Project V8 RX-7: Goin' Legit
(Project RX-7 vs. the State of California)
by Jeff Naeyaert
Now that it doesn't look like the world is gonna end we need to get our RX-7 smog legal and on the road! Since the car has been down for surgery with the heart transplant the registration has long since expired. It's only a matter of time before we get busted by the fuzz for old tags and excessive hooning around. A trip to the DMV and a smile got us a one day pass from the lady behind the counter with the date of issuance left blank so that if it took us more than a day to get our smoggin’ done we wouldn’t have to go back and wait in line again!
We did however have a couple check engine lights to clear before we could visit the referee. The first diagnostic trouble code (DTC) was P1336 “Crankshaft Position System Variation Not Learned” which we expected actually. This code got triggered when we exchanged our ECM calibrated for automatic transmission applications to one for a manual transmission (the only difference being the number of teeth on the reluctor wheel). Apparently every ECM is calibrated to every engine at the factory and the computer cannot “self-relearn” this crankshaft position–you've got to take it to the dealer to have it relearned or find someone with a GM Tech II diagnostic tool. We don't know anyone with a Tech II so it was off to Win Chevrolet in nearby Carson, California.
|We dropped the car off with Win Chevrolet's service department and were able to escape 3 hours later for only $60 for the crankshaft relearn procedure. All the other local stealers quoted us more than twice that amount for the service so we felt like we got a deal. Bet it's not every day those GM techs get to work on a China car!|
The second DTC, P0174 System Too Lean (Bank 2), came on while we were driving down the freeway. Mildly alarmed we might be damaging our brand new engine we looked up possible causes. The most frequent is a dirty MAF sensor, but our MAF is brand new so that's probably not it. We were however worried we might have MAF turbulence from our air filter that was right smack in the middle of the opening in the bumper.
|Got MAF turbulence? We thought we might with our placement of the K&N filter in the air stream and the MAF sensor only 3″ away from the filter.|
Digging a little deeper we found that some LS applications had airflow straighteners ahead of the MAF sensor from the factory to prevent MAF sensor turbulence and reduce ECM fuel trims. Several companies sell honeycomb straighteners but we found the cheapest at saxonpc.com. $10 for the size we needed and they even offer to trim them to fit for free!
|We ordered a 100mm honeycomb and asked for it to be custom cut to about 96.5mm to fit snug inside our 6″ intake tube. A week later it arrived but sadly it hadn't been trimmed.|
|Not too worried we just flattened some of the holes around the edge till it fit into our tube just in front of the mounting boss for the MAF sensor.|
We reinstalled our intake, cleared the DTC and have not seen the trouble code since! We're finally ready to make our smog referee appointment!
As one of our astute readers pointed out in the comments of our last article “Why do you need to go to a CARB Ref? We thought the kit came with an EO sticker?” We thought the same thing, but just to be sure we called the CARB to see if the sticker was sufficient. Unfortunately, the nice lady on the other end of the line informed us that ALL engine changes have to be approved by a referee—EO sticker or not. BOO! It’s not the end of the world for us because we’re not trying to skirt the rules here anyway, it just would have been a lot more convenient if we could have hit up the smog shop down the street. Plan to schedule your appointment at a referee station in Los Angeles at least a week out from when you call because there aren’t that many of them and apparently they have a lot to do! Unfortunately our excitement to get the car legalized was gonna have to be put on hold…