Check engine light after valve adjust and spark plugs

[nsxnate]

Help please.

I have a 1992 with 49,000 miles and have been listening to what sounds like a valve tick to me and a Master Mechanic here at a Honda dealer in Germany so we decide to adjust the valves. Well I'm not a wrench head but I like to learn about cars so I helped him and he taught me about it. It seemed pretty straight forward but after the job the tick was still there and now I get a check engine light(CEL) after about 5 min of driving. I also noticed a very slight amount of white smoke from the exhaust immediately after we finished the work.

Here are the details. We had the proper specs for the intake/exhaust valves and he adjusted them according to the gaps listed in the manual. We also took out the spark plugs and replaced them. The old plugs were white/gray on the sparking tip and where the white ceramic/porcelin type material meets the metal base it was discolored with a rust/brown ring about 1/4" thick. I searched this site and got some good info about checking the CEL code with a grounding paper clip (cool) and it came out with one steady CEL followed by two short CELs then repeated indefinitely. Acording to the code list I think it was the EGR valve(code 12).

So here are some questions:

1. What is the EGR valve and what does it do?

2. What is the condition/color of the old plugs indicitive of... and should I worry?

3. Does it sound like I am running rich?

4. Will it hurt my car to drive it moderately until I can figure this out?

5.What else could sound like a valve tick and how can I cheaply(ha ha) fix it?

6. And of course... what do I do to get the check engine light out?

I plan on selling my car in a couple of weeks and I wanted to fix a few last things for the new owner. It seems like I might have made things worse. I know that is a lot of questions, but I sure appreciate any help.

Oh one more thing. I did not double check the new plugs he put in but they were about $30 each and he said they were OEM.

 

[canuck]

1)Code 12 on H/A vehicles is EGR. EGR is exhaust gas recirculation valve. It uses spent exhaust gases to dilute the intake air and reduce the temperature of combustion. It's sole purpose is to reduce Nox gases.

2+3) Sounds like a healthy plug, if it was overly rich you would see black soot on the plug tips.

4) Shouldn't hurt

5) Injectors ticking? Normal valve train noises? Hard to say without hearing it.

6) A couple of possibilites. You may have knocked the rubber hose off the EGR valve while adjusting the valves. Or disturbed the EGR control solenoid assembly. Rarely does the valve fail in an H/A vehicle. Likely the EGR control side of it. Check all hoses, electrical connectors, etc..


Good luck to you, hope this has been a help.

 

[nsxnate]

thanks for the quick reply

I spoke again to the mechanic today and he said the exact same thing... check the hose and electrics. I, unfortunately, do not know enough to know what I am looking for so I will leave the car with him over the weekend (they don't do T-day in Germany obviously). It gives me a warm fuzzy to leave him the car now since I was skeptical that he may have messed up something big.

As far as the non-valve, valve tick sound goes, is there anything I can do to quite the noise? What about an engine flush then heavier oil?

 

[MarkB]

You might try some injector cleaner with the next couple of fill-ups. It might not help; but, I have heard of cases (not in the NSX) where injector noise was silenced by doing this.

 

[canuck]

Re: thanks for the quick reply

As far as the non-valve, valve tick sound goes, is there anything I can do to quite the noise? What about an engine flush then heavier oil? [/B][/QUOTE]


If you have been diligent with your oil changes, an engine flush won't do anything. Also, stick with the recommended oil viscosity.

 

[nsxnate]

more good advice, thanks

I am running injector cleaner in it right now and engine cleaner/flush as well. This weekend I am going to do an oil change with even another engine flush product then add 20-50 oil which is thicker than what is in it now. Hope this helps unstick whatever is ticking and quiets it down a bit.

Thanks for all the info... please keep the suggestions coming.

 

[Larry Bastanza]

Re: more good advice, thanks

This weekend I am going to do an oil change with even another engine flush product then add 20-50 oil which is thicker than what is in it now.

I do not agree with this at all. If you have a serious "tick", heavier oil, at best, will mask the problem, not solve it. If the valves are adjusted properly, you will need to understand if it is the valve train and find the tick. First thing is to remember that these engines have a screw and nut adjustment (as you obviously have seen), so it will be a bit tappy anyway, like solid lifters.

The other thing to check is to test each LMA (Lost Motion Assembly) to insure one has not collapsed. These LMA's are under each "Mid" VTEC cam follower to make sure the followers are not slapping around in there loosely when you are out of VTEC range. Essentially they are a spring loaded plunger. You can press each VTEC cam follower with a flat blade screwdriver and see that they move freely downward, then return under fairly firm pressure from their internal spring. See page 6-36 in the online service manual and see the "Mid" cam follower, and how the LMA is tested if it is removed from the engine, it will make sense once you see it. I would discuss this with your tech. A bad LMA will cause a distinct valve tap.

HTH,
LarryB

 

[nsxnate]

Please remember I am not excperienced with this I am just learning through people like you and some limited hands on when my tech works on the car. Your post was somewhat hard for me to follow (I know its probably basic stuff to most of you guys out there) since I am not intimately familiar with the engine, but after some careful reading and reference to the manual I realized that you were refering to the same thing my tech told me about when I said the tick was still there after the work was done(same time I saw the faint white smoke from the exhaust. He is actually the one that recommended the flush that I am doing and said it might take two or three flushes to free any particles or unstick whatever is ticking.

I plan on selling the car in a couple weeks and do not have the time (nor does he) to do exstensive engine work if it is not required. I will not sell a car with "masked" problems so if I can't fix it with the flush then I will inform the buyer and probably knock some off the price. The tick is not unbearable but I am anal about the car and really want to sell the car in good condition, but I also don't want to sink a lot of time and money into it right now when I have only a few weeks to get my things together to move back to the states. So, how intesive is checking/changing those things?

Also, concerning the oil grade... I recently switched to synthetic a few months ago along with changing the gaskets so it would not leak in hopes of helping an old engine out. I am now wanting to switch back to quiet things down a bit, not to mask a problem but if you could knock a decible or two off the interior engine noise wouldn't you? Am out in left field here or should I stick with the synthetic after the flush? If not what grade would you recommend? And do you even think that the flush has a chance at helping the tick?

BTW, I pulled the clock fuse to reset the check engine light and it has not come on all day(4-5 drives). Does this mean the problem is gone? What about the EGR code it was giving me for the 2 days earlier?

Well, soon none of this will matter since I pick up my 04 Black/red a few days after Christmas... but that will be an entirely different post. (preview: headers, exhaust, AIS+Uni, Alpine GPS nav, dvd, reverse cam, Vlentine 1 with K40 lazer diffuser f/r). Of course with a new one I won't get to work on it as much and learn... I am chewing on the idea of keeping this one too.

 

[canuck]

First, congratulations on the '04, a beautiful car indeed.
Secondly, the light will only come on if it sees the requisite data needed to turn it on. If the EGR was a temporary malfunction, then the light will not come on again. It needs 2 trip detection logic (complicated to explain, don't worry) so if a problem exists, it will light the MIL again.

 

[nsxnate]

If the EGR was a temporary malfunction, then the light will not come on again

How can the EGR be a temporary malfunction? Wouldn't the problem persist if I did nothing to correct it or does the computer adjust to the new set up? Maybe next time I get a problem I'll just reset something and be real sweet to the car and it will say, "Ok no more problem, I'll fix myself."

I'll keep you posted with if the engine flush helps but could you tell me what I am looking at if it does not work in regards to fixing the other components you were refering to or how much I should deduct if any from the price?

Thanks again for all your help.

 

[canuck]

How can the EGR be a temporary malfunction? Wouldn't the problem persist if I did nothing to correct it or does the computer adjust to the new set up?

As I mentioned, it is 2 trip detection. That means it needs to see the same fault from a computer monitored system on 2 consecutive situations that meet a minimum required standard as programmed into the ECM.

For example, the EGR lift position sensor would need to read a low or high voltage at a minimum operating temperature and vehicle speed (etc.) for two consecutive "trips" (trips being determined by Acura engineers and Federal/state emission requirements.)

 

[Larry Bastanza]

nsxnate,

I think the engine flush is OK, but if the car has been maintained there should be no need for it (oil changes regularly, w/49K miles). 10w30 is what should go in there, nothing else. 49K miles for an nsx engine is very young IMO. These engines run 200k miles if maintained, without any major problems.

I appreciate your situation, but I was working from the perspective to help you address the issue. Cost effective solutions, with the thought of selling it, (aka "bandaid fix") was not in my thinking, and I just think if it is a problem it needs to be addressed. JMO.

At this point, you understood my comments, and how they related to your tech's comments, so I hope you can work it out, sell it, keep it, what ever is best for you. Sounds like you should make the 1992 a track car.

Regards,
LarryB

 

[nsxnate]

Sounds like you should make the 1992 a track car

I would love to, but my new assignment is in Special Ops so bye bye Learjet and hello MC130 TALON II and deployments to Iraq and Afganistan. Hey maybe they will let me bring the NSX to the desert for a moral booster for the troops!!! Any advice out there on lift kits and mud tires?

 

[nsxnate]

Sorry for not updating for those who are reading this but I have been real busy trying to move.

So, I ran the engine flush for a few days then did an oil change with yet another flush product that said to add, then idle for 5 min, then change. I then refilled with 20-50 and the sound is still there. In fact I just took a 400 mile trip at cruising speeds between 90-110mph (occassional spurts to 140) and after the trip the sound seems worse... Did I do that by driving fast?

So... should I try another flush? I heard it could take 3-4 tries before it releases the sticky particles if that is even the problem (just a theory being tossed around).

BTW... I have owned the car for 10 months and the oil has been changed more than needed since I have owned it but I can not vouch for the history.

 

[nsxnate]

Final update for those interested...

After a few more days with the new oil and an oil additive the engine seems fine. There is still a small tick but from what this forum says it sounds normal. There may still be a slight LMA tick but it sounds fine to me for now. The check engine light has not come on again and it seems to be running smoother and quieter after some valve and oil TLC and with the new spark plugs.

I sold the car today as well (for a steal BTW... 25 Gs) and the new owner seems happy with it and I feel good that I am selling it in good condition.

Thank you to this forum for all the advice and help and I hope to get my "04 soon... although the new HSC is getting my attention. All I know is that being without my NSX feels empty!

Cheers