Engine not "broke in" properly?

In the City, I drive a street sweeper. It's a 1999 cabover Ford Model truck, with a 190 hp diesel engine, (don't know what size truck), and the engine is weak as s**te!!! When you sweep, the engine spends most of the day idling, at speeds of no more than 5 mph. They say the engine is so weak because it's been idled or drivien thru town most of it's life and it's never been out on the road (It's been years since the truck even hit 55 mph!)

When driving (not sweeping) you can floor the gas pedal and it will still take a few seconds for the engine to rev up and start pulling itself to accelerate. Down a hill, 45 mph is about wide open, and to drive any faster would probably blow it up, and up a hill, you probably won't even be able to reach over 30 mph. Also it runs hot! While it's idling, the engine temp stays at about 180 degrees F. But when driving thru town it begins to heat up to about 210 and eventually 220 degrees! (You would think it would be the exact opposite...) When it was new, they say it used to have a pretty good bit of power, just like a regular engine should. (I never drove it when it was new), but now it's wore out because it was never 'broke in' right.

SO, MY QUESTION IS, WHAT CAUSES AN ENGINE TO GET WEAK LIKE THIS IF IT'S NEVER OUT ON THE ROAD ANY? AND COULD IT BE FIXED (OTHER THAN GETTING A NEW ENGINE/TRANSMISSION?)

Oh, there's one more weird thing. Although when driving thru town and you've got your foot on the gas pedal, the machine feels like it's got a giant invisible hand pushing it back, until you let your foot off the accelerator. Then you'll find that it will coast,.. and coast and coast and coast. In fact on a downgrade you can save lots of fuel because it will run just as fast coasting at idel as it will if you had your foot on the gas pedal.

Reply to
Ducaire
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Let's assume the routine maintenance like oil and filters including the air cleaner have bee done. Your problem sounds like heavy carbonizing of the valves and probably the muffler. My first instinct would be the air cleaner if it is smoking constantly. Carbo buildup on the valve is a result of the engine never having been used at higher power demands. Diesels are best when working at max loads and actually need this to avoid excessive carbon buildup. Make sure it is in proper tune and has clean filters and put it on a dyno for a few minutes. A good tech should be able to figure it out pretty quickly. A good full power run will often correct the problem if it does not overheat excessively.

Lugnut

Reply to
lugnut

And if its a turbo diesel, the inlet to the turbo may be so coked up that its got about a soda-straw's worth of opening. I agree, sounds a lot like a plugged exhaust system.

Reply to
Steve

There may be one but, I can't think of any onroad applications that were not turbocharged by 1999 model year. It is possible that the turbo is so fouled the engine would be better off without it. The bottom line is that Diesels do much better when worked hard. Easy work like sweepers should probably have small Diesel or gasoline propulsion. Many equipment buyers make the mistake of buying more engine than they can reasonably expect to use economically. I suspect this is one of those cases. In a sweeper the chassis power is not nearly as important as the sweeper powerplant.

Lugnut

Reply to
lugnut

I can believe that. It's probably gunked up with all kinds of crap, both on the intake and exhaust side. I bet if you pop open the throttle body you'll find huge amounts of carbon gunk in there.

Seafoam, combined with some running at high RPM for a while, may help to get the gunk out but I suspect you may have to get the motor pool guys to take apart the throttle body, turbo, and exhaust system and scrape all the crap out of it.

--scott

Reply to
Scott Dorsey

I'd give you a donut hole as a finders fee for the throttle body location on his Diesel!

Lugnut

Reply to
lugnut

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