tkerrigan asks......

[BushWakr - RIP]

"... ..... Does anybody know if it does any good to turn up the injector pump fueling screw on a '93 5sp CPL1579? I've heard that some stock injectors won't take any additional fuel, and I'm wondering if this may be one of them. Any help would be appreciated as I'm doing a favor for somebody. By the way, my rig is a 91, and it does take increases.



Tom..... "



Tom this question more properly belongs in here, not the FAQ section so I moved it here for you to get better exposure.



Pastor bob. .

 

[BushWakr - RIP]

The answer to your question is yes, you can tweak your fuel screw to have the pump push more fuel through the stock injectors.

It is generally accepted that pushing them too far is hard on the pump due to the stock nozzles resistance to heavy fueling which loads the pump up fairly hard.

This is a standard concern/issue with ALL stock pumps/injectors though so it's not unique to this model year/pump/injector.



Hope that helps...



Pastor Bob...

 

[sparks57]

Ussualy about a turn and a half is about what you would want to turn it in from stock. But, of course, every pump is different.



You have to remember that the stock injectors can only flow so much fuel, and trying to shove more fuel than that is just going to put a lot of stress on your injection pump, which already isn't a very tough unit.



I hope that helps.

 

[dpuckett]

You can also do the AFC adjustments that everyone talks about. I'd try that route first, though if you increase the fuelling, be it via the power screw, or the AFC cone, you are going to stress the pump. BUT, it is my understanding that you only stress the pump when you use the extra power.



Get some gauges on that puppy, if not already there. Stock boost should be in the neighborhood of 18psi +/-. Peak EGTs about 1100-1200, depending on a few factors.



In my experience, the 1351 and 1579 CPLs had the same six hole injector tips. Differences were in pump internals, and turbo housings.



Daniel

 

[tkerrigan]

Thanks for all the info, so far I've advanced his timing and done the afc. That alone gave him enough power to pull Willamette pass in fourth rather than third. His towing increased from 11-12 to 14 mpg. His unloaded went from 19 to 22. As soon as he gets gauges we will turn the pump up, and I'll suggest that he buys a 16 cm exhuast housing. By the way, I've bought a 04. 5 6sp laramie and sold my 91, it went for 8400. 00.



Thanks again for all the help:



Tom