1994 Mustang GT - Emissions Help!

FULLSCALE · Apr 23, 2008

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!

CC'S95GT · Apr 23, 2008

pull the spout connector nhen have it tested. mine wouldn't run over 4k rpm but the test doesn't take it that high anyway.
also retard the timing to stock

FULLSCALE · Apr 23, 2008

Where is the spout connector?

CC'S95GT · Apr 24, 2008

behind the air cleaner you should be able to get to it without removing the box. upon reinstalling it DON'T drop it in the fender hole. ask me how I know

MORDENENOUGH · Apr 24, 2008

Check the operation of your coolant temp sensor (ECT), if its not working properly, egr will malfunction, Ford is one of the only companies that does this. I found this out when my car failed its last test and the shop I took it too couldn't figure it out. Even if it seems to be working, if its on the high side of any of the test parameters, replace it, its cheap insurance and it will also tell the CPU when to activate the CCRM for cooling fan operation.

CC'S95GT · Apr 25, 2008

status?

FULLSCALE · Apr 25, 2008

Thanks for the replies everyone... I just have to wait until I have a day off work to take my car to do these things. I don't have anywhere here or any of my tools to work on it as I'm in an apartment. I'll post my results of the test as soon as I get the car in.

Wayne · May 2, 2008

I had a vacuum leak once on the hose that goes under the upper plenum I had to take it off to replace the hose hope thats not your problem but it's not that hard to fix just need a new gasket if you have to pull it. if you need valve cover gaskets that would be the time to do that too.

FULLSCALE · May 9, 2008

here is the update...

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!