I have a 91 Civic Si with a Sohc ZC swap.I need help trying to figure out why it wont pass. It has new plugs, wires, Catalytic convertor, 02 sensor, fuel pump, fuel pressure regulator, water temp snsor, timing belt and a carb legal header. They said its running rich.

This is with the timing off a tooth on the cam

This is with the timing correct

 

Does anybody have an Idea of what could be wrong?

 

Can someone help me figure this out as I need to get my car smogged ASAP so I can get my plates.

 

What gas are you using? (octane/brand?)

 

You didnt fail by much at all, you failed Co by 10ppm, which is small. You should get a new fuel cap, because the one you have now, isnt doing its job. Before you go back load up on 91 octane gas from shell, or chevron or the highest octane you get from those company. Then you should go drive around for 20-30 mins, then go back to the smog guy right after, and you should pass now.

 

I had about 3 gallons of ERC 110 mixed with about 8 gallons of 87 from cheap gas station. What do you recomend that I run?

They tested the gas cap and it passed and you can hear the presure release when you take the cap off. Should I still change it?
I need to drive the car more this time before taking it but dont like to drive it as I dont have plates and Fremont DMV would not give me another temp sticker.

 

Just run straight 87, your timing is already at 15, but I would put it at 14.


I ran Shell 87, my timing set at 14 degrees, and passed BAR with my B16. The results were cleaner than my 97 integra with bolt-ons.

 

running rich dosent seem to be your issue.
although ek-g6 is correct your not to far from passing.
try running some seafoam in your engine.
read the instructions on the bottle for using it in the intake tract.
this will probably get it to pass.
g/l
smog sucks

 

My timing is set to 18 like it says under the hood. He put 15 cause thats what he thought it was supposed to be even after he checked it. All get my buddy to come by so we can set the timing to 14. thanks for the help.

It was running really rich before I changed the coolent temp sensor. All try the seafoam as I have not done that to this engine.

 

bump.....

 

run 87 it useless running higher octane and would get the results worse.

I would recommend warming up the cat (an hour of hard driving. example freeway driving) before taking it in. Use seafoam as well.

 

according to your smog paperwork, your hc% is within range and dosent seem to be making you fail.
if your hydrocarbon % is too high, this is the sign of too much fuel in the exhaust.
for a stock car i wouldnt use anything else but regular unleaded. this will probably balance out your numbers.
using racing fuels or additives will keep your number away from normal

 

The new cat could be masking the fact that it's probably running rich. You said you replaced the fuel pressure regulator, was it with a stock honda part?

 

I bought the B&M adjustable one and I have the B&M fuel preasure gauge installed. I turn down the presure to about 32 PSI with vacum and 42 PSI without

 

It has been a while since I tryed to smog my civic. I have a guy to buy the car as soon as it passes smog. Here is the outcome from todays smog test. The Check engine light I beleave is from him leaving the gas cap off durning the test? I was running 91 octane. The Egr is installed, he seen the block off plate on the back of the block ( ZC swap )


.

 

wow those are really high nox number most probable cause is the block of plate in the egr. Operating the car with a blocked off egr will lead to high nox numbers which can cause detonation and ruing your pistons. the gas cap is not what is causing your check engine light this was incorporated into cars in the future

 

Take the header off! Even if its CARB legal it will never pass the sniffer test. I had a DC header and it wouldnt pass, took it off and passed no problem.

 

The egr is not blocked off.He seen the block of plate for what I was told was for the fuel Pump.
My stock exhaust manifold was bad and thats why it has a header on it.

 

with nox numbers like that stock headers will not help unless it is an hf
why does it say egr visual modified

 

????? as far as i know, the SOHC ZC does not have an EGR valve

 

The guy was an idiot and didnt know what the block off plate was for so he said it was for the egr.He also ran more car on the machine with the gas cap removed.

 

I bought a ZC engine and used all the parts off my original engine.

 

I would change the pcv valve and distributor cap and rotor along with driving with the heat on and accessorys off for a good half hour on the freeway keeping the rpms up

 

The cap and rotor are the only thing I havent changed. I changed the PCV valve when I put the motor in.

 

what ecu do you have?