Hesitation - injectors maybe.

[wobbly]

Ive noticed that the truck has started 'holding back' between 55 - 60mph.

Has been doing it for a while at 60, but now the range is widening.

Fine over that speed, fine under, just a hesitation in that range.

I'm wondering if the injectors need changing?

Its a 3.0 TDi with 110,000 miles, so probably about the right time.

Pete

 

[Rob]

What rpm does this happen at? Can you also make it happen in other gears?

I would first look if you have any perished vacuum lines.

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[fridayman]

Also have a peek in the throttle body to see if everything is moving freely.

 

[Jon Wildsmith]

Any electronics on this engine? If so could be as simple as the throttle position sensor has worn where it has spent the most time rubbing back and forth slightly? Doesn't have to be common rail to need a TPS, might be for EGR and a bit of vacuum manipulation of the pump like on a 24 valve 80 not full electronic control. Seems early for injectors to need doing on a Toyota.

 

[wobbly]

Ok, thanks.

Perished vacuum lines - any particular ones?

Throttle body - where would this be?

Is the throttle position centre inside the throttle body?

Speeds 55-60, will take it out today and see what revs are, then see if I can replicate it in other gears.

Its a 1-kzte with an auto box.

Cheers

Pete

 

[Shayne]

Before spending any real time and money i would pop down to Halfords and get some Wynns formula gold diesel treatment and a can of EGR cleaner .

 

[clivehorridge]

Mine also is hesitant, or at least has less power in the 3k plus rev band. I've had the injectors checked and they tested OK even with 340k Kms behind them. I suggest you have yours tested rather than replacing them as a matter of course, they're mighty expensive!

I've checked fuel supply and other obvious causes. I think I now have to have the injector pump adjusted to fix the problem.

Good luck.

 

[Chris]

Unlikely to be the injectors. Especially on that engine and at very low mileage. Worn injectors tend to result in over fuelling and more smoke. I went to my local pace with a Colorado and he (Trev) just looked at me and said 'Wasting your time. Not an issue on these' The pump is electronic too and not adjustable as far as I know.

 

[Rob]

Just work your way through the engine bay, if any rubber pipe is perished just replace it. Then move onto the sensors and electronics, does it have a MAF? Any boost control actuators or vacuum switches? Leave the most expensive to last.

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[Chris]

Hmm, MAF is a good call Rob.

Isn't that in the plastic pipe between the airbox and the manifold? Been a long time since I had a 1KZ-TE.

Neighbour has a Colorado and it was hugely underpowered. They swapped this and now it's like a rocket.

 

[greengrass]

Not sure if that model has a conventional set up with a throttle cable or not.

My old Hi-lux had exactly the same symptoms, it was the potentiometer on top of the throttle pedal. Never showed up on any diagnostics when I took it to the main dealer.

 

[fridayman]

The 1kz-te doesn't have a maf sensor - the sensor in the inlet tube is an air temp sensor.

 

[Chris]

Ahh, that's what it is. Cheers FM Always wondered.

C

 

[Beau]

My money would be the fuel filter inside the tank or a corroded fuel line sucking in air. You'll have to drop the tank to inspect this.

When last have you changed the in the bonnet fuel filter? Sounds like fuel starvation and if it happens bad enough it can put the car into limp mode and limit the speed around 60mph.

 

[wobbly]

Well, I went on exactly the same stretch of road today, at exactly the same speed - no hesitation at all. !

I wonder if it is fuel tank pick up related, or similar.

Oils and filters changed in June, maybe 3000 miles.

Will try again tomorrow!

 

[wobbly]

Been keeping an eye on this all week, not happened again.

Only difference I can think of is that it was a really windy day (so truck getting buffeted by wind), and low fuel. The last week Ive had a full tank.

Is there an intank filter on the 90 series?

Pete

 

[Shayne]

If it were me Pete i'd let sleeping dogs lie , your more likely to cause problems by searching for them than if you left things alone . Could have been headwind , could have been a bit of sludge in the fuel that has now been burnt away , maybe a lump of carbon dropped in your exhaust and has now been blown away , could have been a touch of deja vu , could have been anything but its guaranteed if you start searching for problems you will find them one after another until you end up wishing you had never started .

 

[chadr]

Been keeping an eye on this all week, not happened again.

Only difference I can think of is that it was a really windy day (so truck getting buffeted by wind), and low fuel. The last week Ive had a full tank.

Is there an intank filter on the 90 series?

Pete

I recall a mention an in-tank fuel pickup getting sludged up.... can't remember whom but I remember pictures of the offending part covered in oily sludge.

 

[sae70]

Is there an intank filter on the 90 series?

there is one on the end of the fuel pike up pipes, I have a photo of it that I will post up for you Tarzan

 

[sae70]

Here's the photos I took of Fiery's fuel tank when I refurbished it, I just never got around to posting them up or it would seem of taking any of the finished item with it's Red Oxide primmer coat and Black Stone Guard finish

You can see on the end of the pick up tubes a push on gauze bag style of filter, but it's very coarse and you'd have to have a pile of pretty thick sludge to block it I would have thought!

I also took some photos of inside the tank and apart from a complex array of baffles and sumps she was as clean as a whistle with no signs of sludge or anything really and she'd done around 160,000 miles