Isuzu Giga loosing acceleration

[Isuzu Giga]

Hello all,

This is my first post , hopefully someone may be able to help with my truck problem.
I own a 1997 Isuzu Giga which has a large aluminum crate big enough to carry 5 large horses.

My problem is the truck all of a sudden is loosing all acceleration under normal driving conditions.
You are driving along and you feel it loose power.
Have tried pumping accelerator and changing gear down but nothing there .

Once pulled over and stopped the truck after a few seconds you get power back and can take off again .
Then within a few minutes it does the same again .

Sometimes when I go to pull over to stop when this happens the motor stops and it is hard to start again .

The truck travelled last Friday approx 100kms with no problems , the next day it stopped over 10 times.

It has a new fuel filter and been bled correctly. Next try is to add an additive for bugs in fuel tank .

Is there a common fault maybe with this model ??? .

Please looking for any ideas as to why it keeps stopping intermittently.

Thanks .

 

[canter tourer]

Hi and welcome,
I have similar symptoms occur in my canter on a long trip, which are fixed immediately by undoing the fuel cap and putting it back on again. Seems I need a vented cap, as the system is so well sealed, the fuel pump cannot suck any more, at least that's what I think is happening and my fix sorts out the problem.

 

[Isuzu Giga]

Thanks for reply.
I never would of thought of that.
I was thinking it may of been something electronic as the pedal goes limp.

Im remembering a couple of weeks ago i put $100 of diesel in the tank but it still did the same thing about 15 minuters later.
I will get another fuel cap and try this though.
Any more thoughts will be much appreciated .
Thanks .

 

[Czechsix]

I had a truck once - had an in tank fuel prefilter. Older truck and there was enough crap in the tank that the prefilter would load up after a bit, starve the vehicle until pulled over and shut off. Once shut off, crap would fall off the prefilter, opening it up enough to flow a bit...restart the truck, and the whole cycle started again. Took a while to figure that one out.

 

[Isuzu Giga]

Thanks for this advice , i will try them out and see if problem goes away .
Cheers .

 

[cameron_a]

check for air ingress or collapsing/squashed fuel lines.
check tank for intake obstructions. they dont have an intake filter AFAIK but there could be rust in tank blocking it up.
check gauze at fuel lift pump banjo fitting for obstruction (most likely)
what engine does it run? v10? 6cyl?
Is fuel primer pump screwed down (if applicable to your primer pump)
if it is a jap import, check along the fuel line from the chassis. nz ones have two fuel filters, one by engine, one on chassis (decent size). jap have a tiny water seperator sometimes not far from the tank in the fuel line, and a fuel filter up by the engine.

 

[Isuzu Giga]

Hi cameron_a,
thanks for those ideas, im about to go out in the rain and check some of your suggestions.
Couple of points you raised.

It is a jap import 6cyl 360 hp.
The misses uses it for horse shows so it has kitchen accomadation etc.

Now because its been set up for kitchen use we took the front diesel tank out and i put in a round plastic barrell to house water .
I have checked the fuel cap (rear diesel tank) where fuel pick and gas gauge etc and there is no breathing hole.

So will drill a hole in this and protect from dust water etc .

I took the fuel filter out to see for contamination as it was replaced approx 6 weeks ago. Totally clean inside bowl , filter still looked new .
It does have the screw down fuel primer. The wife did tell me she primed this but im not sure if she got all the air out.

Question here would be i just primed it and had some good pressure on the prime pump. If she didnt prime this fully leaving a slight bit of air in the bowl would this cause the starvation ?? problem .

Im off to check those fuel lines and the other things you mentioned . Will advise with a cure i hope as we need it for this saturday at a show .
Thanks .

 

[westyss]

Hi cameron_a,
thanks for those ideas, im about to go out in the rain and check some of your suggestions.
Couple of points you raised.

It is a jap import 6cyl 360 hp.
The misses uses it for horse shows so it has kitchen accomadation etc.

Now because its been set up for kitchen use we took the front diesel tank out and i put in a round plastic barrell to house water .
I have checked the fuel cap (rear diesel tank) where fuel pick and gas gauge etc and there is no breathing hole.

So will drill a hole in this and protect from dust water etc .

I took the fuel filter out to see for contamination as it was replaced approx 6 weeks ago. Totally clean inside bowl , filter still looked new .
It does have the screw down fuel primer. The wife did tell me she primed this but im not sure if she got all the air out.

Question here would be i just primed it and had some good pressure on the prime pump. If she didnt prime this fully leaving a slight bit of air in the bowl would this cause the starvation ?? problem .

Im off to check those fuel lines and the other things you mentioned . Will advise with a cure i hope as we need it for this saturday at a show .
Thanks .

While priming a Fuso the bleed valve needs to be open or it will not do anything, not sure if yours is the same, also I find that if the fuel tank is low it will not prime well and needs more persuasion like sucking it up the tube from the tank to get it going.

 

[Czechsix]

Interesting. I wonder if you could add a schraeder valve to a fuel tank cap....then pump five PSI into the tank to help the prime?

 

[kerry]

Sounds like fuel starvation to me. Could be a plugged sock or filter in the tank or a plugged filter before the engine screw on filter. One way to test that is to get a separate fuel supply--one gallon would do--and run it directly to the filter or fuel pump bypassing the existing fuel supply system. If it runs fine that you, you've narrowed down the problem.

 

[cameron_a]

yep. definitely check that gauze in the fuel intake banjos. really common problem.
the tanks usually breathe through the cap, but not through a specific hole. they usually have a rib that kinda bypasses the cap seal from memory? be careful drilling holes that may be a water ingress point.
6cyl 360 is a 6WA1 Turbo I guess.

 

[Isuzu Giga]

Problem solved.
I feel really stupid now, as some of you have mentioned there is a fuel filter running right beside the fuel tank.

When i put in the water barrel and semi hid the filter i failed to check this filter which was absolutley full of crap and clearly this was why the truck was having trouble getting up hills.

I cleaned this out as it was a plastic type refitted, and took the truck up the Bombay hill which is quite a steep hill for those outside of NZ.

Gave the truck all the gas it wanted and this time we actually had acceleration up the last part of the hill.

It was clearly starving for gas.

Thanks to all for your imput on this.

 

[kerry]

Glad you got it sorted, although I'd be careful feeding gas to a diesel.

 

[cameron_a]

p/no for that plastic gauze kit is 1132401410. Just FYI

 

[Isuzu Giga]

Thanks for that guys.
Im sure to be back here as soon as another problem occurs.
Thanks to all.:ylsmoke: