need help passing NC emissions

[dpaschal]

I took my 1987 Accord LXi in last Tuesday for inspection, and it failed emissions with the following results:

Standard Current Reading Result
HC(ppm) 220 327 FAIL
CO(%) 1.2 5.06 FAIL
CO2(%) 11.4

Engine RPM at reading: 985

Ok, so then I wet out this past weekend and put on a new set of plugs, plug wires and I adjusted the idling. I also put in two cans of 104 racing formula octane booster and the CRC G2P oxygenator on a full tank. I ran the car until it was 1/4 tank full, warmed it up good and took it in for inspection again today. Here are the new results:

Standard Current Reading Result
HC(ppm) 220 1279 FAIL
CO(%) 1.2 6.19 FAIL
CO2(%) 9.9

Engine RPM at reading: 1042


Ok, so now what parts should I change out? Oxygen sensor? EGR valve? What should I check next?

[keruhas184]

Definetaly EGR. You sure you got the right heat code plugs? It seems that you put in hotter plugs=raised engine temperature, which would explain why your HX quadrupled. EGR recirculates the exhaust gas to cool it down before spitting it back into the exhaust, so a faulty EGR with hotter plugs made your result even worse.... You might want to check your catalytic converter too.

Now, because you have an 87lxi, your recommended plug is the same as LX: https://www.3geez.com/showthread.php?t=37102 (post #4). But seeing your problem with EGR, I'd try to go one step colder... Oh, and get NGK spark plugs.

[dpaschal]

The ones I got from the NAPA store were NGK V-Power BPR5EY-11. The plugs I pulled out were BOSH Super WR9DCX.

[keruhas184]

Seems like you've got the right plugs... but maybe they were hotter than Bosch. In any case, replace your egr, and see how your cat looks. Bad news is that EGR is $130 from the dealer: http://www.hondaautomotiveparts.com/...%2786-%2787%29

But maybe you could save the $$ by just cleaning the egr piping... maybe its just gummed up...

[dpaschal]

I took the EGR off and cleaned it. See my other posts for engine pictures, etc. There was some carbon buildup on it, but apart from that, the diaphram seemed to move freely. I may replace the O2 sensor next and maybe have the injectors professionally cleaned.

[nswst8]

is all you need for the injectors, change the O2 sensors and check the cat.

[danronian]

If you didn't put many miles on the car between the time when you replaced the plugs and when you took it in for inspection, that could be the problem. I have read "Car Craft" that whenever they are testing emissions on a vehicle to tune the car, replacing old plugs always results in poor emissions at first. Supposedly this is because the hotter plugs are burning off the gunk left in the combustion that was left behind by the colder burning old plugs. Often some heavy-footed highway driving usually cleans out the cylinders enough to lower emissions due to the better plugs. This is a possibility to explain the worse readings after what should have improved your readings, but in no way a definite reason. Good luck with it! Two times when getting my emissions checked my car failed and both times they just adjusted the timing up "real far" (in the words of my mechanic) to get it to squeek by, my mechanic recommended I replace the 02 sensors but after thinking about how they will probably break when I try to take them out (original after 170K mi.), I am also going to just upgrade my coil and plugs to see if that will help it pass.

[SavageG]

Have you tried adjusting the IMA sensor?

[danronian]

Have you tried adjusting the IMA sensor?

Please elaborate. Thanks.

[SavageG]

Idle mixture adjustment sensor, located in the "mystery box." Check 12-34 and 12-43 in the shop manual. Assuming the rest of the engine is OK, this is the factory CO adjustment. It looks like when you added the octane booster it slowed detonation and pushed your HC through the roof. I'd think that with timing and IMA adjustment you should be able to pass.

[rjudgey]

Had the smae problem with my B20A try this unplug the O2 inlet manifold temp sensor, it's just above the fuel rail wiring loom on the inlet manifold on the number one runner, it will throw a code but the ECU will run on a default setting. Then clean your plugs which are probably black if your CO2 is that high, then run it for a bit and check a plug and see if it's been covered in soot or if it looks clean midly brown and whitish then your now running leaner with less CO2 and try the emmission test again.