View Full Version : RB20 Smoke Issue

03-19-2012, 11:19 AM
I realize that I'm probably going to get flamed for this, but my options are a bit limited. I recently purchased an 89 240 with an RB20 swap. The car has a lot of modifications: custom turbo manifold, Apexi N1 exhaust, 550cc injectors, Walbro 255, AEM EMS and custom piping and front mount. The car was running rough and had a slight oil leak at the valve cover. I changed out the plugs and replaced the valve cover gaskets. The car ran fine afterward. After driving the car for a few miles and only boosting once or twice, the car started to smoke heavily from the exhaust. Its smoking blackish gray and heavy amounts. I checked the coolant and it's free of oil. There's no oil in the coolant. Both oil and coolant levels were fine. It doesn't smell like its boiling coolant and the smoke is too dark. I checked the piping on both sides of the turbo and there isn't any oil. So I can't figure out why it's smoking so bad. After letting it sit overnight and starting it back up, it didn't smoke at all. And then when I took it out to drive it, it started smoking again once moving. Thoughts? The car idles smooth. It doesn't smoke on idle. Does it just need a tune?

03-19-2012, 01:52 PM
Maybe a blown turbo seal??

03-21-2012, 09:04 PM
I don't think so. The turbo is still boosting strong and it doesn't smoke on idle. There was no oil on either side of the turbine housing. I'm pretty sure that I'm running too rich and fouled a plug or plugs. Although the idle is normal. I think the EMS (running MAP) is too rich and it's just dumping fuel. Ill pull the plugs this weekend and check. It only smokes under load and doesn't smoke when revving. I'm not consuming any oil and it doesn't smell like oil burning.

04-01-2012, 04:04 PM
walbro 255's run rich on rb20's try to get a fuel pressure regulator (adjustable) hope this helps

04-01-2012, 04:20 PM
It smokes at WOT only? If the turbo isn't leaking then it's prob the motor. get a leak down test done on it or check the plugs to make sure none of them have oil on them.