Cat 416c No Throttle Response HELP?!?!?!

[Joe Hall]

I have a 416c. I bought it 3 months ago worked great until yesterday while i was running the hoe the throttle started bogging down then when i put it in gear i have no throttle response. if i put it in neutral it bogs until i reach 1200 to 1300 rpms then the throttle is very responsive but as soon as i go below that it takes a minute before it revs up...and when i put it in gear i get nothing. wont even pull itself bogs down to around 5 to 6 thousand rpms

 

[Nige]

You don't give a S/N but I'm thinking they are all turbo engines.
When the engine bogs down is it accompanied by any black smoke..?
As a first thought - turbo. Pull off the flexible hose between air cleaner and the turbo at the turbo end. Get your fingers in there (make sure it's cold first or you could be in for a shock...) and see if you can a) rotate the turbo freely, and b) is there any discernable movement on the bearings (there should be none).
Do that and report back your findings.

 

[Delmer]

I was thinking the opposite, you're not getting enough fuel. Unless the injection pump needs boost pressure to bump up the fuel? I don't know? Are you getting any smoke while it's bogging? What color?

In my theory, you get good throttle response because once it finally builds fuel pressure the engine will behave as it should, maybe an air leak in the suction? Substitute clear tubing into the fuel return from the injection pump to the tank to check for air bubbles running, or cranking if it won't start. If there's no air bubbles then put tee into the supply line to the injection pump and run a line to a pressure/vacuum gauge in the cab, if the fuel pressure drops to near zero when bogging and bounces back when it runs smooth then you know which direction to go.

 

[Nige]

Lack of fuel was my 2nd thought TBH.........

 

[Joe Hall]

thanks guys weathers been bad here the last couple days. when i get a chance to check these out ill report back... thanks again

 

[Joe Hall]

hey guys sorry the problem got set aside awhile. update... cranked but. no start. changed all fuel filters. still no fire... while cranking i picked up the front bucketand it fired... to me sounds crazy but i hope u guyscan help.. fires but no thottle responce tachs reading 20 but motor is shaking andsounds like its bogging...

 

[Delmer]

Sounds like the same problem to me, either try the suggestions, answer the questions, or wait for a better response.

 

[Dickjr.]

I have had to replace the transfer pump on mine twice. Also the lower fuel filter can come loose from the mounts and vibrates the connections causing it to suck air. I'd bet on the transfer pump.