Smoke IS what makes electricity work

[CarFreek]

In the 7 years Ive owned this car, Ive had three fires. The first was caused by fuel leak/hot engine. The last two have been caused by MSD #8920s tach adaptors. I get 2 years/25k out of em before they burn. I JUST relocated this last one from behind dash a week ago, because it started to act errattic, and I didnt want a repeat of the behind the dash fire from 2008 . Turn the key, Flame on! Im gonna investigate using my datalogs rpm converter as a tach signal, or make my own, from here on out........

[SuperSubs]

I know the pain of electrical fires! Very scarry indeed. I didn't know the adapters had that much of an issue!

-Mike

[CarFreek]

Both of mine have had "potting" failures, and went to ground internally. Just poor build quality...

[kmfdmk]

Would placing a small 1 amp fuse or so in line to the power prevent this?? I ask because I too use an 8920 adapter and DO NOT WANT a fire. You could just bump up the fuse to the next lowest rating if you were blowing them regularly.

[CarFreek]

Problem is, any current at all will do it-Both times, fuse blew, but after fire/smoke started. I have a feeling that these units were designed for the Hot Rodder/Drag racer/weekend warriors, and are not meant to be daily driven, or used for long periods of time. The step down coil is gonna make heat, and there just isnt any provision for letting it vent, hence the insulation/potting melts away. They only carry a limited 1 yr warranty.

[4SFED]

I let the smoke out of my first tach adapter a couple years ago. I didn't realize others were having this problem too. I mount mine in the engine room away from everything else on the driver's side fender .

[CLToy]

worrisome, as I am wiring one up now. :(

[SilverMk2]

Frankly almost all the aftermarket parts suck for relability IMO. Most manufacturers do about zero testing on anything they make.

[CLToy]

guess there is reason for a fire extinguisher in the car. :( So a fuse on the 12V lead wont help prevent fire?

[4SFED]

I don't know that mine would have actually caused a fire. But it had that burnt epoxy smell you get when you smoke a semiconductor and I wouldn't want that smell lingering in the cabin. Of course, once you let the smoke out, you can't put it back in so I had to buy another tach adapter and so far so good.

[4SFED]

Now that I know that others have had a problem with these, maybe I will fuse it. I thought I'd just had a bad one made on a Monday. I originally mounted it in the engine room so I wouldn't have to hear that buzzing noise it makes but if it has a tendency to smoke that's another reason keep it out of the cabin.

[CLToy]

Mine is under the hood too.

[kmfdmk]

Well I've got the fact it's mounted on the frontside of the left strut housing going for me... only thing next to it is the igniter resistor pack.

QUESTION....

There are TWO TYPES of fuses. Slow Blow, and Fast Acting.

Mike, do you know which one you had? A fast acting *should* prevent a fire as they're designed to protect sensitive electronics and have little to no tolerance for over-current situations (opposed to slow blow which will let you go a little over momentarily).

[turbogoo1]

Cant we figure out how to make one that doesnt require a fire station on stand by?

I remember that someone figured out how to get the 1j-2j to work, so why cant someone with big head intellect try to make one?

Im not trying to sound like an ass or anything, but something better should be found, or go back on the mfg. to get them to improve it.

[CarFreek]

My car still smells like smoke. Scott, there is a schematic for an adaptor, but few have made it work correctly. That diagram is essentially a copy of the MSD, with a 12v-5v stepdown coil on 12v input. This design would share same heating issues, but I can put it on a board with a nice fat heat sink. Rusty, just atc bladeds in an aftermarket fuse holder. I had a bunch of 5 ampers layin around, it was one of those that blew. Unit doesnt pull many amps until it bridges, LOL.

[one2spooku]

Unit doesnt pull many amps until it bridges.

:good:

[cheappower82]

If it's smoking, that means the wizard inside is angry. Refer to DnD manual.

[xr4man]

would that be the players handbook or the dungeon master's guide?

[CLToy]

OMG, horrible flashbacks! :)

[Donn29]

So has anyone had their wiring damaged by these issues? Or just some smoke and then its all over? Full on fire?

[FPZero]

Does it matter if you use the 8910 on this car or can you only use the 8920? If so, does the same issue occur? Is there something better about the 20?

Curious cause I want to install an MSD ignition down the road.

[Donn29]

8920 is what makes the 7M ECU and our stock tach work. 8910 is for use with a MSD BTM and stock tach.

[cheappower82]

I wonder if the 8920 will work with the mitsu ignitor....

[CarFreek]

It should, Donnie. I now has working homemade Tach adaptor! http://forums.celicasupra.com/showthread.php?t=20273From the links in this post, I was able to build and test several different tach adaptors. Some background-I run a 7MGTE with stock ECU, and COPs with twin ignitors. I tried both types of adaptor-The "Camry GT" low level signal/diode method with several different designs/signals-no luck at all. Basically, the stock 7MGTE ignitor to coil signal needs a booster. So I made the "External Relay Weitzel" type, and it works. If you do this, be very careful-the diagrams posted to wire up the COP style are incorrect, and parts chioice and transistor pinout is key on the relay style-Ask me how I know:rolleyes: