Thread: Smoke test help for 3800 series 2 engine running lean, HELP PLEASE

If turning the A/C off made a difference then I would suspect the A/C compressor might be locking/locked up. It will drag the belt and cause a burning smell as it smokes the belt. It can totally drag down an engine if it's not spinning with the rest of the engine, even when A/C is off, and the compressor is located at the front bottom of the engine on the passenger side.

And pro tip- to find an exhaust leak without cooking yourself, stick a shop-vac hose in the exhsust pipe tip with the vacuum set on the "exhaust" or blowing side (I always tape it tight to the exhaust) and push air into the exhuast with the car off obviously. Then you can crawl under it and feel for air leaking and fix all your leaks with no skin lost.

Where exactly did you cut off the exhaust to run the straight pipe on it? What was removed from the factory exhaust system to accompish this?

Originally Posted by FordMan77

If turning the A/C off made a difference then I would suspect the A/C compressor might be locking/locked up. It will drag the belt and cause a burning smell as it smokes the belt. It can totally drag down an engine if it's not spinning with the rest of the engine, even when A/C is off, and the compressor is located at the front bottom of the engine on the passenger side.

And pro tip- to find an exhaust leak without cooking yourself, stick a shop-vac hose in the exhsust pipe tip with the vacuum set on the "exhaust" or blowing side (I always tape it tight to the exhaust) and push air into the exhuast with the car off obviously. Then you can crawl under it and feel for air leaking and fix all your leaks with no skin lost.

Where exactly did you cut off the exhaust to run the straight pipe on it? What was removed from the factory exhaust system to accompish this?

Def not the compressor it was doing this when i had my heat on also even just defroster. When i turned heater off car would run alot better but not normal,after the intake gaskets were redone car was running best it had since November and was fine til i tryed using the A/c and it did exact same thing it was doing when all of this started. Where my cat converter is suppose to be is straight piped. I got a radiator and am doing that tomorrow so after that we shall see if it fixs anything.. hopefully i can use my a/c after that without issue.

The defrost setting will also run the compressor to remove humidity IIRC. Just a thought. As long as the AC compressor pulley is turning with no AC/defrost on then it should be ok.

Do you have an ECM tune to run without the cat converter? If not it's going to run weird since the ECM can't monitor it correctly. You need a cat in there with the downstream O2 sensor.

Originally Posted by FordMan77

The defrost setting will also run the compressor to remove humidity IIRC. Just a thought. As long as the AC compressor pulley is turning with no AC/defrost on then it should be ok.

Do you have an ECM tune to run without the cat converter? If not it's going to run weird since the ECM can't monitor it correctly. You need a cat in there with the downstream O2 sensor.

no but i have been straight piped since 2018 with no problems or issues. Mechanic cancled on me and gotta wait til next week to do radiator now but ill post asap once it gets swapped.