Matt Posted January 11, 2008 Share Posted January 11, 2008 I have a 86 6.9L it runs great. but after it sits for 4hrs you either have to use ether(not good), or crank for ever. The glow plug system is good. I know it is a fuel issue. it has duel tanks anybody know were I could start. Has new pressure line all new orings on the caps and new return hoses on the caps Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted January 12, 2008 Share Posted January 12, 2008 Matt, first off welcome aboard!!! 2nd your in Michigan, land of salt... Check all of your lines for corrosion/leaks sucking air, loosing prime. Check the f/w seperator for leaks, try bypassing and see if it makes a difference. Also check the tank switch valve for leaks I've come across a few. Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted January 12, 2008 Share Posted January 12, 2008 Also the lift pump and the check valve in the filter header (located in the 90 degree fitting) can be problems. I would start by installing a clear hose between the #1 injector return line and the filter header, and a clear hose between the frame rail line and the lift pump. Good luck, and let us know what you find. P.S. watch out for Larry /forums/images/%%GRAEMLIN_URL%%/drinkingdude.gif Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted January 12, 2008 Share Posted January 12, 2008 Jeff's worse than I am /forums/images/%%GRAEMLIN_URL%%/drinkingdude.gif /forums/images/%%GRAEMLIN_URL%%/boxing.gif /forums/images/%%GRAEMLIN_URL%%/drinkingdude.gif /forums/images/%%GRAEMLIN_URL%%/boxing.gif /forums/images/%%GRAEMLIN_URL%%/crybaby2.gif Quote Link to comment Share on other sites More sharing options...
Matt Posted January 12, 2008 Author Share Posted January 12, 2008 Sorry I forgot to add I already replced the line between the selector valve and the mechnical pump on the engine. and already bypassed the water seperator. I was kind of thinking it was the tank selector valve but 120 bucks for a 500 dollar plow truck I didn't want to just try it Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted January 12, 2008 Share Posted January 12, 2008 You could try bypassing the tank selector valve and just hook up 1 tank to see if that is your problem. Also the lift pumps have been known to suck in air as well - thats where the clear hose comes in handy in determining where the air bubbles originate. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 12, 2008 Share Posted January 12, 2008 Good info here. In addition, I've seen the switching valve become restricted on the return side and cause this exact problem. Pull the return line off of the top of the injection pump and gently try to blow air through it back to the tank. I have an old 6.9/7.3 lift pump that I use for a mechanical test. That's a 3" muffler clamp spread out for the second handle, and clear hose from Home Depot. Attach it to the lift pump suction hose and activate it by hand. Look for good flow and air in the clear lines which indicate problems. This not only works well on an old PLN system , but also on almost any diesel system on the road. Good Luck! /forums/images/%%GRAEMLIN_URL%%/grin.gif Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.