Engine/Transmission (1994 - 1998) puzzler of the week

[BSowers]

OK I have one for you. Not sure what the prize is but first one to figure it gets a beer at a brew pub near me.
Truck has cabover camper on its back.
Running B99. (Never had this problem running BioD prior to this summer. )
new auto transmission from Gorend, 4. 10 gears, DD fuel plate, stock injectors, new fuel filter, air filter and prefilter with heater removed.
Checked air intake clamps.
No fuel leaks.
Engine starts with a flick of keys.

Symptoms;
Will get going around town
lack luster power resaponse.
No EGT reading over 900.
Boost ~17
(prior to this could reach 1250 and 32)
On freeway will run up to 55 and sustain it.
Add a head wind, hill or go faster than 55 and engine will start faltering... . (it's embarrasing being passed by semi's)
Falters to the point of slowing down to 40 then it will start picking up again.
Stopped for fuel and filled up with 29 gal #2
Truck ran fine like a batouttahell. Oo. I could do 75-80 with wreckless abandon. Mind you I'm pushing the brick wall thru the headwind.

Guess what the problem was?

 

[LandShark]

Fuel filter?

 

[BigPapa]

I'd say the bio's gelling up on you if the temps are below 50* where your at?



Scott

 

[BSowers]

Landshark... Fuel filter is brand new.
Big Papa... That's a good thought but In Ca central valley at this time of year they are in 90-100+ range.

 

[KYOUNG]

Check your bypass valve going to the return fuel line????

 

[BSowers]

Kyoung... I thought of that as well, just hadn't gotten there yet. Take note of the last comment in symptoms... . it ran headstrong into the headwind at 75 after filling up with #2 at a truck stop. Not sure what it does 0-60 w/camper but it was impressive after that filluo.

 

[Bob Langjahr]

Not enough BTU's from the Bio-D, or bad Bio-D ?

I mean it ran fine after the fill-up with #2.

 

[SRath]

Restricted air system?

 

[MCummings]

I'm gonna go wayyy out on a limb here and say maybe you forgot to put your fuel cap back on after the last fill up?



Merrick

 

[InfernoB]

Pick up tube cracked.

 

[Kiohio]

Seat was too high in the air making it so you couldn't put enough pressure on the GO pedal. :-laf:-laf:-laf

Sorry couldn't resist.

Actually on a serious note, not talking about throttle, but brakes.
We had a truck where I work (Big Freightliner) that the driver complained about the brakes repeatedlty, had them readjusted and everything.
We sent it somewhere else to have it worked on.....
They vacuumed the truck and said "If the driver cleaned the crap from under the pedal occasionally his brakes would work better".

KO

 

[fest3er]

You were out of fuel?

 

[dpuckett]

No boost to AFC? You didnt mention fixing anything, but didnt mention NOT fixing anything.



OR, had filled up with gas, or partial fill up, and the B99 had enough lubricity to keep things lubed, but gas had too little energy to run properly.



DP

 

[Howard Durand]

You put 29 gallons of good fuel in the tank which diluted the stuff in there.

Should run better if you had been burning a load of bad fuel.

 

[Don Tanklage]

OR, had filled up with gas, or partial fill up, and the B99 had enough lubricity to keep things lubed, but gas had too little energy to run properly.



DP

what?



gas?

 

[BSowers]

I dropped the tank this weekend. I didn't see anything extraordinary in the tank. There was some debris but nothing in great quantity to block that screen. With the symptoms cured with a tank of fresh #2 the only thing I can surmise is that I had a bad batch of fuel.
While under there I got fed up with the quick disconnects and replaced the stiff "flexible" fuel line attaching the tank to the steel lines.

Thank you all for the responses. All were good answers.
Bob & Howard win.

Brian

 

[BSowers]

Wellllll On further study, it seems the bioD is just fine. The debris blocking the fuel screen may have been the culprit after all. It fits with the symptoms of getting up to speed then when I pushed it that the engine acted as if it were starved, the lift pump drawing a vacuum, with my speed vascillating between 40-55 on the flats as some fuel was supplied.
After cleaning the tank, 225K on truck, I can tromp on it from a dead stop at the bottom of a 16% grade and be doing 70 within a half mile up the hill. Oo.

 

[BSowers]

OK. After all that, and living with it for 10 months, this is what I realized
Cracked / leaking fuel lines? Nope. Truck starts with a flick of the key hot or cold. Still replaced them any way
Leaking fuel heater? Nope. See #1 removed heater anyway.
Loose intake / Turbo boots? Nope. Blew them loose with 34 boost AFTER fixing problem.
Overflow valve? Nope.
I installed a fuel pressure gauge in cab and when I tromped on it the pressure would drop to 0.
Spent 14 hours swearing at DC while replacing the supposedly bullet proof lift pump.
I now get 2nd gear scratch (with only torque plate and 3k spring mods). And that was while running BioD which supposedly has a 10% less energy rating.
It's amazing the noise made when a turbo boot comes off at the intercooler. Oo.

Brian