flutter condition

[chuck-10]

First to start off I have good clean fuel,all three fuel filters are new.Now that that's out of the way I have a flutter almost maybe a miss fire condition at steady throttle at around 50 mph.If I give it a little more throttle it goes away and when I lift the throttle a little it goes away.It starts up fast and idles perfect.I was going to get the injectors tested first and then maybe replace the pump.Any ideas

 

[Barrman]

Can you hear the turbo spooling up or down when you get this condition? Are you blowing blue smoke under load? I am thinking turbo bearings or seals from the little you described.

 

[Wildchild467]

I know it may not be the cause of the problem, but I am always a fan of making sure basic things with the trucks are adjusted properly. one of those being the valves. It is an in inexpensive PM that can only help your engine last longer. Make sure the air filter is clean also. Blow it out with an air gun even if it looks clean. How long have you had your truck? Have you used any additives in the fuel? I like the power service in the grey bottle. When I got my truck, it seemed to flutter also when it idled. I ended up swapping out injectors and the problem went away. It was not very noticeable and did not seem to effect performance though. Another thing that I notice that seems to make my truck run better is letting it idle at 1000 rpm during the warm up. It allows the truck to warm up faster by creating a higher exhaust temperature/combustion temperature. I think (im saying I think because I am not a multifuel engine expert, but still believe I have a good idea about how these trucks work) the higher temperatures reduce the injectors from gunking up. I think they call it coking or something like that. In the TM, it also says if the engine does not seem to run good, to take the truck out and drive it on the highway. 100 mile road trip starting with fresh fuel is not a bad thing. But again, I think letting them fully warm up to operating temperature (180 degrees) before you take off helps reduce injector coking. Also check your throttle linkage to make sure everything in tight, including the throttle arm on the IP.

If you plan on having the truck for a while, plan on taking good care of it, and need it reliable then checking things over may be worth it. I am not saying you have to rebuild the engine from top to bottom, but maybe having the injectors cleaned and pop tested is not a bad idea if your budget allows. Adjust the valves and check the injection pump timing are inexpensive to do also. I have met a couple people that have worked on these trucks and a couple have scared me a little bit. One of them swore the engine was a Detroit.

 

[chuck-10]

Just injectors cleaned and tested,they came out perfect

 

[chuck-10]

It was $47 to get that done and they gave me new sealing washers.

 

[Wildchild467]

$47 just to pop test all 6? That does not sound bad at all. I got a quote of $120 i think to do mine. I did not have them done though. I reused my washers too. New ones would have been nice. My does run good though. I am guessing the truck still has a misfire? Another thing I did before I changed my injectors was use an infrared thermometer to check the exhaust temperature on the manifold as it comes out of each cylinder. This will let you know what cylinder is off by the difference in temperatures. Mine usually idled real close to 300 degrees when I aimed it on the exhaust manifold. This would be something you could check also. At least that would point to the what cylinder is acting up.

 

[gimpyrobb]

Maybe an rpm limiter issue? (Govenor issue)

 

[Wildchild467]

I had an issue with my governor on my truck. the throttle shaft housing that bolts on the IP that has 4 bolts. I don’t know the exact names of the parts but my problem was the clearance between where the throttle shaft connects to the torque arm (I think that is that is it called). It basically just transfers the rotational force from the throttle shaft to the parts in the governor. Mine had quite a bit of clearance when tighter is better. the symptoms were that it would idle faster pointing downhill and idle slower pointing up hill by about 200 rpm. When it pointed up hill it was enough to make the engine shake more the RPM was down so low. I got another throttle shaft housing assembly and swapped them out. it definitely helped but still does it a very little bit. maybe sometime I will try to "close the gap".... or ill just keep driving it. I need to change my knuckle boots worse though.

 

[Wildchild467]

If everything else seems ok, then check those two clearances. Im sure the TM has the specs for it. Mine never acted like it was skipping though.... just "hunting" for the RPM a little. I hope that explains things good.

 

[chuck-10]

Guy at the diesel shop said it sounded like I had a govener issue,I'm going to go over the tm's on this

 

[hoop]

I think you are sucking air at the primary filter.

 

[chuck-10]

Just changed filters again,There is no leaks at filters or line.Under load you do not notice it,only on steady throttle no or little load

 

[Heath_h49008]

I could be wrong here, but that sounds more like you're pushing a hole. Checking compression and valve adjustment would be my first thought.