Any ideas what's causing high HC emmisions? My idle is very lumpy also, like a Harley running on 1 cylinder. Any ideas?

 

hc = unburnt fuel , missfire / missfires , old gas , cold motor / cat .

 

Motor was at operating temp; recent O2 sensor, recent plugs/cap/rotors/fuel filter. It's more prevalent at low speeds, low idle than at high speeds.

 

Try cleaning the ISV? I think someone did a DIY on it, try a search. Another possible cause is the AFM going bad.

 

Intake air leak, bad plug/wire , bad injector at low flow rate , valve clearance gone tight .

Just to cheer you with a starting place !!!!!!!!!!

The air leak can be checked by squirting something that is not gas around the inlet manifold etc with the motor on idle .

All the best

Geoff

 

Thanks ALL. Keep the ideas coming, and if you have DIY's on these, that would help too. I haven't cleaned the ISV lately, but did last year and that didn't help. I'll have to check the intake too; as I may have overfilled oil last year.

 

I would check the distributor belt first...Jerry

 

Easy way to check the dual distributor system is to pull each ignition module plug in turn and check that the motor starts.
Modules are over on the left , under each coil.

If it starts ok its really unlikely that there is a distributor problem.

Lets see . That will take a few minutes !!

Geoff

 

so I just unplug the wire from each coil to the distributor?

 

no that can cause more damage. You want to unplug the large connector on the ignition module mounted in front of the coils. The engine should run on one ignition system at a time...
good luck, Jerry

 

HC= Hyrocarbons- unburn fuel.

Have a look at the printout, the reading should give you a clue on whats up with the engine, its a great diagnostic tool, if your car failed HC's then i would be looking at the number of HCs it has failed on? for example 300 is ok for an average engine, i cant remember what the fail is on hyrocarbons is on a MOT (even though im a authorised examiner) usually a misfire will create loads of HC's.

HT leads
Plugs
Distributor caps
Rotor arms
Possible failed injector?

I would be careful with running the car for any lengh of time with a misfire as this can cause damage to the cataylst.

 

low speed only- does that help? Here's my printout. passable # was .80, and I ran at .95 g/mile. Mine is in red, typical car is in green.

 

You want to disconnect the wires (individually) circled in blue.



(ignore the red arrow)

 

Thanks. I'll try that. And I do have a working belt light, but it is not on anytime after start-up. I hope it's working properly.

 

There isnt a light to tell you if the little belt in the distribuiter is broken. Sounds like a good excuse to get the wife to let you get a TT