Ducman82

so i this state (new mexico) old cars have to be tested every year for emissions, fine. i went to have it tested today just cuz, and low and behold im at 697 for HC at "high speed" 2500RPM ish, and 655 at 970RPM ish. so i take that i am running rich. how do you adjust that on an L-jet? is it a cat issue?

i dont retest for registering my beast till november. good thing i did it now.


Quack, says the Duc

Ducman82

whats a good fuel pressure to run, now that i have a adj reg? right now its at 35, is that to high?

Imo000

How old is the O2?

Ducman82

not to sure. looked clean when i checked it last. it passed emissions last november when i bought it. but i will order up a new one anyway to be sure.

Mrmerlin

test the O2 first back probe it, see if your getting .5 volts fluctuating while running and the engine warmed up

Ducman82

so test the wire with a volt meter whilst running, for .5 volts. is there any +/- on that?

danglerb

That high of HC the cats must be toast. The FPR should be set to the stock value, and vary with manifold vacuum etc.

Ducman82

talked to my local tech, he thinks the timing is off. so i will swing by his shop tomorrow and check. what is the stock value for the FP? now i need a timing light.

Imo000

Most mechanics will tell you whatever it takes to get your car into their shop. First check the O2 and go from there.

GregBBRD

High HC is usually the result of a miss-fire.

You have any of the other readings? More info would help.

If you don't...start with the obvious. How old are the plugs (correct heat range and style) and what condition are the spark plug wires? Got any vacuum leaks?

Ducman82

no vac leaks, all new lines. plugs are new, not sure on heat range. i will check that in morning. plug wires and cap rotor look great.

GregBBRD

O-ring where the air flow meter pushes in soft and not leaking? Rubber mounts for the air fliter/air flow meter not all distorted, to the rear, and hard as rocks (like they usually are?) O-ring between the lower plenum and the throttle body not leaking? Boot between the throttle body and the upper plenum soft and good? Injector seals good? Power brake booster holds vacuum and doesn't leak? How about the hoses that run from the bottom of the lower plenum to the vacuum to the booster? Brake venturi o-ring doesn't leak?

What was the CO?

Ducman82

CO was 0.02, Co213.2 and O2 was 2.41 . when i re did my intake i replaced everything from spider boots, to the rubber mounts for the throttle body. but i will try the brake cleaner trick to see if i can find a leak anyway, just to be sure.

Ducman82

this is the shop i bought the car from. he never charges me for labor, only parts at his cost when i go there. real nice guy.

GregBBRD

Not enough fuel/intake leak.

Lean miss-fire, driving up the HC.