White Smoke =AOS failure or Injector stuck open ?

[Schnell Gelb]

2001 Boxster S 90k miles newly rebuilt engine.

I just fitted a new AOS and it shows 4.6" but has huge clouds of oil smoke ! Edit - well, maybe not oil but un-burnt gas on a cold start? -see later Posts for diagnostics.
Diagnosis:
1.I suspected the old AOS was due for replacement based on age and some white smoke after start up. The old AOS tested O.K. but replaced it anyway. The new one seemed no different in terms of white oil smoke production.
I dissected the old AOS to see if the diaphragm was sagging/torn. It was perfect .I epoxy-ed it back together to carry as an emergency spare.
Now I have huge plumes of white oil smoke and 4.6" of water vacuum on the Pyle manometer.
BTW the oil pressure at start-up is 75+ lbs on a newly rebuilt engine and the compression/leakdown is perfect and even on all 6 cyl
So is the 4.6" AOS defective/marginal ? What should a new, perfect AOS measure ? Pelican say 4"- 7" is O.K. and above 9 is fail - so I may have to try the block-off hack for diagnosis here:

" If you're still not sure, you can take a closer look at the hose that connects the air-oil separator to the intake manifold (yellow arrow, Figure 2). If the unit is failing, then there will be a significant amount of oil or residue in this tube. If the car is running rough, then removing this tube and blocking off both ends should disable the system and restore previous performance. This is not a long-term fix, but instead a short-term diagnosis step to use before you replace the air-oil separator. "

I ask because there has been discussion of defective,new AOS units from even reputable suppliers. I bought my new (4.6") one from name begins with Auto and ends AZ. I used to buy from RND/SSF in Los Angeles  but they have 'retired'.

2. There is also a ?related?   P0301  Misfire which I had blamed on Ticking Lifters(now replaced). The code persists . There is gasoline seeping from around Cylinder # 1 header tube at the steel gasket. That is near where the SAI pumps into. Coincidence? I did recently repair /completely overhaul the SAI system to pass the Ca Smog Test. It passed easily and ran well until the lifters started ticking(again).

There is a good spark at Cyl 1 and it has good compression/leakdown compared to the other cylinders. Why would a marginal AOS push gasoline out of the gasket near Cyl 1 exhaust pipe?

Car starts easily and runs smoothly other than Cyl 1.

What other tests to do for diagnosis ?

BTW if the Cyl 1 misfire caught your attention ,the best recent ,comprehensive Thread on that subject that I found to help is linked below.

Interesting that there were multiple causes but mainly bad lifters,Variocam issues  and a mismatched/under-performing injector on cyl#1. Fuel Trims were not very  helpful in the diagnosis.

https://rennlist.com/forums/996-forum/917082-yet-another-996-cylinder-1-misfire-thread.html

 

Edited October 9, 2017 by Schnell Gelb

[JFP in PA]

5 inches of water, or slightly below, should be fine. Is the new AOS factory or aftermarket?  I ask because we have had no luck with non factory AOS units, way too many were bad right out of the box; although the ones that failed also showed high vacuum as well. 

 

Have you pulled the intake boots and checked for oil residue?

[Schnell Gelb]

Thank you JFP. I now suspect the AOS is O.K. because it still smokes profusely with the corrugated hose from the AOS to the Intake plugged per Pelican;s suggestion.

There is a small puddle of oil under Cyl # 1 on the floor.So I have removed #1 spark plug again to inspect for oil residue - none. Just dropping the cat+ header to see where the oi is coming from . Ah ,ah ! it was leakage from removing the Oil Pressure Tester from the oil pressure sensor tapping in the crank case.It is directly above Cyl #1 on Bank 1 ! So (amusing)false alarm.Thank goodness for that !

The serious issue is raw gasoline in the Bank 1 header which has been a deteriorating problem for a while.  When I remove the cat/header the 3 exhaust ports up inside the cylinder head are dry and the valves look dry. The steel gasket and header face are very wet with gas. 

As part of the SAI system there are 7 small ports cast into the cylinder head exhaust manifold face. 6 ports are approx 3/16" in diameter & spaced 2 per cylinder .But between 2 &3 there is one much larger port approx. 7/16" in diameter. This seems to be the source of the raw gasoline. What 'feeds' this port, please?

Does this mean (all 3?) Bank 1 fuel injectors are constantly spraying gas in huge quantities regardless of DME signals? Or just jammed open with deposits ? I did have a similar problem on Cyl #4 a while ago.So I replaced the fuel pressure regulator and the #4  injector. I flow tested the removed injector and it seemed perfect on the bench test rig.The engine ran well and did not leak fuel after that .Now the big Bank 1 leak.

Remove all 3 injectors ? These are all the upgraded 4 hole type.

Maybe time to replace all 6 injectors. I can find the correct part # ( ?  0280155890  = 996 606 120 00 ? ) but some say 12 ohms ( Bosch Part number:  0280155890 ) ,others say 15.4 ohms( Part number: 0280156211 ) .Both Listings claim to be compatible with my car ! Does the 3 ohms matter as long as all 6 are identical? BTW the 15.4 ohm are cheaper.

I reeeealy appreciate your insight into this weird problem

 

 

Edited October 4, 2017 by Schnell Gelb

[Ahsai]

Any photos? You got gas in the exhaust header side? How is that even possible? Gas is sprayed toward the intake valves which is isolated from the exhaust/header side.

[Schnell Gelb]

I have no idea how ! I am going to try starting it with the header +plugs removed on Bank 1 to see where the gas flows from.  Dangerous but I am desperate to get this car fixed !

 

A stupid but effective test ! The engine ran for a nanosecond on just Bank 2 -yikes !

The gas is pouring out of cyl #1 exhaust ports when the engine is started. 2 & 3 are dry.Nothing to do with SAI. I shall edit/delete previous reference to SAI .So somehow that injector #1 wiring is grounding itself continuously  ? Nope -the Noid light flashes correctly so really  all 6 injectors should be replaced ? Best to have 6 new,identical, upgraded as a set  I guess.

But which part number? and 15.4 ohm or 12 ohm ? 6 new injectors for $300 seems very reasonable - compared to what I spent on 48 Lifters. And so much easier to replace. See later Post for part # used - it worked great.

15.4 ohm

http://www.ebay.com/itm/6-UPGRADE-OEM-Porsche-Boxster-H6-911-H6-Bosch-4-HOLE-Nozzle-Fuel-Injectors/272857357050?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

12 ohm:

http://www.ebay.com/itm/6-BOSCH-Fuel-Injectors-OEM-Porsche-1997-2001-BOXSTER-BOXSTER-S-2-5-2-7-3-2-NEW/261320663318?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

Here is an older discussion of the subject.If there is a better reference from Renntech, I'll delete this one and insert our own

http://986forum.com/forums/performance-technical-chat/55115-fuel-injector-cleaning-swap.html

 

We are getting closer to a diagnosis but I am still concerned that the white smoke was oil +gas(not just gas) but that diagnosis must wait until the gas leak into Cyl 1 is fixed.

I fitted a NOID light to the Cyl 1 Injector connector.When I crank, it flashes so no circuit problems .

With Key on and engine off there is no leakage from any injector.No, not even #1.

Here is a video showing what the white smoke looks like:

There are lots of videos that show the procedure for checking the cause of overfueling an injector.Most seem to be circuit related and caused by abrasion/heat/oil. Like this:

That is why the Noid Test is important because it is easy and accessible on the M96. The wiring harness for the injectors is in a relatively cool part of the engine.It is very difficult to visually check the harness.

If you suspect one injector and consider replacing it - what if it's performance is slightly different to the others/ That is why I decided to replace all 6. Surprisingly, it was not very expensive if you buy Bosch parts.

In theory a test would be to measure residual pressure at the Bank one fuel rail - but how?

 

Edited October 14, 2017 by Schnell Gelb

[Ahsai]

Checked for compression/leak down on cyl #1? Sounds like it's being flooded by fuel but there's spark.

[Schnell Gelb]

Correct - flooding. Spark is good on ll cylinders.Noid Test light flashes correctly at # 1 injector when cranking.

Leak-down and compression are good on Cyl 1 and similar to the other 5 cylinders -cold.

I'll let the excess fuel evaporate overnight and retest in case that was affecting the readings.

Edit: I failed to evaporate/remove all the old gas from the exhaust system and this caused confusion when I restarted the engine after the fault had been repaired - see later Post.

I'll get some confirmation of the injector part number interchangeability/upgrade  in the morning and add it.

I bought "Bosch Gen III EV1 Fuel Injectors 0280156211" for $200 ,set of 6 delivered.

They worked perfectly - see later Post.

Edited October 14, 2017 by Schnell Gelb

[Schnell Gelb]

IT RUNS GREAT !

First the bad news. When I started it after fitting the upgraded Bosch  injectors the smoke was as bad as ever. Disconsolate I let it smoke at idle for 20 minutes before the smoke began to abate. Eventually it cleared up.

Long fast/slow/heavy/light traffic drive - superb ! No check engine light. But is is now showing "Not Ready " Grrr. Fixed that in the past & have the drive cycle figured out so not worried.

To test leak down and compression the kit linked below was useful because of the included extension/adapter tube. Still a fiddle but doable with care. You can buy the tube from others but it costs more than this entire kit. Be aware the couplers are "Lincoln" not the regular Industrial style 1/4" Amflo style

 

 Great service from this company.

http://www.ebay.com/itm/Engine-Compression-Gauge-Tester-10mm-12mm-14mm-18mm-threads-with-extension-tube-/372029804444?hash=item569eb44f9c:g:uHUAAOSwTyZZeWon

 

Edited October 14, 2017 by Schnell Gelb