Toyota 1HZ revving high

[Red_Nut]

Team,
my 1HZ seems to have contracted an ittermitent problem with revving high. Sometimes it revs approx 600 revs high for 100kmh in 5th gear. The car usually runs at 2400 revs at 100kmh in 5th, this lifts to approx 3000 revs when the issue arises. This does not happen every time the car is started.

I was wondering if there is an automatic choke / butterfly valve somewhere that may be sticking closed / open?

Any thoughts would be appreciated, the fuel usage is an issue with the extra revs.

Cheers.

Ed.

[FNQCairns]

Hi Ed, either your clutch is slipping or the tacho is playing up, there is no other options for your problem other than these two in a manual, if the slipping is constant by the tacho then it must be the tacho as an extra 600rpm of slippage at the clutch surface would burn it out in quick time and you would be going nowhere fast.

cheers fnq

[Red_Nut]

FNQ - thanks for the heads up.

Team - what method would I use for checking if it is the clutch?

Sounds like the clutch would be the source, the engine defintely revs high, not just the tacho being out of whack.

Is there an adjustment somewhere that I can do to save the clutch from burning out (I'm guessing there is a few dollars involved in a clutch).

Cheers.

Ed.

[FNQCairns]

Ed, how long at 100kph does it happen for? If it is more than a little while 1min often then you would have already burnt the clutch out I would guess and should have been stuck on the side of the road.

Couple things to do, check your adjustment at the clutch peddle to make sure it is engaging solidly.

Park the car in high range 4wd, handbrake on, foot on brake even, select a gear like 3rd and see if you can make the clutch slip with higher than normal revs when you let the clutch out, don't go silly with it if ti would rather slip than bog the engine.

IMO the extra revs at speed should trash your clutch, hills will be worse than on the flat, downhill should make the revs come back to normal, so if you have not noticed this it may be the tacho some-how, or 4th gear but I know you said you were in 5 th.

cheers fnq

[Roughasguts]

Hmmm interesting maybe your clutch is slipping, but it should of burnt out by now can you smell anything bad under the car ?

You got any major oil leaks ? a rear engine seal that could easily leak and run on to your clutch and pressure plate and cause a slipping clutch/ higher engine revs.

I got a clutch put in me Paj last year just under a grand, mainly labour it's a bastard of a job,.

[Benny01]

its not your clutch. you would know if its revving at 600rpm higher than normal. you have a fault with your tacho. a lot of older toyota's (including mine) do it

[Red_Nut]

Team - I checked the vehicle today witht he 4wd high range, all brakes on and it stalled as soon as I let the clutch out. As BEnny says above - looks like the other suggestion may be right that it is the tacho.

Anyone done this repair before? Is it something that can be done by an half-handy person (I wire my own sounders and stereos and do some basic mechanical repairs and maintenance) or is it a mechanical job?

Cheers.

Ed.

[Red_Nut]

I checked in with the local mechanic about the tacho job. He said it is an electronic tacho. There is a sensor on the motor and a wire from there to an electronic controller on the back of the tacho. He is going to have a look at it next week for me.

Cheers.

Ed.

[Blackened]

G'day

wires for the tacho should be sitting on the alternator.

Find them and give it a clean up, may be all that is needed

Dave

[Reel Hard]

Alternator .
Might be just about to commit hurry curry. Banzaiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii

[ShaneC]

I had one that did this for years, generally the tacho would rev higher on long trips, the further I went, the higher.

I figured it was minor as it never broke down or increased fuel consumption. The throw out bearing sounded a bit dodgy when I sold it though....::)

I figure it was unrelated.

Shane