[dunejunkie]

Hey guys, first time poster, hope you guys can help me out.

My buddy bought a 98 LS Auto OBD2 with a blown engine that also came with a low mile JDM b20b spare.

We just finished swapping the b20b + LS 5 speed gearbox in last night and took it for a test drive. The car seems to run decently well, pulls smooth though it's a little rough on startup.

The CEL is on, but doesn't display any codes on my scanner. Also the speedo isn't working for some reason. We are running a manual OBD2 ls ecu with the crank sensor bypass (tied into the cam position sensor in the dizzy). Stock manifold and injectors from the b18 with all emissions equipment retained, stock exhaust, cat etc. We are using the original b18 auto engine harness as well.

Do you guys think the CEL is related to the emissions readiness checks being incomplete? Or is there something I am missing with this swap. The car needs to pass state smog tests (Arizona) before we can swap to a obd1 ecu with the proper tune for this engine.

Happy Labor Day everyone

 

[rguttenb]

Emissions checks incomplete will not throw a check engine light. My first thought when you say you have a CEL with no codes according to your scanner is to get another scanner. It is possible the CEL is related to the fact that your speedo doesn't work. I can't speak for the manual ECU in an auto harness, but having used an auto ECU with a manual trans, I can say the auto ECU gets very upset if it doesn't see a valid vehicle speed sensor input. Even the manual ECU is looking for the vehicle speed sensor because it uses it for determine IAC settings, EVAP emissions tests, and probably a handful of other things.

 

[AWDteggy]

Check your speed sensor plug on top of the trans.. make sure it’s plugged in

 

[Siameseclint]

I have a question for you. If you have an 98 obd2 chassis & engine harness & ecu, why do the crank bypass ?

That's probably why you have a CEL. You can just pull the crank gear with the crank sensor teeth from the old motor. And get an obd2 oil pump for mounting the crank sensor, very cheaply. And use the bottom plastic timing cover from the old engine.

Your B20B will run way better with the crank & cam sensors separate & working. Not to mention your ecu will be able to tell you if you're misfiring. And it will net better mpg.

I know it's not super easy to pull the timing belt & oil pan off. But retaining the crank sensor will help.