i just changed all eight coils and plugs on my 99 LX 470. according to the service history two had been changed in aprox 2007. i figured the rest were nearly twenty years old so i just changed them all. what brought this all on was the heater hose T failed and the coil number 7 failed a few weeks later. the car does start with a burst and does run a little better but the car was running fine before the coil went bad anyway. car has 237000 miles.
When to replace Ignition coils. (1 Viewer)
- Thread starter 2001LC
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2001LC
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- #142
Thanks for sharing.
Good to know it starts with a burst now and runs a little better. I've long held the belief Old Coils can deliver weak and uneven spark from one to the next. Resulting in a slight balance issue. Showing up in rough idle, poor acceleration that not smooth. But still the engine will run fine, just not peak.
Pictures of the old?
really nothing strange looking about the old ones. other than just a little discoloration of the boots but not bad. i will keep the other seven coils as spares to use while i order new in case of future failure. i have two other 2uz fe engines to maintain
2001LC
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Brand and parts number info would be nice?
BTW: I put out and alert some time ago: Spark plugs are walking out. We tring 18ft-lbf of torque (FSM is 13ft-lbf) for those changing plugs with coils. One should at minimum clean and inspect spark plugs when replacing coils.
Spark plugs Alert Alert Alert!
BTW: I put out and alert some time ago: Spark plugs are walking out. We tring 18ft-lbf of torque (FSM is 13ft-lbf) for those changing plugs with coils. One should at minimum clean and inspect spark plugs when replacing coils.
Spark plugs Alert Alert Alert!
I ended up blowing a plug out of a vehicle while on vacation in northern Montana a few years ago just outside of Glacier. Shattered the top of the ignition coil and forced a helicoil. Lesson learned, check these regularly just to be safe.
Macine shop, vehicle was a Honda Odyssey, yes still holding 30k miles after.
Yes.
i used OEM coils and plugs. cost a few coins but have only had two coils replaced since 99 and 237000 miles so i figured after this many years it was worth the expense. i took the car out on the road today and i am sure i can feel an improvement in performance,probably because my wallet doesn't weigh as much as it did. the old coils will be used as spares for emergency uses on the other engines.
Thanks for this post. i did read your alert when i was researching before the repair. i was careful not to over tighten the plugs and i did use a wisp or anti seize on the new plugs. there was three that came out hard but with a little time and WD-40 i got them out ok. i would definitely advise any high mileage owners to baseline all eight cylinders with new plugs and coils. i wouldn't say the engine ran rough before the repair but it does run smoother now. i think because all eight are getting the same ignition energy. i wonder how the MPG will be affected?
2001LC
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- #154
So I just did a full 8 coil replacement.
I first replaced one coil that was misfiring only under load with a used coil with similar mileage and age. I'd feel the misfire while sitting at light in "D" with foot on brake. It would go away while driving or idling in "P". Before replacing the one coil, I was also getting a raw fuel smell while idling.
Test drove before replacing all 8:
Pre test drive was after extensive fuel system work (Inspect interior of fuel tank & fuel pump sock, Fuel filter, Fuel injector Clean - rebuild & testing, New Fuel pressure regulator, New OEM air filter, Clean MAF sensor, Throttle body cleaning, All new vacuum lines, New intake manifold gaskets) and new Denso spark plugs.
It ran ok, but felt it could use improvement, I suspected balance of coils was off. Starting was good, but at times a little slow to fully engage. Fuel trims between banks was not as balanced as I'd like to see, Idle seemed ok but could be a touch better. Power cure was ok, but could I get better?
Test drive with 8 new Denso coils in:
I took out on test drive in the heat of the day and monitored fuel trims, once I had the 8 new Denso coils in.
I noticed better balance between bank 1 and bank 2 fuel trims. I notice idle just a little steadier, most noticeable while stopped at light in "D". Also notice it started a little pepier. Also has just a little smoother acceleration onto HWY. These are just incremental changes only few would even notice as I do.
Feeling and seeing the difference, albeit small, has convinced me old coils even though not dead or not even misfiring do loose some spark and fire unevenly.
Denso 673-1303 were shipped to me and inslatted.
I first replaced one coil that was misfiring only under load with a used coil with similar mileage and age. I'd feel the misfire while sitting at light in "D" with foot on brake. It would go away while driving or idling in "P". Before replacing the one coil, I was also getting a raw fuel smell while idling.
Test drove before replacing all 8:
Pre test drive was after extensive fuel system work (Inspect interior of fuel tank & fuel pump sock, Fuel filter, Fuel injector Clean - rebuild & testing, New Fuel pressure regulator, New OEM air filter, Clean MAF sensor, Throttle body cleaning, All new vacuum lines, New intake manifold gaskets) and new Denso spark plugs.
It ran ok, but felt it could use improvement, I suspected balance of coils was off. Starting was good, but at times a little slow to fully engage. Fuel trims between banks was not as balanced as I'd like to see, Idle seemed ok but could be a touch better. Power cure was ok, but could I get better?
Test drive with 8 new Denso coils in:
I took out on test drive in the heat of the day and monitored fuel trims, once I had the 8 new Denso coils in.
I noticed better balance between bank 1 and bank 2 fuel trims. I notice idle just a little steadier, most noticeable while stopped at light in "D". Also notice it started a little pepier. Also has just a little smoother acceleration onto HWY. These are just incremental changes only few would even notice as I do.
Feeling and seeing the difference, albeit small, has convinced me old coils even though not dead or not even misfiring do loose some spark and fire unevenly.
Denso 673-1303 were shipped to me and inslatted.
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I just replaced all my plugs and coils and I can confirm what @2001LC says about performance boost. Throttle response is much smoother and more powerful if that's even possible. Like most others, I didn't have any misfires, albeit occasional stumbles I feel like. I used a tiny bit of anti seize, 3 or 4 plugs were a little resistant to come out. Super happy about it. Do the right thing... treat your motor to new plugs and coils...
Anyone have any idea what was going on with these two coils/plugs? They are remarkably more brown/crusty. They are the front two cylinders drivers side.
Is that something to watch for with the new coils?
Is that something to watch for with the new coils?
....leak... like cracked head?
2001LC
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- #160
Let me add a note here about the NONE Toyota Dealer Denso coils above:
Note: You may have seen I peeled back the part number sticker. It revealed a differ Denso PN. I've not found a cross reference (not looked much) on that revealed part number, which was not in list of numbers I had for the 100 series (I don't have all). So I can't say for sure they're Toyota approve power curve/output or whatever. But they did look like real Denso's and seem to work well. Also my buyer of The Unicorn send me these coils to me from different sources. They all looked the same, but I did not pull sticker back to confirm hidden PN's to see if all the same.
Also I've talked with my Toyota parts guy in the past on why we've different PN for different years of the 100 series and why each different one has superseded part numbers. Bottom-line "we don't know". We can only make assumption.
I'm more comfortable paying a high price at Toyota. But sometimes it's not up to me of which are used.
Note: You may have seen I peeled back the part number sticker. It revealed a differ Denso PN. I've not found a cross reference (not looked much) on that revealed part number, which was not in list of numbers I had for the 100 series (I don't have all). So I can't say for sure they're Toyota approve power curve/output or whatever. But they did look like real Denso's and seem to work well. Also my buyer of The Unicorn send me these coils to me from different sources. They all looked the same, but I did not pull sticker back to confirm hidden PN's to see if all the same.
Also I've talked with my Toyota parts guy in the past on why we've different PN for different years of the 100 series and why each different one has superseded part numbers. Bottom-line "we don't know". We can only make assumption.
I'm more comfortable paying a high price at Toyota. But sometimes it's not up to me of which are used.
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