power loss at 2500 rpm

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

Hi All,
Today I have noticed my Prado is loosing power at around the 2500 rpm mark. It seems to go fine up until there then backs right off. I have tried replacing the fuel filter thinking it wasn't getting enough fuel but that hasn't made any difference. I have noticed the pyro gauge isn't going up much at this point either which says to me it isn't getting enough fuel, but that is a bit of a guess. Any ideas would be appreciated.
Scott

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

Is it surging as if its taking in air or just no go?

Recently service a 80 series and the filter primer pump was taking in air. Surging at 2200 RPM or over and lose of power. After I repaired it (temp fix) it goes like a bought one.

Hazza

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

It doesn't seem to surge Hazza, just seems to loose its acceleration. It will still get up to road speed but doesn't accelerate to it like it should.
Scott

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

Mate what motor do u have? 1KD or 1KZ?

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

Sorry, should have said that, it is a 1KZ

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Fuel pump? Sounds like it's not getting enough motion lotion.

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

Thats the exact symptoms mine showed and it was a cracked head.
Typical early stage symptoms.
Next stages are as follows...
Radiator holds pressure overnight, your coolant will look lower buy 5mm or so, but in the morning feel for hard top radiator hose & take your radiator cap off and see if it releases pressure. If your coolant level rises back to normal level then your coolant system is being pressurised from cylinder compression.
Listen for the smallest pop/misfire on start up... If the head is cracked it may leave a few drops of coolant in cylinder #3 causing a pop on start up.
Exhaust becomes quite smelly... Almost like a pungent stink really.
I hope this is not the case for you, but thays how to do a diagnostic on this particular cylinder head.
Note your oil & water will not show signs of contamination.
Check it out and let me know.
Cheers. Drew

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

Thanks for the replies folks. Well I have just driven the car about 500kms and have a few more ideas but no more answers. Thanks for the detailed response Mackayvx, I am certainly hoping it isn't the head. I think it it is either a fuel supply issue or something to do with the drive by wire. While driving at 100km/h, the car was perfect. It may be not linked, but when I push the accelerator down to the second stage (becomes a little harder to push), this is where the car looses acceleration. I am unsure is this does anything or is just a different spring. I have noticed it surging but only slightly. I have replaced the main fuel filter and climbed under the car but couldn't find the under body filter I have heard about.
Like I said at the start, I have more info but still haven't worked anything out. I am hoping it isn't the fuel pump but I am starting to wonder

[was a 75 Lurker Find all posts View Profile Close was a 75]

not a turbo problem??

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

Possible to do with the boost compensator not adjusting fuel?

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

Didn't some one have an issue with the throttle pedal ?? I remember there been an issue with the flyby wire. Some thing to do with the signal from the foot accelerator pedal back to the ECU. Some thing needed replacing where the pedal is ?? Cheers Steve

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

I do prefer the sound of that to a pump Steve. I had a look at the top of the pedal, there is a black box on the top to control the drive by wire, it is possible, might have to take it some where I think.

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

Hey if your pump is stuffed it will idle ruff and run like a dog.
Possible a sensor on the pump but if its idling ok i doubt its the pump.
Only the D4D has the fuel filter inbetween tanks on the 120 so dont bother looking too hard under the car for that one.
Have you checked the air filter? Is your turbo spooling up? I doubt its turbo.
Did u mention hard radiator hose earlier or was that someone else? Ive looked but wasnt sure if you edited the post.
Check all your vacuum hoses and intake hoses from the air box right thru to the manifole.
You need to get someone to look at the obvious first before pulling too much apart.

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

I like your thinking Mackayvx. It is idling find and up until about 2 - 2500rpm it accelerates fine as well. That is why I was thinking fuel supply. Someone else suggested radiator and head, I don't think that is the issue as it runs fin up until higher revs.

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

As i said earlier... Thats what mine did with a cracked head... No power after 2200 rpm.
Do yourself a favour and do those morning checks to eliminate the head mate.
I chased every possible problem with that car until i diagnosed a cracked head.
Im hoping its not. But the power loss at revs was my first symptom.
Dude how long since youve changed the air filter?