[CShort]

Hi all,

I recently finished an operation on a 1994 Saab 9000 Aero that included pulling the engine and trans, replacing both the head gasket among other things.

After a month or two of daily driving, I've noticed a few strange things. Maybe they're all related, probably not. I'm curious what you guys think or where you would go from here.

It's important to note, I think, that I have a new battery and I've compression tested the engine and all cylinders maintain 155-165 PSI compression.

My latest thoughts are that I may have a failing turbo, but I would expect to see more smoke. Or, because I have compression but oil in cyl3, that maybe that piston ring has failed, but that seems pretty rare.

Symptoms:

• Puff of white smoke at startup, but then runs clear.
• engine cranks hard, but takes 1-5 seconds to turn over. Seems worse when engine is hot.
• Combustion chamber #3 is wet with oil
• Oil is leaking externally from exhaust studs 2 and 3
• turbo is strong in gears 1-2, but seems weaker and harder to get full boost in gears 3-5.
• burns a lot of oil - probably around 1 qt in 500 mi.
• the coolant light comes on and off intermittently.

Any thoughts or suggestions are welcome.

Thanks!

Clark

 

[Banman]

First thoughts are:

Things isolated to the # 3 cylinder:
Oil ring can fail while compression ring is still good...

Valve guide/seal

Head warp/gasket failure

If the turbo seals failed in a way that leaked oil into the # 3 cyl I should think it'd leak oil into all four cylinders...

 

[chengny]

Hi all,



Symptoms:

• Puff of white smoke at startup, but then runs clear.
• engine cranks hard, but takes 1-5 seconds to turn over. Seems worse when engine is hot.
• Combustion chamber #3 is wet with oil
• Oil is leaking externally from exhaust studs 2 and 3
• turbo is strong in gears 1-2, but seems weaker and harder to get full boost in gears 3-5.
• burns a lot of oil - probably around 1 qt in 500 mi.
• the coolant light comes on and off intermittently.

Any thoughts or suggestions are welcome.

Thanks!

Clark

Just my thoughts - so consider the source:


[*]Puff of white smoke at startup, but then runs clear.

Normal - don't stress this one.


[*]engine cranks hard, but takes 1-5 seconds to turn over. Seems worse when engine is hot.

Loss of residual pressure in fuel supply line. Possibly due to a leaky FPR or check valve in the return line. Try this: at cold start, turn key to RUN and wait while fuel pump pre-primes the line (you'll hear a buzz for 2 seconds), then turn to START. Should fire up faster. The pre-prime sequence only occurs when the engine has been turned off for 15 minutes or more - that's why crank time is extended during a hot start


[*]Combustion chamber #3 is wet with oil

This is rare with the Trionic system and usually indicates that there is a problem with that cylinder's spark.
Burn-Off
After the ignition switch has been turned off and the engine has stopped, the main relay remains activated for a further 6 seconds. The Trionic ECM then grounds all the trigger leads 210 times per second for 5 seconds. Each electrode gap bums off impurities with more than 1000 sparks.

Check/change the plugs, primary wiring to the DIC and - if you have one - change the DIC.




[*]Oil is leaking externally from exhaust studs 2 and 3

There are no oil passages behind the exhaust manifold studs. Are you sure it isn't leaking out of the valve cover and dribbling down? Any oil that somehow enters the combustion chambers is burned off and lead away via the exhaust system.


[*]turbo is strong in gears 1-2, but seems weaker and harder to get full boost in gears 3-5.

IDK - not enough info available



[*]burns a lot of oil - probably around 1 qt in 500 mi.

Any blue smoke at the tail pipe? And if so, when does it show? At initial start up - and tapers off - valve seals. A puff upon acceleration after an idle at stop light - turbocharger seals. Blue smoke that tracks along with engine rpm can be an indication of worn oil control rings.



[*]the coolant light comes on and off intermittently.

If the level in the coolant reservoir/expansion tank is observed to be normal, but you are getting a "RADIATOR LEVEL" warning, that would indicate a short in the sensing leg wires (usually right where they enter the reed switch)

 

[davide c]

Possible ? that you inserted the Cam caps screws in the wrong place. Some are grooved to allow oil feed to cam journals.
Incorrectly located and a warped head/bungled head gasket refit could give your symptoms.
Trionic cars Need to crank a bit on startup... There is No cam position sensor, so the engine needs turn over a couple rotations so the ECU can deduce when to fire the plugs.
Boost is Odd.. Your car should pull a lot less in 1 & 2nd gear (it's ecu limited to save the gears)
Your pore car has a plethora of problems.. But you needs solve one at a time.

 

[Superaero]

There is a CPS on Trionic cars. It counts teeth on the starter ring. Only T 8 cars had no CPS.

Trionic start cycle cleans the plug tips by multiple high energy sparking across all four plug gaps simultaneously. The delay is in the injector opening to permit this cleaning process to complete. No fuel is injected into the combustion chambers until this pre sparking is completed. Trionic uses the spark plug gap as an ion sensor so plugs must be clean. All coilpack equipped ignition engines use this system now. This process occurs before every cold start and accounts for the longer initial cranking for Trionic cars over APC (non DI cars.).

Problems with valves and head gaskets between cylinders 3 and 4 are slightly more common due to head temperatures being just slightly the highest at that point.

Oil in the one cylinder might come from a broken oil control ring though I think that unlikely. It might come from an oil passage in the head gasket not sealing fully when the engine is cold.

Valve stem seal failure might also cause oil burning. For the plug to be wet with oil when pulled it must not be firing so I suspect the DI cassette is failing. Try a known good one for a week.

One quart per 500 miles is a lot of oil burning for these engines. My high mileage engine burns zero oil between changes so less than one quart per million miles.....l

Later model engines had to burn very, very little oil to meet emissions requirements. What type and grade of oil are you using? I recommend fully synthetic 0W 40.

 

[davide c]

There is a CPS on Trionic cars. It counts teeth on the starter ring. Only T 8 cars had no CPS.
.

Poor googling.. Mate.
Crankshaft position sensor.. NOT cam shaft position sensor. There IS difference.
Knowing crank position does not accurately indicate where the cams /valves are for spark firing which can be 180 degrees out
Ergo the one or 2 full cycle crank rotations required

 

[Superaero]

Poor googling.. Mate.
Crankshaft position sensor.. NOT cam shaft position sensor. There IS difference.
Knowing crank position does not accurately indicate where the cams /valves are for spark firing which can be 180 degrees out
Ergo the one or 2 full cycle crank rotations required

You suggested the absence of a cam position sensor was a reason for the slow starting. This is not the case. Only one revolution of the crank is theoretically required for correct ignition timing for a four cylinder engine even if only equipped with a crank position sensor. Two cylinder engines do not require a cam position sensor for the same reason.

Even if two revolutions were required that would not account for the delayed starting cycle of the 9000 DI equipped engines.

The reason is as I assert, the DI cassette performs multiple simultaneous sparking of all four plugs before the ecu permits fuel to be injected.