[m8nsman]

Just took my 88 Camry with 2.0L 136k miles to local emissions testing & it failed on the HC (hydrocarbon) reading. I had an HC reading of 1380 & the limit is 220.

The history on the car is that it was parked for 3 years & so far I've replaced the fuel pump, filter, injectors, air filter, muffler & battery.

The engine idles fine in park or neutral once it warms up but has a rough low idle when the engine is cold or while in gear (automatic) & has stalled out a couple times while in traffic while at a red light. I've seen several remedies online as to using seafoam or another type of cleaner to flush things out etc. The tech at the emissions testing center suggested that it could be bad vacuum hoses due to the age of the vehicle & deterioration, also recommended was advancing the timing.

 

[BaronVonOttobat]

Pull off the EGR from the back of the intake manifold, (2 12mm nuts and a 24mm pipe nut) its probably clogged up pretty good.

 

[Doctor J]

Bad EGR will not affect the HC that much.
Need to know readings on CO before proceeding
This reading combined with close to normal CO (0.1 to 1.0 %) indicates leaking valves (too "tight") or ignition missfire

 

[m8nsman]

HC 1394 ppm limit 220 ppm

CO 0.56% limit 1.20

CO2 6.68%

Probable causes as per test results :
Vacuum leaks, ignition system malfunction,faulty computer controls, air injection system failure, incorrect engine timing, incorrect engine idle speed, improper fuel injection operation, low compression in 1 or more cylinders.

This car was last registered & tested in 2009 then parked for 3 years after owner was disabled.



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[BaronVonOttobat]

I'm soo glad that there are NO inspections or testing here.

 

[m8nsman]

Bad EGR will not affect the HC that much.
Need to know readings on CO before proceeding
This reading combined with close to normal CO (0.1 to 1.0 %) indicates leaking valves (too "tight") or ignition missfire

By my 0.56% CO reading am I looking at advancing the timing? If so, how much? Would the distributor be the best place to adjust the timing?


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[m8nsman]

Pulled EGR valve & it had some buildup at the valve but wasn't stopped up.


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[BaronVonOttobat]

It's the easiest, others may disagree. Loosen the two 12mm bolts and run the distributor click wise to advanced, counter to retard.

 

[Doctor J]

Air (vacuum) leaks will cause near ZERO reading of CO (like 0.02%) so the possible vacuum leaks around the injectors are not the top contributors here
If high HC were observed during idle speed test but become normal at 2500 RPM test
the problem is most likely related to the engine mechanical condition
(We saw it back in 1998 on 95 Mitsu Mirage leaking valves; adjustment fixed cold driveability and brought HC to 5 ppm from 750 )
Most logical steps to do:
a) check and adjust ignition timing
b) pull the spark plugs and do compression check
If compression is good, fix ignition components
If compression is low, the problem could be the exhaust valves
( Timing "adjustment" can "fix" 2X normal HC emissions but not something like 20 times average readings

 

[Doctor J]

O2 reading by any chance??
CO2 is very low indicating incomplete combustion (must be between 13 and 15%)
High O2 with normal CO points to low compression

 

[white90dx]

Could it also be the rest of the ignition system? (plugs, wires, coil?)

-Charlie

 

[m8nsman]

New plugs but haven't done wires or coil. I checked at night & didn't see any arcing across wires.


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[white90dx]

New plugs but haven't done wires or coil. I checked at night & didn't see any arcing across wires.

Wires (especially OEM) are less often the problem. If the coil is cracked it will generally cause other issues too (bogging at high loads, etc.) but it is worth a look.

-Charlie