I would check the overflow valve on the Injection pump. a bad overflow valve will make the same symptoms of a bad lift pump.

also check the intercooler boots as they have a tendency to expand under boost and rub on the inner fender, as there is a seam right where they are, and it rubs a hole in them. this causes a boost leak, causes higher EGT's, slower spoolup, excess smoke.... all the conditions you describe.

there is a thread somewhere telling how to build a pressure tester setup to check the intake tract for boost leaks using an air compressor and off the shelf parts from Lowes / home Depot.

 

Not a bad idea as well, I need to fab one up too ..... mosly for work.... like 60 series and such

 

I ordered the AFC hose and a 50hp Injection pump over flow valve. I thought I should also add one more detail. When going 45mph - 55mph or so, if I accelerate moderately to heavily, rpm's and boost rise, egt's rise, but the truck doesn't really go anywhere, it will "rev up" but not "catch" is the only way I can describe it untechnically. At higher speeds however it will do the "hesitate, blow smoke, accelerate." I know this isn't the transmission tech section, but could it also be a tranny problem? Still woldn't explain quick rising and high egt's at idle or light acceleration. I still don't understand why the egt's jump so quickly right after start up to 300 almost instantly, then idle's at 400 when warm. Used to idle at 0-200 about a min after start up, and 400 cruising around.

 

Yeah sounds like ur converter istaking a dump on ya , the lock up clutch is most likley toasted

 

That's what I was afraid of and it's a triple disk, but that wouldn't explain the high egt's at idle?

 

You posted this in post #14
( I didn't like the sound of that at all, because the same place that did the LP said my IP souldn't have been damaged.)

First off, that's wrong. If your lift pump fails, it can burn up your fuel pump. Because your lift pump feeds fuel to your fuel pump. So if the fuel pump doesn't get fuel it will go out, and injectors are fed fuel from the fuel pump.

 

I knew that was a huge issue with the 24 valves the LP failing and starving the VP 44. When I asked the same question, "could I have damaged my IP by starving it with a bad LP?" their response was "nah those pumps are pretty tough, you're fine." I've been told if I have to replace my IP, that the shop will still replace my LP any way otherwise the warrenty wont cover it. I did a TC test. She still spins the tires at 1800 pretty well with a break stand. I'm going to order a new FP guage next I guess. I hope to god it's not the IP, that's going to cost me what $2k? installed. This is a 12v for god's sake I'm not supposed to have to throw this much money at it!! Alright well. One step at a time.

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THE NEXT QUESTON I should ask is, will I see problems with a 50hp Overflow valve and a stock LP. I got in a hurry to order a new one and just saw 50hp and bought it. Didn't bother to read that it is for use with a FASS or AIRDOG electric LP.

 

Sounds like you bought a Tork Tek overflow valve? Yes I would get the adjustable that is safe with factory lift pumps. Reason I think that overflow valve is only reccomended for Fass and Airdog users is because the factory lift pump cant come up with the pressures those pumps provide, so it won't be enough to flow through the valve. Fuel flow through the overflow valve is what helps keep the injection pump cool. with constant fuel flowing through even if it isn't all being used. Think of a pool compared to a river.

 

the fuel pump shouldn't be damaged, as it is lubricated by engine oil and unless you know 100% that the lift pump was dead, and more than likely it wasn't because it did run and drive, it wouldn't contribute damage. the P pump will not pull fuel like the VP or CP3 trucks will to limp home.

that over flow valve should be fine. when using a FASS or Airdog you completely bypass the factory lift pump. with the factory pump being a high pressure, low volume pump the stock overflow valve works OK up to a certain point. the overflow valve acts more like a pressure regulator than anything with the stock pump.

adding a FASS or Airdog will put a lot more volume through the pump and overwork the factory overflow valve causing it to bypass more fuel than normal, therefore causing low pressure at high RPM due to the excess volume it is bypassing it will not allow the pressure needed at high RPMs to build, since pressure is only a measurement of resistance. that is why the Tork Tek valve has a smaller orfice than the stock one. it flows less volume, therefore keeping a more consistent pressure at high RPMs

 

Allright guys so Here's the breakdown so far.

I replaced the Overflow valve with an adjustable one and left it at the stock setting.
I'm still waiting on the AFC boost reference hose in the mail.

Truck Still has same issues

1. Sluggish right off line with less black smoke than before the LP replacement but still more than normal.
2. EGt's climb rapidly. 300-400 at idle. 600-700 cruising around town at 45-55mph. 8-9 under light to moderate acceleration. 1000-1300 under moderate to heavy highway acceleration. Easily bumps 1350 at WOT, or 1400 If I really stay on it.

3. Took the truck to the tans shop had the guy drive it, he said he couldn't feel any slip with the TC. Truck still "winds up" while cruising but doesn't really go anywhere until it downshifts and drops rpms significantly. Then it begrudgingly billows smoke spikes EGT's and and finally takes off.

4. Idle is still low. 660-700 in gear. 760-770 in neutral (warmed up).

5. Bad vibration at idle with wheels turned left and while making slow left turns.

6. Boost reads reads 0 while in od crusing 50 or so, but I think thats just a cheap gauge.

Turbo wheel probably has about 1mm of play back and on the push and pull.

My gut tells me this could be a pump timing issue, but what do you guys think now?