Within 3 HC Points from passing air care. what to do..
- Thread starter jish17
- Start date
Did you put in new plugs? Something this small could easily be solved by plugs, or maybe even just cleaning the contacts on your wires.
HC
unburnt fuel
missfire by old plugs. Old wires.
Running to rich. Make sure to heat the car up throughly and get those cats piping hot.
unburnt fuel
missfire by old plugs. Old wires.
Running to rich. Make sure to heat the car up throughly and get those cats piping hot.
Geared mainly to OBD-II but Chapter 8 is worth reading because it's applicable to any system. Rather simple knowledge compared to what's needed in California though...
It seems good to know either way even though I don't have emissions down here. California can suck it, btw.
3 points is probably within the error margin of the machine... i get more variance than that running back to back tests here. Personally, I'd clean the wires, go back, and hope to get a reading on the good side this time.
jish17;1597392 said:
Put up a copy of the emission trace.
87M-GTE;1597553 said:
Baloney.
Even without the trace posted, do you have the original downpipe and cat in place, or did you replace the downpipe with an aftermarket unit that is a straight pipe? That can easily cause a rise, op temps or not.
My HCs nearly doubled without the precat. As is is, they have been getting slowly worse over the last 10 years. The culprit is most likely a tired 20 year old cat since fuel control is good.
Post up your numbers and we can compute your A/F, but I would be very surprised if fuel control is an issue here.
Post up your numbers and we can compute your A/F, but I would be very surprised if fuel control is an issue here.
I have never dealt with emissions so this is in no way a suggestion. Couldnt you advance your timing a bit, just for the test purpose? Or would that create other problems? I mean over advanced timing runs hotter correct?
Not sure if it varies state to state but maybe by doing that he can lower the hc and still be in range with the increased nox? Also, i have heard of people creating vac leaks to pass, not sure how that would help but guess it depends on where you are at on the scales. Also heard of a pre cat exhaust leak? But then again i have no experience with emission tricks and such. So everything is hear say. but determining fact from fiction is always good.
89supra7mgte;1599510 said:
Wow. I have to reword all of this. I guess that is what happens late at night.
It may be as simple as new spark plugs. But since we still don't have the emission trace posted yet, this is all conjecture. Creating a vacuum leak will cause a lean condition which will drop carbon monoxide, but that will also cause a lean condition and give the ECU a hard time to correct the condition with feedback.
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Nick M;1599513 said:
We need the rest of the readings.
Is the vehicle run on a dyno during the test or simply reved to a higher RPM?
Is timing checked durring the test?
Did the technician have the car at operating temp before the test? (common mistake that "go fast" techs make, bringing me allot of work over the years)
I am not familiar with "air care" standards, but california smog, I know well.
Just a good, hot cat, while in fuel control, and a good ignition system, will pass HC. (as long as CO is in check, pre cat)
I had to rewrite what I wrote. Causing a lean condition doesn't cause a rich condition. I guess it was late when I said that nonsense.