Mechanics

FAILED SMOG TEST - HIGH HC

1986 Honda Civic

Engine Performance problem
1986 Honda Civic 4 cyl Four Wheel Drive Manual 186000 miles

I have a 86 Honda DX Wagon 4wd with a 1.5L carburated engine. I replaced the spark plugs and air filter prior to the first test. It failed on both idle and 2500rpm tests for HCs. Max 120 and 150, my results 142 and 412. Also my idle was 1022 when it should be 750. I then replaced plug wires, cap and rotor. I also checked the timing per Haynes manual which said to plug vacuum advance line. There are three timing marks on the pully a red one in between two white. The manual says to use the red mark. Based on this my timing was off, so I reset it. I also tried turning the idle down to 750 but it ran too rough and would die coming to a stop. It sort of bounces between 750 and 900. I took it back for a retest. This time the HCs were worse, 176 and 558. They also said my timing was at 25 BTDC when it should be 15 BTDC (+/-2). It seems the plugging of the vacuum lines caused the problem with the timing


http://www.2carpros.com/forum/automotive_pictures/64900_PICT0063_2.jpg



http://www.2carpros.com/forum/automotive_pictures/64900_PICT0064_1.jpg

. My idle was 932. Another symptom which I believe is related in some way is, turning the headlights and/or heater on will drop the idle by 50-75 rpms. So I have a couple questions:
Which timing mark on the pully is correct?
Should I plug the two vacuum lines to the distributor when I set the timing?
How is the correct way to set the idle on the carburator?
Do I try to set the timing or the idle first? Does it matter?
How do I get the HCs to an acceptable level?
I've attached a pic of the timing marks. The red mark is under the "En" on the belt.
The second pic is the two vaccum lines to the distributor.
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Irishmustang
May 2, 2009.




1986 Honda Civic Failed smog test - high HC

Elevated hydrocarbon (HC) emissions usually indicate ignition misfire due to fouled spark plugs or a bad plug. But high HC emissions can also be caused by burned exhaust valves (check compression), lean misfire (check for vacuum leaks, low fuel pressure or dirty injectors), or rich fuel conditions (fuel saturated carburetor floats, excessive fuel pressure, leaky injectors or a dead O2 sensor).

Rasmataz
May 2, 2009.
How many pounds of compression should I expect?

Tiny
Irishmustang
May 2, 2009.
Hi irishmustang,

Sorry for the delay in getting back to you. My fellow technician is offline so I will be assisting you.

The minimum compression pressure is 135 psi.

Any other questions, feel free to ask and I would get back to you as soon as possible.

KHLow2008
May 4, 2009.
What about setting the timing? Do I disconnect and plug the two vacuum lines to the distributor?
Also the crankshaft pully has several timing marks on it; a red line between two white lines. Then a third white one an inch or two from the three grouped together. Which is the correct mark? I've been using the red mark. Using the red line and plugging the vacuum lines produced a timing at 25 BTDC per the smog test center. (It should be at 15). Thanks for the help.
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Tiny
Irishmustang
May 5, 2009.
The timing should be on the red mark


http://www.2carpros.com/forum/automotive_pictures/12900_timing_honda_1.jpg




http://www.2carpros.com/forum/automotive_pictures/12900_honda_4.jpg


Rasmataz
May 5, 2009.

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