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Still failed on 3rd test. This time got best results out of all 3 tests for HC at 25 mph but still failed at 15mph. Strange. Also this time, NO levels at both speeds were above the MAX allowed. Which I saw a progression in that through each test. CO lowest out of all 3 at 25mph and still passed both speeds. Did I make it too lean now? I need to figure out wth to do about this because I can't afford to take it to a shop. Automotive work goes for 150 an hour here. I attached the results below for comparison and reference. Obviously need to get it to how it was at the first test because I passed emissions there they just failed me cuz I made my own timing mark smh.
Are you sure your timing mark is accurate now?
Also once every other 3rd blue moon the malleable iron inertia ring will slip on the damper hub and the timing marks will be wrong
The EGR valve needs to work and not be clogged to make the NOx numbers low
If the engine gets too hot or there is some carbon in the combustion chambers
It has the same effect as no exhaust gas being burnt (burning the exhaust lowers the combustion temperature and prevents the forming of oxides of nitrogen NOx)
Wow got that?
Sometimes if your oil is polluted with fuel and is all black the HC numbers will be high
Used to sheet the system by pulling the pcv valve out of the valve cover during the test
That will lower the HC's
As will using the older synthetic oils The old synthetics were an Si O molecule and not HC based
Used to sheet the system some more by running some white gas or Coleman fuel (it has some OH group or alky molecules and not much HC)
They got you by the ***** with that
That CO of .49 and even the .13 is too high (should be .08 and .06) so too much fuel is hard for the cats to burn off
Lean out the mix and be better off (used to cheat there too by causing a small vacuum ;leak) Cruise amp or somewhere inconspicuous
You will not get away with any of that most likely with the CARB boys
We did it ourselves trying to get our cars passed (my 69 Z28 pegged the HC meter at 2000) with a factory cam and a stock motor
By the way I am not into bad air and we all have to breathe the stuff
I have my 69 Boss 302 passing 1980 specs for around here which was 3.0 CO and 300 HC (we only test 2 gasses here in UT)
We have finally gotten to where 30 year old cars can be registered as antiques and no I/M or safety is necessary in UT
You sign the registration yourself stating the car is safe and it costs way less for the antique plate and registration
That is so close to passing James makes me start to think of fuel quality
The independent testers I know around here joke about how Maverik gas will not pass I/M
Those are the I/M test shops with the 30 cans of white gas in the back
Make sure you have Chevron in your tank for the next test
Do you know what give the car a drink of water means?
I would consider doing that for GP's
@manicmechanic007 I do get gas from a no name gas station since the gas at Chevron is like 6.19 for 87 regular. But maybe just for the test a higher quality would make a slight difference. Our lowest octane avaliable here is 87 anyway. I do not know what giving the car a drink of water means. What does that mean?
Absolutely use that gas for the test
They used to have to ship Chevron fuel 600 miles to Detroit to use for EPA testing and to partial fill cars
The fact that they did it means there is enough of a difference to matter
Around here we do it (use Chevron) for the dreaded codes P0420 and P0430 converter efficiency failure codes and can usually get a few more years out of a converter using the better fuel
Giving it a drink is an old term referring to carbon removal from the combustion chambers and the piston tops
Old Cadillacs like the 472's and 500's would carbon up so bad in 50,000 miles that they would blow up if not treated (given a drink)
You would get the engine warmed up, sitting there idling. Take a full coke bottle of water, gun the throttle up to about 2500 rpm knocking or not
Start pouring the water down the throat of the carb slowly. It starts to die or choke out, you stop pouring add more throttle and do it again and again until the H2O is gone
You will see black chit coming out the exhaust big time
It is a little more difficult to do on todays fuel injected engines
If you have a carboned up 7.5 in my opinion it could make the heat necessary to form NOx
Back in the day, Ford offered only a few EGR valves and when you went to replace one you had to choose a washer with the same size hole as the valve you took off
The valves came with a few washers. We used to use a smaller washer and it gave the vehicles a bit more power and we did not test NOx anyway
Maybe someone replaced your EGR valve and you have too small of orifice? Or the valve itself is carboned up blocking some flow?
Forgot to mention the mechanism
When the cold water hits the piston tops it cracks all the carbon away in about 2 seconds
If you are on top of your game on these new fuel injected ones you will do what they call upper end cleaning every 30K miles
Part of the injector cleaning procedure is to spray carb foam past the throttle plate and it will clean the combustion chambers without doing too much damage to the coated throttle plate
I rebuilt then engine less than 1000 miles ago so I don't think there could really be any carbon buildup in there but I could try that. I think my computer is just creating the wrong fuel air mixture and its probably caused by a vacuum leak or faulty sensor.
Okay then I would not give it a drink either then
You can check the intake gaskets pretty easy with just about anything including water in a spray bottle
And if you have not put a wrench on those intake bolts since the rebuild 1000 miles ago
I sure would make sure they are tight. Not common for 7.5 to loosen up intake bolts but check them anyway and damn straight check all over for vacuum leaks
Did the yofuss say anything about possible vacuum leak? Just recalled you said they only test. Do you hear any hissing?
Generally if you cause a vacuum leak your numbers will go up 400 points or so on a engine combo like yours (if the CO is correct)(then it goes into lean misfire) (and the HC's go up)
If your truck is too rich to begin with then causing the vacuum leak solves both issues
We used to add altitude compensators to the ones that needed it here at 5000 feet
Not as much air here anyway and being able to adjust the flow is nice
Not illegal around here because you were fixing the truck to pass I/M
The people were only required to spend a certain amount in repairs before being issued a waiver
Yeah if it's a vacuum leak that would solve everything. I haven't extensively looked and they didn't say anything about it but I mean I know this engine inside out. All of my vacuum lines need to be replaced and I could have an intake leak I will try smoking it out or using a spray bottle.
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3RD Test Failed Again - But Different
