2002V6 Prado engine performance

[donnyb Lurker Find all posts View Profile Close donnyb]

Hi Pradotans,

I have owned my VZJ95R since new - now 132,000klms. I am a retired aircraft mechanic, so a bit fussy. Have always done the maintenance and servicings once out of warranty, and during the warranty period, changed the oil and filter every 5,000klms with Shell Helix semi synthetic, as I have continued to do. I have run the engine on mainly 95 octane and regularly run an injector cleaner (Moreys).
I have noticed the engine has not 'leaped' into life from either a cold or hot start for a while now, taking several cranks (say, since 100,000klms). The engine note is also not as crisp as it used to be, and to my nose, the exhaust fumes smell on the rich side, or, if you like, "fumey". I suspect the air filter, which although I have cleaned it several times as per the manufactures instructions, I have never renewed it. Also, on the ignition side, the spark pugs are due for a change (this would be the 3rd set since new).
I have not yet changed the timing belt, which is due at 150K, but by age (8 years), would be getting close perhaps? So, maybe a bit of stretch might be affecting valve timing a tad too? I have cleaned the air intake volume sensor (think it is called a MAP sensor) with a little metho/cotton bud a while back, with a little improvement.

A few related questions - 1. Any one had a similar experience at around this mileage and what was done to rectify it?
2. Where can I get hold of an online parts catalogue so I can quote correct part numbers, and is there a reputable online parts shop either here or overseas that has the original parts + postage at a reasonable price?
3. I will be adjusting valve clearances soon (first time). Anyone know where to obtain the special tool (09248-55040) or an aftermarket one that works, to facilitate shim replacement? I have a micrometer.
Thanks in anticipation ! Regards, Don

[Taresk Member Find all posts View Profile Close Taresk]

Re: 2002V6 Prado engine performance

You've probably already done this, but have you checked the MAF? it's a hotwire design, and tends to foul easily.

[donnyb Lurker Find all posts View Profile Close donnyb]

Re: 2002V6 Prado engine performance

Yes Tarisk, I did do that sensor a while back (I called it incorrectly a MAP sensor in my post), with just a little improvement noticed. Do you know if it is usual for the ignition timing in this engine (V6 3.4l) at this mileage to get out of specs? Although the engine sounds, as I say, a little rich, that "feel" can also be a symptom of retarded ignition timing.

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

Re: 2002V6 Prado engine performance

hi don,if your pardo is fitted with oxygen sensors,one may be playing up.they can cause it to run rich,you need to have a scan tool fitted & check for faults. also check exhaust, if the cat or muffler are blocked this could also cause the problem! the timing belt wouldn,t strech that far to cause the valve timing to move enough to cause the problem, if it has it would be the frist one i have heard off. cheers warwick.

[donnyb Lurker Find all posts View Profile Close donnyb]

Re: 2002V6 Prado engine performance

hi don,if your pardo is fitted with oxygen sensors,one may be playing up.they can cause it to run rich,you need to have a scan tool fitted & check for faults. also check exhaust, if the cat or muffler are blocked this could also cause the problem! the timing belt wouldn,t strech that far to cause the valve timing to move enough to cause the problem, if it has it would be the frist one i have heard off. cheers warwick.

Thanks Warwick. Do you go to a Toyota dealer for this type of scan, or to a franchise like Ultra Tune etc? I have had experiences during the warranty period that indicated to me that the workshop crews may be on a bonus system based on through - put, which is OK is all the workshop teams are comprised of ethical mechanics. Hmmm. I would prefer to take it to a franchise or even better, an ex toyota mechanic who has the diagnostic experience and equipment. What do you think? Don.

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

Re: 2002V6 Prado engine performance

hi don, iam a toyota trained mechanic and have always thought the dealership was the be all and end all .but since leaving the fold (a long time ago) i have changed my mind. they are dollar driven not customer satifaction driven. i would make some phone calls and not only franchises but quality private mechanics also they should have scan tools.you may need to do some homework to find someone in your area or you may need travel to get the results you need? cheers warwick.

[donnyb Lurker Find all posts View Profile Close donnyb]

Re: 2002V6 Prado engine performance

Yes Warwick. All I really need is for the problem to be reliably diagnosed. I can take it from there. Anyone reading this forum be able to recommend a good mechanic, with the diagnostic gear, in the Gold Coast - Springwood area? Thanks Don.

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

Re: 2002V6 Prado engine performance

They dont have oxygen sensors, didnt come with them. Regards Steve M

hi don,if your pardo is fitted with oxygen sensors,one may be playing up.they can cause it to run rich,you need to have a scan tool fitted & check for faults. also check exhaust, if the cat or muffler are blocked this could also cause the problem! the timing belt wouldn,t strech that far to cause the valve timing to move enough to cause the problem, if it has it would be the frist one i have heard off. cheers warwick.

Thanks Warwick. Do you go to a Toyota dealer for this type of scan, or to a franchise like Ultra Tune etc? I have had experiences during the warranty period that indicated to me that the workshop crews may be on a bonus system based on through - put, which is OK is all the workshop teams are comprised of ethical mechanics. Hmmm. I would prefer to take it to a franchise or even better, an ex toyota mechanic who has the diagnostic experience and equipment. What do you think? Don.

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

Re: 2002V6 Prado engine performance

HI SteveM
You might be confusing earlier 3400V6 90 series with later versions.
Generally.... pre 2000 they didn't have oxy sensors because they didn't have a cat converter. It wasn't law for them to have one (as a light commercial vehicle)

After 2000 it was mandatory for all petrol engined vehicles to have a catalytic converter, and therefore they also got an oxy sensor

IF we are getting a feeling that there's a "richness" in the air/fuel ratio, yes you can plug in a scanner and I recommend that it's done, but also do the basics like spark plugs, test the leads, and be sure to check the earths and wiring loom connections for the engine management system are good. eg was there some other work being done around the time the car started to lose it's edge?
I'd also try a airflow sensor out of another car or a new unit, just to eliminate that as a possibility, they seem to be really temperamental on higher mileage.
Exhausts can block but that's rare unless you squashed a pipe!

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

Re: 2002V6 Prado engine performance

Mallory Black,

The 3.4 V6's don't have a catalytic converter at all, mine is a 2002 model and has no cat or oxygen sensor and yes it is still the original exhaust.

I think you will find it is because the Prado was classed as a commercial vehicle therefore wasn't included in that ADR or emission reg.

Lee

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

Re: 2002V6 Prado engine performance

Was just going to say the same thing, I stuck my head under my mates today, GXL 02 V6 original exhaust and definately no oxygen sensor, I actually had one put on myn when they did the LPG was in a stupid spot was linked upto the computer running the LPG suppose to have controlled the gas flow etc, would have been the first thing to get ripped off from under the vehicle if a branch or some thing got hung up on it. Regards Steve M

Mallory Black,

The 3.4 V6's don't have a catalytic converter at all, mine is a 2002 model and has no cat or oxygen sensor and yes it is still the original exhaust.

I think you will find it is because the Prado was classed as a commercial vehicle therefore wasn't included in that ADR or emission reg.

Lee

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

Re: 2002V6 Prado engine performance

Whoops got my dates wrong, I should not drink and type!
but it was something to do with switch to Euro 2 then Euro 3 emmission standards. I could check but I want to go to sleep now....

[GH4wd Advanced Member Find all posts View Profile Close GH4wd]

Re: 2002V6 Prado engine performance

I suspect the air filter, which although I have cleaned it several times as per the manufactures instructions, I have never renewed it

I'd replace the air filter :wink: Has the fuel filter ever been changed :?:

Cheers,

Glenn

[minh Member Find all posts View Profile Close minh]

Re: 2002V6 Prado engine performance

I will add to the confusion.
My one is a petrol 3.4 litre 2001 VX model and I have a o2 sensor. Im averaging 15l/100kms. I drive very very light footed.

Sound like I got an exhaust leak in the engine bay too when I accelerate. Can this make for worse economy or lose power?

I have changed fuel filter and air filter. Havent done spark plugs.

Have cleaned out Air flow Meter with CRC contact cleaner.

Maybe time to change the o2 sensor as majority of my driving is done below 2000rpm.

my wifes 120 series does wonders on fuel. 13.9 litres per 100kms.

[minh Member Find all posts View Profile Close minh]

Re: 2002V6 Prado engine performance

I must apologise..
I was confused with my wifes one at the time of posting. My one definately does not have an o2 sensor.
Sorry guys.


Steve you up for a weekend bash sometime? I got another mate up for a Lithgow day run or maybe YAwal west of Nowra?

I wonder if Menai is still open.