Help - Diagnostic needed

civic4g · Post by **civic4g** » Wed Nov 07, 2007 6:09 pm

Hi A friend of mine is having this weird situation. Everytime he checks the spark plugs in his B16A2 one of them (cil nÂº3) looks different from the others, the right side one in the pic below. http://filipedua.planetaclix.pt/IMG_1458.JPG To see if it was a injector problem, he switched it's position but after 300km it was again evident that the problem persisted in cil nÂº3 What can be causing this? afr, timing issue or anything else? BTW the engine and ecu are stock, last compression test showed normal values. Thanks in advance

Post by **Synoptic** » Wed Nov 07, 2007 6:13 pm

VE different in cyl 3. Less air is going in. Could be oil deposit (cant tell, not clear enough) caused by worn valve seals.

civic4g · Post by **civic4g** » Wed Nov 07, 2007 7:43 pm

Looks plausible to me. Thanks

xenocron · Post by **xenocron** » Fri Nov 09, 2007 4:58 pm

Is this head ported? Uneven port perhaps... Have you done a leakdown to see if the results are the same in each cyl?

denn · Post by **denn** » Fri Nov 09, 2007 11:34 pm

Idle ok? check injector plug.

HeathN · Post by **HeathN** » Sat Nov 10, 2007 12:14 am

To see if it was a injector problem, he switched it's position but after 300km it was again evident that the problem persisted in cil nÂº3

So he moved the fuel injector or the Spark plug? If it was the fuel injector that he moved, I would check into the wiring for No.3 cylinder. [/quote]

civic4g · Post by **civic4g** » Sat Nov 10, 2007 5:36 pm

Is this head ported? Uneven port perhaps... Have you done a leakdown to see if the results are the same in each cyl?

Head is stock and the leakdowntest hans't bee done yet, i'll suugest him to do that. Thanks

Idle ok? check injector plug.

The cars idle and runs great, is hitting the rev limiter in 5th gear

So he moved the fuel injector or the Spark plug? If it was the fuel injector that he moved, I would check into the wiring for No.3 cylinder.

Yes, it was the injector that has been moved. I think if it was a wire/plug problem with injector @ cylinder 3 the fuel delivery would be restricted (less fuel), and in this case, by the spark plug read, i think we are in a scenario of rich afr, beliving that the 4 injectors are outputting the same amount of fuel the only way i see the cylinder 3 is getting an rich afr scenario is by insufficient air supply to that cylinder.

nitttrous · Post by **nitttrous** » Wed Dec 12, 2007 12:27 pm

somthing to look at is the car turbo or all motor. also make a pull on the street and whill its still hot pull the plugs again and look at them. change the plugs to new ones and see if the cylnder is diffrent from the rest move the infectior to a diffrent cylender and check again if the color moves to a diffrentcylender then you know what it is

Post by **Bugermass** » Wed Dec 12, 2007 11:42 pm

cylinder 3 very often runs hotter and leaner than the rest, and cylinder 4 also, but usually a little less than 3. I ususally end up taking out about 1.5 - 2.5 deg out of cyl3 and adding up to 8% more fuel and .5 - 1.5 in cylinder 4 and up to about 4% to get them all even.. Its pretty common, but not always the case, theres been a few motors here and there that were perfect all the way across and there were some that were running hotter/leaner on 1 or 2, but 3 and 4 are most common.. Remeber you need to check with FRESH plugs after you make your corrections so you can get an accurate reading.

Joey Misanthropy · Post by **Joey Misanthropy** » Thu Dec 13, 2007 10:06 pm

The white on the strap makes me think trace oil residues are burning. The brown on the ceramic is either a good thing, meaning the burn is correct, or the nice chocolate milk speckles you get when you breach the headgasket. Is the coloring of the ceramic smooth and even, or is it in a speckled pattern? I could really do with a higher resolution picture... scanners are god for this. If it's any sort of FI car you need to set individual cylinder trims always always always. I haven't had to add more than 3% to a cyl since I migrated from shiny, but most of the big power stuff I do is on racegas so I don't see #3 taking on as much heat because it isn't running up on knock limit. You having a stock engine/ECU.... meh, that is definitely a cyl going bad.