Leaking pump after tweaks

[MikeO]

Had a little extra time on Tuesday so I decided to play with the pump. The truck has 288,000 miles on it with the original pump, new (stock) injectors at 180,000 and a Banks Stage 3 kit (housing, filter, exhaust, intercooler). For the last six months, I have been unable to get the boost above 15psi and the EGTs above 900F. I decided to take a look at the pump and turn in the power screw a little more than it had been turned in 1993 when we did the Banks kit.



Well, the collar was against the lock nut already. So I decided to remove the power screw and take the collar off. After removing it, I turned the screw in two more turns than it had been.



WOW... what a difference. Boost shoots right to 19. 5psi (that the wastegate pot that is on there now) and pulls like my race Audi (no kidding). Third and fourth are incredible now! EGTs are just about 1050 on a long hill in fifth after lugging it from a low rpm at WOT.



The only downside is the idle... it's at 850 now. A little high for a manual IMHO but I'll live with it.



When I went to see if I could turn down the idle, I noticed that I have a leak coming from the pump. I am getting about 1 drip per second at idle coming out of the spot that the throttle linkage (for lack of a better description) goes into the pump. Is there an o-ring in there that I can replace or am I in for a new pump?



While the pump may have 288,000 on it, we have always treated her well by changing the fuel filter and until now, the pump has never been overworked. Until this tweak, it took forever to get the boost to 19psi and only when fully loaded on long grades. Now I know that the lock collar was holding everything back and we could have had much, much more power out of this thing for the last 10 years... oh well.



Any suggestions on the leak?



Thanks in advance,

Mike O.

 

[formula]

MikeO,

There is a bushing and seal where the throttle shaft enters the top of the pump. It is common to develop a leak there. You do not need to get a new pump just to fix that bushing. I'm not sure if it can be fixed with the pump on the engine. Someone else may have more information on that.



As for the adjustments you recently made to the full load screw... ... It is normal for the idle to increase when you turn in this screw. Idle @ 850rpm is just fine. You may want to consider a larger set of injectors and backing off the full load screw. Reason being is that with it turned in that far with the stock injectors you're gonna put more stress on the pump that it really doesn't need, especially with the miles you have on it.



Cheers,

Sean

 

[Power Wagon]

At least the top cover has to come off the pump, and have a new bushing put in. Also likely, is that your spring-loaded throttle lever, the throttle shaft itself, the drive shaft seal, and possibly advance seals should also be replaced at this time.



In other words, you probably should the pump off and have a good injection shop give it a "cheap" tune-up, including running on the test stand and setting the supply pump pressure and making sure the advance moves correctly, as well as the aneroid parts (also in the top cover).



In theory, the top cover can be pulled with the pump on the engine, but I don't like doing it. It is extremely difficult to do that without introducing dirt into the pump - and dirt is the death of the little VE.