Hi all :)

My partner's '95 Magna - which we bought a year ago for $1,000 - has a few issues.

The newest, most pressing is that after it's been running for a while then shut down, it has trouble idling. The idle itself is smooth - not missing any cylinders, etc. I'm guessing it might be that the idle control stepper motor might be seizing due to heat soak and age, or the ECU(?) is having trouble figuring out what setting will idle correctly.

As to all the other problems, my mechanic wrote thus:


TIMING CHAIN NOISY ON START UP.
REAR MUFFLER REQUIRES REPLACING.
HANDBRAKE REQUIRES ADJSUTING.
TRANSMISSION REQUIRES SERVICE, POWER STEERING FLUID REQUIRES REPLACING & BRAKE FLUID.
LARGE ENGINE OIL LEAKS EVIDENT.
COOLANT LEAK EVIDNET AT REAR OF MOTOR - WATER PUMP OR HOSE.
FRONT DRIVE BELTS REQUIRE REPLACING.
R/HAND MIRROR TAPED TOGETHER.
FRONT TYRES REQUIRE REPLACING.
R/HAND FRONT OUTER CV BOOT SPLIT & REQUIRES REPLACING.
REAR SHOCK ABSORBERS LEAKING OIL HEAVILY.
FRONT BRAKE PADS SLIGHTLY LOW - 10,000KM'S?
EXHUAST SMOKE APPEARS TO BE VALVE STEM SEALS & POSSIBLE OIL RINGS - SMOKES ON ROAD TEST.
COMPRESSION 150PSI ON ALL CYLINDERS(APPROX 180PSI SPEC.)
COULD NOT GET VEHCILE TO CUT OUT AT THIS TIME - IDLE SPEED FLUCTUATED AT TIMES(UP TO 1500RPM) - POSSIBLE ISSUE
WITH IDLE SPEED CONTROL.

When I spoke with him in person he advised that it might not be worth spending money on as 'the motor is not well' - so for now I'm planning on fixing the CV boot and investigating the reported coolant leak. Tyres will be done at Rego time. I replace oil @ 5,000km.

There are simple tests to diagnose a exhaust problem. I saw a video on it some time ago. If you're looking at new rings etc, though even psi across cylinders good, that's a biggie. If not go to the next pricey thing and decide. Is there a point at which spending that money on another car that doesn't have this seeming legacy of poor maintenance makes more sense. And spend to have that car properly inspected. Otherwise, degrease it thoroughly. It'll help in locating leaks It might be you're looking at an accumulation of years of small leaks and not necessarily a critical problem. I'd also consider putting in a thicker oil or a mix of additives and an oil. Does it have a catalytic converter? What's it like?

that list is expensive if you cant do any your self

good thingabout that list it doesnt have to be all don at once


a second hand engine you have heard running would be a better idea

I'm guessing the car has high km and was cheap to buy.
A lot of people would fix a few little problems themselves, and keep the car going for another year or two, then junk it.
Is a 20 year old car worth spending money on? YOU decide!

Baah just lost my reply. Note to self - don't click "Reply to Thread" after typing the reply...

'95 Commodore at 409,000km. Magna at 140,000. I usually fix things and do maintenance.

I'm thinking I will repair the coolant leak, the CV boot and at some point do the tranny fluid; but will let the motor be. When it gets bad enough to fail rego then it might be time to let it go.

Also found this post here re. failing caps in the ECU and TCU, so I'll take care of that even though it's probably not the current problem cause. http://www.aussiemagna.com/forums/showthread.php?t=105097

Current smoke: https://www.facebook.com/michael.kean.127/videos/726481977484724/

Thanks for your help thus far :)

OK now I've got some spare time I've been out and had a look with my own eyes.

To me it looks like I have a significant leak around the rocker cover, and that is spreading oil all over the motor; but I could be wrong. I don't seen any coolant leak evidence and rarely have to top it up.

My next step is to pull the idle control motor and make sure it's clean, then locate the ECU and replace the capacitors, then leave it idle for 15 mins and see if it settles.


https://youtu.be/OGfZlaTP7p0

If it were me I wouldn't bother replacing the caps in the ECU. The ECU is a digital computer and faulty caps are likely to result in the whole ECU playing up (difficult to start, misfiring, random cutouts, poor idle, weird fuel usage, dashboard alarms etc), rather than just the idle speed being off when hot. Occasionally you get lucky by just replacing the caps, but by and large it's not the panacea that a lot of people expect it to be.

Idle speeder motor failure is common. Throttle body may need cleaning, as the idle speed is goverened by the air passages around the butterfly valve. Fast idle air valve may be clogged or sticky which could impact idle RPM when hot. Airflow sensor, coolant temp sensor, air temp sensor, barometric sensor, throttle position sensor all have an impact on fuel enrichment and delivery. Air leak in intake hoses? Air filter needs replacing?

Clean the engine bay with some degreaser to see where the oil is coming from.

PCV valve and associated hoses have been known to get clogged. Crankcase gets pressurised when the PCV goes bad and can force oil to be pushed out through gaps or weak spots.

How it looked on removal:

http://i.imgur.com/KkzWKpfl.jpg

Measurements. A little high on one coil but still in spec.

http://i.imgur.com/FmtR0wDl.jpg

I thought the idle speed motor coil specs were in the manual somewhere but I can't seem to find it...

Looks OK though. I'd be more concerned if the coil with the high reading was completely open circuit. I think you can test its operation by applying +6V to the centre pin of each row of three and then connecting 0V to each of the four outer pins one a a time to make the stepper advance or retract. If all four combinations make the pintle move it's probably fine.

It works fine for a while in the car. I can switch aircon on and it adjusts the revs, etc. But only until the motor reaches operating temperature. I checked the resistance again when hot, they were the same.

I read in the manual that there's also a fast idle air valve. Perhaps once that closes, there's too much constriction in the remaining pathway due to crud.

I'm hopeful that I can flush it out with carbie cleaner by spraying into the area where the idle control motor sits - otherwise I'll have to find new gaskets etc and pull the throttle body.

I have cheated for the time being by rotating the idle adjustment screw 720 degrees clockwise, and nudged the throttle position sensor a tiny bit to match..

Don't squirt carby cleaner into the fast idle air valve itself. It can melt the wax pellet valve actuator and ruin the mechanism. The manual is actually quite explicit that all the byapss passages should be plugged when cleaning the throttle body to prevent cleaning fluid entering the bypass chambers. Doesn't even suggest that the throttle needs to come off the intake assembly to clean it.

Removing the speeder motor and cleaning its chambers is probably OK provided it dries fully before re-assemblng. Finding the right replacement gasket may be difficult these days, although you could probably make your own out of some gasket material using the old one as a template.

Careful when setting the idle speed with screws. There's two screws on the throttle - one opens a third bypass chamber around the butterfly valve, the other sets the butterfly valve stop position itself. The first one is the correct one to trim (plus other tweaks as detailed in the manual). The second one should be set with feeler gauges and shouldn't require adjusting from the factory.

Thanks again for your advice :)

This is the screw I adjusted. I also rotated the TPS slightly to match the movement.

http://i.imgur.com/eYJaa1Nl.jpg

Yep, that's the butterfly valve stop screw (note the white tamper-evidence paint on the threads). If you get to the bottom of your idling issues you'll have to reset it back to factory specs before you attempt to set the base idle again.

The idle speed adjust screw is recessed into the top of the throttle body under a small plastic cap...or at least it is in the V6.

Understood :)

I've recorded the position so I can return it to normal. I knew that adding a little throttle would allow us to drive it until the issue is resolved. I could also understand that turning it the other way could do harm.

http://i.imgur.com/dLs6hpIl.jpg

I think it might be in a different position on the 4 cylinder. I'll have another look on the weekend.

http://i.imgur.com/zd1kKpxl.jpg

Found out some history on this vehicle. Last few years before I got it were short trips of about 5km.

While adding a litre of motor oil (to make up for what has been burnt or escaped) I noticed that the water pump belt looked quite sick. Replaced it today.

http://i.imgur.com/eqPvEm8l.jpg

There's also evidence of oil spray inside the cover and outside as well.

While doing the 5 minute burn-in of the belt, I could see oil leaking out of the cam shaft (I think that's what it's called). I guess that helped end this belt's life - or possibly the belt throwing chunks has given the shaft a rather hard time and added to the problem.

http://i.imgur.com/4plPmQal.jpg

I'm guessing replacing cam shaft seals will be beyond my back yard expertise and should be given to a mechanic. Any old mechanic suitable? Or should I go to the one who advertises as specializing in engine rebuilds? There is a similar leak at the opposite end of the motor even though there's no shaft there - can see fresh oil dropping from a semi-circular plate, although I wouldn't be surprised if the entire rocker cover gasket was leaking too.