Joey Mack Posted September 23 Share Posted September 23 Ok.. i didnt read from the beginning. Sorry..🍻 Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-583276 Share on other sites More sharing options...
Geoff Weeks Posted September 23 Share Posted September 23 I agree with @fjh, check fuel pressure and diaphragm. I had one similar, came on quick, and got worse quick. changing fuel filters helped a bit but not enough. I my case it turned out the suction line was leaking air into it but not fuel out. Would show in fuel pressure reading or a sight glass placed in the fuel line near the pump. Just one of a few things that could be bad. In my case, not obvious to find but easy to fix. Fuel pressure, esp under load where the problem is happening, would help to narrow it down. A hand pump on the smoke limit device would be a good way to check if it is holding pressure or leaking right through. Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-583277 Share on other sites More sharing options...
h67st Posted September 23 Share Posted September 23 +1 on Geoff Weeks' comments. Fuel pressure will definitely cause this, could be a line like has been mentioned or could be the overflow valve (return tee on the top of the pump, if it's worn you won't get enough pressure). Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-583281 Share on other sites More sharing options...
fjh Posted September 23 Share Posted September 23 1 hour ago, h67st said: +1 on Geoff Weeks' comments. Fuel pressure will definitely cause this, could be a line like has been mentioned or could be the overflow valve (return tee on the top of the pump, if it's worn you won't get enough pressure). My bet is the diaphragm! Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-583284 Share on other sites More sharing options...
Joe2007 Posted Saturday at 04:50 PM Author Share Posted Saturday at 04:50 PM FJH Just getting around to working on my truck. I can blow in the smoke-limit device.is there anything else to check on? Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-584133 Share on other sites More sharing options...
fjh Posted Saturday at 07:12 PM Share Posted Saturday at 07:12 PM 2 hours ago, Joe2007 said: FJH Just getting around to working on my truck. I can blow in the smoke-limit device.is there anything else to check on? Nope pull the lid the 4 screws u may have to use vice grips on the anti tamper or zip wheel a screw head on it ! If you can blow thru it it has a hole in it! The other alternative is take the two screws out of the small cap and run the Allen screw right in !but there is no Garrenty you going to get full fuel doing that! Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-584136 Share on other sites More sharing options...
Joe2007 Posted 19 hours ago Author Share Posted 19 hours ago I put a new diaphragm in today, but it’s still doing the same thing. Do you have any other ideas? Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-584187 Share on other sites More sharing options...
Joe2007 Posted 19 hours ago Author Share Posted 19 hours ago I put a new diaphragm in today, but it’s still doing the same thing. Do you have any other ideas? Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-584189 Share on other sites More sharing options...
fjh Posted 6 hours ago Share Posted 6 hours ago 13 hours ago, Joe2007 said: I put a new diaphragm in today, but it’s still doing the same thing. Do you have any other ideas? Did The diaphragm Have a hole Or are we just parts chucking here! I get replacing it cause its old BUT ! We are trouble shooting here ! did you check your work try blow through the diaphragm after you replaced? Also have you checked fuel pressure yet! ??? Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-584198 Share on other sites More sharing options...
Joe2007 Posted 1 hour ago Author Share Posted 1 hour ago I put a new one in it bc the old one had a little hole in it. I did not blow in the new one and I have not checked the fuel pressure I don’t have the tools to do that. Can you tell me what I need and where to check it at? Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-584204 Share on other sites More sharing options...
fjh Posted 1 hour ago Share Posted 1 hour ago You need to tee into the line that goes to the filter before the fuel pump ! Quote Link to comment https://www.bigmacktrucks.com/topic/75724-power-problems/page/2/#findComment-584206 Share on other sites More sharing options...
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