Lack of power
 

My SVX is being troublesome of late. I have just had it serviced in
the hopes that replacing the plugs etc. would cure the lack of power problem that I have been experiencing, but it hasn't. Symptoms are that it is difficult to start, often requiring a couple of pumps on the throttle before it will fire, then when it's cold it does not rev freely, but runs lumpily and has little or no power. When it does warm up, it appears to run reasonably smoothly, but still lacks power occasionally. When power does arrive, it comes in a big burst, and make the car difficult to drive. No 'check engine' lights. There are frequently clouds of white 'smoke' coming out of the exhaust.

Re: Lack of power
 

Blackbird,

SVX not flying for you?:)

Couple of things you should look at. :

With the SVX, the plugs are long-life, and are rarely at fault. When you changed plugs recently, did you keep a note of the colour of each plug from each cylinder? This would tell you if one cylinder was problematic.

Assuming you didn't, and you still have rough running, there are a number of possible causes. Most likely for the SVX, one [or more] of your coils on top of the plugs have failed, or is failing intermittently. To check this, when it is cold and running rough, you disconnect each in turn, carefully. If you unplug a good one, the engine running will get worse. If you disconnect one that is not making spark, there will be no change, that's the one you are looking for. Replace this one, should be problem solved.

Another possibility, you may need to use carb or choke cleaner on the intake butterflies, they can get gunged up.

Also, you could have a bad or dirty slow running jet, situated below the inlet manifold. If you are technical enough to take this off and clean it [recent info in the Technical Forum] don't unscrew the valve or change any factory presets other than cleaning, otherwise you are in deep s**t.

You should also look to make sure your plastic and rubber inlet box is properly fitted over the two butterfly flanges. This can get folded up underneath due to careless fitment, and will allow in air which will upset the tuning.

My best guess is you have a bad coil.

Best of luck with it.

Joe:)

Dropping cylinders.............
 

Joe, Blackbir2001.

Rather than pulling the coil demand wires it would be far easier to pull demand wires off injectors. Same effect, it would knock out a good cylinder, but no effect on an "dead" one.

Having replaced some cheap "regular" plugs with the correct Platinum tipped ones my feeling is that the pick-up and responsiveness of the engine improved no end.

Butterfly plate would have to be *really* dirty to cause that much problem, although Idle Air Control Valve (IACV) could be causing poor idle. It's a stepper motor actuated valve under the butterflys in the throttle body. It could well be cacked up with oily gunge as the crank-case ventilation air/oil vapour is drawn back into the air intake upstream of the butterflies.

This wouldn't necessarily cause poor performance. There could be air leaks. Have you checked all the connections from air-filter housing and MAF meter, up the rubber hose to the throttle body, throttle body to inlet mani, and inlet mani to cylinder heads ?? Could try a "squirt" test with some light oil, see if it gets drawn into the manifold by vacuum.

I would be more concerned with the white smoke. Does it smell of fuel, I mean really smell strongly of fuel ?? This could indicate multiple plugs/coils shut down and simply not burning the fuel. If it doesn't smell strongly of fuel is it seriously hot ?? Scaulding hot, like steam ?? Could be a head-gasket type problem.

I really don't know how you would get a compression tester/leak-down tester in there to check..............

Re: Dropping cylinders.............
 

Thanks for the info Phil. That makes a load of sense.

Joe:)

Any update, Blackbird?

You get to test the coils?

Joe:)

Joe,
Not yet. The car is now with the local Subaru dealer. They should check it out over the next couple of days. I will let you the outcome. I just have the fear that it could be the head gasket in which case it becomes history! Let's hope not.
Dave

Joe, things have gone from bad to worse! It appears that the problem is that the the Woodruff key which holds the camshaft drive belt pulley on to the crankshaft has gradually been moving around to the extent there is now considerable play causing the timing to be very variable and hence the reduction in power. The really bad news is that it needs a new crankshaft, which makes it too expensive to repair. So, I will now be posting another thread to see if anyone wants to take it off my hands. And then I have to find a replacement. Dave

Sorry to hear this Dave.

Whatever mechanic/dealership fitted the last cam belt do not seem to have done a great job on the cam pulley.

Put on properly, this should not happen. There is a million flat four Subarus out there with the same system, and still they are reliable.

Joe

Joe, I agree! I have now stopped using him, but it is a bit too late! The latest suggestion is to replace the cambelt and then weld the cambelt and ancillary pulleys to the crankshaft. By the time the cambelt needs replacing again, the rest of the car will be past it anyway. Any thoughts? Sounds a bit drastic, but should work.

Go for it!

You have a lot of money to lose the other way.

Unfortunately the crank can't be dropped to be worked on in our cars, has to be engine out and split. My instinct would be have a machine shop cut a slot in the crankshaft to take a standard taper key. Without getting the crank out, this is not an option.

Your biggest challenge is identifying where exactly the pulley needs to be on the shaft to give you TDC on the timing. And then you must weld it exactly there, and nowhere else. You will not have the luxury of minor adjustment.

Difficult, but not impossible. Any suggestions from Phil Hill or any of the engineers among us as to best way to accomplish this?

Help keep another SVX on the road?

Guys? Ideas?

Joe:)

Replacement for sick SVX
 

Sorry to hear of your troubles,It's never good to hear of a sick suby.
Just thought i'd let you know, i was told last week that there were two SVX's in southampton docks, there's an importer through dock gate 4. When this person saw them, i don't know,but he said there was a white and a silver one,if you're serious about getting a replacement, it might be worth looking.
Good luck what ever you do. Fran

Sorry Andy - not with you. What are you suggesting?

Click on the link in the previous post

Thanks. I'll watch with interest, and may even participate.