Major power loss! Please help
 

One of my SVX’s has a major loss of power. For a few weeks now when I would get the rough idle after driving on the freeway several miles and returning home. The rough idle, accompanied by sort of a roar that could be heard and also noted at the exhaust pipe. This would happen mostly with the shifter in Park when stopped. The other day, going up a hill, I did the Petal to the metal and had no power but engine revved up like crazy. It had a bunch of that unusual sound, the roar. It started losing some power before that happened. Today I got the spray cleaner from Subaru and gave it a treat. It didn’t help a bit. Later today I could hardly get up to the legal speed on the freeway. not the high limit, the other one. You know… get moving or get off the freeway speed.
I scored the cam shaft a while back taking out the seal to replace it and it has an oil leak that gets some oil in the area with the timing belt, over a period of time
I was wondering if this could have been enough to get on the belt and make it slip a bit. Also if the oil could have an effect on the cam sensors if oil has gotten on them. I Don’t know anything about them.:confused:
My loss of power is consistent now and never runs as it should. Now it always has the roar.
I am taking it apart to see if it is out of time tomorrow. If it isn’t do you think the throttle body should maybe be removed and totally cleaned? Any ideas?
Thanks,
Keith

No mechanic here, but with the engine revving "like crazy" and the car going nowhere, I'd suspect a drivetrain problem. Could be the rough idle and other things you described are secondary problems.

dcb

Yup, high revving and no moving says "Broken drivetrain" to me as well. The roaring indicates a differential - probably the front one.

buy a 5 speed

Is not a drive train problem
 

I can drive 65 mph on the freeway just takes a while to get up to speed
Loss of power. transmission does not slip but with the petal to the metal it stays in lowest gear and doesn't have the power to go fast enough to change to another gear.

Everything is wonderful!!!! just has no power :(

and.............
 

thanks for trying to help!:)
I seriously appreciate it!
Have a great weekend,
Keith

and........... it went from the rough idle...
 

to running rough and then to running real rough the last couple of days.
The check engine lite comes on a lot now:confused:

should do a diagnostic and see what the check engine light is for. that might give a clue to whats wrong

definatly diagnose... this will be the first place to start... however this is consistant right? it almost sounds mechanical

Throttle Position Sensor and MAF seem like logical culprits to me. If we've cleared the "It's not the drivetrain" stage, then those two places are where I'd look. Check to make sure that the TPS is set to .48v - .52v and the MAF is in good working order.

Keith

It sounds a lot to me like your engine has gone into "limp home" mode. In limp home it will stay in 3 range, and it will run [poorly] to set parameters.

It's very likely that the ECU has lost signal from one or more of the critical sensors, possibly something like the crank position sensor or maybe the MAF sensor. I would lean towards thinking, though, that it has lost the run of the engine timing and has gone into get-you-home mode.

Like the guys say, run the diagnostic and see what the ECU "thinks" it needs fixed. And maybe it would be wise not to drive it too much in that mode, you could be building up other problems, better to fix it.

Best of luck with it.

Joe :)

Just to get off the subject a little. Is there anyway to check if a MAF is in "good working order" when it is off the car?

The short answer is no, Paul, not easily anyway.

You know what the maf does, I suspect. It runs a current through a wire to heat it up. The cooling effect of the air flowing past the hot wire cools it, requiring more current to heat the wire.

This variation in current is sent to the ECU as a range of voltage. If the ECU see voltages coming across that are outside the range it expects to use to define the fuel map, it sees this as a "fault".

From people working with the standard maf and superchargers or turbochargers, we already know by measuring the voltage on the car that at near to max airflow the voltage can be unstable. Unstable = inaccurate metering.

There is one thing you can do. Way, way back somebody took the top off the square part of a malfunctioning maf, got access to the circuits, and soldered loose connections inside that were causing his problem. He stuck it all back together, sealed properly, problem solved! :D

It would not surprise me at all if this fix would actually repair more than half the bad mafs out there; the bad connections are caused by a combination of age and temperature cycling from underbonnet heat.

To check the maf off the car you would need a factory set-up. You would need to feed the correct current through the pins, plus read the voltages coming off on the signal wire. You would also need to feed air through the chamber in a controlled arrangement to mimic the feed to the manifold, so that you could graph airfeed vs voltage output. It could be done but it's too much trouble.

Joe:)

Thanks Joe fpr the info. That was very informative. and no I didn't know what the MAF actually does:o but now I do:D

;)

OK Paul, now that you know what it does, do you reckon you could fix one?!

:rolleyes: :D :D

Joe:)