Gutless wonder....

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Hoping some can shed some light here. Our Prado is an absolute gutless bloody wonder. Towing anything bigger than a 6x4 it will struggle to maintain 100kph. Going up hills can be forgotten about. It also have a fairly rough idle more often than not.

I know its got 370,000 on the clock but this is beyond a joke. So far to try and resolve the issue...

New air filter
New fuel filter
New plugs
New leads
Cleaned MAF

Thought, I'd change the O2 sensor and put a new cat in place.... doesn't have one!

Heard talk of power valve in the exhaust... what is it? Any ideas for other things to clean, change, throw away or hit with a hammer?

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

If it makes any difference, I just threw the multimeter on the MAF and it shows 1.3K Ohm and air temp would currently be about 20C. If I remember correctly, thats a bit low. At this temp, MAF should show about 3K ohm I THINK. If someone has a workshop manual to confirm that...

[rightway Junior Member Find all posts View Profile Close rightway]

How much blow by does the engine have? Take the oil cap off while it's running and see how much fumes come out, possibly the piston rings are worn or the valve guides, you could also get a compression check done at your mechanic or by a compression tester and do it your self.

Worn rings or guides will give the systems you described

Ben

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Fumes as in petrol fumes? Good point. Will have a look in the morning.

Interesting note, the engine does NOT use oil at all and right now it's about 10,000 overdue for a change, it's a litre low (at the MIN mark) and oil is clean. I have not added oil.

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

""Heard talk of power valve in the exhaust"" I think this is referring to the flap thing on the back of the first muffler. For memory when I looked at mine it has 2 springs on it. Apparently they block up or some thing like that and can reduce power. Not a real clear answer sorry but Im sure some one will explain it better.....but may give you some thing to google lolCheers Steve

[Chaser Member Find all posts View Profile Close Chaser]

Try dropping the exhaust off before the first muffler and see of there's a improvement. Old Toyotas are renown for blocking mufflers, or it may have a blocked cat. Will it rev freely? Defiantly do a compression and cylinder leak down test.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

@Steven, thanks mate, will have a googley oogley of that.

@chaser, it doesn't have a cat. Never came worthwhile surprisingly. Was one of the things I was going to replace. No cat or o2 Sensor.

[marshy Lurker Find all posts View Profile Close marshy]

the flap on the first muffler pretty much builds up compression and opens releasing the exhaust, its a bit of a power killer, I have taken mine out and it turns almost into a straight through muffler if that makes since and u do notice a little power gain as the engine doesn't have to revas hard.

[letsgoplaces Advanced Member Find all posts View Profile Close letsgoplaces]

I'm replacing my mufflers next service for the same reason. Absolutely no power trying to get up a hill at a 4wd play weekend!
The short term fix was to undo the mufflers and shove a rod through them to help the exhaust flow. Unfortunately didn't have enough time to replace them last time i was in town

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

is there any way to test its operation? If it has failed then I would either remove or replace it.

Lastly. if it does appear to have a poor compression or blowby which means it's up for a rebuild... Can I get heads up on places for parts, OEM vs Aftermarket, Potential power adders or economy savers... and which service manual to pick up.

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

If the engine needs a rebuild and your thinking of heads. Heads alone would cost 3 k would be cheaper to get a low k engine from a wreckers, heaps around. I don't think the engine itself will be your issue if it's been we'll serviced. I'd drop the exhaust and give it a go first. Would take little time to do that or even a compression check first as suggested and go from there. Cheers Steve

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Don't get me wrong, I'm not jumping straight into a rebuild without confirming everything else first.

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

What spark plugs did you use, they must be twin electrode as a minimum. If the MAF sensor is faulty, you will notice it in the gear changes (if auto), if man then you will notice it with massive increase in fuel consumption, also check the idle control sensor, this is often overlooked. With over 370K on the clock, the motor should still be ok.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

What spark plugs did you use, they must be twin electrode as a minimum. If the MAF sensor is faulty, you will notice it in the gear changes (if auto), if man then you will notice it with massive increase in fuel consumption, also check the idle control sensor, this is often overlooked. With over 370K on the clock, the motor should still be ok.

I don't remember what plugs they were, the problem was there before the plugs though, I do remember them having twin electrode.

It's an auto, but what will I notice in the gear changes?

Idle control sensor? IAC? sticks? needs a clean? any idea how to check it?

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

I don't remember what plugs they were, the problem was there before the plugs though, I do remember them having twin electrode.

It's an auto, but what will I notice in the gear changes?

Idle control sensor? IAC? sticks? needs a clean? any idea how to check it?

The auto will change up early and not kick down when you plant your foot. Idle control sensor sits at the bottom of the throttle body, it needs to be removed and cleaned in the same way as the MAF.