Help with surge in 1hd-ft 80 series Landcruiser motor

[hdj81cruiser]

Hi Fellow 80's series owners,
I have a 1995 80's series with the 1hdft 24 valve diesel turbo engine its a auto......when I first bought It I didnt notice the slight surge it had at around 1600 to 2000 rpm since i've had it the surge has got worse the motor's revs going up and down at the same speed, I've only done 20,000km in it since i've had it and have changed the fuel filter 3 times, the first two changes the surge remained there and seemed to be getting worse, but a couple of months ago I put a new fuel filter on it again and the surge almost completely disapearred but I took it out the other day and it surging as bad as ever I'm wondering if I have a problem or whether i've been getting bad diesel it has seemed to get worse since they completely took the sulphur out of the diesel...I got some advice from a Guy at the local diesel injection specialist who said they had a problem with what he called a power valve causing the motors to surge like mine, but only on the 1hdt 12 valve motor, does anyone know what this power valve is and how to replace it?Also has anyone had a similar problem in there cruiser?

any help would be much appreciated


Cheers
Harley

 

[Tapage]

I never ear about power valvle .. at least not in mine 1HDT 12V .. did you already check your injectors and spray pathern . ?

Diesel additive for lubircity . ?

 

[canucksafari]

A very small fuel system air leak can also cause surging. Also, if it is starving for fuel because of a blocked filter, it can surge; but, you would also notice very little power at the higher rpms. Besides your fuel filter, on the denso pumps there is sometimes a small screen strainer at the fitting where the fuel line comes into the pump. There should also be a strainer on the pick-up in your tank. If you have had a poblem with algae blooms, then this could be clogged. I think it is a good bet, considering you have done three filter changes and the last one resulted in an improvement, that your problem is either a dirty fuel system clogging up filters and screen strainers or a small air leak at you fuel filter "o" ring. When you changed the filters did you take a look to see how dirty they were? I'd be careful of diesel injection shops telling you that you need your pump pulled apart.

 

[roscoFJ73]

Hi Fellow 80's series owners,
I have a 1995 80's series with the 1hdft 24 valve diesel turbo engine its a auto......when I first bought It I didnt notice the slight surge it had at around 1600 to 2000 rpm since i've had it the surge has got worse the motor's revs going up and down at the same speed, I've only done 20,000km in it since i've had it and have changed the fuel filter 3 times, the first two changes the surge remained there and seemed to be getting worse, but a couple of months ago I put a new fuel filter on it again and the surge almost completely disapearred but I took it out the other day and it surging as bad as ever I'm wondering if I have a problem or whether i've been getting bad diesel it has seemed to get worse since they completely took the sulphur out of the diesel...I got some advice from a Guy at the local diesel injection specialist who said they had a problem with what he called a power valve causing the motors to surge like mine, but only on the 1hdt 12 valve motor, does anyone know what this power valve is and how to replace it?Also has anyone had a similar problem in there cruiser?

any help would be much appreciated


Cheers
Harley

I never ear about power valvle .. at least not in mine 1HDT 12V .. did you already check your injectors and spray pathern . ?

Diesel additive for lubircity . ?

There is only a delivery valve and a regulator valve.Maybe they are talking about one of them??

Harley ,one simple check you can do yourself is check the small mesh filter inside the fuel pump.
Its sits under the banjo bolt where the fuel enters the pump.

They have been known to accumalate crud and cause uneven accelleration.

 

[mudstorm]

sounds like you have a air leak in your primer
(cracked diaphragm)
to find air in fuel system put clear hose on return line
and watch for air bubbles

 

[rove_mcanus]

I'm not sure there is a filter in the fuel inlet banjo, but there is a strainer under the fuel cutoff valve. Also the power valve is on some 1hdt's at least with manual transmissions. it cuts power output when 1st is selected to avoid burning up the clutch. Toyota call it the Power control system (PCS)

I had surging in a 1hz once but it was really really really bad. the throttle was completely unresponsive and it wouldn't idle. I think it may have been bad fuel. I drained the tanks and changed the filter and it came good.

 

[roscoFJ73]

I'm not sure there is a filter in the fuel inlet banjo, .

There is a mesh filter/strainer there,or should be.

 

[T.Stanford]

There is a screen on your pick up tube within your fuel tank.... a pain to get to because the rear seats have to come out to have access. There is a panel in the floor you must remove to get to the lines. My screen eventually caused more restricted power flow than you currently seem to have. I was initially a little lazy about going through this, instead, changing lines,filter,filter body etc. So on the tank side of the filter, I blew compressed air into the fuel tank, which I later found out, blew the screen clear off the pick up tube. The new fuel filter clogged in no time (with no screen in place). I bit the bullet and went to the pick up tube, The good new was the tank was NOW clean as a whistle. I found the screen was sitting on the bottom of the tank and was completely obstructed with a colourless "film"(algae?). I cleaned the screen out with a spray carb. cleaner, reinstalled, and, touch wood, it seems to have done the trick. Good luck , there are many potential sources of problems of this nature on diesel engines,.... their one weak area. Tony

 

[TAHR HUNTER]

hi there. did enybody ever find out the problem with the vx surging? i have the 1996 vx 24valve as well and its doing the same surging problem only when I cruise....if I flat foot it threw the auto It wont do it at all but around town it surges real bad like im pumping the accerrater. would love too solve this problem as its doing my head in....would love it fixed

 

[djsherif]

sounds like you have a air leak in your primer
(cracked diaphragm)
to find air in fuel system put clear hose on return line
and watch for air bubbles

Help,


I have air bubbles coming out of the pump return line. What does this mean?

 

[IanB]

I'd take that to mean you're taking in air at some point. Run clear hose from the filter housing to the injection pump and see if you have bubbles there as well. If yes, I'd suspect a failed filter housing/primer pump.

 

[djsherif]

Used a bucket with clear house, nothing in the inlet, only the return

 

[IanB]

Hmmm, air is getting in somewhere, if it's not the filter housing, maybe it's time to have the pump resealed/rebuilt? I've not dealt with this myself, maybe others are able to chime in with some suggestions.

 

[niffa]

Here i was thinking the power valve was next to the flux capacitor

 

[VX 12HT]

I do know and read about in a couple of 4wd mags that toyota did have trouble with those motors with surging saying there was a fair few people taking it back to the dealer to sort it out unfortunately they did not say what caused it at the time....

 

[finderscuba]

I'm not sure there is a filter in the fuel inlet banjo, but there is a strainer under the fuel cutoff valve. Also the power valve is on some 1hdt's at least with manual transmissions. it cuts power output when 1st is selected to avoid burning up the clutch. Toyota call it the Power control system (PCS)

I had surging in a 1hz once but it was really really really bad. the throttle was completely unresponsive and it wouldn't idle. I think it may have been bad fuel. I drained the tanks and changed the filter and it came good.

No PCS on a manual 1HDT. I speak from experience. I believe this was on the Coaster buses only.

 

[Yota76]

1hdft owner in Canada. I have the surging on my 96 but only if I mash the throttle. It hits 3k rpm then starts bouncing down to 2.7 and back to 3. Very annoying.