[LarryGee]

I'm experiencing power loss after the vehicle has been running at operating temps for a while.

What I mean by that is; Normally, when run from a cold start, at 3/4 throttle she will accelerate properly, rpms increasing, retarding the shift points correctly, allowing for brisk acceleration. Well, as brisk as it gets for a 240.

At 1/4 throttle, she accelerates properly, going through the gears at lower rpms correctly.

However, after having run at higher speeds for a while, I can't get her to respond to 3/4 throttle. Even when I'm doing say, 40mph, and I depress the kick down switch, there is no downshifting. I know it's not the kick down switch because the kick down works fine when she's run after a cold start. There is no throttle response after she's been run at high speeds for a while.....very frustrating.

I have no idea what might be causing this? Is it a throttle issue? Transmission issue? Anyone have any idea?

 

[cooljjay]

Could be a whole combination of issues...

First I suppose I would look at the throttle pivot mount on the fire wall and/or any rubber in the shift linkage...and go from there...

Post some engine bay photos and maybe I can pinpoint something...

 

[Forcedinduction]

Have a helper press the throttle to the kickdown, make sure the linkage is contacting the mechanical stop on the side of the pump.
Replace the fuel filters, even if they are only a few thousand miles old.
Check the ATF for level, color and smell.
Count the gears accelerating from a stop to make sure its shifting through all 4.

 

[LarryGee]

Could be a whole combination of issues...

First I suppose I would look at the throttle pivot mount on the fire wall and/or any rubber in the shift linkage...and go from there...

Post some engine bay photos and maybe I can pinpoint something...

I'm 90% confident in my observation that it happens when its been running for a while......

If so, how would linkage be affected by temp ? Just asking....

 

[LarryGee]

Have a helper press the throttle to the kickdown, make sure the linkage is contacting the mechanical stop on the side of the pump.
Replace the fuel filters, even if they are only a few thousand miles old.
Check the ATF for level, color and smell.
Count the gears accelerating from a stop to make sure its shifting through all 4.

Hmm...ATF properties....

Gear count is correct.

Fuel filters? ....If fuel filter, wouldn't it affect power even when cold?

 

[Forcedinduction]

Nope. Fuel pressure is lower when the engine is hot from the return flow heating the fuel tank.

Filters are cheap. Better to toss a new pair on and quickly eliminate them as a potential problem than to do everything around it first.
Start with the simplest solutions and work towards complexity.

 

[Stretch]

Nope. Fuel pressure is lower when the engine is hot from the return flow heating the fuel tank.

...

I'd be interested to see some data on that including the time this effect would take.

 

[Forcedinduction]

Here you go.

 

[LarryGee]

Nope. Fuel pressure is lower when the engine is hot from the return flow heating the fuel tank.

Filters are cheap. Better to toss a new pair on and quickly eliminate them as a potential problem than to do everything around it first.
Start with the simplest solutions and work towards complexity.

So, there are 3 filters on my car, the large spin filter which looks like an oil filter, the small inline filter and the filter in the tank. Well, i checked the small inline filter which I had replaced maybe 6 months ago. It was black.

I had also replaced the filter in the tank at the same time. When we replaced it, it was gunked up from sediment in the tank.

I ordered all 3 and will replace them and see what happens.

Transmission fluid was recently replaced and looks good.

Thanks,

 

[Forcedinduction]

Black is organic growth contamination. Let the tank run low then remove the level gauge to see how bad it really is on the bottom.
Finding a source of B100 biodiesel will help wash off anything clinging to the walls and baffles, but long term you should consider removing the tank and having it cleaned if there is much debris in there.

 

[Stretch]

Nope. Fuel pressure is lower when the engine is hot from the return flow heating the fuel tank.

...

I'd be interested to see some data on that including the time this effect would take.

Here you go.

I'm interested to see information that shows how fuel gets heated by passing through a lift pump and being sent back to the tank warms up the fuel tank (as you stated above).

 

[LarryGee]

Black is organic growth contamination. Let the tank run low then remove the level gauge to see how bad it really is on the bottom.
Finding a source of B100 biodiesel will help wash off anything clinging to the walls and baffles, but long term you should consider removing the tank and having it cleaned if there is much debris in there.

My mechanic confirmed your observation. Organic Growth or what he called algae. Where the heck does that come from????

Anyway, I identified ONE company that sell B100 fuel about 20 miles form here. Are you suggesting that I run a tank of B100 through the engine? If it is successful at "washing off anything clinging to the walls and baffles", is that residue going to plug anything else up and cause the vehicle to stop running entirely?

My mechanic suggested using an additive to the tank which eats the algae? Then, replacing all filters after draining the tank of remaining fuel.

 

[Forcedinduction]

I'm interested to see information that shows how fuel gets heated by passing through a lift pump and being sent back to the tank warms up the fuel tank (as you stated above).

Here is your answer.

"The transfer pump, a single action none positive displacement plunger type pump, is driven by the injection pump camshaft.
The transfer pump can supply more fuel than is required for injection. Excess fuel, utilized for cooling injection pump, is routed from the injection pump fuel gallery back to the fuel pump."

Any other fundamental engine functions I can explain for you?

Organic Growth or what he called algae. Where the heck does that come from?

Water, they need it to grow, then they die when the oxygen in the water is depleted and turn into black sludge like on the bottom of a pond. It could come from condensation (sitting a long time) or contamination from the source (a recent fuel delivery or compromised in-ground tank).
All diesel storage tanks contain some water in the bottom. Delivery tankers pump at 300-600gpm so all that water on the bottom gets mixed into the main product for a time until it settles out.
Thats why the fleet I work for schedules fuel delivery in the late morning so it will have settled by the time fleet fueling starts at 6pm.

Anyway, I identified ONE company that sell B100 fuel about 20 miles form here. Are you suggesting that I run a tank of B100 through the engine?

Yes, its a good habit to do that at least once per year, even if you have to go out of your way or pay $1-2 more per gallon than diesel or B20. The solvent properties of biodiesel help clean any carbon and organic debris from the tank and lines.
Keep several spare filters on hand in the car, in a situation like yours it will plug at least one more filter before you're over the hill.

My mechanic suggested using an additive to the tank which eats the algae?

Fungicide/biocide additives are only effective at killing living organisms to stop the problem from getting worse.
Bio Kleen Diesel Fuel Biocide | Power Service
Mechanical cleaning (filtering or tank removal) is the only thing that will remove the leftovers.

 

[Stretch]

Here is your answer.

"The transfer pump, a single action none positive displacement plunger type pump, is driven by the injection pump camshaft.
The transfer pump can supply more fuel than is required for injection. Excess fuel, utilized for cooling injection pump, is routed from the injection pump fuel gallery back to the fuel pump."

Any other fundamental engine functions I can explain for you?

...

I'll ignore the last comment.

Your link does not work for me.

If you can quote the origin of your source rather than directing me to some intermediary site - that would be great - I am genuinely interested.