Bigben89 Posted March 31, 2016 Share Posted March 31, 2016 All, I've recently noticed a problem with the throttle response on my B61 w/ 673T. I'll be driving in top gear (5/High) and be running about 45 to 50 mph with a 1/4 throttle and then my rpms will slowly back off until I have to down shift. Applying additional gas even down to the floor yields no response (almost as if its bogging). I'll down shift, stop and run up through the gears again no problem and drive for another 5 to 10 minutes before it happens again. My guess is fuel system, injection pump or governor? Any thoughts? Quote Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/ Share on other sites More sharing options...
seyser Posted March 31, 2016 Share Posted March 31, 2016 Start with the fuel filter. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329138 Share on other sites More sharing options...
Mike Posted March 31, 2016 Share Posted March 31, 2016 Fuel System. Yes, start with the least difficult. Filters back to Tanks. Kids did like to put things inside the tanks. Quote Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329140 Share on other sites More sharing options...
Bigben89 Posted March 31, 2016 Author Share Posted March 31, 2016 That's where I was leaning towards and where I will start. Just wanted to make sure it wasn't something that "simple". Appreciate the help as always. Quote Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329150 Share on other sites More sharing options...
j hancock Posted March 31, 2016 Share Posted March 31, 2016 If the filter checks out. It may be an old fuel line deteriorating or collapsing and restricting the fuel. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329158 Share on other sites More sharing options...
wingman Posted March 31, 2016 Share Posted March 31, 2016 Always start simple (cheap) first on everything! Quote Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329163 Share on other sites More sharing options...
theakerstwo Posted April 1, 2016 Share Posted April 1, 2016 If you don't find it then make you up a tee and put it inline from the filter to the injection pump.Connect a 50 psi gauge to it with a hose that will come up to your cab.Drive it and watch the fuel pressure and it should keep at least 30 psi under load as we as unloaded.This is checking for a restriction in a line and also the supply pump and it will also show a stoppd up filter.There should be two filters on that truck. Make sure your throddle lever is ok. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329169 Share on other sites More sharing options...
gvam Posted April 1, 2016 Share Posted April 1, 2016 The other guys on here are much more versed than I, but may have some other thoughts. I worked at a place that a truck and it did that same sort of thing as you described. Finally ended up being some rust chunks in the fuel tank. When you drove it it would suck up some chunks and restrict fuel flow, so then when you let off and the engine was not calling for as much fuel the chunks would drop off and it would mostly get right with the program again. After a few rounds of this I got sick of that routine and we dropped and cleaned the tank and lines. Quote Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329203 Share on other sites More sharing options...
theakerstwo Posted April 1, 2016 Share Posted April 1, 2016 That could be what it is but that's also reason I told him to check the fuel pressure when running down the road.That test will tell you more than one thing about the system. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329226 Share on other sites More sharing options...
gvam Posted April 6, 2016 Share Posted April 6, 2016 Gotcha Glenn. I wrote down your pressure gauge instructions as I am sure that will come in handy in the future. George Quote Link to comment https://www.bigmacktrucks.com/topic/44607-b-61-throttle-response-troubleshooting/#findComment-329749 Share on other sites More sharing options...
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