loosing boost - real time help

[rideglobally]

sorry i posted on lvz187 thread about lossing power but then i realize maybe my issue is different. i am currently on a trip in Baja California, Mexico. currently in Bahia de Los Angeles to be exact.

here is my issue. i am driving along at 15psi boost then all of a sudden i loose boost it goes down to about 6 psi. then i down shift and it seem to be ok again. i though maybe it is being on a proper gear or altitude issue but i notice yesterday that it seems to happen on flat road. the engine has not stalled. i just started my engine prior to posting here it start no problem.

i check my intercooler and lines connecting to the boost control, everything seems to be fine.

i will check my fuel lines and change my fuel filters when i get back to camp.

please 12ht gurus help me out.... thanks and happy holidays!!!

 

[ForealBoreal]

Any hesitation from the engine when this happens?

 

[rideglobally]

Any hesitation from the engine when this happens?

when i am on an incline yes, then i down shift and it is fine again. i can understand that this may happen when i am on an incline and not on proper gear. however, what concerns me is when in happen while on flat road there is a sudden drop on the boost and power. all the vital signs of the engine are perfect, oil pressure between 40 to 60psi, egt is between 800 to 900 F, never above 900F, water temperature is at 160F to 180F never above 190F.

this morning i change my fuel filter found no water on it, also drained my racor fuel filter also no water. i did find a very, very small sipping leak on the fuel line near the tank coming from my tank number 1. i fixed that. i don't know if this is a factor because i am using tank # 2 when these happens.

maybe my question should be what are the things that will cause a lost in boost?

i know my rig will start no problem. my concern is being out of nowhere and this happen. i am carrying an electric fuel pump. if my engines stalls while i am out in now where i am thinking of installing the electric fuel pump and by passing my mechanical pump. what do you think about this option?

thank you very much. i will not be able to check internet again till tomm morning.

 

[Tim-HJ61]

Hi Amado,

Any leak in your fuel lines is not a good thing, and will suck enough air to cause problems. Low fuel supply equals low boost.

The standard lift pump is very strong and reliable.

Given you've checked the turbo lines under the bonnet, and the boost returns after a hiccup, it points to fuel supply/ air.

After all the work you've done, you'll need to drive from your place to the Nullabor ten times before doing anything mechanical!

Keep us across how things go.

Tim

Sent from my iPad using IH8MUD

 

[rideglobally]

Hi Amado,

Any leak in your fuel lines is not a good thing, and will suck enough air to cause problems. Low fuel supply equals low boost.

The standard lift pump is very strong and reliable.

Given you've checked the turbo lines under the bonnet, and the boost returns after a hiccup, it points to fuel supply/ air.

After all the work you've done, you'll need to drive from your place to the Nullabor ten times before doing anything mechanical!

Keep us across how things go.

Tim

Sent from my iPad using IH8MUD

Hi Tim, ten times between Nullarbor and Los Angeles i will take you up on that when i wake up from my deep sleep.

i bled the fuel lines this morning and getting ready to continue on along the Sea of Cortez going first east then north. leaving first thing tomm morning.

Happy New Year and good to hear from you.

 

[rideglobally]

still losing power

for sure it is not the altitude. today i lost power while in the desert with an small incline on the road. three day ago it stalled while i was on a steep incline then started right up. it runs fine for a period of time then all of a sudden this happens. again i normally cruise at 15psi boost. then all of a sudden it loses boost, then it comes back up again. this happens intermittently.

i check my fuel did not see any water on it.

we are on our way back home tomorrow i am hoping all will be ok.

any ideas? let me know..... thanks

 

[DanS HJ-45]

for sure it is not the altitude. today i lost power while in the desert with an small incline on the road. three day ago it stalled while i was on a steep incline then started right up. it runs fine for a period of time then all of a sudden this happens. again i normally cruise at 15psi boost. then all of a sudden it loses boost, then it comes back up again. this happens intermittently.

i check my fuel did not see any water on it.

we are on our way back home tomorrow i am hoping all will be ok.

any ideas? let me know..... thanks

Since you are on your way home, you're already pointed in the right direction.

This sounds a lot like what our 3B-T was doing just before the head gasket failed. For maybe the 500 miles before the HG failed it would not quit, just sort of hesitate sometimes under load, and then get better as soon as I downshifted or let the engine idle a bit.

One day I was coming home, driving up the driveway when it lost just about all of it's power and I needed low range just to get it into my parking spot. The next morning it wouldn't start at all, so you're clearly not at that point yet, if your engine has a similar problem to ours.

I'd plan on a compression test when you get home.

Dan

 

[Captain Caveman]

I had a similar problem. When on an incline I would lose power. I don't remember looking at the boost gauge, but if I had it would have been close to zero psi.

First, I changed the fuel filters (I have two), and it went away for a while. Then, it stalled out on a big incline and I had to tow it home.

I didn't have the money to go replacing turbos, injectors, and fuel pumps, so I started with the cheap stuff that only required time. I pulled the supply line at the fuel/water separator (the first of two filters) and found debris lodged in the hose at the fitting. Thinking there was likely more in the tank, I dropped the fuel tank and found that the fuel pick-up was clogged with debris. I then blasted out all of the fuel lines with compressed air, built a little mesh screen around the fuel pick-up, and put it all back together again. I haven't had the problem since.

In retrospect, on inclines you demand more fuel, which makes perfect sense. This may or may not be your problem, but it is low cost to check. Good luck!

 

[ozwallaby]

Something in the tank blocking the pickup or cr@p fuel (bad fuel is an outside chance).... Can/have you changed between your two tanks or does the no boost situation happen from one tank only.... late reply I know, hope you made it home man..

 

[Dieseler]

A few questions;
How many kilometers on the 12Ht motor.
Did you ever have the injector pump serviced.
Was the turbo rebuilt and is it the Garret factory model.
Were your injectors serviced.
Do you have a water seperator factory or aftermarket.
When you did the install did you wire in the boost GREEN and RED indicator lights which would have been in the HJ61 if so does the red light come on when this happens.
You mention a electric fuel pump to replace the mechanical,I do not have as much knowledge on the 12Ht as the B motors but is there a mechanical pump prior to the IP or are you refering to bypassing the injector pump.

I am leaning towards your turbo may be going out on you whether it is the boost bypass or oil leaking past the bearings are you using up oil(I am not sure if these are water cooled or just oil cooled)do you get smoking when the boost drops out , it could very much be a fuel delivery issue also but this would probably be a IP or injector issue if they have not been serviced before.

A line blockage to me does not add up since when you down shift it corrsects itself when you down shift your RPMs go up resulting in more fuel being required for the higher RPMs so if there was a blockage your power band would flatten out on the down shift from fuel starvation if this makes sense.

Will be following your progress.

 

[neetu]

remove the racor, try then. Hope this helps.

 

[Captain Caveman]

A line blockage to me does not add up since when you down shift ...

You could be right, no doubt about it. Although, when you downshift, you let off the throttle and as a result, the pump suction is reduced. In my case, it was intermittent suggesting some sort of "self clearing obstruction" as I later identified.

Is it not best to start with the cheap and easy stuff versus head gaskets, fuel pumps, and turbos? Would it not be easy to clear the fuel line while it is in place and see if that resolves it, if at least temporarily?

 

[Dieseler]

Yeh I would blow out the lines first and check for any blocked micro screens as in the B models not sure if the 12HT has any in the line routing.
I assume your dual tanks are custom fabbed what kind of pick do you have and are they screened.

By the way great expedition rig you have there.

 

[rideglobally]

Officially stuck

We made it out of Mexico and we are just 50 miles from San Diego at a town called Campo @ golden acorn casino.

Here what I have notice about the engine:
1. I am getting boost. I have notice my boost is at 15psi but it doesn't not have power. It seems that the engine is missing and not getting enough fuel in the injectors. When it does get fuel it surges.

2. When the engine stalls it will start right up no problem and it seems to do better after a little rest.

3. Engine was just rebuild 20,000 miles ago so don't think it is the head gasket.

4. Feels to me that it it staving for fuel.

5. I have switch tank, check fuel line, checked my air filter none of these have fixed the problem.

6. I read the manual it say the fuel injector pump hardly ever breaks, when it does break can you tell me how the engine would function.

Tomorrow I plan to install the electric fuel pump, by pass the lift pump. see if that fixes is, I do have a roycor fuel filter that never had problem with in the past maybe I will disconnect that we will see. If this does not fix it we will get it towed to a diesel shop near by if there is one. Pls let us know if you know one.

Tonite we will be sleeping in the parking lot of the casino.

We are very thankful to all of your input pls keep them coming.

 

[Dieseler]

I would look into the electronics relating to boost and fueling IIR this motor has a fuel compensator which adds fueling on boost demands (similar to a high altitude compensator on the 13BT).
Do you have the 12HT service manual.

 

[rideglobally]

I would look into the electronics relating to boost and fueling IIR this motor has a fuel compensator which adds fueling on boost demands (similar to a high altitude compensator on the 13BT).
Do you have the 12HT service manual.

Yes, I do have a service manual for the 12ht with me. I did not see any thing like thAt on the manual but I will look again. As far as I know there Are only three things electrical on this engine, the pre heating at the intake, the switch to shut it down that choke the engine and the starter to start the engine.

Thanks

 

[RufusTheDufus]

Do you still have the factory sedimenter mounted to the frame rail or did the Racor unit replace that?

What type of valve switches between tanks? I have a rear fuel tank mounted in my Troopy where the spare tire usually goes. The stock lift pump did a poor job of pulling fuel from the rear tank, through an inline filter, the tank switching valve, factory sedimenter and up to the fuel filter. That's a lot of plumbing for the stock lift pump to draw through.

My Troopy would seem like it's starving for fuel on boost at cruising RPMs in 5th gear. When I switched to the front tank the under-powered condition went away. I ended up switching to a transfer pump setup to move fuel from the back tank to the front fuel tank and did away with the tank switching valve. It cured my problems. I did buy a Facet fuel pump that puts out 4 psi that I was thinking about trying as a supplemental lift pump for the rear tank. I haven't gotten around to that because the transfer pump works for me.

The injection pump requires a certain amount of pressure at its input from fuel filter. If the lift pump is having a hard time drawing fuel from the tank due to a tiny leak or slight amount of gunk it might drop a few PSI on the outlet. The lift pump was only designed to pull fuel through a few feet of fuel line from the factory tank location.

 

[Tim-HJ61]

Amado I'm wondering if the shutoff butterfly is closing on you.

Can you check all your vacuum lines for cracks. I'll try and check tomorrow to see if the shutoff needs vacuum to hold it open, or just to close it. I think it is the latter, maybe someone else knows.

Tim

Sent from my iPad using IH8MUD

 

[rideglobally]

we are home - thanks you all!!!

remove the racor, try then. Hope this helps.

Do you still have the factory sedimenter mounted to the frame rail or did the Racor unit replace that?

What type of valve switches between tanks? I have a rear fuel tank mounted in my Troopy where the spare tire usually goes. The stock lift pump did a poor job of pulling fuel from the rear tank, through an inline filter, the tank switching valve, factory sedimenter and up to the fuel filter. That's a lot of plumbing for the stock lift pump to draw through.

My Troopy would seem like it's starving for fuel on boost at cruising RPMs in 5th gear. When I switched to the front tank the under-powered condition went away. I ended up switching to a transfer pump setup to move fuel from the back tank to the front fuel tank and did away with the tank switching valve. It cured my problems. I did buy a Facet fuel pump that puts out 4 psi that I was thinking about trying as a supplemental lift pump for the rear tank. I haven't gotten around to that because the transfer pump works for me.

The injection pump requires a certain amount of pressure at its input from fuel filter. If the lift pump is having a hard time drawing fuel from the tank due to a tiny leak or slight amount of gunk it might drop a few PSI on the outlet. The lift pump was only designed to pull fuel through a few feet of fuel line from the factory tank location.

i by passed the racor fuel filter and install the electric fuel pump this allowed enough fuel to flow into the injector pump. Rufusthedufus is correct the oem lift pump was not strong enough to pull enough fuel at high rpm so that the engine was starving for fuel at high rpm, that is the reason we had no problem at low rpm or starting the engine. it probably would have work if i just by pass the racor filter and connected directly to the lift pump.

in my experience with this engine getting the fuel to flow correctly has been an ongoing issue for me. here is my future plan to address this issue.
1. i will install an electric fuel pump after the lift pump and before the fuel enters the fuel filter. i will keep the lift pump connected. the electric fuel pump will help the mechanical fuel pump for the added pressure that it needs. my concern here is too much pressure for the injector pump, is this a problem? i do not want to screw up the my injector pump.

2. i will re connect my racor filter and the oem water separator. i know this might be over engineering but having clean fuel is a good thing especially in some places i might end up getting fuel. i think having both will probably be ok because the electric fuel pump will help in the needed pressure to pull the fuel to the injector pump.

3. the other option is to choose between the oem water separator and the racor filter and only install one of them.

i want to know what are your thinking of the above solution, especially it's effect to the fuel injector pump. or tell me if you have suggestion on how to improve the system.

by the way to add to the excitement i also broke my accelerator cable when we left San Felipe, so from there to home i drove the nulla with a rope tied to accelerator lever pulling the rope with my right hand from outside the window in place of a gas pedal...... this makes nulla qualify as a simple "expedition vehicle"

we want to thank you all for all those helpful diagnosis that you made all where very helpful, that is why we value greatly the ih8mud community. especially when you are on the top of the mountain and the temp outside is 24F, nothing for many of you but remember we are from Los Angeles, California where the sun shines everyday this is not the first time and we know will not be the last.

 

[Tapage]

I replace my factory water separator on Tencha with delphy unit wich water separator ..