diesel surge

Submitted: Thursday, Oct 16, 2014 at 22:00
ThreadID: 109839 Views:5782 Replies:8 FollowUps:5
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Hi all,

We have two long range tanks in our 1hz troopy when we are running off the tanks there is no way of telling how much fuel is in them.

we try to judge by consumption/km but dont always get it right. Sometimes we will feel a surge or hesitation then quickly flick across to the main tank and all is good.

we have on a few occasions been a bit to slow and the engine has cut out. I was under the impression that with a diesel motor if you got air in the system you then have to bleed it out.
However on all occasions we cranked the car over for a little while, no more than say 15 sec and it started.

On the contrary we felt the surge just recently and flicked it over just before the engine cut out. Since then over the last few hundred km we feel a slight surge from time to time same as when its running out. More so on big hills and under heavy load, Regardless of how much fuel we have.

So the questions rise, would there still be air trapped in the system after about 500km of driving?

Does running it til we feel the surge cause any damage to the pump?

Lastly, will cranking it until it starts again instead of bleeding it cause issues?

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Reply By: Member - sdr00y (Beecroft,NSW) - Thursday, Oct 16, 2014 at 22:48

Thursday, Oct 16, 2014 at 22:48
A 1HZ troopie does not need to be bled. You can simply prime the fuel line again by manually pumping the fuel through.

Steps to take if you run out and the engine stops: (hopefully you are in a safe place to get out of the car... ie not the middle of a freeway)

Flick the control to the full fuel tank.
Pop the bonnet.
Depress the pump (it's a black button about the size of a 20c piece) on top of one of the fuel filters. This is located drivers side up near the windscreen end of the engine bay from memory.
Depress the pump button till it becomes hard, about 20 times I think. That will have primed the fuel system and you should be able to crank the engine over like a normal start up.

I would not think there is still air trapped after 500km of driving, but give it a pump and see if that fixes it.

I don't think running it till you feel the surge does any damage, but newer fuel pumps don't like to be run without fuel... but the 1hz is old school.

Cranking it till it starts again should not cause issues, it will eventually get running but you run the risk of flattening the battery I guess. Again, you don't need to bleed, just manually pump it up. Should be something in the owners manual about it.

The 1HZ toyota engine repair manual on page FU-2 Engine fuel - fuel filter, describes the changing of a fuel filter and at the end of that process says to, "Operate the hand pump until you feel more resistance." which primes the fuel system ready for starting the engine.

Hope that helps.

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AnswerID: 540461

Follow Up By: Slow one - Friday, Oct 17, 2014 at 06:53

Friday, Oct 17, 2014 at 06:53
Your question has been answered but just to add a little.

Inline or rotary diesel fuel pumps don't like being run out of fuel, as part of the process the diesel lubricates them, you are also picking up any contaminates that lay in the bottom of the tanks.

I make sure I never run tanks to empty.

FollowupID: 826343

Reply By: Athol W1 - Friday, Oct 17, 2014 at 08:54

Friday, Oct 17, 2014 at 08:54
As this surging only started since you ran it out of fuel and changed tanks, and more so on hills, I would suggest that the problem is a dirty fuel filter.

As for cranking it till it starts the biggest issue is battery life, firstly will it survive long enough to start the engine and secondly the greater the discharge on the battery the greater effect it has on the life of the battery. It is not advisable from the issue of lubrication of the pump also.

If you have air in the fuel system the diesel engine will STOP, as air is compressible and it only takes a very small amount of air before the injector pump can not provide sufficient pressure in the injector lines to crack the injectors.

Hope this helps.
AnswerID: 540468

Follow Up By: member - mazcan - Saturday, Oct 18, 2014 at 12:59

Saturday, Oct 18, 2014 at 12:59
I second what Athol W1 is saying
when filters are near their use by date I have experienced surging on 2 different diesels the surge is simular to when your running out out of fuel but a bit more intermittent at first and also lack of power if pulling heavy will be noticed
FollowupID: 826390

Reply By: The Bantam - Friday, Oct 17, 2014 at 09:40

Friday, Oct 17, 2014 at 09:40
If you did run the system dry...and especially if you did not pump the system up with the primer.....it is entirely reasonable that there is a little bit of air lurking....as has been mentooned it wont need to be much.

Changing the fuel filter and repriming is a trivial exercise......maybe you should do it anyway.

It might also be worth throwing a couple of doses of diesel doctor down its throat......if there is any water or such crap lurking, it should flush it out.

BTW.....have you investigated running two stroke in your diesel.....it works for me and a great many others running older school diesels.

AnswerID: 540472

Follow Up By: Bigfish - Friday, Oct 17, 2014 at 14:38

Friday, Oct 17, 2014 at 14:38
Like Bantam I ran 2 stroke oil. No issues and helped with the free chopper fuel I got.

Also there is an inline filter under the body. Was on my troopy anyway. Check this is not blocked. The electric cutover switch pump under the body can also get blocked with gunk- will cause surge or lack of power. Easy to take out and clean..
FollowupID: 826355

Reply By: get outmore - Friday, Oct 17, 2014 at 18:12

Friday, Oct 17, 2014 at 18:12
where do you go to put up with the unreliability of lr tanks?
factory they go mInimum 1000km .
...... minimum
AnswerID: 540499

Follow Up By: rb30e - Saturday, Oct 18, 2014 at 04:01

Saturday, Oct 18, 2014 at 04:01
I wish this was the case. Our troopy has been converted to auto with constant all wheel drive. This is so I can drive it as a para. It also has an aftermarket turbo and we are nearing 4 tonnes, fully laden. The fuel economy is not so good, 1000km on the standard tank, only in our wildest dreams.
Where have we been going? Uzbekistan was the first place we needed to fill up before entering as diesel is not available to the public except for through the black market which is renoun for its poor quality.
We are now in Turkey, the fuel in Georgia is half the price of here so we filled it up to full capacity again.
FollowupID: 826381

Reply By: rb30e - Saturday, Oct 18, 2014 at 04:02

Saturday, Oct 18, 2014 at 04:02
I we tried pumping it but it hasn't made much difference. We will change the filter as we carry two spares of both.
Have done 20,000km since leaving oz and got some fuel from some really dodgy places. Had to empty water out of it once before so probably more than due for a change. Will try that in the morning and see how we go.
AnswerID: 540506

Reply By: Tim HJ61 (WA) - Saturday, Oct 18, 2014 at 09:33

Saturday, Oct 18, 2014 at 09:33
Aha, an overseas traveller! I've just returned from taking my GTurbo'd 1HZ to China, Mongolia, Magadan and Vladivostok so I understand your concerns with fuel quality.

There are three places that need to be filled with diesel for the engine to run, plus some in the tank of course.

The fuel filter, the injection pump and the injectors. Air in any of these will cause problems, primarily because air 'compresses' and diesel is more 'solid'. The injectors need to have a pressure of 3000psi in order for them to open. If there is a spongy effect from air in the system, then the injectors cannot open and the engine will not run. I do NOT subscribe to the 'just keep cranking it' philosophy. As much air as possible must be bled out first.

The primer pump on top of your fuel filter is designed to fill the lines with fuel after a filter change. The injection pump WILL deal with a bit of air as (I think) there is a return line that carries air out of the injection pump.

As others have said, you may just need to change the filter. This will resolve most fuelling problems with diesels.

However, the primer pump on the fuel filter can leak and under the suction of high loads, i.e. big hills, it can easily suck a bit of air in.

The solution can be one of two options.
One option is to replace the filter head. This might not be as impossible as it seems. You'd be surprised what is lurking in those dodgy looking roadside workshops.
The second option is to install an electric primer pump. Facet are the common ones and what I used. Install the pump prior to the fuel filter and it provides a bit of positive pressure to the injection pump, always a good thing, and it also fills your fuel filter after a filter change - no more pumping.

The pump can be powered from a wire that goes to the windscreen wiper motor. A check with a multimeter will show you which wire is live when the ignition is turned on. No relay is necessary, they don't draw much current.

Another potential problem is that yes indeed you have damaged the IP, or it has worn out over time (300k) and needs replacing.

Changing the filter, installing a Facet pump, are much easier and cheaper :-)


AnswerID: 540507

Reply By: passionfruit - Saturday, Oct 18, 2014 at 16:17

Saturday, Oct 18, 2014 at 16:17
Change the fuel filter(s).Some Troopy's have two.Good luck.
AnswerID: 540516

Reply By: rb30e - Saturday, Oct 18, 2014 at 20:59

Saturday, Oct 18, 2014 at 20:59
Thanks all for the advice, we replaced both the filters this morning. They were both loaded with crap. Should have done it earlier in hindsight. Runs much better now.
Thanks again
AnswerID: 540519

Follow Up By: get outmore - Monday, Oct 20, 2014 at 00:28

Monday, Oct 20, 2014 at 00:28
dont change them both the pre filter element cops pretty much all the crap.
I suffered bad fuel and had to change it several times tgen drain the tanks to fix it
FollowupID: 826480

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