Cylinder #2 misfire mystery
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Just found these forums yesterday. What a great resource!
Yesterday on the way home My wife's '02 RX300 started misfiring. I have a codescout 2500 which says "Cylinder #2 misfire". I figured 'hey, it just crossed 100k, probably time to change the plugs.' Picked up some iridiums and put all six of them in. Same code. Swapped coils 2 & 4. Same code - #2. Changed coils with 2 & 6, same code. Can feel the injector firing, but swapped 2 & 4 anyway (careful not to lose any o-rings!). #2 doesn't look as nice as #4 around the base, but no change. Same code. Each time I change something I reset the code and it takes about 45 seconds to 2 minutes to re-display the code, and it's always code #2 misfiring.
I know I'm on the right cylinder because if I pull the injector control wire or coil wire from 4 or 6 the engine *really* bogs down, but if I pull #2 nothing happens. It's still missing, it just doesn't get any worse.
I've left the injectors swapped just because I don't want to take the rail off again, but everything else is back (except for the new plugs).
Any ideas?
Yesterday on the way home My wife's '02 RX300 started misfiring. I have a codescout 2500 which says "Cylinder #2 misfire". I figured 'hey, it just crossed 100k, probably time to change the plugs.' Picked up some iridiums and put all six of them in. Same code. Swapped coils 2 & 4. Same code - #2. Changed coils with 2 & 6, same code. Can feel the injector firing, but swapped 2 & 4 anyway (careful not to lose any o-rings!). #2 doesn't look as nice as #4 around the base, but no change. Same code. Each time I change something I reset the code and it takes about 45 seconds to 2 minutes to re-display the code, and it's always code #2 misfiring.
I know I'm on the right cylinder because if I pull the injector control wire or coil wire from 4 or 6 the engine *really* bogs down, but if I pull #2 nothing happens. It's still missing, it just doesn't get any worse.
I've left the injectors swapped just because I don't want to take the rail off again, but everything else is back (except for the new plugs).
Any ideas?
#2
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Just found these forums yesterday. What a great resource!
Yesterday on the way home My wife's '02 RX300 started misfiring. I have a codescout 2500 which says "Cylinder #2 misfire". I figured 'hey, it just crossed 100k, probably time to change the plugs.' Picked up some iridiums and put all six of them in. Same code. Swapped coils 2 & 4. Same code - #2. Changed coils with 2 & 6, same code. Can feel the injector firing, but swapped 2 & 4 anyway (careful not to lose any o-rings!). #2 doesn't look as nice as #4 around the base, but no change. Same code. Each time I change something I reset the code and it takes about 45 seconds to 2 minutes to re-display the code, and it's always code #2 misfiring.
I know I'm on the right cylinder because if I pull the injector control wire or coil wire from 4 or 6 the engine *really* bogs down, but if I pull #2 nothing happens. It's still missing, it just doesn't get any worse.
I've left the injectors swapped just because I don't want to take the rail off again, but everything else is back (except for the new plugs).
Any ideas?
Yesterday on the way home My wife's '02 RX300 started misfiring. I have a codescout 2500 which says "Cylinder #2 misfire". I figured 'hey, it just crossed 100k, probably time to change the plugs.' Picked up some iridiums and put all six of them in. Same code. Swapped coils 2 & 4. Same code - #2. Changed coils with 2 & 6, same code. Can feel the injector firing, but swapped 2 & 4 anyway (careful not to lose any o-rings!). #2 doesn't look as nice as #4 around the base, but no change. Same code. Each time I change something I reset the code and it takes about 45 seconds to 2 minutes to re-display the code, and it's always code #2 misfiring.
I know I'm on the right cylinder because if I pull the injector control wire or coil wire from 4 or 6 the engine *really* bogs down, but if I pull #2 nothing happens. It's still missing, it just doesn't get any worse.
I've left the injectors swapped just because I don't want to take the rail off again, but everything else is back (except for the new plugs).
Any ideas?
#3
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Getting a code is one thing, but if possible, you should verify the problem. Cylinder misfire (actual) can be experienced by rough engine and loss of power. Without these, there is some other problem. I would suspect it is the sensor or wiring to-from-cpu.
If it was the actual misfire then you would trace the spark path or fuel.
Salim
If it was the actual misfire then you would trace the spark path or fuel.
Salim
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It definitely runs rough and has loss of power. I had moved the coil to Cyl #4 and the problem didn't move with it. I'm going to go over my troubleshooting again this morning, and move the new plug from 2 to 4 to make sure I didn't get a bad one out of the box.
Cyl #2 is in the front-left, as I'm facing the engine, right? Like this:
Firewall
_______________
|--1---3---5--|
|-------------|
|--2---4---6--|
|_____________|
Front of car
--JATF
Cyl #2 is in the front-left, as I'm facing the engine, right? Like this:
Firewall
_______________
|--1---3---5--|
|-------------|
|--2---4---6--|
|_____________|
Front of car
--JATF
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My bad ... your picture is correct.
Incidentally when I lost #2 at 140K miles, I replaced all plugs. When I started the engine the problem moved to #4 and it ignition pack died on #4. After replacing that, every thing went to normal for me.
Salim
Incidentally when I lost #2 at 140K miles, I replaced all plugs. When I started the engine the problem moved to #4 and it ignition pack died on #4. After replacing that, every thing went to normal for me.
Salim
#6
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Two other possibilities:
1. Bad injector. (like you said)
2. Low to no compression on cylinder 2. (worse one)
I would do a compression test first to rule out a bad cylinder. Then replace the injector.
1. Bad injector. (like you said)
2. Low to no compression on cylinder 2. (worse one)
I would do a compression test first to rule out a bad cylinder. Then replace the injector.
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I wound up checking the spark against the frame and it worked fine.
Unfortunately, the compression meter does not lie. 70psi on C2, 195 on C4 & 6.![Crying](https://www.clublexus.com/forums/images/smilies/Peace.gif)
I've turned it over to my local shop. He has a scope to see if it's a broken valve, a pulled seat or worse. It happened all of a sudden so I don't think it's the rings. Well, at least I can hope, right?![Sad](https://www.clublexus.com/forums/images/smilies/sad.gif)
Thanks for all your help. It helped me keep from going crazy chasing it down.
--JATF
Unfortunately, the compression meter does not lie. 70psi on C2, 195 on C4 & 6.
![Crying](https://www.clublexus.com/forums/images/smilies/Peace.gif)
I've turned it over to my local shop. He has a scope to see if it's a broken valve, a pulled seat or worse. It happened all of a sudden so I don't think it's the rings. Well, at least I can hope, right?
![Sad](https://www.clublexus.com/forums/images/smilies/sad.gif)
Thanks for all your help. It helped me keep from going crazy chasing it down.
--JATF
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#9
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Lexus parts will most likely have a different part number than a Toyota part number of a sister model offered under Toyota badge.
Should a Lexus customer blindly cross over and purchase Toyota part from its sister model?
Let me take it a step further and ask should '98 model Lexus RX purchase 02 Lexus RX part? For generic part the answer is yes. But if it is a specific part which interfaces with certain model ecu, then NO. Provide the VIN to get the right part. [Ex: Knock sensors --- they have different part number based on manufacture date ... do not confuse it with superseded ...more on superseded part later].
My way is to buy parts from online Lexus retailer and my savings comes from DIY.
Salim
PS: Superseded parts: Based on use/quality_concerns/cost Toyota/Lexus may discontinue and substitute with another part number. I would alway urge members to call Lexus parts and get the latest part number before purchasing genuine yet discontinued part.
On lighter note: Is Lexus the same as Toyota? I jokingly say if you purchase Toyota parts, you should openly state that you drive a Toyota.
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