M818 Question

[rumplecat]

My 818 accelerates fine meaning it is pretty responsive, however whenever I let off the accelerator there is a lag with the engine responding, not long but noticeable, the power falls off but not as quickly as I would think it would, not like any of my mulitfuel engines, is this normal for this power plant? I know I have a fuel issue, with my hard starting on this truck but I can't see how that would influence deceleration of the engine?
James

 

[Westech]

That is a huge engine.. lost of rotating mass. Its not going to drop like a NASCAR engine. There is nothing wrong. Mine does the same thing along with all the 250's I have driven.

 

[ncduece]

sounds like your sucking air in to the fuel. do your engine rpms stay up after you let off the accelerator pedal? pressurize the fuel tank with air check all the hoses from the tank to the engine. mine had a cracked fitting on the fuel selector switch. my symptoms were hard starting. rpms stayed up after i let off the fuel

 

[bulldog_mack13]

It should drop like a multifuel on a Duece. All the trucks with 2 fuel tanks have this problem. ncduece is correct on the way to fix it If its that. Thats what it took on the 818 outside. - Jay

 

[TedG]

You might also want to replace your throttle return spring and make sure your ip crankarm is properly adjusted. My 813A1 responds nicely once I did these two things.

 

[WillWagner]

Take the return line off at the engine and see if this helps. (run it into a bucket, it is a messy test!). Too much return restriction will cause an issue like you are explaining. Someone said the two tanked trucks all do it? The return lines I have seen are all coiled up on top of the tanks. The correct thing to do is to have the straightest, shortest, flat or downhill route back to the tanks so the return line pressure is minimal. IIRC, 2 psi is the max spec.

 

[jasonjc]

This has come up be for and it seems most if not say to check for a air/fuel leak. It also seems to be the M818's with the 2 tanks and the line on and around the fuel selector valve.
Mine does the same thing, as soon as I get time I will be looking at the lines on mine.

 

[rumplecat]

I have new fuel lines in the works for the 818, I just run out of time each week, I am going to have to move it up on the priority list. It is a super truck and drives well, but this truck has been a challenge from the beginning, the oil photo is from picking it up at Hooks, took four visits to get it home.
James G.

 

[rumplecat]

The photos didn't stick for some reason?

 

[jimmcld]

My 816 does the same thing. I fixed one leak and that seemed to help, but it still does it. Also, I had a run away with it once when I tried to use the manual throttle. I pulled it out just a little until the idle increased to about 1000. I walked away and heard it starting to scream and saw it belching out a large amount of black smoke. It idled back down on it's own almost as fast as it reved up, but I won't use the manual throttle again.

 

[jasonjc]

Both of my M818 do that with the manual throttle not the smoke but they will idle up to red line. I have to push the handle back in they will not idle down on there own thought.

 

[bulldog_mack13]

jimmcld , When you did that were you warming the truck up ? My 813does that but slowly then I back it back down only when its warming up. I figured it was just the truck warming up some.

 

[rhinob]

I'm having the same M818 hard-starting, slow acceleration, and slow to idle symptoms described. Found the emergency cut-off puking fuel so I rebuilt it. Put it all back together and the hard-starting, etc., still continues. Will try to pressurize fuel system to see if a fuel leak will be more obvious. I don't see any at the moment. Will also check the fuel return lines for back-pressure.

I need an intake hose between the air filter / body, and the intake manifold, if anyone knows where I can find one. Mine is split at the bottom and sucking unfiltered air.

Oh, and as the diesels (all of mine) warm-up with the hand-throttle set, they will at some point dart for the governed max RPM. Swiss, German, US diesels all seem to do the same thing.

 

[WillWagner]

Try here for your intake hose. It's under the EDPM sleeve or hose section.

Purosil Silicone Hose