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MXS smoking and missing until starts heating up

Created On Monday February 02, 2015 21:04

swanny

Posts: 2
Joined: Feb 2015

Monday February 02, 2015 21:04

2006 with platinum overhaul, new camshaft, all rocker arms, and shafts. New transfer pump and fuel check valve in base. Ran fuel line from tank straight to transfer pump. Timing checked and timing calibration done. Fuel pressure 80-85 idle and 90-100 wot. No air in fuel system. Starts right up with no smoke and no miss but starts smoking and missing once you get in 6th-7th gear, looks like over-fueling. Only does it for a few miles then clears up and runs great. WILL NOT smoke or miss again until following day. You can run it first time at 7:00 am and shut it off by 7:30, then start it up at 4:30 pm and drive it again with no smoke or miss. Start it up the following morning and drive it with the smoke and miss returning. All injectors are new (and correct part#), installed new vva assembly and swapped to all 3 positions with no difference, adjusted valves again just to be sure. Installed new ecm with no difference, can cut each injector out while missing and smoking with no change to miss or smoke. Ran several injector cutout tests (1 cyl and 4 cyl) and several vva tests with all testing OK every time. ANY IDEAS???

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JoeZ

Posts: 938
Joined: Dec 2008

Tuesday February 03, 2015 05:20
Could be a boost problem, my first guess when I hear over fueling...if not maybe electronic or fuel. You may have to bite the bullet and put it on a dyno to get closer to what it's doing. ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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swanny

Posts: 2
Joined: Feb 2015

Tuesday February 03, 2015 05:30
Monitoring boost with ET it stays around 35-37 while it is missing/smoking, only jumps to 38-40 after it clears up. Only reason we haven't tried dyno is it won't miss/smoke for long, and will not re-occur in same day once it clears up.

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JoeZ

Posts: 938
Joined: Dec 2008

Wednesday February 04, 2015 14:01
The boost is not low enough to cause a problem....is the smoke black or blue?? ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.