Question for 1HZ experts only...

[tlcruiserman]

Hello experts,

I am asking those that are very familiar with the 1HZ because my issue I think is more specific in this area. I think this is mainly for the guys in Aus.

I am having a problem again with my HJZ75 series, it seems if I rev the engine it only wants to go a little above 3k rpm. I had this happen earlier this year and it only got worse and I found out it was a failing injector pump, which I have replaced with a brand new one (not a rebuilt). I am hoping the problem is just a clogged fuel filter or line and not the pump again, that seem way too weird. I am going to check the filter and things tonight but I am wondering if this symtom is common to a bad filter or something other than a bad pump. The truck has been fine until know but I do not drive it a lot so it sits for weeks or a month before it is driven. I have dual tanks and it makes no difference what tank I am running the result is the same plenty of power up to around 3k then the idle will go no higher and the power flattens out, I am thinking a lack of fuel but it does not sputter at all just will not rev higher. Normally it will rev all the up past 4k and power all the way up that high. I have a turbo on this rig, and that seems to be fine and I get not smoke or anything like that, when I had the other problem with the pump I got smoke as it was reved up, another reason I think it might just be a filter.

Any thought from the 1HZ expert is much appreciated.

Thanks,

Michael

 

[roscoFJ73]

The times I have seen or heard of others with this problem it turned out to be partially blocked fuel switch valves on the dual tanks.
Another time it was the mesh filter where the fuel line joins the pump.
But theirs didnt run smoothly and had lots of surging and stalling.

Were the pump settings preset,or did it need fine tuning?
Were new injectors fitted at the same time?

 

[tlcruiserman]

The times I have seen or heard of others with this problem it turned out to be partially blocked fuel switch valves on the dual tanks.
Another time it was the mesh filter where the fuel line joins the pump.
But theirs didnt run smoothly and had lots of surging and stalling.

Were the pump settings preset,or did it need fine tuning?
Were new injectors fitted at the same time?

The pump was good with the preset on the fuel, all I did was adjust the timing after installing it. It ran great from that point until now which is about 6 months. I did not put new injectors in at that time, they were in good shape.

That is the odd part is it is does not run rough at any point just stops building RPM. I will post my results after I swap out the filter, I will probably blow out the fuel line as well, maybe put some conditioner in the fuel.

Thanks,

Michael

 

[tlcruiserman]

Well Rosco good call, it looks like I have an issue with one of my switching solenoids. I took off the fuel line to the tanks and blew some air into it and I could hear a click and then the air was flowing into the primary tank so I think it is sticking or something.

I am going to replace them both just to make sure. Amazing that it runs fine but just limits the RPM's. Live and learn its all better for now.

Cheers,

Michael

 

[roscoFJ73]

Well Rosco good call, it looks like I have an issue with one of my switching solenoids. I took off the fuel line to the tanks and blew some air into it and I could hear a click and then the air was flowing into the primary tank so I think it is sticking or something.

I am going to replace them both just to make sure. Amazing that it runs fine but just limits the RPM's. Live and learn its all better for now.

Cheers,

Michael

Is there something inside blocking them? Ive never heard of them malfunctioning before, the ones I heard about were blocked with plastic wrap.
Possible electrical problem ,bad earth maybe??
You need to make sure as I think they are hideously expensive

 

[owensexport]

Give it to me, I will scrap it for you

 

[lowenbrau]

Tank full of algae?

 

[jamescharrison]

Algae?

Interesting, Bruce. Why would you say that? Experience talking? The reason I ask is that my 1HZ is still running like a s#*&-house, after $4,000 in a rebuilt injection pump (that literally puked & ate its guts out coming home from BHCC) & a rebuilt head, new filters (primary & secondary). It will not rev above 1800 rpms & then all power is lost, Also, there is some bucking, etc, on acceleration as well & a touch of black smoke, but then it was a touch cold on Saturday when I picked it up & brought it home. Needless to say, I am not a camper. I've heard about bum fuel causing a type of sulfur-eating (growing?) algae to grow in / plug the fuel tank, etc. Could this be my case? I am inclined to just let her rest for the winter as she is normally parked in the winter (Ashley is on a NO-SALT diet), but I'd like to get to the root of the problem & make her "better".

Thx.

Jim

 

[roscoFJ73]

I suspect your problem is deeper than bad fuel.
I would be checking the timing belt to see if it is is on correctly and check the pump to timing case alignment mark.
I also would do a compression test to see if the valves have been set right(and that the rings are good).

Is the rough running happening all the time ,or just when its cold?
Why did you take the pump for a a rebuild?

Its a pity you didnt come here earlier,others on this site have bought brand new fuel pumps for under
$2k.

From my experience with algea in the tank,it only lives in the upper empty half of the tank where condensation forms on the roof of the tank.
When you fill the tank it gets washed off and can cause blockages and rough running.
If your not convinced ,remove the bung on the tank,empty it, and use fresh fuel.

 

[lshobie]

You can get pumps rebuilt in Sask by the shop ENS uses, I have to send mine in soon to be rebuilt as my truck is starting like a piece of crap in this weather - everything else is fine but I suspect the tolerances are out after 5500 hours on the injection pump. The rebuild should be between 800-1000cdn.

Started my truck this morning, it was plugged in all night, minus 24 here this am - truck started 1cylinder at a time and that is not a nice sound.

 

[lowenbrau]

Interesting, Bruce. Why would you say that? Experience talking? The reason I ask is that my 1HZ is still running like a s#*&-house, after $4

Jim

Yeah, unfortunately I have some experience with it. The fuel turns black and is nearly impossible to kill. We ended up replacing the tank and running biobor (uber nasty stuff, read the label) through for years.

Its easy to diagnose, just chop your fuel filter in half. It'll be all black inside.

We were clogging filters twice a day for a while.

 

[tlcruiserman]

Nothing like a good hi-jack of a post....not

Thanks to Rosco for the help, if you missed it in the posted the problem was a blocked fuel line or stuck switch, once I blew air into the line it was all set.

I think it could be stuff from the bottom of the tank that got in the line, I do run Bio-diesel in this truck from time to time and I did notice a while ago that if the truck seats with Bio in it algae will form and because I do mix the two sometimes I get stuff in the bottom of the primary tank.

Since I blew it out I have been on one expedition trip to the desert and have gone thru a tank in the primary and secondary and truck is still fine, so all is well that ends well.

Thanks again.

Cheers,

Michael

 

[prado t]

Nice fix! You might want to put in a repudable brand of conditioner , Howes or Power Service