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Ignition Coil Question


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35 replies to this topic

#1 Markus

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Posted 06 June 2004 - 12:55 AM

I have a 90 Legacy Auto - Hitachi ignition coil and ignitor and think the coil may be faulty. The coil's primary resistance is slightly over the .77 ohm spec. but the secondary is 14.5k cold and 15.6k warm. I wouldn't think this alone makes it bad. The car misses at idle and whenever it has a load. The ignitor seems to be ok as a test of the terminals 1 to 2 and 3 to 2 makes a test light flash with engine cranking.

I understand the wasted spark works that the coil fires cylinder 3 & 4 at the same time but only one of them would be at compression thus being able to make use of the spark since the other is in exhaust.

When I hook up a timing light to plug wires 1 or 3 the light flashes at twice the rate when hooked to plug wires 2 or 4. I would not think this is a by-product of the wasted spark thing and think it may point to a bad ignition coil.

Is there someone that can confirm with a good running legacy if this is the case with timing light flash rate? I'm thinking that I am only getting half the cylinder fires that I need on cylinders 4 & 2 because of the light flash rate thing.

It would be a great help in my situation.

#2 alia176

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Posted 14 June 2004 - 02:49 PM

Markus,

Have you had this question answered? If so, what did you find out? If you still want to know, I'll try this experiement tonight for you. I'm trying to figure out a misfire on #3 and #1 so I'll be in there messing around.

Ali

.

Is there someone that can confirm with a good running legacy if this is the case with timing light flash rate? I'm thinking that I am only getting half the cylinder fires that I need on cylinders 4 & 2 because of the light flash rate thing.

It would be a great help in my situation.



#3 Markus

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Posted 14 June 2004 - 11:42 PM

Ali,

No I haven't gotten it answered. It must be a tough one.

Over the weekend I looked at the alignment of the timing belt on the cam sprockets. The head I was having the misfires on (drivers side) was one tooth off. I thought that was the problem, replaced the timing belt (not rocket science but not a oil change either) and it still has a problem. I thought that the ECU was messing with the spark some how based on a late signal from the cam sensor but that does NOT appear to be the problem as after I installed the belt (alignment alright now) I did the timing light check and the blink rate was still the same, twice as fast on the passenger side (good) versus the drivers side.

There must be something odd with the coil so today I placed and order to get a new coil. The ignitor seems to be firing the coil properly but the indication is that both coils seem to not fire the drivers side as much. I know it is one coil per back/front cylinders but maybe it has some weird failure mode.

Its getting real old.

#4 avk

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Posted 15 June 2004 - 06:34 AM

It might have to do with the timing light. Does it depend on a specific polarity of the current in the secondary circuit? On one side, the direction is from the ground and into the coil.

#5 alia176

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Posted 15 June 2004 - 10:29 AM

I understand your frustration as I'm in teh same boat! My wife's car is grounded until I fix this stalling issue. Once, she almost got rear ended on the hwy with a 18wheeler due to this problem. In my case, I'm experiencing the famous #1 and #3 cyl misfires.

Let us know how the new coil works out. I"m on my second coil.

We'll figure it out :banghead:

Ali


Ali,

No I haven't gotten it answered. It must be a tough one.

Over the weekend I looked at the alignment of the timing belt on the cam sprockets. The head I was having the misfires on (drivers side) was one tooth off. I thought that was the problem, replaced the timing belt (not rocket science but not a oil change either) and it still has a problem. I thought that the ECU was messing with the spark some how based on a late signal from the cam sensor but that does NOT appear to be the problem as after I installed the belt (alignment alright now) I did the timing light check and the blink rate was still the same, twice as fast on the passenger side (good) versus the drivers side.

There must be something odd with the coil so today I placed and order to get a new coil. The ignitor seems to be firing the coil properly but the indication is that both coils seem to not fire the drivers side as much. I know it is one coil per back/front cylinders but maybe it has some weird failure mode.

Its getting real old.



#6 Markus

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Posted 15 June 2004 - 12:06 PM

I'm not sure how the timing light can be effected in its operation. How would I check this out? Flip the orientation of the inductive pickup that I clamp onto the wire?

Ali, you're on your second coil? What did you do to determine to get the coil and was it a new one? With the construction of the coil I don't see how the cylinders can misfire in your or my case. 1 & 2 are on a coil and 3 & 4 are on a coil- right?

I also have another thread(s) where all of this really started:
Posted Image 90 Legacy loping idle - HELP!
'90 Legacy Poor Running

Markus

#7 avk

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Posted 15 June 2004 - 12:32 PM

Yes, flip the pick-up coil.

#8 alia176

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Posted 15 June 2004 - 01:47 PM

Yes, the coil was a new one. I simply checked the resistance values per the manual and one of the values came out slightly out of spec. Car still ran great except those occasional stalling.

I don't see how the coil misfires either...you'd think that 1 and 2 would both experience misfires. That's why I'm going to change the injectors from one side to the other to see what happens. If the fault follows the injectors then I have something concrete to go on.

THe spark plugs and wires were changed. I just don't want to throw any more parts at it.

Ali

Ali, you're on your second coil? What did you do to determine to get the coil and was it a new one? With the construction of the coil I don't see how the cylinders can misfire in your or my case. 1 & 2 are on a coil and 3 & 4 are on a coil- right?

I also have another thread(s) where all of this really started:
Posted Image 90 Legacy loping idle - HELP!
'90 Legacy Poor Running

Markus



#9 Markus

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Posted 15 June 2004 - 11:09 PM

The coil is with the UPS man now.

My injectors seem to be consistently firing use the screwdriver stethescope trick.

I tried the timing light thing and while I saw the flash rate change at times when I flipped the pickup it wasn't very consistent.

#10 alia176

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Posted 16 June 2004 - 09:22 AM

I've used the stethescope on the injectors and wasn't able to ascertain whether I was hearing that injector or something else. But it was a very rythmic sound. Interesting thing about my timing....it seems not as it should be. I'll check it again since I can't remember the degrees...but it seemed to me that the timing was way off. This was before I did the timing belt. Afterwards, the timing was still off. This is neither here nor there, but I just couldn't understand why the timing wasn't on spec. According to my Haynes manual, there really wasn't any way to change it. Is this really true?

Ali


The coil is with the UPS man now.

My injectors seem to be consistently firing use the screwdriver stethescope trick.

I tried the timing light thing and while I saw the flash rate change at times when I flipped the pickup it wasn't very consistent.



#11 Markus

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Posted 16 June 2004 - 07:18 PM

Its true. you can't adjust the timing as it is controlled by the ECU. When I had cars with distributors you were able to rotate the dist. CW or CCW to advance or retard the timing if it was off. The Soob is all ECU adjusted. Mine is right in at 20 deg Before TDC which I think is in spec, when I can get a read while it idles somewhat stable.

I hope to know my fate on Monday....when the new coil arrives.

Markus

#12 alia176

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Posted 17 June 2004 - 09:24 PM

I hooked up my timing light to all spark plugs to look for anomalies. Unfortunately, I didn't see anything unusual. They all seem to fire at the same rate. Maybe tomorrow, I'll try to switch the injectors from one side to the other!

Ali


Its true. you can't adjust the timing as it is controlled by the ECU. When I had cars with distributors you were able to rotate the dist. CW or CCW to advance or retard the timing if it was off. The Soob is all ECU adjusted. Mine is right in at 20 deg Before TDC which I think is in spec, when I can get a read while it idles somewhat stable.

I hope to know my fate on Monday....when the new coil arrives.

Markus



#13 Markus

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Posted 21 June 2004 - 08:07 PM

I got the coil, replaced it ANNNDDD.........NO CHANGE, ARGGG! :banghead:

My fuel delivery system checks out OK and it sounds like all the injectors fire but maybe I need to give them a cleaning. When I pull a plug wire on any cylinder the engine runs worse.

Just in case I am going to do an ECU reset but I am not hopeful.

The engine ran the same way before new plugs (with anti seize) and wires.

I need to think........

#14 alia176

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Posted 21 June 2004 - 08:54 PM

Sorry to hear bro, that truly sucks! I posted a plea for the use of a select monitor so that I can attack this thing intelligently. Let's keep at this and get :drunk: while we're at it!

Ali



I got the coil, replaced it ANNNDDD.........NO CHANGE, ARGGG! :banghead:

My fuel delivery system checks out OK and it sounds like all the injectors fire but maybe I need to give them a cleaning. When I pull a plug wire on any cylinder the engine runs worse.

Just in case I am going to do an ECU reset but I am not hopeful.

The engine ran the same way before new plugs (with anti seize) and wires.

I need to think........



#15 Markus

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Posted 21 June 2004 - 10:39 PM

That's a new term for me...what's a "select monitor"?

After the injectors I may be out of ideas. The only thing left is mechanical problems with the head. Has anyone seen this as a cause of the bad idle?

Markus

#16 alia176

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Posted 22 June 2004 - 06:30 PM

Select monitor is Subaru's diagostic device. Do a search on this board and you'll get lots of hits. You might be another candidate for this device..seeing as how we're sort of flying blind!

Ali



That's a new term for me...what's a "select monitor"?

After the injectors I may be out of ideas. The only thing left is mechanical problems with the head. Has anyone seen this as a cause of the bad idle?

Markus



#17 Markus

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Posted 22 June 2004 - 10:40 PM

Looking through my Haynes manual troubleshooting section for the descriptions of my problem the most recurring item is fuel injection trouble, then vacuum leaks (hoses, intake manfold & head) and then more serious mechanical problems.

I'll take another look at vacuum hoses and then check and clean the injectors.......and pray.

My timing belt was off a tooth and this I'm sure happened after it started running bad. Could one tooth off cause damage in EJ22?

Oh yeah.....used coil, make offer.

Markus

#18 alia176

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Posted 23 June 2004 - 08:52 AM

I tried spraying carb cleaner around the engine bay while the engine was idling. Didn't find any apparent leak and vacuum gauge showed proper readings. I tried removing injector #1 but the two phillips are corroded and refuses to budge. So I'm letting the soak with PB Blaster for a couple of days. Not trying to discourage you....but I ran a few injector cleaners through her tank to no avail. Hopefully, you'll have better luck than me.

Ali



Looking through my Haynes manual troubleshooting section for the descriptions of my problem the most recurring item is fuel injection trouble, then vacuum leaks (hoses, intake manfold & head) and then more serious mechanical problems.

I'll take another look at vacuum hoses and then check and clean the injectors.......and pray.

My timing belt was off a tooth and this I'm sure happened after it started running bad. Could one tooth off cause damage in EJ22?

Oh yeah.....used coil, make offer.

Markus



#19 Markus

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Posted 26 June 2004 - 05:35 PM

I used a vacuum gage to check out the system. Sweeps between 15 and 22 in correlation with the idle. When I run the engine around 1500 rpm a nice solid 21. So all seems ok with the vacuum system. It suggests ignition etc. problem as I was also going to check.

Well checking the resistance on all the injectors none of them are in; I have 17 ohms, 16, 15, 13 ohms. Replace all of them? Well the budget can't take that now and it does run, not well but runs. While its idling I pull the connector off of each injector. Cylinders 1,2 and 4 all idle worse, #3 no real change (this was the 15 ohm injector). I pull the plug wire on 1,2 & 4 runs worse or dies and #3 no real change. A surrogate plug in #3 wire fires fine. So I go for a drive with #3 injector unplugged. Get CEL, of course, ECU can't see injector, and it runs like it has a couple times on wet days, obviously missing #3 ALL THE TIME. Stop to put #3 back on and it runs better, just missing a lot but sometimes with real power like it used to run. Also, a small test light in the injector connectors for #3 and #1 both blink about the same so the ECU signal is ok?

So...can I remove the injector to clean/test it myself? I think I would be able to test it at work on the bench. Shouldn't I be able to (for electrical types out there) set a function generator to a 10V peak square wave at some low frequency and see the little guy operate? I would think I might be able to clean it some how.

Would this do any damage to the injector on the bench without fuel running through it?

Markus

#20 alia176

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Posted 26 June 2004 - 07:26 PM

Markus,

You sure are doing great diagnosing! Your idea of cycling the injector sounds good. I don't think you'll damage the injector as long as the duty cycle is not long. However, if you have a way to shoot some liquid through there then it'd nice to see the spray pattern. However, that'd require some serious plumbing.

Report back with your findings!

Ali

So...can I remove the injector to clean/test it myself? I think I would be able to test it at work on the bench. Shouldn't I be able to (for electrical types out there) set a function generator to a 10V peak square wave at some low frequency and see the little guy operate? I would think I might be able to clean it some how.

Would this do any damage to the injector on the bench without fuel running through it?

Markus



#21 Markus

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Posted 27 June 2004 - 09:46 PM

Well Ali,

The injector cap came off quite easy but I was not able to get the injector out of the bore. I didn't get to aggressive because if I broke it there would have been no driving for a while. I was able to get it to rotate about 90° but it would not back out and I was not ready to pull the fuel rail off.

I think I'm going to call around to some bone yards to see if I can get some used injectors. I suppose I could test those for operation (debug the test procedure on the bench) and try them out. Then if I break the current injector at removal I would at least have something to plug the hole and maybe even work!

If not.....I'll guess I'll need to buy one.

Did you have any luck getting a select monitor? I read about it in the shop manual.

#22 alia176

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Posted 28 June 2004 - 08:38 AM

I haven't had any luck with a select monitor yet and I don't really expect to I guess. I may just end up buying one if I something comes up on Ebay.

Good idea on acquiring spare injectors. If you have access to a diesel place, perhaps you can remove them and have them cleaned. You'll prolly need to buy the O rings along the way I imagine.

Tomorrow night, I'll check the resistance of each injector and will try to remove the injector cap. Hopefully the PB blaster has done its job by now on the two screws per injector.

Right now, my immediate issue is her front brakes. I replaced the pads and rotors and now she's squealing like a stuck pig :-\ I'll see if I can purchase some anti squeal shims for the pads tonight. This car is really starting to piss me off.

Ali



Well Ali,

The injector cap came off quite easy but I was not able to get the injector out of the bore. I didn't get to aggressive because if I broke it there would have been no driving for a while. I was able to get it to rotate about 90° but it would not back out and I was not ready to pull the fuel rail off.

I think I'm going to call around to some bone yards to see if I can get some used injectors. I suppose I could test those for operation (debug the test procedure on the bench) and try them out. Then if I break the current injector at removal I would at least have something to plug the hole and maybe even work!

If not.....I'll guess I'll need to buy one.

Did you have any luck getting a select monitor? I read about it in the shop manual.



#23 alia176

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Posted 03 July 2004 - 09:10 AM

I checked the injector resistance last night. Can someone tell me what's the spec? I can't seem to find them in my downloaded manual from Subaru


#1 11.6 ohm
#2 11.4
#3 11.4
#4 11.4

Markus, these #s are different from yours. :grin:

Also, I noticed lots of corrosion in the engine bay (which is why I can't remove the injector caps). Of particular concern is the Igniter. I wonder if it'd help to run a separate ground wire from the chassis to the battery NEG term?
Ali
'95 Legacy wagon

#24 Markus

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Posted 03 July 2004 - 04:57 PM

Ali,

Those values are dead on. Haynes says 11 to 12 ohms. I should probably try my DMM from work before writing off all my injectors just in case my old Radio Shack analog meter is inaccurate.

So...all your injectors are ok? What next?

I wouldn't run a separate ground as that could cause a ground loop, clean your mounting surfaces. Check your ground from the Neg terminal to the intake manifold/engine block with a DMM. You should be around an ohm or less. I checked mine a few weeks ago and was ok.

I broke down and bought a new injector from 1st Subaru and will be putting it in tonight/tomorrow. I hope the gods from Mount Fuji will smile on my injector offering...:D ...

Markus

#25 alia176

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Posted 10 July 2004 - 10:15 PM

Let us know of your outcome with the new injector.

In my case, I'm sort of wondering if a tired fuel pump could be the culprit of the famous #1 and #3 cyl misfire. I may just throw one more part at this SOB before selling it! My frustration is at an all time high with this car.

Ali




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