Hey everyone,

My emission problem is costing me way more then I have to spend andI could really use a little advice!

My truck:
It is a 1992 F50 that I bought last summer from a guy that seemed very knowleadgeable about mechanics and real straight-up. Motor is a rebuilt 5.0 L 302 Mustang HO roller cam with about 40,000 miles on it. Extras include, Ford Racing Ignition and an MSD 6A and he stated that almost all sensors on the engine were new.

The Problem:
I can't get it to pass emissions because of two things, Hydrocarbons (HC) limit is "220" and CO the Standard is "1".

First time through and my HC was 608 and my CO 6.9955. I took it to a local shop that has been around for a long time and they changed the cap and rotor, new spark plugs, put in a new Idle Air Control Valve, and I think that they said something about the timing too.

I could barely drive it home and back to the repair garage, it was stalling and running a bizilion times worse then ever.

I took it back in the next day and they kept it for a week. They told me that the thing was driving them around in cirlces. When I picked it up they had replaced the Collant Temp Sensor, the Manifold Pressure Sensor and the Throttle Position Sensor. I asked them if it would run through emissions...." Oh yeah" he said.

It did run better, but did it pass emissions? No.

First idle results, HC 238 and CO 1.37333. Close but no cigar.
The tech had me run the engine at 2500 RPM for about half a minit and we tried again. This time the numbers went up, HC 337 and CO 4.177.

I took it back to the mechanic and now he is saying to just drive it some more and that maybe the Cat is going bad...

I don't know if this shop is screwing me or if I really do have some kind of wierd problem going on that is really hard to track down. All I know is that I'm into this about 600$ of money that I don't have.....Things are really tight right now.

What should I do next?

 

You need to pull the codes. Even if the CEL isn't on, with it being emissions related, I can say with about 99% certainty that there will be some codes stored. If there aren't, get it hooked up to a scanner and read the sensors (i.e. O2 sensor). Blindly changing parts is a very ineffective and expensive diagnostic method. Let us know what you find.

 

Thanks for the quick reply. The mechanic should be pulling the codes right? I better ask him about that, even though I think he said something about having a hard time getting what he needed from them. I'm going to ask about scanning the sensors too.

 

High hc is usualy due to a misfire plugs. wires, coil, or low compresion [bad valve brocken ring. High co is asign of over rich mixture, O2 senser bad cat restricted air cleaner I think in the end you will find you have a mismatched bunch of performance parts that just dont work well together Bubbabud

 

Thanks Bubba....I hope not. The best way out of this might be to get some help from the guy who sold me the truck but I don't think he wants to be of any help. I had only owned the thing for a month or so when it just quit running and he started helping me trouble shoot over the phone and after the 2nd or third call he quit answering...Thanks to the forums help, I changed out the ECM and it solved the problem.

I changed the distrubuter cap then too and like now, it had been really hammered. Maybe I should switch it back to the stock ignition?

 

I was just talking to someone on the phone and they said to "pull the timing spout connecter" right before I go in....retards the timing or something

 

try high octane gas + 104 octane boost