Engine miss or exhaust burble

Post by **Legacy777** » Thu Aug 28, 2008 3:31 am

In a continuation from this thread:
http://bbs.legacycentral.org/viewtopic.php?t=36996

I got new NGK power wires today. I gotten new wires since the old magnecor's had been in there since 97 or so. However they appeared fine. Anyway, as a check I put new wires in. No change in the original miss, or what I think is a miss.

The engine runs fine, I don't have any issues to really speak of. When revving in neutral if you go to the rear of the car you can hear what kind of sounds like misses or an interuption of the steady exhaust not. What I can't say for sure is, is that miss or interuption burble due to something in the exhaust, or is it an actual miss. Like I said, the engine runs fine, and it passed emissions test two weeks or so ago.

Anyway, the only thing left in the ignition system is the ignitor. That is original. Getting to is going to super suck. I'd consider swapping in another one to see if anything changes, but I kind of have my doubts. I don't know if it's something with the stock ECU either. Maybe putting the Link in might change things....make it better, or make it worse......who knows.

Thoughts, comments, diarrhea of the mouth....

Here's pics of the new wires
http://www.main.experiencetherave.com/s ... owerwires/

Only issue with the new wires is that they are not as fat as the magnecor's so they don't want to stay put in the plastic clips, as they're all stretched out. I may need to get new ones. We'll see.

93forestpearl · Post by **93forestpearl** » Tue Sep 02, 2008 2:48 am

How do those NGK wires feel vs. the Magnecors? What do they run a set?

Damn, you could seriously eat off anything in your engine bay.

RJ93SS · Post by **RJ93SS** » Wed Sep 03, 2008 4:45 am

, maybe a long shot josh but i have seen it a thousand times, are any of your plug wires arching maybe to metal or to eachother

Post by **Legacy777** » Wed Sep 03, 2008 6:26 pm

I honestly didn't notice any difference between the NGK's & Magnecor's. However the NGK's had significantly less resistance. I tested them before I put them in to compare to the Magnecor. So in theory, it's possible more spark energy is being released, but I didn't feel any seat of the pants difference.

As for cost, with shipping, they were $63.89 from www.sparkplugs.com

Yeah I can't stand dirty engine bays.....it helps too that I don't drive the car every day.

Post by **Legacy777** » Wed Sep 03, 2008 6:31 pm

RJ93SS wrote:, maybe a long shot josh but i have seen it a thousand times, are any of your plug wires arching maybe to metal or to eachother

It's possible, but since I changed wires and the same occurs.

What I might try and do is take a spray bottle and mist water over the ignition components at night and see if I notice any little archs/sparks.

Post by **Legacy777** » Wed Sep 03, 2008 6:34 pm

The other day I was showing a buddy, and getting his opinion and it just so happens I had the air conditioner on. Low-and-behold, I didn't have the issue, or if it was present it was much less pronounced.

It appears that providing load on the engine makes it go away or reduces it. So based on that, I'm not sure that it's necessarily a miss, but more so an issue with the factory tune.

Post by **Legacy777** » Thu Sep 04, 2008 2:35 am

Here's the resistance difference between the Magnecor & NGK

NGK

1. 0.533 kohms
2. 0.513 kohms
3. 0.519 kohms
4. 0.533 kohms

Magnecor

1. 4.16 kohms
2. 3.76 kohms
3. 4.26 kohms
4. 4.18 kohms

Note, the order on the Magnecor wires are probably not the same as the NGK.

IronMonkeyL255 · Post by **IronMonkeyL255** » Thu Sep 04, 2008 3:42 am

Um..... Don't you have the wires on incorrectly? Not that it would cause an issue, but you seem to have the 2 and 3 wires reversed.

Not that it makes much difference........

Post by **Legacy777** » Thu Sep 04, 2008 5:11 am

You got me. They came labeled that way from NGK.

IronMonkeyL255 · Post by **IronMonkeyL255** » Thu Sep 04, 2008 5:56 am

I actually just ordered the same wires the other day.

Along with all the stuff to get my car not smoking again.

93Leg-c · Post by **93Leg-c** » Sun Sep 14, 2008 12:39 am

My KV85's readings:

1--.481k
2--.535k
3--.195k
4--.555k

Wire #3 was the oddball but repeated testings came out to within .001k of each test.

tmarcel · Post by **tmarcel** » Fri Sep 19, 2008 2:51 am

Small vac leak? I'm finishing up a tune right now on a Toyota and this thing decided to pop several vac leaks (high mileage with a turbo). Ran great at first and then slowly but surely several leaks popped up. They were identified by the 'ol starter fluid trick, i.e. spray starter fluid around the intake manifold connection points. Fixed one then found two other small ones.

You can also measure the resistance on the fuel injectors and the voltage at the connectors. If you have one that has lower ohms than the others then it may very well be your problem.

Post by **Legacy777** » Fri Sep 19, 2008 6:57 pm

I don't think it's a vacuum leak due to everything being new, and the fact it idles fine. However I can't completely rule it out.

I have to take the intake manifold off to drill and tap the IAT sensor, and will be putting in new injectors, so we'll see how things go after I've done that work.

tmarcel · Post by **tmarcel** » Fri Sep 19, 2008 10:59 pm

Legacy777 wrote:I don't think it's a vacuum leak due to everything being new, and the fact it idles fine. However I can't completely rule it out.

I have to take the intake manifold off to drill and tap the IAT sensor, and will be putting in new injectors, so we'll see how things go after I've done that work.

Cool. I ended up just drilling and "attempting" to tap the intake manifold on mine for a GM IAT sensor. So now it's in there with JB Weld, although it's a very tight fit as some of the threads catch nicely.

tmarcel · Post by **tmarcel** » Fri Sep 19, 2008 11:01 pm

Legacy777 wrote:I don't think it's a vacuum leak due to everything being new, and the fact it idles fine. However I can't completely rule it out.

I have to take the intake manifold off to drill and tap the IAT sensor, and will be putting in new injectors, so we'll see how things go after I've done that work.

Cool. I ended up just drilling and "attempting" to tap the intake manifold on mine for a GM IAT sensor because I was being lazy

I did vacuum it from time to time but the hole came out too big. So now it's in there with JB Weld, although it's a very tight fit as some of the threads catch nicely.

entirelyturbo · Post by **entirelyturbo** » Tue Sep 23, 2008 10:50 pm

I've written this off as another Subaru quirk. Possibly because the idle is set slightly too low. Maybe that's why it didn't do it as much with the A/C on, since that raises the idle a tad.

My car has done it since the first day I've owned it, regardless of condition of plugs, wires, air filter, whatever.

As a matter of fact, I'd be a little disappointed if it didn't do it.

These aren't V12 Jags.

Post by **Legacy777** » Wed Sep 24, 2008 12:46 am

It doesn't really do it at idle per say, but at a high idle. I still think everything is fine, and that it's just a quirk of the engine management.

ciper · Post by **ciper** » Wed Oct 01, 2008 2:06 am

My 91 sedan does this. I'm wondering if there is a difference if the ECU is wired as automatic or manual. I thought I remember hearing the auto ECU jumper makes it adjust timing at idle...

How is your ECU configured?

tmarcel · Post by **tmarcel** » Wed Oct 01, 2008 4:04 am

ciper wrote:My 91 sedan does this. I'm wondering if there is a difference if the ECU is wired as automatic or manual. I thought I remember hearing the auto ECU jumper makes it adjust timing at idle...

How is your ECU configured?

Wouldn't surprise me if there's a table to adjust timing per the AT model vs MT.

Post by **Legacy777** » Wed Oct 01, 2008 7:36 pm

Mine is configured as a MT. If you configure as an AT, idle will be too high.

Funny you mention it though. The ECU I'm using is a 91 turbo ECU I believe. I think I have one of the 92-94 turbo ECU's. I could try that and see if it makes any difference in how the engine runs.

ciper · Post by **ciper** » Thu Oct 02, 2008 10:01 pm

Legacy777 wrote:Mine is configured as a MT. If you configure as an AT, idle will be too high.

What about when the auto is in park or neutral? The idle RPM seems to stabilize.

Post by **Legacy777** » Fri Oct 03, 2008 12:19 am

The neutral switch inputs are backwards for the AT & MT. So just hooking up the neutral switch for the manual trans and keeping the ECU pinned as an AT will produce some weird results.

WoodsWagon · Post by **WoodsWagon** » Tue Oct 07, 2008 2:02 am

I had a problem like this on my EJ22 that I'd swapped into my loyale. What it turned out being was that we had swapped the two passenger side injector plugs. In other words, cyl 3 plug on cyl 1 injector. Ran fine, but would miss occasionally at idle. As soon as you brought the idle up it would go away.

Brat4by4 · Post by **Brat4by4** » Tue Oct 07, 2008 3:41 am

Legacy777 wrote:It doesn't really do it at idle per say, but at a high idle. I still think everything is fine, and that it's just a quirk of the engine management.

My '93 has had the slight miss at high idle since the day I got it over 5 years ago.

Nothing has ever made it gone away, I've made it a lot worse at times... but never better.

I'd say an ECU anomally or side effect of the "bang-bang" exhaust setup.

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Engine miss or exhaust burble

Engine miss or exhaust burble