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Jaston47 · 07-16-2013, 11:01 AM

I have noticed that my motorhome diesel will hesitate from a stop when I push the gas pedal to go. I can push it all the way to the floor and it will hesitate before it finally takes off. Any help on this. I have had it put on a computer and they say they can find nothing wrong with it and I don't know where to go from here.

Gearhead383 · 07-16-2013, 11:16 AM

How about some specifics?

What kind of coach? What size and make of engine? Does it hesitate warm or cold or both. The more specifics you can provide, the better the answer will be.

Dupdyke · 07-16-2013, 11:29 AM

You are not driving a corvette there is turbo lag, inertia to overcome and it takes torque to move 30,000 lbs. I taught emergency veh operations for years and the first thing was you gotta think ahead with moving or stopping it dont happen fast. My isl 400 and 37,000 lbs you push on peddle and it will start to move in 3 5 sec and it will take a few sec to pick up speed. Once you get it moving you might want the jake and think ahead to slow down...

Jaston47 · 07-16-2013, 12:23 PM

Phaeton 40 ft 2005 cat 350 it has about ten sec delay after driving a half a mile

Scottybdivin · 07-16-2013, 12:29 PM

Turbo lag, rears it's ugly head, when you need it the least.

Coaster1 · 07-16-2013, 12:30 PM

10 seconds is way too long, but you already know that. There is an electronic communication problem with the engine in that it is calling for fuel too late. When it does begin to accelerate, watch for black smoke. That will indicate that the turbo is not spooling up in time for the fuel demand.

BFlinn181 · 07-16-2013, 12:44 PM

Quote:

Originally Posted by Jaston47

I have noticed that my motorhome diesel will hesitate from a stop when I push the gas pedal to go. I can push it all the way to the floor and it will hesitate before it finally takes off. Any help on this. I have had it put on a computer and they say they can find nothing wrong with it and I don't know where to go from here.

There's your problem, you're giving gas to a diesel.

Seriously, if you are in neutral and push on the accelerator, does the engine increase RPM quickly or still a big hesitation? How about slowly depressing pedal, does engine respond in kind? I'm thinking perhaps you have an air powered accelerator that is binding up. You might want to look at the mechanism on the engine as someone depresses pedal to see if it has smooth motion. I say this since computer scan found no issues.

Jaston47 · 07-16-2013, 12:45 PM

Quote:

Originally Posted by Coaster1

10 seconds is way too long, but you already know that. There is an electronic communication problem with the engine in that it is calling for fuel too late. When it does begin to accelerate, watch for black smoke. That will indicate that the turbo is not spooling up in time for the fuel demand.

What do I do now will the computer tell the problem?

Skip426 · 07-16-2013, 01:04 PM

I don't know if this will be any help; but here goes. When I picked up my MH the carpets had been shampooed , 2 months later it started jumping off the line when accelerating. What I found after much searching, was the hinge on the throttle pedal was rusted and binding and the humidity from the carpet drying had compromised the connectors from the Throttle position sensor under the dash.
Lubed the hinge and roller on the TPS, and cleaned the connectors between the TPS ( spray contact cleaner ) and the dash wiring and no repeat of the trouble in 2 years .

gatorcq · 07-16-2013, 05:37 PM

When you had it at a CAT service shop, did you specified that they ride along with you? The ET system is a great tool, when used correctly. The tech, has to know what parameters to look at. You could call the CAT hot line and ask them for a shop in your area or wherever you are traveling to.