since your are directly driving the coils you have many options. But point is if the coils burnt up your stock ECU and there is something up. Time to replace. I'd also try the MS in the car with the coils disconnected to see if things act up. If so then the MS may be damaged. If not probably just your coils are bad. Testing coils with an ohm meter only tells you so much. Things can happen when coils start to heat up. So they may seem good but who knows. It also may be worth replacing the driver transistor since it did get so hot it most likely is damaged as well.

A.J.

[mops]

i'd start with replacing coils and vb921.

on my bmw, vb921 was getting hot, so I eventually added custom ignitor form a mitsi (wreckers), with huge heatsink (located in the engine bay) to drive the coil.

can you describe what coil setup you have ? from the context it appears you have more than one ? how do you run them then ? what's your dwell set to ? have you tried lowering it ?

[Jim]

You probably have an intermittent electrical short circuit .

Yes , having the dwell at zero could cause a coil to overheat and
short-out internally , this can be intermittant .

You need to check everything in the wiring harness between the coils and MS .

I'm guessing that you used at least part of your original wiring harness ,
something smoked your original factory driver transistor and the problem
is still there trying to smoke your MS .

If your wiring is all brand new , then you probably have a bad coil .
The fact that your problem occurred while the engine was warming up
makes a bad coil more likely .

Something is connecting 12volts+ directly to your ignition transistor(s) ,
without going through the coils first .

You should have blown a fuse ,
what size fuse do you have powering your coils ?
It should be no more than 15 amps (this is plenty for any stock ignition) .
It should also run though it's own separate relay directly to the battery ,
this helps keep electrical noise out of the rest of your wiring .

If you really want to get picky , you would be much safer and have
more reliablility and less potential for problems if you would run
separate Ignition Module(s) instead of running that
high current , noisy coil voltage directly into your MS .

...................Jim

[Karl]

To describe my setup, I am using two vb921a to drive two coil packs. I am using the leds on the MS to turn them on and off. As for the wiring it is all new from the Ms to the coil packs. I do have it fused Jim but for 20 amps. The relay is shared with the fuel pump. The MS is not acting properly on the car but it works fine on the stim. I disconnect the vb921s from the MS and I cant get the leds to flash on the car. I do get rpms in megatune when I crank it, but not always. On the stim I get the leds, but this is with the stim to wheel function on. Do you think maybe I hurt the tach in circuit on the MS? Right before it died, I tried to burn a table to the MS and it said the voltage is too low do you want to contiune. I thought hmmm and check the voltage in megatune and it read 13 ish. Then everything died. I am getting new coil packs before I do anything to the car, but I am afraid the MS is fried.

[Keithg]

It sounds like you have no tach input. Stim for wheel just cycles through the outputs. It knows nothing about a missing tooth wheel.  Make sure 'stim for wheel' is off and see if you get regular, steady rpms during cranking. If you do and the outputs are set properly, the leds should flash as well. This should be all that is necessary to drive the VB921s. You may just not have a good VR signal from the wheel sensor.

KeithG

Posted by email.

[jsmcortina]

Have you re-loaded a known good configuration? Sending data when "voltage too low" may result in scrambled tables.

James