Thread: Part throttle backfire..???
10-04-2009, 09:48 PM #1
Part throttle backfire..???
BEEN HAVING A FEW ISSUES WITH MY SKI ..
RUNNING GREAT THEN BAM ...WAS RUNNING POOR.... HAD NO POWER...SPUDDERING ...LIKE IT WAS RUNNING ON 2 CYL..CHANGED PLUGS NO DIFF... COMP CHECK ..GOOD ..INJECTORS GOOD... EXCHANGED COIL PACKS TO TEST .....GOOD... CHECKED VALVE TRAIN VISUALLY GOOD.... GOOD COMP....135 ACROSS THE BOARD...
WE ALSO CHANGED THE MAP SENSOR ..TO A DIFFERENT ONE JUST TO SEE IF THAT WAS THE PROBLEM ....AND THE INTAKE TEMP SENSOR WAS REPLACED...IT POPPED A CODE ...HAD IT CLEARED ON BUDS..IT DIDNT COME BACK...
FOUND .HAD A SUPERCHARGER WASHER FAILER...SO NO BOOST BREATHING THROUGH THE CHARGER AND INTERCOOLER ..IT DIDNT LIKE IT ..IT WAS BACKFIRING THROUGH THE INTAKE ...NO POWER ...ECT ..TOOK THE MOTOR OUT REMOVED THE REAR ..FOUND MOST OF THE PIECES OF WASHER...ALL THE GEARS WER GOOD.. NO MARKS ON THE TIMING CHAIN...OR RING GEAR...PUT IT ALL BACK TOGETHER..ALL IS GOOD ON THE TRAILER...
TOOK IT OUT IDLES FINE ....NO LEAKS ..GOT ALL THE HOSES TIGHT...WOT RUNS GREAT ...THINK ALL IS GOOD TO GO ...HIT A NO WAKE SLOW ZONE....AT PART THRODDLE SAY 15 TO 25 % IT BACKFIRES THROUGH THE INTAKE ... AND MISSES ..COIL PACKS ARE ALL THE WAY ON ..WIDE OPEN IT IS GOOD...GETTING 8100 DOUBLE UP ONLY 50 LESS THAN NORMAL SINGLE ..MAY SITLL NEED TO ADJUST THE OIL LEVEL...
IT ISNT THROWING ANY CODES....
THINKING TPS ..BUT THOSE DONT USUALLY GO BAD...
10-05-2009, 03:43 PM #2
got the kids this weekend want to toss them off the tube ...anyone
10-10-2009, 02:25 PM #3
still looking for some insite
10-10-2009, 03:32 PM #4
wow, I wish I had some ideas ... I really don't know what could be causing that. Strange that it runs great top speed ... no rpm or speed loss at WOT at all?
10-10-2009, 05:18 PM #5
thnaks for thinking about it ...ya it was real strong..top end....just back fires as you roll on..from a no wake or up it just a bit in the slow zones........its right about where you would tow a tube....about 25 mph under load
10-11-2009, 07:05 AM #6
10-11-2009, 08:24 AM #7
it was running great before the charger failer...
the ski set up has been the same for 2 years...
what could cause it to all of the sudden belean there ...
could cam timing cause that...???
but it still runs great top.. and has great comp....
i know valves to tight loose can cause things but we dont adjust ours??
just trying tothink it through
10-11-2009, 11:05 AM #8
Bad or clogged injector? Intermittent spark coil?
10-11-2009, 03:31 PM #9
Is the backfire coming back through the intake valves or exhaust valves? If it's coming back through the intake valves, has it cracked the plastic intake manifold yet? I don't think that you would hear it if it was coming through the exhaust system unless you have a through hull exhaust system... Ron
10-11-2009, 05:14 PM #10
pulled the fuel rail and watched them seems fine ...coili packs are a possibility ....but why only at 15 to 20 % under load ..on the trailer it is fine ...
i appreciate the thoughts and helping me think it through .
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