Truck is acting retarded

cheri1122 · Jul 2, 2011

For a week now, the truck [an 04 Sterling, small Mercedes engine, automatic shift] has been acting retarded: not stupid, but s l o w. It was diagnosed on the computer, no codes, nothing wrong, everything looks just right. Had the fuel filter changed, ran out fuel in tank with a quart of Diesel 911, no change.
What it feels like is running with the Jake brake 'on' all the time, so I'm wondering if it's possible that whatever keeps the brake disengaged is malfunctioning?

I'm taking it to WW Williams Tues morning, but would appreciate any feedback.....

jjoerger · Jul 2, 2011

This may sound like strange advice, but check you batteries and cables. All of the electronically controlled stuff depends on a good connection and well charged batteries.

moose · Jul 2, 2011

Sleep well, no worry, i'd bet W.W.W will get it right...the 1st time.
while the truck is there, they are also very good in other unrelated items, like running the overhead, replacing the tranny fluid, checking the CAC, flushing the radiators,and alike.

greg334 · Jul 2, 2011

Sounds like the Charged Air Cooler has sprung a leak.

skyraider · Jul 3, 2011

cheri1122 said:
For a week now, the truck [an 04 Sterling, small Mercedes engine, automatic shift] has been acting retarded: not stupid, but s l o w. It was diagnosed on the computer, no codes, nothing wrong, everything looks just right. Had the fuel filter changed, ran out fuel in tank with a quart of Diesel 911, no change.
What it feels like is running with the Jake brake 'on' all the time, so I'm wondering if it's possible that whatever keeps the brake disengaged is malfunctioning? I'm taking it to WW Williams Tues morning, but would appreciate any feedback.....

Wow, u have described the symtoms of one of my x wives( acts retarded,not stupid,but slow, and everything looks just right). Could ww williams fix her. LOL

nightcreacher · Jul 3, 2011

Cheri,is it smoking a lot?Greg may have hit the nail right dead center.CAC can make your truck feel exactly like that,but so can the EGR system,although that would have popped a 39 code.I take it your motor is a Detroit,Williams should be able to fix it for you

cheri1122 · Jul 3, 2011

Not smoking at all - the only other thing is that the last shift [or two] also takes a looooong time: shifts @ 2400rpm, and can hover @ 2300 for a couple miles. I tried the up/down arrows and playing with the accelerator pedal to nudge it, no dice.
WW Williams, here I come [but not very fast - I swear I was passed by a kid on a Big Wheel at one point!].

cheri1122 · Jul 3, 2011

jjoerger said:
This may sound like strange advice, but check you batteries and cables. All of the electronically controlled stuff depends on a good connection and well charged batteries.

Thanks - I know that the transmission will go into 'defense mode' and refuse to shift if there's any electrical irregularities, so I checked already, don't see anything wrong, voltmeter shows no difference from the norm.
#%!#$@ computers, sigh.
The good news is that it's not broke down, right? It's just one of those frustrating mysteries, so far.

ts675 · Jul 3, 2011

Does your truck use DEF? My regenerate system got plugged up and mine did the same thing.

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cheri1122 · Jul 4, 2011

ts675 said:
Does your truck use DEF? My regenerate system got plugged up and mine did the same thing.

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No DEF. It's frustrating, cause the diagnostic computer showed no codes, but there is definitely something wrong.
Tomorrow,it goes in the shop - it'll be inneresting.

ts675 · Jul 5, 2011

You have my curiosity peaked now. Please let us or me know what the shop says.

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usafk9 · Jul 5, 2011

I say EGR valve or cooler.....if it's an EGR engine.

Fuel pump maybe? Or maybe the CAC, as Greg sez.

davekc · Jul 5, 2011

Could be a couple of those issues but I would also check the exhaust brake if it has one. That little engine likely doesn't have a actual "engine brake".
It is a PAC brake. Sometimes the fuse can blow, bad solenoid (easy test) or the butterfly in the exhaust is rusted and isn't fully open.
All of those issues will give the symptoms you are describing especially if they aren't getting any variables or codes from the engine.

cheri1122 · Jul 5, 2011

Thanks, guys. I took notes [except for Skyraider's comment, the goober!

] so the mechs will be soooo glad. If they ever get around to me, still waiting my turn.....

purgoose10 · Jul 5, 2011

Gate valve in the turbo is not opening all the way. To much back pressure. If thats not it you have restriction on the boost side of the engine. That's where the air goes to the in/ side of the engine. The hoses that connect the aluminum boost tubes sometimes seperate on the inside and collapse not allowing the air to pass through. No boost no power.

cheri1122 · Jul 5, 2011

The turbo would be my guess - it behaved nearly the same a year ago, [in Montana, where the truckstops don't have mechanics, but they have casinos

and the climb up the Rockies was as slow as I've ever gone in a 'moving vehicle'] and it was a hose that fell off the turbo. But why no code?

and I don't recall any retarded shifting then, either.]

davekc · Jul 5, 2011

cheri1122 said:
The turbo would be my guess - it behaved nearly the same a year ago, [in Montana, where the truckstops don't have mechanics, but they have casinos and the climb up the Rockies was as slow as I've ever gone in a 'moving vehicle'] and it was a hose that fell off the turbo. But why no code? and I don't recall any retarded shifting then, either.]

It would show up in a diagnostic tests, but wouldn't throw a code because it is directly a electrical issue. Same if a injector goes bad. Truck will run rough but show no codes.

cheri1122 · Jul 5, 2011

Cripes - it was a loose clamp on a turbo hose. I made him show me, cause I hadn't seen it, and it's in a place I can't see, without standing on the tire - which I absolutely will do, if it happens again.
Dang - I specifically looked at the hose, and didn't see the loose clamp. I feel pretty stupid [and short].

davekc · Jul 5, 2011

cheri1122 said:
Cripes - it was a loose clamp on a turbo hose. I made him show me, cause I hadn't seen it, and it's in a place I can't see, without standing on the tire - which I absolutely will do, if it happens again.
Dang - I specifically looked at the hose, and didn't see the loose clamp. I feel pretty stupid [and short].

Sometimes it can be the simplest of things.