geniusnouman

To begin with, my car has 147K miles. This all started this summer when I took my car to track (Englishtown, NJ) and did some intense runs around the road course. During one of the laps, I noticed the blinking engine light, which essentially means that the engine is misfiring, but went away after blinking for a couple of seconds, so I ignored it.
So my car was fine after that and nothing unusual. But about a month ago, while I was driving to work, I saw the blinking engine light again, and this time it did not went away. So I decided to reset by disconnecting the battery terminal. After about 50-60 miles, the light came back on, and would intermittently start blinking in between. However, I was not noticing anything unusual, no vibration or anything from the engine. But this time I decided to take it to my mechanic. He plugged in the computer to check the code, and found out that all cylinders are misfiring. So he started by checking the spark plugs and coils. He noticed that all the spark plugs were loose, and he said that that was the reason of misfiring. So he tighten all of them to spec and reset the engine light.
The engine light did not came back and I was reliefed. However, just last week, the light came back. The same thing, blinking intermittently. So I took it back to the garage. The computer gave the same code. Random misfire from all cylinders. So my mechanic checked the spark plugs again, nothing wrong with them. He said it could be the EGR, or a vacuum leak. He tried to find any vacuum leak but nothing. So at this point they had to close the shop and my mechanic told me to bring it back and he will disassemble the valve cover and try to find any leaks or anything.
My question is, if it is the EGR, would that not show up in the code? Does anyone have had a similar issue? Any thoughts on what this could be?

EL_PIC

EGR should show up in code.
If the timing belt gets stretched you will have the same condition.
In most cases it breaks and you replace it. Unless you re time after replacement you will have same condition.

overboost78

I have seen similar problems, Assuming your car is stock. there are a few possibilities. there is a code for the EGR, however these new cars are very sensitive. your problem could be your EGR, vacuum leak, intake port or sensor clogged, coils, fuel injectors, or signal and other possibilities. I would start with the basics. since you changed the plugs ( hopefully you used NGK Iridium) I would check the coils. easy test is while it's misfiring to unplug each coil connector one at a time. a good coil will have a change in RPM, if you unplug one and nothing changes then that cylinder is dead, or misfiring. at lease you can rule out your coils. if your spark plugs are new and the coils are good. then you could have a clogged injector or 2. at this point the only thing that worked for me is to take off the intake manifold and clean all the carbon from it, including cleaning and checking the EGR valve for operation and cleaning the throttle body, IAC motor and all the ports. also clean the injectors. that is basically a full tuneup, but it should solve any misfire problems, and you also have to clear all the DTC's. I hope this helps

geniusnouman

I did my timing belt maintenance at 140K so it's only been 7K miles since that. Is it possible for the timing belt to get stretched so soon? Are there any other signs for a strected timing belt?

I appreciate your help. Yes, I replaced the spark plugs this summer w/ NGK iridium. When my mechanic was testing, he did the same procedure. He unplugged each coil to see a drop in RPM. So he ruled out spark plugs and coils. I will take the car back sometime this week and ask him to check for carbon built-up on the throttle body and injectors.
My question is, could it be that my valves need adjustment? I have never gotten a valve adjustment and I do not know if the previous owner ever did. While googling this problem, I came across some posts where people said that their valve adjustment was bad and was the cause of engine misfire.

nfnsquared

Highly unlikely that is the cause. As in almost zero chance.

It's also unlikely that all 6 plugs and/or coils are bad, so I'd tend to rule those out.

You don't say what the codes were. I assume you had P300 through P306? Were there any other codes present?

What year is your car? I assume it's an 04 or 05? There is a known issue where the ECM/PCM erroneously gives a MIL (misfire) when under hard acceleration (into VTEC). There was a TSB to flash the ECM/PCM that fixes this. See if your ECM/PCM has the updated flash.

It sounds like your problems started after you changed the belt? Is that correct? If so, it could be the crankshaft position sensor. It's possible it got messed up during the TB changeout.

I'd be suspicious of something that affects all cylinders:

ECM/PCM reflash
CPS
Fuel pressure
Manifold leak
VTEC system

Of course, if you have a code other than P300-P306, that could point to the specific cause.

InFaMouSLink

iTrader: (10)

a/t or m/t?

geniusnouman

I don't recall the actual codes but they stated something like cylinder 1 misfire and so on for all cylinders. There was an additional code stating random cylinder misfire. The car is 2004.
True, there is a chance that my ECU needs a reflash. But I saw the TSB and the condition states that it applies only if the engine light came on while the RPM was above 4K, and I am pretty sure I was cruising with my RPM at 2K range the last time check engine light came on. So for that reason, I am going to assume there is an actual misfire.
I will keep that list on my mind and I'll be taking my car to the garage sometime this week and start troubleshooting. Hopefully we'll be able to narrow it down to something that doesn't costs a fortune to replace. The best part is, my uncle owns a garage so I only pay for the parts and not the labor. Thanks for your help though.


manual

InFaMouSLink

iTrader: (10)

Ever misshifted? Bent valves? compression test?

https://acurazine.com/forums/3g-tl-performance-parts-modifications-112/omg-piston-valve-contact-issues-w-pics-752015/

geniusnouman

holy crap! took me an hour to read that thread. But very helpful! Well I hope I don't have bent valves. MY CEL is not that bad. Like I reset it last week and it still hasn't shown up yet, and I have driven about 200 miles. But I know it's gonna come back and I'm waiting on that before I take it to my mechanic.

InFaMouSLink

iTrader: (10)

hope it points you in the right direction. I had to get a new motor. Luckily my TL is a parking lot bitch and it really didn't affect me having my car down for some time.

overboost78

you welcome. well loose lifters will not really cause a distinct misfire but it will cause some shaking, if your lifters are not making noise then your lifters don't need adjusting. Also noisey lifters shouldn't cause a random misfire code. Unless they are so loose that they are almost comming out. this is unlikely. Also did you get an O2 code? This can tell you a lot. I think the best thing is to hook up your car to an engine analyzer before you continue. while the car is misfiring if the mechanic hooks up the analyzer he can actually see all the engine parameters, even the coils, cylinders and the fuel injectors. this is the quickest way to troubleshoot. not all shops have this scanner but it's worth spending $50 or so to have them do it. plus it will save you money, because some mechanics just use trial and error, and you end up paying for the error. If your mechanic can;t pin point the problem, Don't hesitate to contact Acura and see how much they will charge just to troubleshoot the problem. don't fix it with them because they will charge you an arm and a leg, let your mechanic fix it after. I have found that sometimes Acura has been cheaper than some of these shops out there and they have all the equipment to Troubleshoot your Acura quickly.

geniusnouman

So I decided to take it to Acura dealer for diagnostics as there is no other code other than P300-P306 and also "Random Cylinder Misfire" and its hard to figure what what is causing this. I told the service manager all I have been able to troubleshoot so far and all the symptoms I have noticed.
Now I got a call from the service manager that the spark plugs and coils are good and they would have to do a valve adjustment before they can continue with diagnostics and that would be $600. Such bullshit. I already told that guy that it wasn't the spark plugs or coils. I just wasted $130 at Acura dealership.

gwiffer

iTrader: (7)

There's some misinformation going around about J series valve adjustments. It's been proven by some very knowledgeable members/techs that the exhaust valves tend to tighten up (no identifiable noises) over time as opposed to the intake valves, which loosen up and cause excessive noise/ticking. You should definitely get a proper valve adjustment done at your mileage and vehicle age.

Also, there was a thread on v 6 p about someone experiencing all cylinder misfires and random misfires...it was a faulty CPS (crank position sensor). You would have to remove all three TB covers to get to it; you'd be able to see if your TB was installed correctly (all TDC marks aligned) at the same time.

BTW, did you put 140k miles on the stock timing belt & water pump? Are the new TB/WP/tensioners/pulley OEM or aftermarket (Gates, Aisin, Mitsuboshi, etc.)?

good luck!

geniusnouman

I did replaced my timing belt/water pump at 140K with OEM parts. Everything is OEM except UR crank pulley.
So are you suggesting that valves could cause all cylinders to misfire?
Thanks, I'll check out that thread.

geniusnouman

Thought I'll give you guys an update:
I decided to get the valve adjustment done from the dealer. The service advisor told me that the exhaust valves were so tight that the mechanic had trouble fitting in the feeler guage under them.
So far, so good. The check engine light is gone, the car feels more smooth at idle, and I have noticed an increase in mileage.

nfnsquared

But he was able to get the feeler gauge in? If he could get a 0.011" feeler gauge in (albeit with a little difficulty), then they were only slightly tight and highly unlikely to be the cause of the MIL and misfire codes. The exhaust valve specs are 0.011" - 0.013".

That or your service manager is an idiot and has no clue what he is talking about... (I vote for the later)

My experience and research seems to indicate that our exhaust valves tighten and intake valves loosen with time/age:

https://acurazine.com/forums/3g-tl-problems-fixes-114/valves-still-noisy-after-valve-adjustment-804186/

http://classic.artsautomotive.com/Ho...Adjustment.htm
.

geniusnouman

lol, now that i think about it, what my service manager said does sounds stupid. if the exhaust valves are tight, you obviously cannot fit in a feeler guage. but i guess what he really was trying to explain was that the exhaust valves were out-of-spec by a lot.
but thank you all for your help. Your knowledge was of termendous help to me in understanding the issue at hand.
I will be keeping an eye on my CEL to see if it shows up again.

pb06

Was that your first belt replacement? Do you know the condition it was in when you replaced it?