3406b Not making hardly any power

Yes if it sits for a few days it starts right up but you can hear it's running differently until it runs for a bit then it sounds normal again. When I run it after letting it warm a bit the only time it hesitates is when I'm really into the pedal in the higher gears. Empty it's hard to tell anything is wrong but as soon as you put a jag on the trailer and work the Motor it starts to hesitate again when really working.

 

Best way I can describe it is what a bad fuel filter feels like. Feels very similar to that. The transfer pump is about $100 oem or almost $200 for cat part. So mechanic said he's almost certain that's what it is and the cheap part is best to start with. He said if we replace transfer pump and same issue is there then we'll have to start thinking about Inside the pump assembly. But 99% sure it's the transfer pump

 

Although you can't feel the hesitation in the lower half of the tranny, there's only about 5-7 psi manifold pressure through the lower half of tranny. Not sure why exactly you can only feel hesitation in top end but it's definitely lacking power throughout every gear.

 

So on the Pete the fuel transfer pump is good. Went for a ride with manifold gauge hooked up at elbow above in take manifold. Hooked up vacuum gauge hooked to primary fuel filter. Hooked up fuel pressure gauge to secondary filter. Gauges in truck work but wanted to be sure. After some research my mechanic who was a foreman at Mack when they had a dealer in Waterbury CT found out the vacuum pressure was normal even below 1 and up to about 4 psi. My manifold psi doesn't get above 7psi until in the high side of Tranny. Then it'll only reach about 15 psi. I've already checked and replaced the intake hose clamps, pressure tested all the hoses and charged Air cooler. All good. We noticed the elbow right before the turbo was a tad loose. We took it apart and realized the o rings were Definitely leaking a tad. When you drive the truck there's a weird whining noise. We're hoping this is where I'm loosing pressure. We wire brushed everything and cleaned everything up. I'm going to get new o rings and clamp. Put it back together and hope for the best. I'll update.

 

H2OBURYMATT, did you get it worked out? whats the update?


Im having real similar issues.