'95 960 Running very rough

1FastCookie · Post by **1FastCookie** » 07 Jun 2012, 16:55

My 960 is running poorly. It has good compression across all cylinders, all plugs are new, injectors are all functioning ok, all coils are ok. One cylinder is dead. Any on have any ideas? could it have a bad lobe on the cam?

Post by **MoVolvos** » 07 Jun 2012, 17:18

1FastCookie wrote:It has good compression across all cylinders, all plugs are new, injectors are all functioning ok, all coils are ok. One cylinder is dead.

Can you elaborate on the "dead" cylinder as you have spark, fuel and compression?

Blessings,
BKM
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1FastCookie · Post by **1FastCookie** » 07 Jun 2012, 19:42

That doesn't make much sense... Sorry. No compression in the one cylinder but there is spark and fuel

Post by **MoVolvos** » 07 Jun 2012, 21:34

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Can you please provide a little more info on your vehicle condition, maintenance background or any unusual problems or repairs leading to this dead cylinder?

What were the Compression Test numbers on that cylinder wet and dry and how does it compare to the rest?

Mileage of vehicle?

How was it running before this problem?

Regular oil changes?

Timing Belt Issues?

Overheating?

Blessings,
BKM
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1FastCookie · Post by **1FastCookie** » 10 Jun 2012, 13:09

BKM98 S70 T5 wrote:-
Can you please provide a little more info on your vehicle condition, maintenance background or any unusual problems or repairs leading to this dead cylinder?

This car is a new vehicle to me. What I do have is an extensive list of maintenance to the car. All dealer maintained untill a short time ago when the original owner passed away and the son and grand son acquired the car. I believe a relatively short time...

What were the Compression Test numbers on that cylinder wet and dry and how does it compare to the rest? Mechanic could not remember the numbers just stated compression IN ALL 6 CYLINDERS

Mileage of vehicle? 85000 miles

How was it running before this problem? All I can do is assume it was normally operating

Regular oil changes? Every 3,000 with Mobil1 synthetic

Timing Belt Issues? Belt changed at exactly 70,000 miles

Overheating?

Blessings,
BKM
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My mechanic explained to me today that there IS spark and compression in all 6 cylinders, fuel at the "dead cylinder" injector but not in the cylinder. He feels as though the cam may have a bad lobe so that the valve is not opening to allow fuel in to the cylinder. He wants to remove the head to check this theory

Post by **jimmy57** » 10 Jun 2012, 17:19

I have never seen a worn cam on one of these and it would have to be two worn lobes since it is a 4 valve/cylinder engine.
Was the bad cylinder injector moved to another cylinder to see if the misfire goes to the other cylinder or stays in the same cylinder?
Same with coil. A coil that has spark out of cylinder may internally arc under cylinder pressure load as firing voltage is greater with plug screwed into the cylinder.

Oh, another thing. He can check for worn lobes by taking the intake manifold off and marking the valves stems where they come of out the guides on that cylinder with valves closed. Then turn engine over and see what the rough lift of the valves is.
It should be 9mm lift and equal for both valves of course.
I'd be swapping coils and then injectors first as those are a lot less time consuming.

1FastCookie · Post by **1FastCookie** » 10 Jun 2012, 21:42

He told me he had swapped the coils. The injector was delivering fuel. I'm not sure he swapped injectors

1FastCookie · Post by **1FastCookie** » 14 Jun 2012, 10:40

Latest possibility...
Collapsed hydraulic lifter

Post by **MoVolvos** » 14 Jun 2012, 16:42

1FastCookie wrote:
My mechanic explained to me today that there IS spark and compression in all 6 cylinders, fuel at the "dead cylinder" injector but not in the cylinder. He feels as though the cam may have a bad lobe so that the valve is not opening to allow fuel in to the cylinder. He wants to remove the head to check this theory

Compression, Spark and Fuel are all good but no fuel into the single Cylinder in question. How is your Mechanic verifying/measuring the no fuel condition in the cylinder in question?

For Reference Only
http://www.curbsideclassic.com/wp-conte ... chnitt.jpg

For Reference Only Cutaway in Middle of Page - No Fuel in Red Area of the Cylinder. How was that verified?
http://musclecarclub.com/library/tech/engine.shtml

Blessings,
BKM
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gmtgmt · Post by **gmtgmt** » 16 Jun 2012, 15:15

There are 5 possible coases to this.

1. The valves are full of carbon and dosent oprate proberly, This is a problem for these Whiteblocks when they run alot short trips.

2. Blown head gasket, also a problem that has been seen alot on these both my 960er had this problem.

3. Bad injector, not very commen but have seen it before

4. Collapsed Hydrulic cam followers, also seen before.

5. last but not least burnt valves. This happend to my coworks 91 850 GLT 20V