Bit juddery at 60km/h

[Lincoln]

Hey all

My '93 2.4Lt Turbo Diesel EFI Hilux Surf seems to run well except when cruising along at about 60km/h where the engine seems to be a bit juddery. It's nothing I feel through the steering wheel, more a backwards and forwards motion through the whole car. Passengers don't really notice it but it's definitely there.

Any thoughts?

[skid]

how old are the tyres if you don't mind me asking

[Heath]

does sound like an out of round tyre. I would think it would be noticeable before that though.

As another side thought, are you running tubes or tubless? Had herard of a case where the tube shreeded itself but the valve section stayed in place due to the pressure (and the tyre stayed on like a tubless also). The loose portion of the tyre moved around and wreaked havoc with the tyre balance and cause erratic shakes and shudders.

Yours does sound like an out of round tyre though, that at 60kms has reached its "harmonic point" (I think I got that term right) and really sets off the vibes

[Lincoln]

They're actually pretty new all round. The front two are a different type of tread to the back two but that shouldn't change anything. I might take it down to the fellas at beaurepaires and see if they can figure anything out. It really does feel like some kind of engine consistency problem though. It isn't a side to side shake or a up and down shake - more a forwards and backwards shake! Hope that makes sense. It's like the power is flickering on and off. You'd get the same effect (although more enhanced) if you rapidly pushed and released the accelerator.

[skid]

maybe check the unis on your driveshafts

mine did that when they were about ready to fly apart

[Lincoln]

What are the unis? I guess me even asking that means I should take it to a garage rather than sort it myself!

[tweake]

It's like the power is flickering on and off. You'd get the same effect (although more enhanced) if you rapidly pushed and released the accelerator.

is EGR and and EGR butterfly disabled ?

the other thing fairly common with these is TPS fault, often a cause of driveablity problems.

[skid]

What are the unis? I guess me even asking that means I should take it to a garage rather than sort it myself!

universal joints

climb underneath and give your driveshafts a good shaking to see if they are sloppy.

mine were rather sloppy and about to fly apart which was causing it to be a bit juddery

[Lincoln]

Sorry Tweake, you're talking another language to me! I need to learn a bit more before I can udnerstand EGRs and TPS's!

Skid, I'll give that a go. Slammin' with rain at the moment so hopefully it'll clear up over the weekend so I can have a play.

[tweake]

get unis checked first.

EGR is exhaust gas reticulation, basically poor exhaust into the air intake to reduce emissions. unfortunately it does cause problems and contributes to the head cracking these motors are know for.

TPS is throttle position sensor. thats what your foot operates to tell the motor how much fuel to put in. its just a variable resistor and they do wear out causing some erratic things.

more info at http://www.toyotasurf.asn.au/forum/

[Lincoln]

I still haven't got round to checking this out yet as it's been raining every weekend and now it's snowing! Can't complain though. Makes for fun driving.

[Lincoln]

Driveshafts seem pretty firm so yeah I'm at a loss. Hopefully it's not doing any damage. I haven't been on particularly long trip yet except out to Purau bay and that didn't involve any constant speed at 60km/h. I'll just have to stick to either 50km/h or 80km/h!

[Steve_t647]

It could also be your fuel filter, you may find you have stirred up the fuel in the bottom of your tank (I have with the cost of fuel I only run it half tank or lower most of the time). This could be causing a fuel restriction the filters (they are cheap) do tend to fall apart a bit too.

If you can find the filter look for the arrow (fuel flow direction) and try pour the fuel out in the direction of the arrow (it should flow freely) air in the in and fuel straight out if it doesn't replace it and see if the problem is gone.

You may want to try clean out your tank if this solves it, drain the tank and wash clean fuel into it (1/4 of a tank will do most of it), drain again and let your fuel settle for a day or two then filter the fuel you have and mix it with a half full tank when you are going on a long trip.

[Lincoln]

Thanks Steve. I'll take a look at that this weekend.

[Lincoln]

Just to update this post a bit: the problem is still unresolved but it's at Beaurepaires at the moment getting the alignment done so I'll see if that does anything to fix it.

Since the last post, I found out that it had a cracked head so had a load of work done on it, including amongst other things a new fuel filter, cam belt, oil filter, oil change, injector servicing, new glow plugs etc. etc. etc. ... and it's still doing it!

I did read in a manual that it could be due to the drive shaft. The best way to check was to get to 60kph (the point where it started to judder) then change gears (or switch on the O/D on my auto) to see if it's still doing it. If it's the driveshaft it should stop as it will be spinning at a different speed. From what I could tell, it's still doing it so I've taken it for a wheel alignment instead.

I think the only thing left after that would be the TPS. I didn't really think it would be the alignment as it didn't feel like a left-and-right judder that you could feel through the steering wheel. More of a backwards-and-forwards judder that you could feel through the whole car ... but we'll see!

[DieselBoy]

An easy way to tell if its the motor surging is to make a note of the rev's the engine is pulling when it starts doing it a 60k's, then when you get home, sit in the drive way and get the engine up to those rev's under no load and listen for any uneveness in the sound, i.e missing etc etc

A way to rule out the engine as an issue is to try doing 60k's in various gears and see if it still judders at that speed, i.e if it starts juddering, drop down a gear and keep the same speed and see if it goes away.

[Smurf]

I did read in a manual that it could be due to the drive shaft. The best way to check was to get to 60kph (the point where it started to judder) then change gears (or switch on the O/D on my auto) to see if it's still doing it. If it's the driveshaft it should stop as it will be spinning at a different speed.

If your speed is constant your driveshft rpm doesn't change when you change gear

[Lincoln]

Cheers Dieselboy. I've got an automatic so can't do the gears thing but I can put it in ECT mode and O/D mode etc. to change the gear.

Smurf ... yeah that's a bloody good point! Think I must have read that wrong. Pretty dumb thing to say when you think about it really!!

Incidentally, I got the truck back after the alignment had been done and it's still doing it so no joy there.

Oh and I forgot to mention the EGR has been disabled now too so it ain't that.

[Heath]

is the rear drive shaft out of phase?

I know the next question will be "how do I tell?" but I cant say it in words (too confussing) how to check. Someone here will be able to give you the good oil on that or show you a pic (or if you drive to their house they will look underneath and see it is out of phase.

Is the rear shaft out of balance? Maybe you lost a weight off it?

Are the U/J's stuffed? if this is like the double cab hilux, it may have a rubber centre bearing that can wear out.

Just all options to check I guess.

Oh yeah, at 60km/h no matter what gear you are in the rear drive shaft will turn at the same speed (to get 60km at the wheels) as the speedo is driven off the output to the transfer case and gives the final speed. This isnt affected by hi/lo or gear changes only by vehicle speed. When the vehicle is moving at a constant speed it will always show the same on the dash, even if the gear or ratio is changed.

Heath

[Lincoln]

Cheers Heath. Yeah "how do I tell" was gonna be my question! Might take it to a 4WD garage and ask them to have a quick look. I'm supposed to be taking it on holiday in November, about 9 hours drive along a winding coastal road so I really don't want it to fall apart!