Gutless wonder....

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

ok, she definetly kicks down... it spends its life kicking down to climb a hill! bottom of the throttle body? I guess thats what I call the Idle Air Control valve. Will give it a clean tomorrow with MAF cleaner.

[Chaser Member Find all posts View Profile Close Chaser]

Pull the exhaust off before the first muffler and see how it goes then.

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

Do you just unbolt the throttle body and spray it clean??
mine is doing the same.. down on power and not really kicking back when planting foot... ?

[Snaga Wishing I was lost Find all posts View Profile Close Snaga]

How much 'kit' have you got on your 90 series?
My 1998 was a little rocket when I first got it but by the time I put all the accessories on it, it really hated towing and hills... just sayn'

Here's what I had on it before I sold it...


One thing that did give the old girl a kick up the bum was the 'third' mechanic to look at it found a vacuum leak and that gave it a bit of an extra boost... stiil, my 2008 D4D 120 has more 'get up and go' off the line than my 90 and also handles hills towing our CT much better.

[Mallory Black Junior Member Find all posts View Profile Close Mallory Black]

gutless, rough idle... has anyone been messing with the camshaft drive belt? might have slipped a tooth or been incorrectly installed back in the day.
also get a compression test done to be sure that all cylinders have the right compression in them

as well as all the other stuff

[SWR Banned Find all posts View Profile Close SWR]

Gday RanJ

To be honest i really do not know much about the 90 series but do they have an OD button on the T-bar?

If so and the OD (Over-Drive) light is on then it will automatically head for top gear as soon as possible (Economy Mode)

When in "OD" mode you will find it would tend to change down more frequent and that you have to floor it more often to change down!

If "OD" mode is switched off then it will hold in lower gears for longer before changing gear and not engage overdrive (Better known as sport mode!).

ALSO! if the kick-down cable is not set properly it can also interfere with gear-change characteristics if the cable is not set properly.

Here is a link worth reading

[PDF]
Toyota Electronic Transmission Checks and Diagnosis - Autoshop 1

Cheers

PS. I sent you directly to the sorce so dont think i'm breaking any rules? ... Lol

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

Ranj, everything skywalkerrun is pretty correct except he may have got the buttons mixed up. The 90's auto both diesel and petrol have a power button (as well as OD button). I use to use this button (power button) a lot in hillier areas to stop it hunting between overdrive and drive and also when climbing hills, towing, it will hold what ever gear your in for longer but also makes the throttle a lot more responsive and kick back a lot quicker then if you had the power button off. My 120 (no power button or O/D button does it automatically obviously more advanced and they detect when your climbing or going down hill hence the gears in a 120 will drop down a gear if you dab the brakes on a down hill run, it detects your going down hill (pretty smart). The 90's don't have the same features in there auto box except 2nd gear start. Also you will notice the difference with the lock up torque converter when using the power button manually dropping the O/D button out instead of putting the boot down and waiting for the box to do it automatically for you. Personally I don't think this is your problem as you obviously have used the vehicle for towing for a fair while and you obviously have noticed it not as responsive as previously with out driving the vehicle a different way to how you normally drive..... Hope you make some progress with it, can be extremely annoying....Cheers Steve

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

This is the cable skywalker is referring to. This will make a big difference if not adjusted properly. Mine needed adjusting due to the cable stretching over age, it certainly made it more responsive..... [IMG][/IMG]

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

OD is not the problem but thanks for pointing that out to me. Currently the 90 is up on blocks as I'm still waiting on suspension after I snapped a strut. I don't think the kickdown is the problem either but I know it's never been checked and certainly wouldn't hurt. So thanks for that link, I've saved it and will check it out when I get the prado back on the road.

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

So a couple of months ago I finally put the car back on the road after some suspension issues and a lack of funds.

Its now my work car and is 800kms a week at the moment. So obviously this fuel guzzling, gutless wonder needs help before I burn it!
Now I've come to realize a few things and these are on the list. The engine has been well maintained but the gearbox hasnt. Intact, no fluid change in at least four years! New filter kit is on its way.

Need to do diffs and transfer case as well.

Still have a couple of worn bushes to replace.

There is what appears to fuel mixture screw next to the airbox. Marked L and R. I'm guessing this means Lean and Rich? I've always noticed her to be smelling a bit rich. Since I have turned that adjuster to the halfway mark the fuel smell at idle has greatly reduced. I can't think of any other to set my AF ratio without having someone weld in an o2 sensor with a narrow band gauge at the minimum. Or using a four gas analyzer at a workshop. Open to ideas?

Will pick up a compression tester this week. Can someone fill me in on what range and tolerance is acceptable for our motors

Will also inspect plugs closely at same time.

Will throw the timing light on the old girl also as I've come to realize its timing belt was due 50,000km ago! Does the motor need to be in diagnostic mode or anything like that before I can check the timing?

Will drop the exhaust tomorrow and go for a scoot around the block to see what happens. If they're blocked, would I expect to see a massive improvement when I go around the block? Can I just whack in a pair of universal mufflers that my mate with a welder can make fit?

Sorry for all the questions... But I'm now ready to tackle the problem head on.

Oh, BTW the way, can someone measure the resistance on their MAF and let me know so I can compare it? I clean ygr maf on a regular basis and the IAC got a squirt of the same stuff to be sure.

[Pugaree Member Find all posts View Profile Close Pugaree]

Just read this thread, for all the mucking around and time this has taken, why don't you just take it to a decent mechanic? I'm all for doing things myself but sometime you just have to suck it up, Who knows what sort of damage you are doing by driving this in this state.

[scottkz Senior Member Find all posts View Profile Close scottkz]

Have you got any codes come up?
How much power do you think your down by?
Even if all the cyls are way down on compression you probly won't notice a power loss , if just one was way down you might
If it's definitely down on power big time and no codes come up the problem lies in a area with no sensors.... Fuel pumps, fuel lines, exhaust , that type thing
The air box has a blocked filter light on the dash
I would doubt the gearbox would be a problem , there hydraulic so if the oil is cactus or burnt or failing you'll probly see other symptoms first like slipping of taking a long time to go into drive or reverse
I pulled my V6 out and swapped it with a 1KZ auto.... It absolutely shits on the V6 for towing and it's got 35kw less power
The D4D has 5kw less that the V6 and with more torque it's always going to be better at towing
I found the gear ratios in the V6 were terrible 1st would have lots of power but 2nd would lack power and pick up to what the previous gear had

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

Funny scott I had 2 grande's one 1KZ the other 3.4V6 and I reckon the 1KZ was a complete dog and my V6 shit over the diesel. I was actually pissed that I sold my V6 to get the diesel. Then the head went at 103k 4K later. Both vehicles well serviced all genuine parts etc. and there wasn't much difference In economy on the open road 12.2L per in the V6 and any where from 11 to just under 16 with the 1kz depending on weather and if I sat on 95 or 110. I was disappointed with the KZ, other then that nice vehicle. Looove my 120 V6 have no intentions of selling any time soon, can't anyway just bought the wife a new mazda 3, that's nice to drive lol keeps her out of my Prado now lol..... Cheers Steve

[scottkz Senior Member Find all posts View Profile Close scottkz]

Well there wouldn't be any fights in the car yard then!
I never got economy even close to 14/15 in the V6 , and I have 2 mates both with V6s or had them but sold them coz of the economy
One of those mates has just converted another v6 to diesel
My motor has 258000 on it and all original

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

Just read this thread, for all the mucking around and time this has taken, why don't you just take it to a decent mechanic? I'm all for doing things myself but sometime you just have to suck it up, Who knows what sort of damage you are doing by driving this in this state.

What you aren't probably aware of mate is that since I started this thread nearly 12 months ago, the Prado stood not going anywhere. I've since brought it back on the road and am ready to get it fixed. Going to a mechanic is unfortunately not a financial option. To pay someone to investigate as to why a 12 year old car with 370K is down on power yet still runs smooth would probably cost me the same as a reco engine. Also as you've probably noticed, I'm not really asking people how to fix my car as I am trying to get ideas on what to check and also what correct specifications should be to compare to what I have. As an auto accessories fitter for over 15 years and a vehicle emissions tester in Alaska, I feel I'm more than capable of fixing this, I just want some ideas from people who are far more familiar with the quirks of this motor than myself. But your opinion is appreciated. Thanks mate!

Have you got any codes come up?
How much power do you think your down by?
Even if all the cyls are way down on compression you probly won't notice a power loss , if just one was way down you might
If it's definitely down on power big time and no codes come up the problem lies in a area with no sensors.... Fuel pumps, fuel lines, exhaust , that type thing
The air box has a blocked filter light on the dash
I would doubt the gearbox would be a problem , there hydraulic so if the oil is cactus or burnt or failing you'll probly see other symptoms first like slipping of taking a long time to go into drive or reverse
I pulled my V6 out and swapped it with a 1KZ auto.... It absolutely shits on the V6 for towing and it's got 35kw less power
The D4D has 5kw less that the V6 and with more torque it's always going to be better at towing
I found the gear ratios in the V6 were terrible 1st would have lots of power but 2nd would lack power and pick up to what the previous gear had

Hey Scott, good point... No codes are being thrown neither current or historical. So you're right, it must be a non sensor area. I'm yet to drop the exhaust, that is on the to do list later today.

Any thoughts on that mixture control near the airbox? I was wondering if it only adjusts idle.mixture or constant mixture. If it had an O2 sensor then it would only be idle as the stft and ltft would handle the fuel mapping. But I'm not too sure how its done on these motors with obd1.

My fuel economy would be estimated at 17L/combines driving. Which seems a bit on the excessive side but I do definetly have a habit or ripping away from the lights which undoubtedly has an effect.

Further thought on my power loss tells me its not drastic as the vehicle is very driveable but noticeable. I notice the power loss mostly when climbing any incline and accelerating from a roll. Taking off I seem to find the acceleration acceptable for a vehicle of its size although I think it should still have a bit more boogie from a take off.

IF AND ONLY IF the motor is shot, I'd be extremely interested in learning about diesel swap and what's required and problems I'd face. I can handle the work no problems but advice to reduce its downtime and also pre sourcing components would be awesome.

Thanks guys.