Running Rich During Cruising

[Chris28]

Since I swapped my new engine in, my AFR's have been pretty rich while i'm cruising, like around 11.5 - 12.5. When I let off the gas afr's go up like normal, but when I get back on the gas they go right back to around 12. Idle is around 15-16, so it's all normal except for cruising. I was thinking it might be my TPS, but I was wondering if anyone knew what it could be before I go and swap that out.


I'm also about to go back to N/A for a while, I'm burning a lot of oil so I want to rule out the turbo. I went through almost 4 quarts in like a week, I just went out to change my oil and literally nothing came out. It was pretty scary, I think I caught it right before it caused a lot of damage. Not really sure how going N/A applies to my AFR question, but I'll be able to see if the rich thing continues without boost.

Thanks for the answers/opinions.

-Chris

[Rhapsody]

with that much oil loss you probably would see smoke upon boost/driving if the turbo was burning the oil. You can check the compression housing and exhaust housing on the turbo and look for any filmy grease or something like that to check for burning oil. As far as your AFR readings it could be that the oxygen sensor is gummed up because of burning oil and causeing afr reading to be off or something. Pull that baby out and see how dirty it is.

[WDRacing]

I'd suggest swapping in a new O2 sensor. I had luck using a generic Bosch unit, IIRC it was only $23.

How the hell did you lose 4 quarts of oil? Are you sure it was full at one point? Did you have a CEL light? Talk about a sure method for killing a motor...lol.

[Chris28]

Haha no clue how I lost that much oil, I has a pretty bad leak though so over the course of a week I'm sure it just leaked out. My feed and return lines were loose, my return line had a drip about every 15 seconds, it was pretty bad. My CHRA was covered in oil as was my downpipe, so it was probably just wasn't sealed right. Surprisingly I didn't have a CEL.

My oil pressure gauge was reading 0 but I thought the gauge was messed up haha. After changing the oil it's back to normal. I'm back to N/A for now, it barely smokes anymore, I'm thinking it's the valve stem seals. I'm putting the turbo back on for my next drift event, and in the meantime I'm doing a stock rebuild on my '96 engine. Once that's done I'll hopefully be done with this stupid smoking/oil loss issue.

[biggie]

I was going to say new O2 and new ECU Temp Sensor would be the first guesses.

[Rhapsody]

you gotta watch out for that oil pressure. If its anything less than 5psi shut your engine off. It can cause your main bearings to start scorring and pieces will break off. Once that happeneds s*** just goes to hell and you will have to rebuild before you know it.

[Chris28]

Alright after driving for about a week N/A I've come to the conclusion that it must have been the turbo that was causing the smoke. When I got back from my cross-state trip (before I found out about the lack of oil thing) the back of the car was covered in oily grime, it must have been smoking the entire way home.

Here's my newest question: What would cause a turbo to all of a sudden produce smoke? I'd been boosting my broken ring-land engine for a few months and it only smoked at idle and under heavy vacuum. I swapped my new engine in and it was fine for about 500 miles, then literally all of a sudden started smoking. A friend was following me and it had been fine all day, then when I pulled up to a stop light it started pouring smoke. The only thing I can think of is my oil restrictor (screw-in allen key type) somehow back it's way out so I effectively had no oil restriction. Once I started driving, however, the smoke went away.

Another thing is that my oil feed and return lines were kinda loose, loose enough to cause a drip every 2-3 seconds (that's where I'm assuming all my oil leaked from). The CHRA was covered in oil when I took the turbo off. Is it possible that oil leaked from outside the CHRA ino the exhaust housing through the outside?

The thing is the inside of my hotside intercooler piping is super clean, no traces of oil. Why would oil only be dumped into the exhaust turbine? Unless it was coming from the engine it must have come from the turbo seals. This turbo has less than 5000 miles on it, I don't think it's seals would be gone this soon.

The engine still runs fine and I've checked my oil level about every other day, it's right where it should be. Hopefully I put more oil in before it caused noticeable damage.


Sorry for the long post, I'm just trying to get opinions on what could be causing so much smoke.

[Razi]

It might be your oil restrictor or your seals.
Not really sure though..
I'd check the oil restrictor.

[Chris28]

Yeah, once I get home I'll check it before putting everything back on. I have a track event July 3rd that I need boost for so I'm going to put everything on and make sure my fittings are on tight. I'll keep a close eye on it and if it starts leaking again I'll go back to N/A.

Little update, I pulled up to a stop light tonight and it started smoking again. I guess it's the engine and it just randomly decides to smoke. I'm kind of annoyed that a "rebuilt 15k miles ago" engine that I literally just put in has something wrong with it, but I guess a 200 dollar engine being bad is better than a 500 dollar turbo being bad.

[WDRacing]

Engines don't just randomly smoke. There has to be something causing it, lets figure that out and press on.

Is your sump vented to the atmosphere? If not do so, just to be sure. Just pop the line off the valve cover, or have the line run to a clear bottle, just for now so we can "see" if there is excess blowby. Plug the line coming from the PCV if you can, kind of a PITA. This will insure you're not ingesting blowby.

Get a can of seafoam and a can of engine restore. Put the restore into the oil. The when you start the car use one of the intake vacuum lines to suck out about 1/2 a can of seafoam. Once you've sucked out half a can of seafoam and the egine has been idling for 10 minutes shut it down and change the oil. When you restart the car it's gonna smoke like a demon for about 5-10 minutes. This is normal.

The seafoam and restore combined should free up any frozen rings and or crud and gunk in the oil and intake mani. So we're starting "as fresh" as possible with a used motor.

The PCV delete is just so we can remove all of the things that could cause smoke from the outside. When you refill the oil you may want to try a 20W-50 Synthetic. It's thicker obviously so it will be less prone to "seep" into any places it shouldn't be.

After all of the above is done do a compression test.

What color is the smoke?

[Chris28]

Smoke is white, but smells like oil.

Is the PCV thing just temporary? I've been meaning to put an in-line filter down there to catch blow-by before it gets to the intake manifold but I haven't had a chance. I really need to install some sort of catch can setup, I've been researching how to correctly route the lines but haven't gotten around to actually doing it.

When I have time to work on it I'll run the VC to a bottle and try to cap the PCV, as well as do the engine restore and seafoam. Thanks for the tips.

[Idahos13]

If you are N/A right now, I believe that it is your valve seals. Best of luck to you! I hope you solve your problems!