Jump to content
Ultimate Subaru Message Board

coil hookup problems (help needed wiring)


Recommended Posts

Ok so i got the new distributor in (thanks brian) and hooked up the coil and all but where does the little cylinder thing that is grounded to the top bolt of the coil bracket get hooked up to? The mechanic just left it unhooked and im thinking thats a no no. I believe its a capicitor or diode? I only had one side of it hooked up before cause the other side of it had been missing since i owned the car. Any thoughts on this? I really need my car back asap.

Link to comment
Share on other sites

If its not complete, then its not worth it. It should run from the negative on the coil to the body but, if the wire that goes to either the coil or the body from the cylinder is broken, its worthless. I've removed some before and never had issues.

Link to comment
Share on other sites

wow interesting..that would explain why my stereo is so/ has always been so fuzzy..i never had that thing connected. Ok thanks for the help. Ill go pick up my car tonight with relative confidence that its all hooked up correctly.

Link to comment
Share on other sites

I believe its a capicitor or diode?

 

It's a capacitor, it's function is to limit radio static caused in the ignition coil, depending on it's age it could be bad, or good. Not connecting it up will not hurt anything, (other than maybe a bit of radio static), connecting it up if defective will cause all manner of ignition "gremlins". The safest route is disconnected. If you find excessive amounts of ignition noise results by not connecting it up buy a new one, they are only a couple of bucks.

Link to comment
Share on other sites

Well i drove it home and it made it home without a problem. Well unless u count the fact that it was a bit out of time..i heard it missing when i gave it light gas and it bucked a good amount as well. Ill have to advance the timing a bit since it felt good at heavier gas. Too bad for me though as i lost/misplaced my subaru 8/10 mm wrench. I hope it turns up otherwise ill be on the lookout for a replacement. that thing comes in handy a lot on this car.

Link to comment
Share on other sites

  • 2 months later...

Well when i did all this i took the shortcut since my shop told me that the original coil was still ok. I didnt even mess with the coil i just dropped in the distributor and went. Well last night the coil went out on me. Luckily i had thought ahead and had the spare that subarujunkie had sent with the distributor. Bolted that in and off i went. Anyone got any ideas as to why the old one went out? Maybe it was just time and i had stressed it from hooking it up wrong?

Link to comment
Share on other sites

Well last night the coil went out on me. Anyone got any ideas as to why the old one went out? Maybe it was just time and i had stressed it from hooking it up wrong?

 

Check to see if the coil is getting excessively hot after running for a while. You may need to install a current limiting resistor in the ignition power side of the coil.

 

Another tidbit of info on the capacitor. Along with suppressing noise in the electrical system it also helps protect the ignition circuit. When the ignition module opens the coil circuit to create the spark there is a "inductive kickback" in the circuit that creates a fairly large voltage spike. The capacitor reacts to the spike by shunting most of that energy to ground. The voltage spike has a lot of high frequency noise in it and that is what can cause trouble with the radio.

 

Capacitors normally block DC current due to the way they are constructed (two conductive materials seperated by a insulator), but if the capacitor has a internal short it will pass DC current, and in this case, to ground. You can use you ohmmeter to check the capacitor for a DC fault. As always, when taking resistance readings, remove power to the circuit and isolate the device being measured from the circuit. If a cap is good the ohmmeter will just show a reading climbing up to infinity. A shorted cap will have a steady low resistance. Normally they are very reliable unless they take an excessive voltage hit. Make sure your capacitor isn't shorted as it may be the reason the coil went bad.

Link to comment
Share on other sites

um i dont even have the capicitor hooked up :(. Damn. My capacitor doesnt have wires coming out of both ends. Anyone have a capacitor they can send me with both wires on it? I only have a wire on one side of it.

 

If the cap isn't hooked up then that eliminates it as a possible source of trouble for the coil damage. As far as the second wire goes it is really there. It is the metal case, that bonds to ground. The wire ties to the minus side of the coil.

Link to comment
Share on other sites

I think for the most part the voltmeters in the dash are pretty accurate. They do tend to read about 1 volt lower than the actual battery voltage due to wire losses between the battery and the meter. By checking the actual battery voltage with a good meter and comparing it to the dash meter you can make your own mental note for an adjustment factor.

 

Check to see if the coil is getting real hot after a drive. If it is then you will have to add a limiting resistor in the primary side. If the battery voltage is greater than 15 volts then there is a regulator problem.

Link to comment
Share on other sites

You're welcome. Be sure to feel the coil temperature and see how hot it gets. The voltage at the coil will hopefully be around 10 volts while the engine is running. If it is at the battery voltage you will most likely need the limiting resistor.

Link to comment
Share on other sites

ok just checked everything out. Heres what i found

 

With the car off the battery had 12.57 volts

With the car on the battery had 13.67 volts (so its not overcharging)

With the car on the coil had somewhere in the neighborhood of .98-1.04 volts. Does this mean there is something wrong? I would think i would see bigger numbers than these off the coil.

 

And to answer GDs question..yes they are both ND...the coil and the distributor. No mixing and matching here.

 

Oh and another thing to throw into the mix. It backfires...kinda pop pop pop through the muffler if i leave it in gear and let off the gas. Im thinking this is ignition related as well..but i also have a straight pipe out to a high flow muffler. Im just wondering if all this (the distributor or the coil) has to do with my hessitation/bucking problem that i cant seem to get rid of.

Link to comment
Share on other sites

Well it sounds like your coil problems are over with. I don't understand the voltage reading you took for the coil unless you are reading across the plus and minus connections. Regardless, the coil isn't getting hot and the engine is working so you are good there.

 

The poping you are hearing may be due to misfire in one of the cylinders or a exhaust valve mat be sticking. If a valve is sticking you could try the dollar bill trick at the exhaust pipe.

Link to comment
Share on other sites

For the coil yes i was reading across the positive and negative of the coil. What was the correct way of reading it? The cars got new plugs, wires, rotor, cap, and a used distributor from subarujunkie off a 4wd hatch. I doubt for some reason a valve is sticking cause of the way the car runs and sounds. Its just when you let off the gas that it does this. It did it very slightly before and now its noticable since i have no cats. Whats the dollar bill trick?

Link to comment
Share on other sites

To see how many volts are getting to the coil you need to place the probes between the positive side of the coil and ground. Your reading just shows there is very little voltage drop across the coil, which is as it should be. An open coil winding would have a lot of voltage across the contacts.

 

The dollar bill trick is done by holding a bill against the exhaust while at idle. If there is a valve problem the bill will try to go back into the pipe due to the vacuum.

Link to comment
Share on other sites

I would say that the noises are normal. My maroon Brat had no cat, just an empty shell(unknown to me, swear on my life) and 2"ish exhaust back to an el cheapo muffler. It would pop and crackel when I let off the gas. Its just an open exhausted subaru thing.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...