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Discussion Starter · #1 ·
I just took my car for an etest yesterday and passed everything but the HC at idle. I was nowhere near passing it there.
My results were:

40km/h
HC - limit 57 reading 57
CO - limit 0.32 reading 0.00
NO - limit 0421 reading 93

idle
HC - limit 200 reading 880
CO - limit 1 reading 0.34

I read elsewhere that high HC with low CO could mean misfire or vacuum leaks.
So it looks as though I need to check for some vacuum leaks, as a couple weeks ago I did plugs/wires/cap/rotor/coil before I pulled it out of storage.
It seems to be running smooth. I pulled some codes from it yesterday and I came up with:

172 - HEGO HO2S sensor fault/lean bank 1
334 - EGR closed valve voltage high
33 - EGR valve not opening properly

From these I talked to an old neighbour who is a Ford tech and he said the EGR position sensor is fairly common on these.
I figure they're fairly cheap so I may as well just do it. The other thing I was going to do what to do both 02's because they do look pretty old if I remember right. I'm going to clean the air filter/MAF sensor/IAC valve and whatever else I can think of and try again. I also read that I should only be running 87 in it unless I need 91 as 91 will burn slower, raising HC? I'll list the mods on my car but I guess there is likely nothing there that needs 91. I do have a different cam in it tho, so do I have any choice but to have it tuned?

1994 Mustang GT
Cobra upper/lower intake
GT40X heads
1.7 rockers
B303 Cam
65mm TB
BBK CAI
March Underdrive Pulleys
Mac equal length shortys
Bassani x-pipe
Borla SVO side exhaust

Sorry for the long post... but I really need this car to pass, I'm soon going to run out of temporary permits! Any help is greatly appreciated!
 

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id clean the mas sensor be care full not to break the little spring thingy's in there, id do the position sensor like you're neighbor said also double check for vacume lines i mean check the hoses and all the plastic connectors i just did my pcv valve last night and it seemed like i broke every damb vacume hose there is so check double check, then id do the o2 sensors just because it proley needs em anyways, then try it and yea you should run 87 in it unless you advanced you're timing.
 

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You might not get it to pass with that B303 cam, it's not smog legal due to excessive HC levels that it creates. That's probably the problem. But do address the EGR and O2's, it wouldn't hurt to get new components.
 

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Discussion Starter · #4 ·
I was kind of wondering about the cam too... the previous owner said it was put in before the last e-test he had, and I even have the test results from that test. If it is in fact the cam that is causing it, is there anything I can do with it? I'm not too sure about the timing... I've never don't anything with it and not sure how to do it... He may have advanced it though?
 

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Discussion Starter · #5 ·
well here is an update on my emissions tests...

I had a bad wire going to one of the 02 sensors, which helped a bit when it was fixed. The car still failed, but it's down to 544 on hydrocarbons with the 200 limit.
The car has 24lb injectors with a F1ZF-12B579-AA mass air flow sensor, which I believe is off of a 90-93 5.0L car.
I bought the car this way, but I'm still in contact with the previous owner and have the last e-test results which only had a reading of 26. He says the only thing that he has changed since that test was the injectors, going from the factory 19's to the 24's, and then putting this MAF in I guess. Would there be any problem in swapping the 19's back in and the factory MAF sensor with my mods listed above in this thread? He gave these to me with the car. Do I really need the 24's with my modifications or am I okay with the 19's? I was thinking about putting the 19's in for the test, and then the 24's back in when I get the car to pass, if I need them. Would you have any idea if this could make me pass?
My mechanic here is going to check the timing, and for vacuum leaks, etc too before I retest again.
I just cleaned the MAF, IAC valve, air filter, Throttle Body and put kleen flo emissions kleen in the tank.
I'm really stuck here and need to get this car to pass... sorry for the long post!
 

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well here is an update on my emissions tests...

I had a bad wire going to one of the 02 sensors, which helped a bit when it was fixed. The car still failed, but it's down to 544 on hydrocarbons with the 200 limit.
The car has 24lb injectors with a F1ZF-12B579-AA mass air flow sensor, which I believe is off of a 90-93 5.0L car.
I bought the car this way, but I'm still in contact with the previous owner and have the last e-test results which only had a reading of 26. He says the only thing that he has changed since that test was the injectors, going from the factory 19's to the 24's, and then putting this MAF in I guess. Would there be any problem in swapping the 19's back in and the factory MAF sensor with my mods listed above in this thread? He gave these to me with the car. Do I really need the 24's with my modifications or am I okay with the 19's? I was thinking about putting the 19's in for the test, and then the 24's back in when I get the car to pass, if I need them. Would you have any idea if this could make me pass?
My mechanic here is going to check the timing, and for vacuum leaks, etc too before I retest again.
I just cleaned the MAF, IAC valve, air filter, Throttle Body and put kleen flo emissions kleen in the tank.
I'm really stuck here and need to get this car to pass... sorry for the long post!
haha yea if its untuned and has 24lb injectors, then put the stock 19s back in with the stock maf. if you have an adjustable fuel pressure regulator then scale the pressure down a little bit, or you can put a one way valve in the fuel pressure regulator line to hold vacuum on it. (that will help with the 40 km test portion. you have waay too much fuel delivery at idle.
 

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I had the same problems at idle with my 91 ... I have a friend at work with a 94 that has the same problem to ... but both of us had removed our CATs ... we unoplug the SPOUT connector and run the car for about 15 minutes before going for emissions test ... idle passes fine then reconnect SPOUT after the test is comeplete :)
 
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