Rsc1717 Posted September 30, 2022 Share Posted September 30, 2022 Ok here’s the issue I have a 2014 with the mp8 having problems starting up truck in the mornings . Once it’s on , drives good and if you turn it off it starts right back up . Today I did something different I primed it from the fuel filter housing and it started right up . Also I do have bubbles coming out passenger tank return line I believe it is the return line . What could be the issue? Cups, injector , or fuel filter housing . Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/ Share on other sites More sharing options...
Joey Mack Posted September 30, 2022 Share Posted September 30, 2022 Possibly any of those reasons.. did fuel leak from the primer, when you pumped it? If so... Replace it.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-510644 Share on other sites More sharing options...
Rsc1717 Posted September 30, 2022 Author Share Posted September 30, 2022 1 minute ago, Joey Mack said: Possibly any of those reasons.. did fuel leak from the primer, when you pumped it? If so... Replace it.. no fuel dint leak from the housing . Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-510645 Share on other sites More sharing options...
Joey Mack Posted September 30, 2022 Share Posted September 30, 2022 Any visible fuel leaks or dampness on fuel lines from the tanks to the filter pad? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-510646 Share on other sites More sharing options...
Joey Mack Posted September 30, 2022 Share Posted September 30, 2022 There several postings about this issue, that you can read.. air in the fuel is common in MP engines... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-510647 Share on other sites More sharing options...
Rsc1717 Posted September 30, 2022 Author Share Posted September 30, 2022 1 hour ago, Joey Mack said: Possibly any of those reasons.. did fuel leak from the primer, when you pumped it? If so... Replace it.. no fuel dint leak from the housin 1 hour ago, Joey Mack said: There several postings about this issue, that you can read.. air in the fuel is common in MP engines... ok I’ll check all fittings coming from tank to filter housing thanks . 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-510650 Share on other sites More sharing options...
Onyx610 Posted September 30, 2022 Share Posted September 30, 2022 I posted a diagram of the 7th injector for you in your other post in engine/transmission. However that is not your issue. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-510687 Share on other sites More sharing options...
Onyx610 Posted October 1, 2022 Share Posted October 1, 2022 (edited) Start with a clear hose at the fuel return overflow valve at the head to the return at fuel filter housing. Check for aeration. If you have aeration you have bad cup/cups. If you don’t, which I hope is the answer then we can start to look at things like a fuel filter stand. Do you happen to have a davco filter on the truck? Edited October 1, 2022 by Onyx610 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-510706 Share on other sites More sharing options...
Rsc1717 Posted October 13, 2022 Author Share Posted October 13, 2022 I don’t know if it’s davco filter housing or not it has the Manuel primer pump that comes out when you twist it . Ok as soon as I get a change I’m going to run that hose from the head and see aeration . 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-511759 Share on other sites More sharing options...
Onyx610 Posted October 13, 2022 Share Posted October 13, 2022 You must not have one, or else you would know. It looks like this… https://www.otherstock.com/parts/details/550144765420?gclid=EAIaIQobChMI_PPLqJnc-gIVlrrICh3ahQgTEAQYAyABEgLZhvD_BwE Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-511760 Share on other sites More sharing options...
Onyx610 Posted October 13, 2022 Share Posted October 13, 2022 Inlet of those have a check valve. Which can also cause starting issues. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-511761 Share on other sites More sharing options...
Onyx610 Posted October 13, 2022 Share Posted October 13, 2022 12 minutes ago, Rsc1717 said: I don’t know if it’s davco filter housing or not it has the Manuel primer pump that comes out when you twist it . Ok as soon as I get a change I’m going to run that hose from the head and see aeration . You can also run the hose back to the tank if you wish. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-511762 Share on other sites More sharing options...
Rsc1717 Posted October 18, 2022 Author Share Posted October 18, 2022 Yes I don’t have that davco filter housing mine is a 2014 don’t know if that makes a difference . Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-512471 Share on other sites More sharing options...
Onyx610 Posted October 18, 2022 Share Posted October 18, 2022 No, it was typically and option. We have them all on our trucks. From 97-2018 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-512485 Share on other sites More sharing options...
Popular Post Joey Mack Posted October 18, 2022 Popular Post Share Posted October 18, 2022 you were leaning towards a real issue, Onyx... The Davco 382 is a great setup, and you are correct about the $8.00 check valve allowing fuel to bleed back when worn.. My guess is He doesnt have that added to the MP.. Too bad.. at times I try to recommend adding one to trucks just because... I like the drain and the ability to see the filter as it gets dirty.. I also like the fuel heater option that it offers.. Just tossing my opinion in the mix... jojo 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-512609 Share on other sites More sharing options...
Onyx610 Posted October 18, 2022 Share Posted October 18, 2022 1 minute ago, Joey Mack said: you were leaning towards a real issue, Onyx... The Davco 382 is a great setup, and you are correct about the $8.00 check valve allowing fuel to bleed back when worn.. My guess is He doesnt have that added to the MP.. Too bad.. at times I try to recommend adding one to trucks just because... I like the drain and the ability to see the filter as it gets dirty.. I also like the fuel heater option that it offers.. Just tossing my opinion in the mix... jojo I like them too for all the same reasons. I really like them on MPs for the extra filtration on that sensitive/expensive fuel system. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-512613 Share on other sites More sharing options...
Joey Mack Posted October 18, 2022 Share Posted October 18, 2022 Well maybe he will see these post's, and consider adding one... 👍 jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-512615 Share on other sites More sharing options...
Rsc1717 Posted November 1, 2022 Author Share Posted November 1, 2022 Hello guys , Ok I ran clear hose from the front of head and yes getting a lot of aeration so guessing it’s cups ? Any other thoughts ? Here’s the pic Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514177 Share on other sites More sharing options...
Onyx610 Posted November 1, 2022 Share Posted November 1, 2022 Cups 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514183 Share on other sites More sharing options...
Mackpro Posted November 1, 2022 Share Posted November 1, 2022 I vote cups as well. Unless no other visible leaks or damp spots in the fuel piping it’s always cups. Only 4 other things I have ever seen cause hard starting. 1 , fuel pressure relief valve that screwed in front of head . The updated one is really rounded on the end , the old style is flat all the way out to the end , takes a 7/8” wrench to replace. Yours being a 14 should have the new one . I had a 13 year model with the old one a couple weeks ago though. 2, fuel filter stand hand primer pump leaking when you pump on it. 3, tandem pump leaking at weep hole. The power steering pump and fuel supply pump are bolted together and there is a weep hole between them , if this is really wet or fuel dripping them it can cause hard starting , usually on trucks with 650,000plus miles. 4 , plastic fuel line connector at filter stand transition. The plastic fuel line from the fuel tanks quick connects to a fitting on a bracket on the filter stand. I’ve seen the factory zip tie the fuel lines so tight that in a hard pull the engine tilts and it pulls the fuel line back slightly and sucks air . Also a cracked plastic fuel fitting at fuel tank that was cracked by running over a deer. Now after all that is said. If your engine starts but dies after a few seconds then it could be leaking reman injectiors or a bad oil control valve for the engine brake . 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514189 Share on other sites More sharing options...
Mackpro Posted November 1, 2022 Share Posted November 1, 2022 Also , at least your truck is a 2014 , injectors are available your yours . One of our 2008-2009 MP8 has be waiting for injectors since first week of August . They are finally supposed to ship out today but still have no tracking number. I believe there are 5 different MP8 injectors not counting common rail engines. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514190 Share on other sites More sharing options...
Rsc1717 Posted November 1, 2022 Author Share Posted November 1, 2022 My engine starts and runs it’s just when I shut it down has hard time starting back up . Have been getting less response and shake or vibration up hill . Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514192 Share on other sites More sharing options...
fjh Posted November 1, 2022 Share Posted November 1, 2022 Now Thats uptime! Volvo trash! Just an observation when doing that test our guys would also watch for an intermittent large bubble passing down the tube every 6 to twelve inches! The foam is not a firm indicator! when a bubble passed by your assured its cups! There is always some fine bubbles from what I observed! Again just an observation! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514193 Share on other sites More sharing options...
fjh Posted November 1, 2022 Share Posted November 1, 2022 24 minutes ago, Rsc1717 said: My engine starts and runs it’s just when I shut it down has hard time starting back up . Have been getting less response and shake or vibration up hill . CUPS ! It will only get worse! Mackpro nailed it from the get go in my mind! When you have this job done have them check the engine brake slaves as well your already in there! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514194 Share on other sites More sharing options...
Mackpro Posted November 1, 2022 Share Posted November 1, 2022 If it’s to the point of vibration and shake under a load pulling a hill we automatically pull all 6 injectors and cups , it comes in a kit 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70506-problem-starting/#findComment-514195 Share on other sites More sharing options...
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