kstinson

I recently purchased a 93' Mustang LX 5.0l 5-Speed and it has failed emissions twice now. The I drove from my house to the test center that is about 3miles away. When the ran it they got these readings.

HC GPM 4.4 LIMIT 2.500
CO GPM 18.3 LIMIT 20.000

Buy suggestion of a person at the auto parts store they said to use some guaranteed to pass emissions forumal, new spark plugs, and drive the car around for about an hour before testing it. So that is what I did. This is what happened.

HC GPM 6.4161 LIMIT 2.500
CO GPM 21.2096 LIMIT 20.000

It looks like the emissions formula made it worse. I can smell gas in the exhaust and occassionally get a check engine light when I start it and between shifts. I tried to scan it with my Auto X-Ray but I always have trouble getting it to connect (its the scanner it does it on all our cars.) The only this changed on the car is the exhaust, headers, and H-Pipe. I am not sure of the manufacture but the H-Pipe does have converters and the O2 Sensors look new. Any suggestions?

roundman

Do you know if it has the stock 190 degree themostat in it? If it has a lower temp one, this might be causing some of the problem. Suggest you check this out and also check the timing and set it to factory specs. You might also check the EGR valve to make sure it is not plugged up and working properly. and maybe change the PCV too. run out the gas in it now as soon as you can and put some fresh gas in it too before the next test you do and make sure the engine is fully warmed up when you get there.

kstinson

I ran about 4 tanks through it since the last emissions test. I am not sure about the thermostat but the in dash gauge shows it running right in the middle (I guess about 200*F). I haven't changed the PCV but I am going to replace it in a few minutes. I recently had someone follow me and they said they saw some blue smoke when I shifted but it only happened once in the 30minute total trip, the engine was completely warmed up when this happened so I am guessing it was just from running rich. What kind of timing light is required to set the ignition timing on the 5.0l? I have a standard inductive timing light that I have used on a Camaro but when I connect it to the Mustang it doesn't show anything on the balancer. It is the type that connects to the battery and then to the first spark plug wire. Also does anyone know the factory timing specs for my car?

roundman

not positive but most are based timed at 10 degrees BTDC with the spout connector unplugged. it should be shown on the decal under the hood somewhere. the light you decribe should work fine don't know why it isn't. is the light blinking at all? are you sure you are on the #1 plug, first one on left or passenger side of block?

kstinson

The hood was replaced with a fiberglass hood before I bought the car. The timing light I am using is blinking but it is not showing on the damper. This is with the SPOUT disconnected. Maybe this is the cause of the emissions failure. I am going to look at the car again when I get home. I will also try a different timing light though I doubt it is the light because it works on our other cars. Actually from what you said I connected the light to the first cylinder on the drivers side, does Ford order the cylinders different than Chevy? If so this could be the reason for the light not working properly.

kstinson

Since the car does have 114k miles on it and the accessories are getting noisy I figured I would just go ahead and replace the stuff I need to for now. You know Smog Pump, Tensioner Pulley, Air Divert, Air Bypass, etc.

kstinson

Ok I checked the ignition timing on the first plug wire it read 24degrees BTDC. I moved it to 10degrees BTDC. The car takes off alot smoother and the smell of gas isn't so bad. I also replaced the air pump because no air was coming out of the tube on it. The car runs quite a bit better and only has a faint smell of fuel in the exhaust, however the check engine light still comes on and off when the engine is under load. I am going to pull the MAS sensor and clean the wires, does anyone else have and suggestions? The EGO sensors are new. Maybe some problem connections that could make it run rich?

luckythirteen13

wow 24*!! i cant believe the thing ran

roundman

YOU THINK THEY MIGHT? Yes they do use different numbering systems. see this link for the Ford system
https://mustangforums.com/thumb.aspx...DEA4927EEA.jpg
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