How many miles on this vehical?? Worn engine components are always a possibility.
read on .... . . . ==Replies Inline== . . Nexus7 writes to us...........
What are the factors that determine HC output at the tailpipe from the
3.0 V6 (Vulcan)?
========== Nexus, unburned petroleum is the only factor. =========
I have this engine in an Aerostar 5 speed, and barely passed emission.
It failed at 1.65 ppm (allowable 1.60). But the plugs were > 4 years old.
I changed the plugs to Bosch +2s, changed PCV valve, O2 sensor, and the air filter.
The dist cap and rotor are < 1 year old.
I put in fresh synthetic blend oil (just for good luck) and ran through
1 tankful of gas with "Outlaw" fuel injector cleaner.
It was pinging only on heavy acceleration (pedal all the way down) as opposed to every on-ramp, and the engine had quietened down considerably compared to before. Possibly it had better acceleration too.
Then I put in another tankful of gas with Chevron Techron injector cleaner, but time was running out, so only about 80 miles into that tank, I filled it up again, gave it a 30 min whirl on the highway and took it in.
... They tested it right away, and it got... 1.59 ppm. I can't understand what else I can do... - cat?
====== I wouldn't be so hasty as to go installing a cat without exploring other opitions that the money may be better spent on. ======
... Was the Techron making it run rich?
====== No....but....having the Techron in the tank could have made the readings a bit higher than normal, simply because the truck is evidently not burning the fuel as efficiently as it should in the first place. So any additive is very likely to contribute to the readings. =======
I'm sorry, all units below are gpm (grams per mile), not ppm as stated earlier.
The readings were as follows.
HC 1.59 (pass 1.60 composite) CO 10.4 (pass 40.0 composite) CO2 472.9 (no standard) NOx 3.00 (no standard)
========= Nexus, by your numbers it appears that you passed the testing. Regardless, it's good to see you care enough to try to get them even lower.
I would HIGHLY suggest that you consider taking a look inside the distributer cap. Just to be sure that the 4 year old plugs did not cause the rotor or cap to deteriorate, from overworking to compensate for worn plugs. Same holds true for the plug wires, be sure you have optimum voltage supply to those new plugs.
I would also HIGHLY suggest checking out the carbon canister, the crankcase filter, and THE TIMING.
that ping your getting is a sign that alls not well somewhere.
hopefully helpfull..and... let us know.
marshmonster ~:~ ============