So I failed my emissions test today after my car gas been sitting for almost 3 years. It has fresh synthethic oil, fresh fuel, new fuel filter, newer spark plug wires, and msd cap. The motor was fully warm and has a cat. The car is turboed but I put on a short ram intake, oem injectors, and a stock ecu so I could pass since my other ecu just has a basemap. I passed everthing except the idle part of the test on the hydrocarbons level (hc), and I was at 224 and the limit is 220. So I was only 4 points away from passing. My hc level for the 2500 rpm test was 60 points below the limit so I pass that part no problem. I know high hc levels is unburnt fuel coming out the tailpipe. I just need some help from you guys on how to lower my hc level at idle. It doesnt need to be lowered that much since im only off by 4 points to be able to pass. I already lowered my fuel pressure like 5 psi lower than stock for the first test. And iv heard of people putting in acetone in your fuel tank because it allows the fuel to be completley burnt. Thus lowering hc levels. What do you guys think…
retard ignition timing 1 or 2 degrees
Retard timing? I thought you need to advance timing so your burning up the fuel… I think im gonna try to turn up my idle a tad and maybe turn fuel pressure down a tad bit more.
actually, the reverse is true. retarding timing, to an extent, yields a fuller burn. as cylinder pressure will be higher during early combustion. this will also raise egt’s, which, in turn, aids in the catalysts function.
what’s your timing set at now?
It should be stock, I have not messed with it since iv owned the car. Prob would be a good idea to see where its at. I also checked my plugs and they look good, they have that light grey/brown color. I need to order a wideband so I know what my a/f is at all times, I have a reg a/f gauge now and it sucks. But anyways I put in new spark plugs and I also put acetone in the fuel tank, it burns hotter and makes it so you burn every molecule of fuel better, so hopefully I will pass now. I just need to lower my Hc number by 4 points. I might lower my fuel pressure another 4 psi too before I take it in. I bet I could have the guy at the emission place just make it pass if you know what I mean lol. He was so impressed with my motor, I was scared at first when he popped the hood and saw the turbo, but he was saying how he repected me and that im not a poser lol.
4 points is nada. the temperature/humidity in the air could change that. i think you’re overthinking this. check your base timing. then, just retard it 2 degrees. it’ll pass. you’re messing about too much. you have to remember that this is a balance. adjusting for one pollutant will directly effect another.
also, just for future reference, you’re not technically running rich. you’re just not burning fuel efficiently. so don’t worry at all about a/f ratios. it isn’t the issue here
take care and good luck
So I passed, Lowered my hc level 12 points. What would cause my engine to have high hc levels? It has new plugs, plug wires, and a cap. They only thing I have not replaced is the rotor.
checked base timing?
is it an oem cat or aftermarket?
when was the o2 sensor changed?
there are many variables
How did you pass this time?
When I bought the car from my boss. He said it had a aftermarket exhaust and a high flow cat. the 02 I got from a junk yard and it looked brand new.
I put new sparkplugs in, made sure the cap/rotor looked good, lowered the fuel pressure and put a ounce of acetone in the fuel. Oh yea and hauled ass on the freeway right before I went.