88 3.2 Getting smoke on deceleration after valve adjustment

[brizzity]

I've got an 88 3.2 with about 131k miles. I recently had a 15k mile service done with filters, plugs, oil, and valve adjustment done. Prior to the service, i really had no issue with smoke beyond a little puff at startup here and there. Since the service, I've got and increasing amount during operation, mostly during deceleration and some at idle. My mechanic claims it's likely the valve guides which seems to be the common answer for smoke during decel. I find the timing a little suspect, that it'd start showing itself right after the servicing. So my question, is there anything that could've been done during the valve adjustment that could be the cause of this?

I believe the car is running a little rich since the service. When I first got it back, upon start up as it was doing the gradual drop from about 1200rpm, the idle would surge about 1k rpm a couple times before settling at about 800-900 rpm. It would also occasionally dip significantly or even stall after pulling off the accelerator after my first touch of it. The surging has stopped. The stalling is very rare now.

It's been almost 3 months since the service and about 2200 miles. I haven't tallied oil consumption during this time as it didn't seem out of the ordinary, I don't think I've put more than 3 quarts in.

Some history on the car:
I've owned the car about 2 years and put about 10k miles on it, it's been really healthy during this time. Previous owner had kept good records and spared no expense. No top end done though. I had a PPI done before purchase, compression on all cylinders was 125psi, and leak down 6%-8% between all cylinders.

Any thoughts would be appreciated. I know this is a common topic here. My mechanic is usually good, but there have been multiple times where he's missed the mark. I guess I'm just trying to find out if this could be the result of something he did or didn't do, or if it's just coincidental timing of expected wear.

[azhodge]

follow your instincts, if it feels wrong it probably is.... nothing worse then a a bad valve adjustment....

[db_cooper]

Could be air leaks..does the idle change and become rough if you remove the oil filler cap at idle?

The valve adjustment itself should not effect a smoke problem..however if when reassembling if something is not tight or reconnected..you could have a problem.

911s are easy to overfill with engine oil too..too much oil and it will get into the intake..and smoke.

Oil level check engine running, at idle, engine oil hot..should be between the MIN and MAX marks. My 911 engines always like to blow off a quart if I run the oil level at the MAX mark hot..they always settled down to somewhere in the middle of the marks..

[DRACO A5OG]

+1 check to see all hoses are reconnected. When my wrench returned my car after service. I found the cruise control hose disconnected causing idle hunting.

As far as smoking, very strange it started right after service.

[Canada Kev]

Originally Posted by db_cooper

Could be air leaks..does the idle change and become rough if you remove the oil filler cap at idle?

The idle is supposed to change when you remove the oil cap at idle.

[brizzity]

Originally Posted by db_cooper

Could be air leaks..does the idle change and become rough if you remove the oil filler cap at idle?

The valve adjustment itself should not effect a smoke problem..however if when reassembling if something is not tight or reconnected..you could have a problem.

911s are easy to overfill with engine oil too..too much oil and it will get into the intake..and smoke.

Oil level check engine running, at idle, engine oil hot..should be between the MIN and MAX marks. My 911 engines always like to blow off a quart if I run the oil level at the MAX mark hot..they always settled down to somewhere in the middle of the marks..

I can't say that I've noticed any change in idle without the oil filler cap on. If there is, it's probably not enough to notice while back in the engine compartment. I'd have to check the tach I guess to see if there's anything subtle.

I usually run the oil somewhere between the middle of min and max and 3/4. Since i noticed the smoke, I've kept it in the middle. My wrench suggested trying to run it a little closer to min to see if there's a difference.

[DanielDudley]

There isn't any way you could accidentally ruin a valve guide by doing an adjustment, but If you think that three quarts in 2200 miles is normal oil consumption, I'd say that is a little on the high side.

Any way you could be using a different oil ? some engines that consume are really sensitive to the oil they are running. Check the connection to your oxygen sensor.

[Chuck.H]

Have you checked the breather hoses are looped into the air box? I think this raises them and makes it harder for the oil to seep into the intake.

I recently (10k miles ago) put a breather in place of the oil tank connection to the air intake, and it dramatically reduced the amount of oil in the intake... very noticeably smoother running and throttle response (my throttle body used to get coated in oil).

I also run my oil tank on the low side of the marks - I'm happy if the needle just moves off the bottom of the gauge.

My oil usage is about what you report, but then I have all these miles on the original rings and valve guides. I don't have any noticeable smoking though. If it didn't run so good I'd tear it down.

Chuck.H
'89 TurboLookTarga, 428k miles

[db_cooper]

Originally Posted by brizzity

I can't say that I've noticed any change in idle without the oil filler cap on. If there is, it's probably not enough to notice while back in the engine compartment. I'd have to check the tach I guess to see if there's anything subtle.

I usually run the oil somewhere between the middle of min and max and 3/4. Since i noticed the smoke, I've kept it in the middle. My wrench suggested trying to run it a little closer to min to see if there's a difference.

When you remove the oil cap, engine warm at idle..the engine should have a noticeable drop in rpm and struggle to idle. If not..you have a problem..air leak..very rich mixture..something.

[Drisump]

Originally Posted by db_cooper

When you remove the oil cap, engine warm at idle..the engine should have a noticeable drop in rpm and struggle to idle. If not..you have a problem..air leak..very rich mixture..something.

Yes, the idle speed should lower immediatly. If not, a vacuum leak is indicated. Cheers

[T77911S]

smoke can be from too rich.

same plugs?
cap and rotor?
O2 sensor connected

[r_towle]

Have you properly checked the oil level?
It will smoke with too much oil...and that happens when its not checked HOT...

same thing happened to me after an oil change and valve adjustment....the mechanics don't wait long enough to check the level sometimes.


Rich

[DRACO A5OG]

OP, I would be happy to take a look at your baby since we are neighbors :-)

PM me

[Hnichols]

Does the valve train sound different -- more clattering than before?

As others have said, I don't think there's a connection between valve adjust and smoke.

At 130K your 3.2 is likely showing some valve guide wear, so your mechanic is probably right about that. But I'm guessing a bit too much oil is giving you more smoke than usual, although you probably always had a bit of valve guide smoke on decel, but didn't notice it.

[Jherriott]

What kind of oil? Synthetic squeezes thru smaller gaps than Dinosaur oil

[brizzity]

Thanks for all the input thus far. A few follow up points...

I've been running Castrol GTX 20-50 for as long as i've had the car.

Spark plugs were replaced at service, same cap and rotor. o2 sensor connected. Oil level is correct, still right in the middle.

I went back and took another look at the mileage, looks like I've done 3k miles not 2200 so the 3 quarts should be more in line.

The valves don't sound any different from what I can tell. The car sounds like a smooth running sewing machine and I can only hear the valves when outside the back end.

I just took it out and got it up to temp and then removed the oil cap, no noticeable drop in idle. It sits right at 800rpm throughout so I guess that means vacuum leak.

I think from here I'm going to take it to another wrench I know is top notch and get his assessment. I'll report back when I have some news to close the loop.

[darrin]

presume you're still running a catalytic converter and that it's still good -- the catalytic converter will burn off a lot of oil smoke and removal of a cat (or a failed cat) would let the smoke through

[Avanti]

Originally Posted by Drisump

Yes, the idle speed should lower immediatly. If not, a vacuum leak is indicated. Cheers

About how many rpm should the idle speed drop when the oil cap is remover? Is there a difference between CIS and Motronic fuel injection systems?

[dan88911]

I have a 88, 58K mile Garage Queen I purchased a few yrs. ago.
When I purchased it had 50K miles. It idles at 800rpm.
With no change with oil cap off, if I recall correctly in some other thread that only occurs with the CIS systems. And not with the Motronic systems thanks to the DME unit.

[brizzity]

Originally Posted by darrin

presume you're still running a catalytic converter and that it's still good -- the catalytic converter will burn off a lot of oil smoke and removal of a cat (or a failed cat) would let the smoke through

i do have a cat in place, a new one went on the car when I bought it 2 years ago/10k miles ago. I guess checking the condition of that should be added to the list.