A question to auto mechanics about spark plugs

fishnguy · #1 10-18-2017, 05:24 PM

I have a question to car mechanics, if there are any on this forum.

Long story short, I have had misfire on my car since... A long time. Could be since i bought the vehicle, actually. The vehicle is 2003 Acura 3.2 CL Type S and I bought it when it was 5 years old or so. The misfire used to be insignificant for the longest time, but then it started progressing a couple of years ago. This car is now and has been for a while my "secondary driver" and I cannot say I care much about what happens to it.

I changed the spark plugs on it many years ago. I purchased them from an Acura dealer (they actually had them cheaper than anywhere else) and paid about $200 for 6 of them. I am pretty sure they were supposed to be good for 100,000 miles (not km). I have no clue how many kms I drove on this car since then, but since the misfire has been getting quite a bit worse, I figured it might be time to change them.

Disclosure: Misfire on these vehicles is fairly common (also Acura MDX of similar year, since they have the same engine). The most common reason for it are:
1. they placed the intake gasket on many of these vehicles upside down at the factory (I think these were first Acuras assembled in the US) (my gasket is fine, so not the reason);
2. egr valves get cloaked and need to be cleaned (mine was very dirty, but I cleaned it last fall, I think).

Back to spark plugs. I really do not want to spend anything close to $200 on this vehicle (you may say I am driving it to the ground). However, I have a set of plugs I bought for a Cadillac I owned many many years ago but I ended up selling the vehicle before changing the plugs and the plugs were lying in the garage all these years. The thread on these plugs is identical to the Acura ones and they fit in perfectly, as I already tried with one of them.

The gap on the Cadillac plugs is 0.039 (according to one of the websites), however they are copper plugs. The gap on the Acura plugs is 0.043 (recommended is 0.04, according the Acura manual and 0.039-0.045, according to HELMS manual - I read that on some forum on the Internet, so it is not necessarily true) and they are platinum plugs.

Here are the plugs (let me know if you can't see the photos):

I know i am downgrading from platinum to copper, but is it really a big deal on a vehicle like this?

How does the used plug look? Do you think it should be replaced in the first place?

Finally, the question of the thread, what's your opinion on putting these Cadillac plugs into my Acura?

Thanks a lot for the replies, guys!

EDIT: Forgot to mention, that the engine light is on and last time I checked (looooong time ago) there were 7 codes: misfire for each cylinder (6 of them) and a general misfire.

kennedy · #2 10-18-2017, 06:03 PM

If you changed the plugs and still have a misfire check what cylinder the misfire is coming from and check the coils. I would also use ngk plugs

fishnguy · #3 10-18-2017, 06:22 PM

I haven't changed the plugs yet this time around. I cannot recall the moment the misfire started: it could have been before I changed the plugs or after. I really do not remember.

The plugs that are in now are NGK. THe ones from Cadillac are Bosch.

gmcmax05 · #4 10-18-2017, 06:24 PM

You say misfire on all 6 cylinders? Not going to have 6 bad plugs, or wires or fuel injectors, could be the PCM.

neilsledder · #5 10-18-2017, 06:42 PM

Look on the white porcelain of the plug, where the spark plug boot/cap goes over it. If one has marks that look like you drew on it with a pencil you will have a bad cap on that cylinder which causes a mis fire also.

Sent from my iPhone using Tapatalk

neilsledder · #6 10-18-2017, 06:46 PM

Google carbon tracking.

Sent from my iPhone using Tapatalk

fishnguy · #7 10-18-2017, 06:51 PM

Here is what the complete spark plug looks like. They haven't been touched for a long time. I have not pulled any of the other ones out yet.

fishnguy · #8 10-18-2017, 06:58 PM

Quote:

Originally Posted by gmcmax05

You say misfire on all 6 cylinders? Not going to have 6 bad plugs, or wires or fuel injectors, could be the PCM.

Yes, a code for misfire in every individual cylinder, so six of them in total. Plus one for a misfire in general. Last time I checked on the internet (again, looong time ago) the two reason I mentioned in the original post were the only reasons mentioned anywhere and apparently fixing one thing or the other solved everyone's problems from what I remember. Did not work out for me though. I was confident it was the EGR valve, especially after I saw the condition it was in. The problem did not go away once I cleaned it though.

sweld · #9 10-18-2017, 07:09 PM

Even though there the same thread the plugs could be different lengths and could be to long and hit the top of the piston. Also they could be different heat ranges. Cross reference the numbers to make sure they will work

Sent from my iPhone using Tapatalk

elkhunter11 · #10 10-18-2017, 07:17 PM

Just because a plug has the same thread and gap, doesn't mean that it is the same heat range. The wrong heat range can cause serious issues.

overhere · #11 10-18-2017, 07:42 PM

Quote:

Originally Posted by elkhunter11

Just because a plug has the same thread and gap, doesn't mean that it is the same heat range. The wrong heat range can cause serious issues.

X2 ... as in too hot and engine seizure too cold and missfires also as mentioned can be too long and touch piston . Use only the proper plugs ...

And if you dont want to pay for maintenance. Dont own a vehicle simple

xxclaro · #12 10-18-2017, 07:57 PM

Egr valve may still not be working properly even if you cleaned it. If you can scan it, see if it can tell you the conditions at the time the misfire occured. If it's at or near idle I would still treat the egr as suspect

fishnguy · #13 10-18-2017, 08:37 PM

Thanks for mentioning the heat range, guys. It has not crossed my mind. Yes, I am pretty sure these plugs won't work due to this very reason.

Also, I have a feeling that if I replace the plugs, the problem will remain. The only reason I thought of doing it is because I had these other plugs I have no use for otherwise.

I will probably run another scan and see. Could very well be that there is another problem now as well, or a few more.

Quote:

Originally Posted by overhere

And if you dont want to pay for maintenance. Don't own a vehicle simple

Lol. Thanks!

CaberTosser · #14 10-18-2017, 09:14 PM

rockauto dot com. The most expensive ones they have for you car are iridium NGK's @ $10.80/each

You paid $200 for 6 plugs many years ago?

silverdoctor · #15 10-18-2017, 09:32 PM

Have you ever changed the plug wires? In the dark, run the car, spray the plug wires with water, you might see an arc.

CaberTosser · #16 10-18-2017, 11:02 PM

Not knowing your car but knowing about other makes that had issues with things such as ignition coil packs that would crack and result in short circuits and electrical 'leakage' to points other than where they were intended it would seem prudent to check those possibilities too. Lots of coil-on-plug around since but your car could be around a transitional time so I don't know exactly what you'll have in that regard. Oh and my disclaimer is I'm just a hobby mechanic ...

Red Bullets · #17 10-18-2017, 11:10 PM

Something else to consider if the older vehicle is misfiring... My older truck was having similar symptoms and my brother the HD mechanic told me to wait until it got dark and go start the truck and look over all my spark plug wires. When I did that it was easy to see that the problem was the spark plug wires. They were older plug wires and were lighting up like christmas trees. New plug wires solved all the problems.

Edit* sent after silverdoc suggested the same thing.

Red Bullets · #18 10-18-2017, 11:17 PM

The OP asked,"I know i am downgrading from platinum to copper, but is it really a big deal on a vehicle like this?"

I would just make sure your plugs have the proper resistors or you may get static on the am/fm radio.

sako1 · #19 10-18-2017, 11:20 PM

Those models are VERY prone to ignition coil failures. If 1 coil happens to be bad it can cause the ECM to throw multiple cylinder misfire codes. If you can get the car to misfire unplug 1 coil at a time until there is no change in how it runs. Replace that coil and move on. I would definitely be checking the rest of the plugs as well.

brslk · #20 10-19-2017, 05:31 AM

Where are you located? If in Edmonton, I'd be glad to take a look at it for you.

Buckhorn2 · #21 10-19-2017, 06:12 AM

with the honda v6 its probably egr related. It doesnt always throw an egr code. Its not just the valve that gets clogged its the port on the engine side that needs cleaned. I was a honda tech for 8 years. I can tell you from experience that I would only run the ngk plugs as from the dealer. Its the cheapest place and we used to have misfires from "premium" aftermarket plugs. or as mentioned earlier wrong heat range/reach of the plug.

fishnguy · #22 10-20-2017, 01:06 AM

Quote:

Originally Posted by CaberTosser

You paid $200 for 6 plugs many years ago?

Believe it or not, I paid something like 180 and some dollars for the six plugs and the dealer had them for less than anyone else. They were NGK whatever and that was back when I cared much about this car.
Plugs for the Cadillac were even more. If I remember correctly, they were something close to $40 per plug and even more at the dealer; that was a really long time ago though and there were only two or three places one could get them from, including the dealer. I have not checked the online prices in the US back then. Also, that was the first and last Cadi for me. Never again!

Quote:

Originally Posted by brslk

Where are you located? If in Edmonton, I'd be glad to take a look at it for you.

That is a very generous offer! I would be all over it, but I am about 5 hours north from there. I greatly appreciate it though.
P.S. I read you post in the anti-peeve thread the other day - good stuff. Hope you find the health you are looking for! Also, big congrats on dropping the habits in the last year! I really wish I could quit the damn smoking. It's killing me softly and I pay for it and I still keep going.

Quote:

Originally Posted by Buckhorn2

with the honda v6 its probably egr related. It doesnt always throw an egr code. Its not just the valve that gets clogged its the port on the engine side that needs cleaned. I was a honda tech for 8 years. I can tell you from experience that I would only run the ngk plugs as from the dealer. Its the cheapest place and we used to have misfires from "premium" aftermarket plugs. or as mentioned earlier wrong heat range/reach of the plug.

Thanks. I still think it is the EGR valve that is causing this. I will take a look at it again when I get a chance.

Thanks to everyone else who replied in this thread! Last time I checked the coils and wires were fine (could be that it is no longer the case though). I will poke around it some more and see if I can find the cause. If I resolve the problem, I will bump this thread.

Best money on the car ever spent for me with this vehicle. I got it at a great price and aside from the regular maintenance (liquids, brakes, belts, clutch (that was pricey), etc), I only had to change the thermostat on it (twice, actually).