HELP! Codes after Spark Plug Change
10-07-21, 08:09 PM
#16
I think a good starting point would be to get a laser thermometer (Walmart for $20...i was surprised), start the engine in the morning when its cold and give it 10 min to warm up to operating temperature. Start checking the exhaust header cylinder by cylinder to check if temps are within 5-10% of each other. Not enough fuel it would be hotter and too much would be cooler, that would be a injector issue. If all are in range of each other the next step would be to check coils and their resistance or ohms.... Easier way to check the coils is to buy new ones 😜. Unlikely the PCV would effect just 1 cylinder but its cheap and easy to swap out so just do it for peace of mind and can eliminate that. Im not sure if he said anything about noticing any driveability issues, but that would give a good idea to what direction to look going forward. Additionally, getting a cheap bore scope off amazon for about $30-$40 would be great for sticking down through the spark plug hole to check the top of the piston and valves for anomaly's.
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Neophyte2b (10-08-21)
10-08-21, 05:08 AM
#17
Intermediate
Thread Starter
10-08-21, 05:14 AM
#18
Intermediate
Thread Starter
After looking at the base of the plug where the threads are above your fingers, is that wetness? Did you spray WD-40 in the spark plug hole before trying to remove? Or by any chance was the plug very easy to remove? Have you ever replaced your PCV (Positive Crankcase Ventilation)? Do you ever notice sluggish acceleration? Lots of questions but you got me Wondering whats going on.. 😃
2) No WD40 was used.
3) It a little bit of elbow grease, but the plugs came out fine.
4) I've never changed out the PCV.
5) I don't think that the car accelerates as quickly as it did when I first purchased the car at 34K miles. It's now at 60k. However, I wouldn't say that the acceleration is sluggish.
What are you thinking is going on with each of the questions?
10-08-21, 05:15 AM
#19
Intermediate
Thread Starter
10-08-21, 05:26 AM
#20
Intermediate
Thread Starter
I think a good starting point would be to get a laser thermometer (Walmart for $20...i was surprised), start the engine in the morning when its cold and give it 10 min to warm up to operating temperature. Start checking the exhaust header cylinder by cylinder to check if temps are within 5-10% of each other. Not enough fuel it would be hotter and too much would be cooler, that would be a injector issue. If all are in range of each other the next step would be to check coils and their resistance or ohms.... Easier way to check the coils is to buy new ones 😜. Unlikely the PCV would effect just 1 cylinder but its cheap and easy to swap out so just do it for peace of mind and can eliminate that. Im not sure if he said anything about noticing any driveability issues, but that would give a good idea to what direction to look going forward. Additionally, getting a cheap bore scope off amazon for about $30-$40 would be great for sticking down through the spark plug hole to check the top of the piston and valves for anomaly's.
2) How does a bore scope work, and what would I be looking for?
3) Do you happen to know the part number for the OEM PCV?
4) No driving issues other than occasionally at idle the car "hiccups".
10-08-21, 06:52 AM
#21
Instructor
2) A bore scope allows you to insert a small camera into the cylinder to see if anything out of the ordinary is visible, a burnt valve, scored piston wall or excessive carbon build-up on the head.
10-08-21, 06:56 AM
#22
Pole Position
10-08-21, 07:04 AM
#23
Instructor
Basically, 10% ethanol in gas is a pretty good injector cleaner as well as water absorber. It isn't as powerful a fuel but it improves cleaning and cools combustion to avoid ping/knock.
10-08-21, 07:45 AM
#24
So after reading your replies to the abundance of questions i asked, i would continue to drive the car as you would normally and to make sure to use "Top Tier" gas if possible. In 3-5k pull that same plug again and re-inspect, if it looks like the others it could have just been an anomaly with that plug. But if not i would swap out that coil with another one and continue to drive to see if the plug condition follows the coil. Or just replace the coil with a good quality one, i was suspecting the coil at first before the line of questioning but after your reply and your comment of a slight shake/stutter at idle it really makes me think its a spark issue. Hope this helps and check back in after a few thousand miles have passed👍🏻
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Neophyte2b (10-08-21)
10-08-21, 08:42 AM
#25
Instructor
If it were a coil or a misfire condition, I would think the code it throws would indicate that long before you changed plugs. The codes you have indicate lean condition (no fuel somewhere in bank 2?) and open circuit which might be a loose/broken wire if you removed the harness anywhere while changing the plugs. I would concentrate on bank 2 and check the coil, wiring harness and injector plug at that suspect plug.
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Neophyte2b (10-08-21)
10-08-21, 09:38 AM
#26
Im researching this plug and finding multiple issues that could be happening. Detonation because of the tiny specks all around.. oil in the cylinder from the wetish portion at the bottom of the plug and threads... Overheating since the ground electrode is light colored... Weak spark creating fuel/carbon deposits... I could keep going. I think using the laser thermometer to check the cylinder temp will narrow down possibilities so we can pin point the issue. If detonation is occurring then quick action needs to take place because it is damaging your engine.
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Neophyte2b (10-08-21)
10-08-21, 09:42 AM
#27
You would need to pull and look down in the intake valves to tell if you had a problem. I know someone here with a GS who actually did. It was a problem. May not have been a problem to you, but it was to them and would have been to me too. A decrease of 25% = flow in the head is a problem to me. But you would not know unless you checked. Have you?
10-08-21, 11:00 AM
#28
Intermediate
Thread Starter
You would need to pull and look down in the intake valves to tell if you had a problem. I know someone here with a GS who actually did. It was a problem. May not have been a problem to you, but it was to them and would have been to me too. A decrease of 25% = flow in the head is a problem to me. But you would not know unless you checked. Have you?
10-08-21, 11:04 AM
#29
Lexus Test Driver
I'm afraid some of the advice being given has spilled over into areas that are highly unlikely (valves, oil leaking into cylinder, etc.) To check this (pulling intake, buying micro camera, etc. would create extensive and expensive, unnecessary work to confirm or refute.
I think the cause of that one spark plug's condition lies in either the fuel injector or coil for that cylinder, or a sensor.
Last edited by bclexus; 10-08-21 at 12:40 PM.
10-08-21, 01:03 PM
#30
Intermediate
Thread Starter
Correct! I suspect the circumstance that caused that spark plug's condition took place a significant period of time before the plug was ever removed, which would have almost certainly thrown codes before he starting pulling the plugs.
I'm afraid some of the advice has spilled over into areas that are highly unlikely (valves, oil leaking into cylinder, etc.) To check this would create extensive and unnecessary work to confirm or refute.
I think the cause of that one spark plug's condition lies in either the fuel injector or coil for that cylinder, or a sensor.
I'm afraid some of the advice has spilled over into areas that are highly unlikely (valves, oil leaking into cylinder, etc.) To check this would create extensive and unnecessary work to confirm or refute.
I think the cause of that one spark plug's condition lies in either the fuel injector or coil for that cylinder, or a sensor.
2) How would I check to see if it's the coil?
3) If it's a sensor, wouldn't the car have thrown a code?