So I bought an 88 Civic Hatch Si. Engine swapped out for same engine type due to thrown rod. Tach reads 217k, actual engine(D16A6) mileage around 3k. Failing smog on NO at 15mph but passing at 25mph, Passing fine on all the rest. It is manual so therefore if I am correct, No EGR Valve? Changed the PCV. Checked vacuum for leaks with Carb cleaner. Have a few lines in the back of the engine which seem to be dead and no suction or push from either side.
Have ran Sea Foam to clean pistons, they are shiny. I just replaced the CAT CONV. with a Magnaflow Cat. No Exhaust leaks before CAT. CONV.
A little history on my smog checks.

With old CAT CONV., in time at 16 deg. I was failing both tests as Gross Polluter, Not only NO, but HCs. Can't recall where HCs were. But NOs at 2300 on 15mph, forget the 25mph

Still with old CAT CONV., Fully Retarded to 10 deg. I fail both with a fail (no Gross Polluter) 1200 on the 15mph, forget the 25mph

New CAT CONV. installed, In time at 16deg. I pass the the 25mph no problems, numbers are good. As for the 15mph test my NOs are at 1700.

Once again New CAT CONV. installed, retarded to 10 degrees. my car passes both tests beautifully, except I fail ign. timing.

With every pre-test I run on it, I run it at highway speeds for 30+ minutes prior to testing, then it is on the Dyno and being tested within 5minutes, not left idling long, and not turned off.

I have also noticed horrible fuel mileage for a stock car. should be in the 40+ MPG range, am only getting about 28mpg.

A Full list of everything done to the car to try to get it to smog.

Changed CAT CONV. with Magnaflow High Flow CAT CONV.
Professional Fuel System Cleaning.
SeaFoam through Vacuum Lines.
Checked for Vacuum Leaks with Carb Cleaner.
Had car checked for Exhaust Leaks.
Fresh Tune-Up.
Replaced PCV.
Replaced Distributor.

Any Suggestions? any help appreciated. Maybe main relay? It runs lean one minute, rich the next, periodically the car will stall and take about 15minutes to star back up. Periodically I do get get a check engine code 16. Leaving me to believe the Main Relay as well. Thanks!

 

Youve got to be kidding me man...


A Magnaflow high flow cat converter is NOT catalytic converter. It is a resonator in a sense. It will not help you pass smog it will make it worse. People use that for race cars, so it definitely will not pass smog.
Buy a cat converter from a muffler shop and have them install it for. It will run you about $250 installed and make sure it is CARB certified.

Retarding your timing is not the way to pass smog, since you failed the ignition timing test. If you cant pass smog with stock timing then somethings wrong. Put timing back to 16BTDC I believe and work around that.

Your incorrect timing is also giving you bad MPG.

 

Fuel Injector System defective circuit or unplugged / defective fuel injector

I believe thats code 16 if the FAQ section is right.


Buy new injectors or get some used ones from a junkyard. Clean them out good before you install.

 

Alright,So took the advice on the CAT CONV., Made no difference.Fuel Injectors are new. I wrote that wrong. I do not get any check engine any more since I replaced main relay. but was getting it prior to changing main relay... Would you suggest when I rebuilt the engine, I put the timing belt on a tooth or two wrong?

*NOTE* Was late and getting tired when I got to the timing belt.

 

Then it's very possible you put it on wrong.

 

Okay so I have not yet messed with the belt, however I am getting code 6 now. So Coolant Temp... Would I start with Sensor? thermostat? What? Have a brand new Water Pump, Radiator, Cap, all new hoses... Coolant is completely filled... Any thoughts on that?

 

Now that I think of it, Could that be my issue? This whole time.... I tested the o2 and it's reading at 862 constant. Therefore it's reading that I am running rich constantly.. as if the car is cold, and the loop is either open or the computer isn't responding... Could that be the route of this whole mess?

 

It would make sense for it to be it. Let's wait for the honda gods to fill us in.

 

dude change your o2 sensor thats why cuz its probably still on open loop and can u just post up the whole sheet with ur numbers

 

wut?

where did you get your info from...i went through the california state CAP program and they installed a Magnaflow hi-flow cat which made my car pass smog and this was a legit Bureau of Automotive Repair station.

 

true i have a magnflow one too and i passed with flying colors and a honda cat contains platinum,iridium which reduces the hc and co and rodium reduces Nox. which the magnaflow hi flow cat uses the same concept. as long as its a 95 and down u can buy aftermarket cats in the state of CA anything 96 and newer have to have cats from the dealer and the smog tech needs to visually inspect the cat for the laser etched serial on the cat during the visual to verify a non aftermarket cat.

 

All catalytic converters must be CA compliant. Magnaflow makes both OBD2 and Pre-OBD2 CA compliant cats. I don't think the high flow ones are approved.


Test out the coolant temp sensor. That affects fuel mixture as well. The code just means there is a problem in the circuit. Most likely the sensor is bad but you could just have a short somewhere or something unplugged. Think smart, don't just throw money at it. Test the O2 sensor as well, but I think the sensor is telling you the CTS is bad. When the sensor is bad it tells the computer it is -40 degrees making the mixture very rich. That will make you fail smog real fast and have poor gas mileage.

Do you have a printout of the most recent test/pre-test?

 

Okay, Well, I spoke with a Smog tech and the Exhaust tech who sold me the Hi-Flow.... It is actually legal to use, I have found out, and with it my #s actually came down just a bit more then with the regular cat... I purchased after the fact. Now I have 2 Cats!!! GRRRR! As I said before I tested the o2 and tested fine, but ran high telling me The ECU isn't responding to the o2 Sensor saying hey! your running rich. I replaced the CTS, and Voila! Like clock work! I am legal! now to finish reg which temp tag expired a month ago... tired of ridin dirty... Thanks Everyone!

 

[QUOTE=flush_EJ1;45143006] Most likely the sensor is bad but you could just have a short somewhere or something unplugged. Think smart, don't just throw money at it. Test the O2 sensor as well, but I think the sensor is telling you the CTS is bad. When the sensor is bad it tells the computer it is -40 degrees making the mixture very rich. That will make you fail smog real fast and have poor gas mileage. [QUOTE]

What is a CTS yeah a newbie question but i think it runs with my issue as well any help?

 

It is the Coolant Temperature Sensor, on the D16A6 it is located right behind the distributor in the side of the engine, it just screws in, I payed $15 for mine from Autozone with a LT Warranty. Fixed my issue, Best of Luck!

 

Off topic but there was no Si in 88, first came out in 89

 

Haha, Yea thank you for noticing my typo. It is in fact an 89 I don't know how I did that, or how I missed that so many times. thanks