Coils Going Bad

[tmastres]

OK I know a scant few of you RX300 owners have had a coil go bad on you and a few months ago I had one go bad too. Problem is last night I had another one go bad and I'm wondering if this is more common than I realize. Alternatively I'd love to find out why this seems to be a recurring problem fro me. My question is to anyone who has had a coil go bad previously: did you have the others go bad soon after or did you replace them all as a preventative measure?

I've got a 2000 with 97,000 ,, Thanks

[blk_on_blk]

Hey Tmastres, when your coil went bad, did the code point you to right one, and when you replaced it, was the problem remedied?

[tmastres]

Hey Tmastres, when your coil went bad, did the code point you to right one, and when you replaced it, was the problem remedied?

Yes, Unfortunately I don't remember the code but after looking it up I was able to determine that I had a mis-fire in cyl. #5. In the back, of course! Originally I suspected the spark plug and knowing what a nightmare they are to get out of the back I chugged the car over to my mechanic. He figured out right away that it was the coil and got a new one sent over and that cleared the whole thing up.

I had another one go bad about 6 mos. later, this one in#2 cyl. I was planning on replacing it myself but when I called my mech. to get the part number info he insisted on me bringing the car in and did it for me for the cost of the part, geuss he wasn't impressed by my DIY capabilities :D ( I do send him a lot of referrals though )

Anyhow , hope this helps. Are you currently experiencing a dead coil? If yo fix it let me/us know how it goes.

[blk_on_blk]

Thanks for the insight. Yeah, I went to start the vehicle yesterday and it had that rumbling "miss" feel to it, which was accentuated in "Drive" while stopped at a light. The 'check engine' light came on, and it started to flash on and off, which I thought was strange... I've usually seen them come on and stay on (nothing in the manual to say what the flashing means).

I'm pretty sure it's a coil... and hopefully just one, and hopefully in the front.... please, oh please . The odd thing was the vehicle had been running smooth, but every once in a while I'd get a little bit of engine shudder while sitting at a red light, but then it'd go away. That should have been an indicator something was starting to act up, but the engine light never came on... and it ran smoothly till the other day when I started it. I've never had problems with coil packs before... do you know if they show any 'symptoms' as they start to go bad, or do they just give out at some point?

I've got my buddy's code reader today (and driving my wife's ES), so I'll check codes tonight and report on the findings. Thanks again for the post and info. Now off to see if i can find the right codes for the coil banks and where they are.... whoops, spoke too soon, here's a link to the codes: http://www.troublecodes.net/Lexus/ I'm guessing 1,2,3 are in the rear, and 4,5,6 are in the front of the engine bay? From left to right?

[blk_on_blk]

Alright (sigh), so I pulled the codes, and three came up... P0302, P0446, and P0302. I'm guessing the P0302 is a repeat at different times and just stored in the computer, and it's a coil failure alright... the P0446 one kind of caught me off guard.

Starting with the P0302, it's a "Misfired Detected, Cylinder 2". Ah man, let me guess, cylinder 2 is the one in the dead center in the back, isn't it? Lucky me. So, at 117K miles, I think I'm going to be doing the plugs at the same time... gonna have to mentally prepare to dig into this one.

Now the P0446 looks to be a bit of a buggar to figure out... I'm going to do a little search on this one.

[tmastres]

Alright (sigh), so I pulled the codes, and three came up... P0302, P0446, and P0302. I'm guessing the P0302 is a repeat at different times and just stored in the computer, and it's a coil failure alright... the P0446 one kind of caught me off guard.

Starting with the P0302, it's a "Misfired Detected, Cylinder 2". Ah man, let me guess, cylinder 2 is the one in the dead center in the back, isn't it? Lucky me. So, at 117K miles, I think I'm going to be doing the plugs at the same time... gonna have to mentally prepare to dig into this one.

Now the P0446 looks to be a bit of a buggar to figure out... I'm going to do a little search on this one.

Actually , you may be in luck, well sort of. If I remember correctly the firing/cylinder order is

1 3 5

2 4 6

Front

So it may be an easier job than you thought. As I mentioned I've never done the coil replacement myself but I'd be intersted in knowing how difficult it is. On the surface , it seems like it should be pretty straightforward , but I found that things that we're a breeze on other vehicles become quite a chore on these rigs.

I'm also curious as to why these things go bad, and seemingly so randomly. I don't remember any warning signs either time I had a coil go out. One time I drove to work and all was fine and when I came out in the evening and started the car, it just ran , well like a car running on 5 cylinders. The second time I was sitting at a stoplight and it was idling fine, then, the old "5 cylinder" treatment. I really didn't notice a thing beforehand.

[blk_on_blk]

Ooooooh MAN!!! Tmastres, you just made my day! I did a quick check for the firing sequence, and you are spot on, which means this repair is a brrrrrrrrrreeze!!! Now it's a 3-minute repair! Now that it's such and easy repair, maybe I'll wait a bit on the plugs :whistles: :P ...I pulled the front three when I started having the problem just to see how the plugs looked, and they look great, so I think I'll leave the for a while. Chainging the front coil packs is about as straighforward as you can get... unhook a wiring harness, take out a bolt, replace the part, reconnect the wiring, and you're off and running (at least that's the hope ;) ).

I'm with you on not really understanding the coil pack and it's operation. I mean, I understand the basic concept of a charge/discharge unit to create spark, and I understand there is cyclical fatigue involve, but I have no idea about the stresses. I used to work in the dielectric development field where we had thermoset polymers we created for capacitive devices, and those took a heck of a fatigue during cycling, but there seemed to always be a lower limit to where the cycle was "infinite". I don't know if heat is involved in the coil pack design/operation, or if it's just electrical energy transfer, but I know this was also a frequent problem with other owners when I had my BMW 3-series. They run a coil pack technology and had failures... although there was a discussion regarding when one fails, the others could be right behind it, and so it was advisable to replace all six at once. I don't know how much validity there is to that statement, but seeing you had a second one fail in a relatively short period of time, there could be some truth. Maybe these just have a finite life cycle, and if they are all original, and one hits the end of it's life cycle, the others are close behind. Don't know if one failure can trigger the failure of another due to a load surge or not. I'm just not that proficient in it... but it's kind of unsettling to have one go out for no foreseen 'reason'.

Ah... man... thanks again for that. So the #2 cylinder is right front and center... phew, I was dreading spending a couple hours out there hugging the engine trying to replace the rear coils/plugs by feel. I'm sure I'll be doing that at some point, but not this weekend B) Thanks again...

[lenore]

Please note I also add some dielectric grease to the plug connection to alleviate any moisture corrosion on the contact.

[tmastres]

Awesome, man, Hope things go smoothly, let us know.

[blk_on_blk]

Yep, went smooth as silk. The part just showed up today, I installed it in about 3 minutes, and it runs nice and smooth. Took care of that code, but now I have EVAP canister code showing. One down and one to go!! Thanks again for all the input... made the job clear and easy

[tmastres]

Yep, went smooth as silk. The part just showed up today, I installed it in about 3 minutes, and it runs nice and smooth. Took care of that code, but now I have EVAP canister code showing. One down and one to go!! Thanks again for all the input... made the job clear and easy

Great news, look forward to doing the last four of mine (not). Glad it went well!