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I had replace a number of components under the hood and things were running well, except for an occasional p0305. Checked all likely culprits, ran a smoke machine but never found the source. After clearing the error with my scanner we were running smooth again. Than after a period of time that I did not note, the error would appear again. No new damage. Clear the error and things are fine again. Then the loop would repeat.
A few days ago I pulled the intake manifold checked for dirt and confirmed that the gaskets did not cover egr ports or were installed backward. I checked the fuel rails for dirt (absolutely sparkling clean) and confirmed the relatively new injectors were seated correctly. Also replaced the lower intake gasket.
Last night after the first snow of the season I noticed a rumble. Grabbed the scanner and saw an p0304.
So I did something that resolved the cylinder 5 error and shifted to cylinder 4. It has to be something silly but I am blind to it.
Hate those intermittent moving problems. I am sure you have checked the plugs but I have found that when I tried other supposed newer "super" plugs I had random problems like you have mentioned. So if you are using any other plugs but ones recommended in the manual I would replace them.
Have you tried marking the ignition coil on the problematic cylinder, and moving it around to see if the problem follows? typically a singular misfire event (as opposed to many, random misfires) suggest something electrical. btw...it is possible to have a bad ignition coil from the store and has happened more than once for me; for denso brand which some swear by. Bad coil = some rough idling without misfire code. not usable = rough idle and occasional misfiring. check the inside of the coil too to make sure the contact spring is making good contact with the top of the plug.
I actually ran into that problem awhile back. Also learned there is a big difference between OEM and aftermarket.
But that thought led me to check the electrical connections on the injectors and coils. I confirmed a good click this time and took it around the block. I have hope. It makes sense that I fixed the intermittent issue on 5 by resetting the connection, so I feel good about fixing 4 since it was fine before my magical fingers reached in there.
Last Winter I had a rough idle with thumping. Found it was the rear engine mount so I replaced it and the front which was also damaged. The car nearly runs so smooth I can't tell its on (like when it was new) except for a slightly rough idle. If I look at the engine I see it shake. I've retraced my previous fixes and I think I may have at least 1 torn mount again.
When I do a power brake with the hood up and peak over the dash I can see the engine move. I do not recall how much movement was normal for new mounts and I don't want to dive in and remove them just to look.
So is there a "measurement" or some technique where I can say one way or the other.
yeah, you bought oem coils from Honda? Coils can be DOA in a way that doesn't trigger a misfire, but they will produce an inconsistent idle that will make the engine feel like a mount is out; or that you have something else wrong. You can feel it in drive at a stop, and hear it in the exhaust with an occasional PUFF. It's hard to pin down because it could be 1/6 coils.
I bought 6 denso coils, 1 was DOA, and since 3 have all died (in the way described above) just past the warranty period. have replaced them all with hitachi which is the oem.
If your problem is more severe than what I described above, you can always test the mounts by applying a small vacuum to them as described in the service manual.
yeah, you bought oem coils from Honda? Coils can be DOA in a way that doesn't trigger a misfire, but they will produce an inconsistent idle that will make the engine feel like a mount is out; or that you have something else wrong. You can feel it in drive at a stop, and hear it in the exhaust with an occasional PUFF. It's hard to pin down because it could be 1/6 coils.
I bought 6 denso coils, 1 was DOA, and since 3 have all died (in the way described above) just past the warranty period. have replaced them all with hitachi which is the oem.
Well, I started writing about my experience replacing all 6 coils back in 2020 with a 6-pack of U5051 NGK coils. I went to verify my order on RockAuto and then looked up the coils on NGK and low-and-behold they don't even LIST the TL as compatible for these coils.
My receipt on RockAuto shows they are for the 2001 Acura TL, but they no longer list that as an application for them.
I will be placing a phone call to NGK And asking them about it.
When looking at coils for the TL a LOT of them list the TL/CL/RL/Accord/Odyssey as the engines that are compatible, yet a few list those along with the EL/Pilot/etc as well...
I wonder if anyone knows the difference. Are the EL/Pilot applications lower output and the TL/CL/RL/Accord/Odyssey higher output, or the other way around?
All I know is I don't get the gas mileage I should be getting. I did just change the front O2 sensor a tank or so ago so I can't tell if that is why, but it is very strange that the various coils sometimes list as compatible and other times as not.
^
619rcr found the Hitachi's below that are basically the same as OEM's found on 2G CL /TL's, they just have a slight difference in mounting configuration as discussed on the thread below: OE replacement coils? - AcuraZine - Acura Enthusiast Community
I dug out the multimeter, pulled all 6 coils. 1, 2, 3, 6 all read nearly identical. The two that caused an occasional error gave clearly different readings. So it would be consistent to think that those coils are on the way out.
I am just stunned that OEM (Hitachi) coils would die that soon.
I know a lot will claim that Denso and even more so NGK coils are the best; but neither of those have outlasted my original coils (made by Hitachi).
When the coils on my 4 cylinder Toyota fail; I get clear and obvious misfire codes. However all of the denso and NKG coils I bought produce an idle that "stumbles" without producing any error codes...very difficult to diagnose.
Perhaps with the wider availability of sparkplugs made from less conductive materials like iridium, these coils tend to produce similar failed results and thus become no longer recommended for certain applications, like engines with a higher compression ratio perhaps?
I dug out the multimeter, pulled all 6 coils. 1, 2, 3, 6 all read nearly identical. The two that caused an occasional error gave clearly different readings. So it would be consistent to think that those coils are on the way out.
I am just stunned that OEM (Hitachi) coils would die that soon.
surprises me too!
Any chance the plugs on those cylinders are gapped differently?
Pull up to a stop light and before you roll those last few feet the B&B lights turn on. Warm or cold engine. Fast deceleration of slow. Sit there awhile and the lights turn off.
I don't see a pattern. I saw a frayed ground wire from the engine to the frame under the battery and replaced. I replaced the battery and the positive terminal end.
I thought maybe a loose wire and tried to trigger it with an abrupt stop, but no difference from an orderly deceleration.
Do you have a multimeter? What is the voltage of the battery, when off, when idling, and when you increase the RPM's to say 2500-3000?
My initial guess would be the alternator but that can be confirmed by the voltage at the battery under different conditions. The battery voltage should be 12.6 - 12.8 Vdc at rest. The battery voltage at idle should be about 13.6 - 14.4 Vdc, The battery voltage at the higher RPM should be about the same as it is at idle if idle voltage is low and it goes up at higher RPM's it would mean either the alternator belt is loose or the alternator is going.
Auto tensioners go bad, belts stretch out past the capabilities of the tensioner or break down, so do new and rebuilt alternators, You can check the tensioner; below is what you need to look for on the belt. First though you should check the voltage in the different modes.
Whitetiger5, While we all probably heard belt slipping noise, I have personally had bad belts that didn't make any noise unless it was at high RPM's (6k) but I don't drive that way anymore. I am sure most belts slipping issues would make noise but after my previous experience, I check. I mentioned it to Craig as I didn't want to leave anything out of the basic first look. I was also looking for the simple things that could cause a consistent result. Other things I can think of are more out there and well, a lot less likely.
As you stated there were several alternator amperages, I think the CL Manual used a 95A and the TLS was 110A but my memory my be out I am sure with a search he can find which one he has. That is one reason I asked him to check the voltages. If a unit is reaching its maximum current the voltage will start decreasing. Hope you are doing well. Are you doing anything special for Thanksgiving?
ah ok, just thought I would ask. I haven't ever had a belt slipping without any obvious noise. It sounds like an alternator issue...the Brake light makes it a bit confusing to pinpoint.
nothing special this week, just the usual thanksgiving shenanigans. eat all day, eat dinner at lunch time, keep eating throughout the day and try to stay awake until a reasonable time; you?
craig, how long ago was the new alternator put in?
The battery / alternator are from early October. I thought these would be a good place to start since Winter is coming and I didn't want to be dead trying to go home late night in -13 temps. I have a higher output alternator and battery.
I assume there is measurement error involved here.
Voltage on battery 12.856. At idle 14.356. At 2500 - 3000 RPMs 14.56.
Craig,
So much for the easy stuff. From the voltage it looks like the alternator and battery are fine. Now onto more esoteric stuff:
1.) Does the problem occur when the car is cold? I assume from your previous description that the car is warm when you come to a stop.
2.) Does this occur when the car is cool, like just after you start and drive to the end of the block and come to a stop?
3.) What happens if you start to slow down (without using the brake) take your foot off the pedals and just downshift as you slow down? Obviously, do this where it is safe to do without traffic.
4.) Did downshifting without using the brake cause the same symptoms?
Thought of a few things. first, have you checked the brake fluid level? is it full? Second to confirm the alternator isn't overvoltage for the battery you can disconnect the alternator and do some short testing while running only on the battery. If the problem goes away then it will eliminate the alternator as any source over/under voltage for the issue. usually over voltage issues don't show up till you get up to 15v or more but who knows if you battery is oversensitive to higher voltages.
Craig,
So much for the easy stuff. From the voltage it looks like the alternator and battery are fine. Now onto more esoteric stuff:
1.) Does the problem occur when the car is cold? I assume from your previous description that the car is warm when you come to a stop.
2.) Does this occur when the car is cool, like just after you start and drive to the end of the block and come to a stop?
3.) What happens if you start to slow down (without using the brake) take your foot off the pedals and just downshift as you slow down? Obviously, do this where it is safe to do without traffic.
4.) Did downshifting without using the brake cause the same symptoms?
Normally I'm pulling up to a stop light and hence the brake. I haven't had opportunity to coast, but did notice the lights kick on while slowing below 15mph.
Thought of a few things. first, have you checked the brake fluid level? is it full? Second to confirm the alternator isn't overvoltage for the battery you can disconnect the alternator and do some short testing while running only on the battery. If the problem goes away then it will eliminate the alternator as any source over/under voltage for the issue. usually over voltage issues don't show up till you get up to 15v or more but who knows if you battery is oversensitive to higher voltages.
When this started I had a different battery and alternator. Both on the weaker side. Thought it was one or both and replaced them. As I think about it the lights came on just before a stall which it no longer does - bad coils.
i don't know if it is some how related but i just discovered a crack in the exaust flex tube. Replacing tomorrow.
Craig, I saw on normal forum threads that you found the ground line from the battery to the engine was breaking apart. Sorry, I made the assumptions that all the electrical wires were checked (usually first thing to do when having electrical issues). I add extra ground cables to the engine and back to the battery on all my vehicles just be sure I won't voltage/current fluctuations. Have a Happy Thanksgiving.
The next time you have electrical type issues that are not obvious (burned out part, etc) I would always recommend tracing the wires. I have an 89 Volvo 244 DL that has about 500,000 miles on it and had a problem with the reverse lights, Tried the obvious bulb checks and it was not obvious I started checking the wiring and nothing bad by the light, I finally went all the way back to the signal generation coming out of the transmission, I removed the shift cover (manual Tranny) and found that the insulation material used in the car ate through the wire coverings. This left bright copper wires, touching each other and shorting everything out. Apparently, the engineers never looked at the chemical interactions of the wires and insulation or they figured nobody would have the car that long. From that time I always go from one end to another, if possible. Good luck with you car, safe driving!
Come to find out, that wasn't it. The lights came on a few more times and I was ready to ignore it but after addressing a slight shake with a valve lash adjustment the lights have not returned. The exhaust settings were frequently too tight.
My idle was off just enough that I after replacing coils on 4 and 5 I received a repeated mis-fire on 5. Reset plug gaps, swapped coils, scratched my head. Then did a valve lash adjustment. All is well now.
Just so I understand the brake lights came on when going slow or coming to a stop, you still had some misfires, and you did a valve adjustment on the exhaust valves and the misfires stopped and the brake light indicator stopped coming on?
The lights were a simultaneous issue with a repeat #5 misfire. I focused on the misfire thinking it would be easier to "find." After the fact, I think the exhaust valves were not able to open completely and produced both issues. Like it was about to stall. I haven't seen either for awhile now and the weather has been fluctuating enough to trigger something.
11-01-2023, 12:13 PM
