Idling / Timing fault

[Countess]

Can any of you guys please help me out ???

My 1992 has idling (or timing?) issues. After 2-3 minutes from a cold start, it shakes and splutters and feels like it is going to stall. This only lasts 2-3 minutes, and then everything is perfectly fine. The mechanic has replaced spark plugs with platinums, and it was better for 2 days, then starting to get worse again.

$1000 and 3 days later (found 3 engine mounts that were "missing", and now my engine does not move when you rev, that was not cool). He is at a loss as to the cause, as it is hard to catch it being faulty. Ignition coils, perhaps??

Anyone had the same issues, and could give me a clue???

Thanks heaps !!

[North Ursalia]

Dunno but you only have three mounts holding the engine in place- two to the engine crossmember and the pitch mount on the back to the firewall. If all three were actually missing, believe me, you'd notice it.

[Cam]

I was about to say the same thing. Did the mechanic show you the missing mounts when the car was on a lift? I feel like you need to ask some questions and crawl under the car to verify you have new mounts.

[North Ursalia]

Especially since new mounts are under $300 and it doesn't take $700 worth of labor to put them in .

[Cam]

Agreed again.

[92 SVX]

What about the Aux Air Control Valve, if im not mistaken that only applies when the engine is cold, it just puts air in to help idle if that is bad or blocked might be causing that.

[JDW-SVX]

There are three things that come to mind........

You may have one or more fuel injectors that are leaking when the engine is shut off, and flooding one or more cylinders.

It could also be a faulty Coolant Temperature Sensor - if so, then the ECU may assume that the engine is warm even when it it cold, and will therefore not inject the extra fuel required for cold start enrichment.

The CTS is easy to test - you should have around 2.5 Kohms of resistance across the pins of the sensor when the engine is cold.

A blocked Auxiliary Air Valve will not cause rough running - but a blocked or sticking Bypass Air Control Solenoid Valve will, if the valve is not able to allow enough air to bypass the throttle to reach the desired idle speed.

Jason.

[Countess]

He said 2 were missing, and 1 was worn or stripped, I dont think I paid particular attention. He revved the car while I was watching the engine and it lifted up, now it does not. He also did other work that made up the labour, the ABS was not working correctly, sparkplugs, don't remember what else. He did offer to give me the 1 mount he had, but I have no need for that. And, I was not about to say no to replacing them, as 7 years ago when someone wrote off my SVX, the engine dented the bonnet because it came out of its mounts when I got rear ended, so I am all for safety and protecting my precious SVX that it took me 7 years to get again!

Thanks for the insights into the idling fault, I will print off and take into him next time it is in there.

There are not a lot of places locally that don't screw up their noses and tell me "we don't touch imports" so they are not even willing to look at it. These guys, their eyes lit up when they saw it. That is good enough for me.

[Dessertrunner]

Hi Countess,
Trust me it will cost 1,000 to replace 3 engine mount, I haven't checked with Subaru Australia for a while but they use to cost $500 each.
I need a bit more info does the problem happen when the engines cold or all the time at idle?
What are the idle revs?
Does the car lack power?

Okay my suggestions for your problem and I assume you are not getting any error codes.
- MAF so get him to take it off the airfilter and spray throttle bodie cleaner on the sensor behind the mesh screen.
- The next possiable problem will be the cam angle sensor near the battery, have had plenty of these go over the years, don't know if you can borrow one to swap out and test.

The things I don't think it is:-
Cold idle valve sticking
Air leak,
Bad injector,
Spark plugs (it was good to change anyway),
Coil pack,
Timing is controled by computer so you can't change.

Happy to explain my logic if needed.
Tony

[Dessertrunner]

Countess are you still around, how did you go with the car?
Tony