California smog analysis, ask a smog tech

[camoit]

Hey guys, whats the deal with the first converter on a the 2.0 engine? I have an 84 and noticed the 2nd one can be purchased as a direct bolt on California legal but the 1st one is obsolete and no longer available. Can they be gutted out? Mine only has 33,000 original miles so I'm sure there good for awhile but I am investigating poor mileage and a miss when shes cold. Also surges here and there when cold. I am building up a parts cache to keep her serviceable for time to come LOL.

Mike

The first one is a cat pre-heater. If you replace the cat with a new one you don't need the heater. The newer cats can clean up emissions better and will work at the lower temperature then the old ones needed to run. There also more efficient then the old one. And for the cost of the new replacement it is less money then trying to replace the heater and the cat. If you could find one. At least that's what I have herd.

And as for the EGR you can probably get away with using the single. I don't think the tech will notice. The duel diagram type is to give a finer control of the gas flow. Not just on or off like the single. Unless the Tech is supper hip to what these trucks have I can't see him asking any questions. All he is going to do is look to see if it's hooked up. I don't think they even put a vacuum pump on them any more to test them. But I do know if you reset the computer in new cars you must first drive them about 20 miles before you can test them, or they will send you out the door.

[mikewarme]

The first one is a cat pre-heater. If you replace the cat with a new one you don't need the heater. The newer cats can clean up emissions better and will work at the lower temperature then the old ones needed to run. There also more efficient then the old one. And for the cost of the new replacement it is less money then trying to replace the heater and the cat. If you could find one. At least that's what I have herd.

And as for the EGR you can probably get away with using the single. I don't think the tech will notice. The duel diagram type is to give a finer control of the gas flow. Not just on or off like the single. Unless the Tech is supper hip to what these trucks have I can't see him asking any questions. All he is going to do is look to see if it's hooked up. I don't think they even put a vacuum pump on them any more to test them. But I do know if you reset the computer in new cars you must first drive them about 20 miles before you can test them, or they will send you out the door.

*****, Thanks for the clarification. Now the trick is to find a manifold that does not have the mounting for a pre heater.

Thanks!

[noahwins]

Unless the Tech is supper hip to what these trucks have I can't see him asking any questions. All he is going to do is look to see if it's hooked up. I don't think they even put a vacuum pump on them any more to test them. But I do know if you reset the computer in new cars you must first drive them about 20 miles before you can test them, or they will send you out the door.

I don't test EGR functionality unless it's pre-OBD2 (1995 or older) and a Two Speed Idle test. So either AWD or if you live in a Basic Area where they don't do the dyno test.

If someone fails you for a non-stock EGR, I'd go to the state referee and appeal it. Because we're not looking for CARB EO#s on any emissions equipment except cats. So long as the EGR is there and it works, you should have no problems.

You can gut the cat because obviously it's not going to throw an OBD code. So long as the second cat is nice and hot and cleans the exhaust enough to pass the tailpipe, the inspector will have no way of knowing the first cat is gutted.