signs of bad coil?

well the Jeep sh!t the bed on me tonite, 1 hour into a 3 hour drive home.
Everything seemed fine, then the voltmeter went to 0. It happens so I pulled over, popped the hood and wiggled the wires going to the Alt (jimmy rigged clips to Durango alt, not same plug as stock)
Lights got brighter, idle picked up a bit and all seemed fine. Drove another 20 minutes, pulled out to pass someone, and it happens again.
Pulled over, went to giggle wire again (will not stay on male plug coming out of alt) I pull the female part off, to squeeze it with pliers so it will hold better, but when I goto put it back on it shorts out on the case of the Alt and the truck shuts off. I finish putting the wire where it supposed to be, go inside to start it... and nothing.
Sounds good, everything is in right place, volts are still high, just won't catch.
After trying lots of dif things I check for spark, and don't have any. Check distributor, seems fine, clean, dry and everything on tight. Unplug dist. from the coil to check the coil... nothing coming out. Hooked the multimeter to the coil, and never got anything. Now I could see a spark when I first pulled over and it was running (in the dark I could see each of the spark plugs firing, or atleast lights from it) But now there is no spark, and it seems the coild isn't sending anything to make a spark.

what I have done = multimeter battery, and checked for current getting to coil. unplugged battery to reset anything could be wrong that way. checked for spark (none), checked coil output (put mm on 12v red to coil, black to battery, nothing registers) fuel line has pressure, drained it, tried again, built pressure again... now I am lost.

Any ideas on what this could be?

The only thing I can think of is to get a new coil and replace this one. But since its 2 hours away I need to have other ideas incase I get there and this doesn't work. Worst case I will have it towed and fix it here, but I would like to be able to drive it away.

Ask away, if I can add anything I will, or tell you anything I will... but I need some help.

So you are getting current to the coil?

Sounds like its bad then.

Put a spark plug in the socket at the end of the coil wire.

Ground the shell of the plug to the engine somehow (rest it against metal, use a clip lead - something.)

Connect the coil directly to the battery.

Disconnect the coil from the battery.

When you disconnect the coil, you should see a spark at the plug gap. You should not see a spark when or while the coil is connected - it doesn't work that way. If you don't see the spark when you remove power from the coil, it's shot.

Simple and definitive test.

ok, will look into the coil test.
my main concern is that I have to travel 2 horus to get to it, so I want to go there with a few ideas, and ways to fix what I hope is wrong.
Picking up a new coil (Accel or whatver the parts place has I guess) is not a big deal, but if there are any other ideas I can take with me the better.

I have cut n pasted 5-90's test, and will take it with me.

I am just wondering what it was I could have fried when I shorted out the wires going to the Alt. When I put the Durango Alt in, the plugs were different, so I just used the smallest female clips I could find, they work, but obviouslty aren't the best piece for the job. The wires don't seem to have a specific destination, the rig runs fine (ran fine) with either wire attached to either clip off the alt. I take it these are switches to engage the alt clutch... and not sure the other.

I am hoping its just the coil, not a big deal, new one, replace old... boost and drive home. But could I have fried the Computer instead?

Thanks both for your help so far, looking forward to any further.

Taking off early today, getting membership for CAA (AAA Canadian style) and hopefully won't need them, but worst case call them a few hours after getting membership for a long tow home.

It's possible that it's the CPS or Computer. Mine was showing those same symptoms when the CPS went out.

Just some ideas...

passxj
will add it to the list, thanks.

5-90
just so I don't screw your instructions up, there are 2 large wires going to the coil, one towards the front of the vehicle, one to the rear. which of those do I attach to the battery (and I am thinking to the POS/Red side right?)


gonna give the dealership a call, hope they can give me a hand over the phone, or some ideas atleast.

The one that doesn't look like the end of a spark plug goes to the battery. It is a "female" recepticle +12 and ground.

The other end, which looks like the end of a spark plug; goes directly to the center of your distributor cap.

Blaine B. said:

The one that doesn't look like the end of a spark plug goes to the battery. It is a "female" recepticle +12 and ground.

The other end, which looks like the end of a spark plug; goes directly to the center of your distributor cap.

Click to expand...

Well the Jeep is back, tow was gonna be $325... instead, Uhual trailer was $75, $100 in gas with buddies truck. Its sitting in the garage awaiting repairs.

On my coil, I know the wire that goes to the dist. but than there are two others (battery cable size) on the pass side... one going to the alt I think and the other to the starter maybe, can't think of it right now, I will either get a better explanation or take a picture.

Now I am wondering it if buying a used coil is worth it (if thats the prob) or if its worth buying an Accel unit. Not that I am looking for a super upgrade, but is the extra money for a new unit (which may be upgrade too?) worth it?

Thanks again for all the help, I am constantly blown away by the assitance given, and in such a timely fashion.
Much Appreciated.

more on this subject
just got into this problem for the first time since it happened.

I tried running the coil test that 5-90 posted, but I couldn't get it to work without shorting out the jumper cables I was using.
First I had spark plug attached to coil and casing grounded to the battery, and just tried starting the engine to see if there was any spark. None
Second I did what 5-90 said, but when I tried attaching the coil to the battery, it sparked and the clip starting glowing red hot... so I took it off quickly.

SO with this info I would guess it is the coil and it needs replacing. Does this sound about right?

Also, if replacing the coil, is it worth the extra to get a new one (Accel should be readily available) or is a used junker one ok? If new, OEM or do I wait for a Mallory/MSD/Accel one to be shipped in?

I once had jeep shut off on the road. I pulled a wire and stuck a screwdriver in it and held it to ground (metal). had a buddy crank it, noticed the spark was very faint. Put on a unit with 100,000 on it, and it works fine.

simple: check to see if coil is getting current. My best guess is YES. Coil is pad or rotor/cap problem. NO. crankshaft sensor. My brothers 97 had 90K when the CKS went. Plastic end was worn through to metal.

It may be obvious, but check your ignition fuse... a buddy of mine's tacoma blew it and we had to tin foil it to get it to start and run... hope its that simple for ya man

well it turns out I did the coil test incorrectly. after replacing the coil and taking the old one out, I see what I was connecting too was the engine grounds... since I had no idea what it was I was looking for, I went with the wires that were most obvious. so with a new coil in... no change.
So the search continues.

as for the ignition fuse, will have to look for it, not sure what or where it is.

not sure how to test if the coil is getting current. but can look for a CPS to replace this one. Worst case I have an extra one for the future if thats not the problem.

Find some one with a scan tool. The voltage regulator is part of the engine computer. If you shorted the alt wires, you may have killed the PCM. Also, with a scanner you can test injector pulse and make the coil fire to test them. I'm guessing from previous Chrysler experience you wont get any response from the computer. It would be worth the diagnostic charge to find out before you spend a lot of money on parts you don't need.

Neal

had the same issue when my o2 sensor wires melted to the exhaust and shorted out it blows a maxi fuse in the relay box in the engine compartment, i believe its labeled for the ECM but i would go through and check them all with a multimeter/ test light not just visually because those MAXI's can be deceiving. let me know if its that easy, im thinking your looking in the wrong direction with the coil.

ya I am thinking the coil is not the problem anymore.

so when a scan tool is mentioned, is that just the one you can pick up at NAPA and such? or the one the mech has?
just so happens the local store has one for sale
http://www.canadiantire.ca/browse/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524443293139&FOLDER%3C%3Efolder_id=1408474396672077&bmUID=1195966785115

I have thought about picking one up before, I guess this is as good a time as any.

Now since I am unable to get it running, will the tool still be able to get info from the system? The battery has been disconnected sine it was shorted out.

I think I will pick it up anyway... find out the hard way.

If your getting spark, check for fuel. If neither, again I'd put money on CKS. In no way is a 97 'too new' to have the cks go, seen it on a couple 97's earlier than usual.

no spark, got fuel pressure tho, bled it, tried again, re-pressurized no problem.
Still trying to figure out which Code reader to buy. But will look into CKS too.

The problem with a cheap code reader is it doesn't give any data, just trouble codes. If the check engine light isn't on, it won't tell you any thing. The most you will get is a no communication message. I know you are trying to learn to do this yourself and save money, but I would try to find a real scan tool and some one who knows how to use it. Even if you get a code, it doesn't tell you whats wrong. The code just gives you an idea of where to start looking.

The fuel pressure is a good sign, at least the computer has control over something.

Does the check engine light come on with the key on?

check engine light does come on, but when I try the key on-off-on-off-on trick nothing comes up.
Also, the voltmeter goes to 12v in key on position, than after a few seconds it drops to 0... I know they aren't exactly reliable, but I found it odd that it happens now and then since this problem has arisen.

OK So I am stupid.
Little pissy right now at my own ignorance.
20amp fuze was blown, my fuze tester showed it was working but my multimeter said otherwise, visual was quite obvious... blown. Replaced it, started right up.
However the Alt is bugared, won't recharge, so me thinks I may have fried the diode in the alt when I shorted it out a week ago.
Thanks to all for the help, advice, assitance and everything else you did to aid me.
I tested the fuzes as my new $280 OBD2 Code Reader was doing its thing.
Reader gives this info, will be looking that up after I relax a bit here.
P1389 - No ASD relay output voltage at PCM
P1694 - No CCD message from PCM - Aisin transmission