Domore Posted January 2, 2017 Share Posted January 2, 2017 My 2005 Mack700 as been losing power/motor slowing down when plowing snow.Thought is might be starving for fuel, so one of my guys checked the primary filter and it was half full. Thought that was the problem so we changed the fuel filters. Same problem, checked the primary filter and it is still only half full of fuel. I would think the filter should be full. Open the bleed cocks while truck was running, but nothing come out. Don't understand how the motor runs with a 1/2 full filter. Truck will idle and rev fine in neutral. But will have no power under load. Truck has a automatic transmission. Thanks in advance... Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/ Share on other sites More sharing options...
fjh Posted January 2, 2017 Share Posted January 2, 2017 Half fuel is normal! is your oil level rising ? the fuel transfer pump may be in its way out! Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356884 Share on other sites More sharing options...
Domore Posted January 2, 2017 Author Share Posted January 2, 2017 Thanks for the quick reply. Don't think the level is rising, but will check with the guys. Any ideas on what else could cause this problem? Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356887 Share on other sites More sharing options...
hatcity Posted January 2, 2017 Share Posted January 2, 2017 you're plowing snow when this happens. 2 thoughts 1) fuel is gelling 2) air intake is getting restricted due to blowing snow Quote Success is only a stones throw away.................................................................for a Palestinian Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356896 Share on other sites More sharing options...
theakerstwo Posted January 2, 2017 Share Posted January 2, 2017 I to say if the filter is half full it dont tell you much. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356901 Share on other sites More sharing options...
fjh Posted January 2, 2017 Share Posted January 2, 2017 plugged tank vent Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356907 Share on other sites More sharing options...
Domore Posted January 2, 2017 Author Share Posted January 2, 2017 2 hours ago, hatcity said: you're plowing snow when this happens. 2 thoughts 1) fuel is gelling 2) air intake is getting restricted due to blowing snow Fuel is not gelling. Truck comes right out of the garage. We have installed a new air filter and we checked that also. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356908 Share on other sites More sharing options...
Domore Posted January 2, 2017 Author Share Posted January 2, 2017 4 minutes ago, fjh said: plugged tank vent Thought of that also. But if the vent was blocked, wouldn't there be a vacuum like release when we remove the fill cap? You said before that the filter being 1/2 full was normal. This filter is the red screw on filter, not the glass bowl type. Why I didn't think being 1/2 full is normal is because it has 2 bleed screws on the top where the inlet from the tank and the outlet to the 2nd filter is. Is there a fuel pump to bring fuel from the tank to the filter? Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356910 Share on other sites More sharing options...
hatcity Posted January 2, 2017 Share Posted January 2, 2017 another thought- are you filling fuel tank at the end of day and then parking? warm fuel tank then cools overnite. condensation in tank-water in fuel Quote Success is only a stones throw away.................................................................for a Palestinian Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356913 Share on other sites More sharing options...
Domore Posted January 3, 2017 Author Share Posted January 3, 2017 11 minutes ago, hatcity said: another thought- are you filling fuel tank at the end of day and then parking? warm fuel tank then cools overnite. condensation in tank-water in fuel Thats exactly what we do.Normally the last driver will fill the tank and then park it for the next time it's needed. When this problem started we parked it in the garage and changed the filters. The next day we had a storm and we took it out to use. The driver drove about 3kms and had to bring it back and park it in the garage. The garage is heated but the is still snow and ice melting off, so it is possible to be some ice in the fuel line. Is there anything between the primary filter and the tank? Can I blow back through the fuel line?Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356916 Share on other sites More sharing options...
terry Posted January 3, 2017 Share Posted January 3, 2017 should be a primary and a secondary filter, on every fuel filter change on this system that i have done the secondary will be completely full and the primary is always aliitle low, when you drop filters. terry Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356918 Share on other sites More sharing options...
Domore Posted January 3, 2017 Author Share Posted January 3, 2017 8 minutes ago, terry said: should be a primary and a secondary filter, on every fuel filter change on this system that i have done the secondary will be completely full and the primary is always aliitle low, when you drop filters. terry My primary is only about 1/4 to 1/2 full. Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-356921 Share on other sites More sharing options...
Domore Posted January 3, 2017 Author Share Posted January 3, 2017 I think we found the problem. We think it was ice. We removed the fuel lines and blew them out. Primed everything, tried the truck plowing snow and everything seem back to normal. Now my primary is almost full. Guess we didn't leave the truck in the garage long enough before to completely thaw the fuel lines. Thanks to everyone for their replies. Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-357022 Share on other sites More sharing options...
j hancock Posted January 3, 2017 Share Posted January 3, 2017 Have had good luck with this product. Treats the fuel for winter time use. http://powerservice.com/psp_product/diesel-fuel-supplement-cetane-boost/ Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-357023 Share on other sites More sharing options...
Domore Posted January 3, 2017 Author Share Posted January 3, 2017 I put some of this in the tanks today. Should be good? Quote Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-357025 Share on other sites More sharing options...
j hancock Posted January 3, 2017 Share Posted January 3, 2017 Should be. It says it contains anti-gel properties. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/48185-primary-fuel-filter/#findComment-357027 Share on other sites More sharing options...
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