s52 questions. I'm starting to miss the m20..

[ZekeTheSneak]

So its a bone stock s52 obd1 converted that has been rebuilt by a reputable shop. It also has the stock s52 tune 413red label. Stock headers, y pipe to vibrant ultra quiet res then muffler. No kittys.

So when engine breaking going down a hill after awhile it starts to puff out some white smoke, this is the only time I notice the smoke. What could be the cause?

If the CEL is on, does the 24v run correctly like it is supposed to or does it switch to a safe map or anything weird like that?

Now that my CEL is cleared (missing charcoal canister, DME reset) and an oil change to mobil 1 5w40 I will be testing her out again. I understand the dme needs some miles to fully relaern the motor.

Any advice would be appreciated.

[EN318isPDX]

I have no charcoal hooked up but I did leave the purge valve plugged in and have no CEL

[DesertBMW]

It could have bad valve stem job. During deceleration throttle is closed and there is great vacuum created by the engine and if valve stems are old it would cause oil to get sucked in and burned.

[ZekeTheSneak]

Heads refreshed, my buddy made a good point of just running it. Let the rings seat.

[Spitfi-r]

If it a fully rebuilt engine with new rings etc did you do a proper break in procedure?

Mine left a cloud of smoke for the first few miles until the ring seated.
I did a hard break-in, so it only took a few miles.

[ZekeTheSneak]

The rings were the only untouched part. I bought it from someone on here who had it built. The engine sat for 2 years before i finally bought it and installed it. I was nice to it for 50 miles then did some pulls and what not. It runs and drives awesome other then the smoke on decel. I hope it just needs some miles for the rings to reseat.

[e30austin]

So its a bone stock s52 obd1 converted that has been rebuilt by a reputable shop. It also has the stock s52 tune 413red label. Stock headers, y pipe to vibrant ultra quiet res then muffler. No kittys.

So when engine breaking going down a hill after awhile it starts to puff out some white smoke, this is the only time I notice the smoke. What could be the cause?

If the CEL is on, does the 24v run correctly like it is supposed to or does it switch to a safe map or anything weird like that?

Now that my CEL is cleared (missing charcoal canister, DME reset) and an oil change to mobil 1 5w40 I will be testing her out again. I understand the dme needs some miles to fully relaern the motor.

Any advice would be appreciated.

What do you mean by a stock S52 chip in your OBD1 DME? That wouldn't work.

I deleted all that on my S50, no lights and it runs awesome.

[mtlbloodshot]

I had this problem too when I put in my TRM TUNE. I thought there was a problem with the seals too but then let the engine run for 15-20 min and everything was good.