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#3 not firing - help!
Posted: Thu Jan 29, 2009 12:50 am
by woodrat
So, as I explained in my previous post "engine missing question" my legacy suddenly developed a miss one night on the way home. I went to put in new spark plugs and found that #3 was apparently stripped.
Today I finally dug in there, and pulled all the plugs, chased the threads, and replaced all the plugs with new ones, using antisieze. The one I thought was stripped was actually a little loose and it was obvious that it had not been firing, so I chased those threads too, and ended up saving myself from having to put a heli coil in there. Put it all back together, and it still misses. So I changed out the plug wires for ones off of another engine ( I tried buying beldens from NAPA first, but the boots were too small for the coil terminals, and they kept sliding off). Still misses, so I went back to the original wires.
So then I tried another coil off of another parts engine. Still misses. So I went back to the original coil, which looks pretty clean and new.
Took the #1 and #3 plugs back out and it was obvious that #3 had still not been firing. It was wet with gasoline, and looked like it had not fired yet at all. Double checked the threads again with the chase tap, put on anitsieze again and reinstalled those plugs. They tightened down nicely, but the car still misses the same as it always did.
Now I am stumped! I bought this engine with 80k on a rebuild and it was shiny and clean with new looking injectors and coil and has run like a top with no troubles until now, for about 17K since I put it in. the car has 276k on it now. Is it possible that the computer is not telling #3 to fire? I can't think of what else would be so cylinder specific if plugs, wires and coil didn't change anything.
Posted: Thu Jan 29, 2009 5:03 am
by entirelyturbo
Have you actually determined that #3 is not firing at all?
As in, have you tried maybe trying to arc the wire against a ground to see if it sparks?
Most cars with coilpacks use a waste-spark design. That means that the coilpack on a 4cyl engine, for example, only has two coils. In this case, the #1 and #3 plugs fire simultaneously, as do the #2 and #4. One of the sparks fires in the power stroke, like it's supposed to. The other fires I think in the exhaust stroke, essentially doing nothing, being 'wasted.'
So I don't think #1 is firing while #3 is not. You changing coilpacks and getting the same result is, to me, further indication of that.
Is the #3 injector stuck open, thus drowning the spark, causing the misfire, and soaking the plug in fuel?
Posted: Thu Jan 29, 2009 6:15 am
by woodrat
I had just finished reading the waste spark description a few minutes ago in the haynes manual and had just realized that it could not be just number 3 that was not firing. The plug was not soaking wet, but damp with fuel and showed no signs of having fired at all since I put in the new plugs, ie, metal still shiny and clean, with no combustion residue on it like the one next to it had. I will have to pull the injectors tomorrow and see about that.
The haynes manual told me I should use a calibrated spark tester, and I was wondering if I could just put a spark plug in the end of the wire and ground it like I've been doing to other cars for years, or if I would somehow hurt the system if I did not use this calibrated thingy.
Posted: Thu Jan 29, 2009 6:13 pm
by woodrat
OK, so I read the Haynes, and figured that I am not going to be able to pull the injector out and look at the spray when it fires, but I did listen to each one with a screwdriver. All are clicking away, but the number 3 one did sound a little less crisp or sharp than the other three. The injectors are red tops, and the engine is supposedly from a 94. Will the black top injectors off of my original 90 motor fit these fuel rails? are they so different that I should not mix them even if they do fit?
Posted: Thu Jan 29, 2009 6:35 pm
by glennda5id
Injectors prior to 92 will not fit. They will not work at all.
I would recommend putting a fuel pressure gauge on. Priming the pump and then seeing how long pressure holds. That will tell you if you have one stuck open or leaking.
Posted: Thu Jan 29, 2009 6:42 pm
by woodrat
if I had a fuel pressure gauge, I would do that. Am I correct that I cannot pull a fuel rail loose enough to see whether the injector is dribbling or not?
Posted: Thu Jan 29, 2009 11:46 pm
by glennda5id
I don't think its possible without bending the steel lines.
Posted: Thu Jan 29, 2009 11:51 pm
by woodrat
I went ahead and ordered a rebuilt injector. I'll get it tomorrow afternoon and hopefully that will be what the problem was.
Posted: Thu Jan 29, 2009 11:56 pm
by ericem
How much was the injector? I am thinking about replacing all 4 on my car in hopes of better fuel economy. A mechanic told me if they tick that means there bad.
Posted: Fri Jan 30, 2009 12:10 am
by magicmike
i'd swap injector 2 and 3 and see if the problem follows the injector before i'd spend a dime buying another one. also a fuel pressure gauge has to be cheaper than an injector and you can use it if thats not your issue ultimately
Posted: Fri Jan 30, 2009 12:17 am
by woodrat
a rebuilt injector from the import parts house in Portland is $60, with a $12 core. A new one is $110.
I'm way out in the sticks and couldn't find a pressure gauge any closer than 40 miles, and if I drive my truck 80 miles roundtrip to get a gauge, and then find out I need an injector, then it would be Monday before I get a new injector ordered in in Portland, and I would be making a 200 mile round trip there in the truck. Time and diesel cost money too, so I am going to spring for the injector and maybe I'll pick up a gauge while I am in the big city, too.
I'm used to working on older VW FI where I can pull an injector out and look at the spray pattern like that.
at this point, when I don't think it is the coil, and it doesn't seem to be the wire, and the plugs are brand new and that injector sounds different that the rest of them, then I think my odds are pretty good that it's the injector.
Posted: Fri Jan 30, 2009 12:28 am
by magicmike
its free to do what I mentioned and would save you the trip to go pick up an injector. Its just my opinion. I exhaust every possible option before spending money lol
Posted: Fri Jan 30, 2009 1:03 am
by glennda5id
I would second the idea to swap injector 2 and 3.
Posted: Sat Jan 31, 2009 10:16 pm
by woodrat
Got the new injector, got it home and then realized it is the wrong one. Totally different shape. So I guess this 94 engine is either not actually a 94, or has some other kind of injectors on it. What fun!
I will post a few pictures in a minute of what I have and hopefully someone can point me in the right direction. Since I am down for the weekend now without the correct part, I figure I would kill some time swapping injectors around as was suggested. But first, how are those things supposed to come out of there? I don't want to break it, but all I can seem to do is turn it around and around. It looks like maybe there is some special tool that grabs these little holes on the side for pulling, but I don't have that tool. How do mere mortals remove these without damaging them?
Posted: Sat Jan 31, 2009 10:35 pm
by woodrat
OK, here's some pix:
new injector that is not the right one:
Injector that I am trying to replace, on an engine that is allegedly a 1994 model:
Injector that is on my old dead engine that was the one that my 1990 car had in it when I got it:
The part numbers on the 1994 fuel rail are
17522 AA 170
A46-701 R65
Part numbers on the old 1990 fuel rail are
17523AA060
FU100-1011
Is there somewhere I can look up an engine number to tell me in what year it was manufactured?
Posted: Sat Jan 31, 2009 10:57 pm
by magicmike
how did you make it all the way home with the injector? you should have had the old injector in your hand at the counter to verify it was correct before you left. As for taking it out just pull.
Posted: Sat Jan 31, 2009 11:16 pm
by woodrat
I did not drive the subaru to the parts store. You're right, I should have taken the old injector with me, but I've almost never had these guys get me the wrong part in 20 years of dealing with them, so I got lazy.
Still would have been a wasted trip though, since the injector was ordered in, not stocked.
So in terms of switching injectors around, why switch 2 and 3, instead of 1 and 3?
Posted: Sun Feb 01, 2009 12:11 am
by tahiti350
1 & 3 are on the same coil, switching with #2 will make it obvious if it's the injector or a power problem.
Posted: Sun Feb 01, 2009 12:18 am
by magicmike
tahiti350 wrote:1 & 3 are on the same coil, switching with #2 will make it obvious if it's the injector or a power problem.
indeed.
Posted: Sun Feb 01, 2009 12:38 am
by woodrat
Got it.
Although, I was kind of leaning towards it not being a coil problem when changing to a different coil didn't change the problem.
Soon as I can get these suckers to come out, I'll try the switch. In the meantime, is there anyplace I can find some basic info about what injectors were on what cars and what they look like? I found this post (
http://bbs.legacycentral.org/viewtopic. ... 3549#63549 ), but the pictures are long gone.
Posted: Sun Feb 01, 2009 1:11 am
by magicmike
You have the correct injector that you thought you had. They go mainly by color from what I understand. I know the red are for the ej22t. might take a few days to ship but you might want to contact Blackbart from here. He sells used parts to people all the time.
also, have you swapped plug wires from 2 and 3? Make sure to only try one thing at a time to rule things out.
Posted: Sun Feb 01, 2009 1:48 am
by glennda5id
If you go to rockauto.com you can look up the parts for the different years. Prior to 92, things were pretty crazy with different injectors for turbo and NA and manual and auto, so that is atl east 4 different combos. Starting in 92 they starting using the red top ones for mostly both trans types in the NA's and pink top ones for both trans in the turbos.
Posted: Sun Feb 01, 2009 1:50 am
by woodrat
I tried a whole different set of plug wires, and nothing changed.
So this is a turbo injector? That might explain why I got the wrong one, since I told the parts guy I did not have a turbo. It makes sense, the guy I got the engine from had bought it from a subaru mechanic who had built it for his own car that then got wrecked.
thanks!
Posted: Sun Feb 01, 2009 1:51 am
by woodrat
I notice that most of the posts concerning injectors are about hotrodding and getting more fuel. Is there an injector that is better for fuel economy?
Posted: Sun Feb 01, 2009 7:04 pm
by magicmike
woodrat wrote:I tried a whole different set of plug wires, and nothing changed.
So this is a turbo injector? That might explain why I got the wrong one, since I told the parts guy I did not have a turbo. It makes sense, the guy I got the engine from had bought it from a subaru mechanic who had built it for his own car that then got wrecked.
thanks!
I'm not an expert in this area, all I'm saying is that it looks just like the injector thats on both of my 1994 ej22t's