Viper Running mystery

R

RXMax

Member
Joined
Nov 17, 2003
Messages
149
Age
48
Location
Central MN
Have a 04 viper Mtn with DCS. It intermittently has a miss in the mid range. Not all the time however. If you are cruising and pick up the throttle is hesitates. Things we have tried:

New plugs
New wires
New caps
New coil packs
New grounds
Different set of carbs
different TPS
All new parts in orignal carbs
Exhaust valve servo assy
Relays

The only thing we have yet to try is a CDI but we do not have another with DCS. We are stumped? Anyone have an idea. Please help.

Thanks!
 

Is it a miss or a bog? In other words, does the engine actually misfire, or does it simply hesitate?
 
If you are running steady state in the midrange, say half throttle and then roll into it and it happens, raise the needles up a little, might just be a little lean at part throttle.
 
Not a bog it is a miss you can see it on the tach it flutters. Sled has 1200 miles on it. Tried a complete set of carbs from an 03 that runs perfect, same problem. Have traced it to the PTO cylinder. The plug is not as nice as the center and the mag. Head gasket, base gasket or crank seal sucking air? Doesn't overheat, otherwise runs perfect. Everything in the carbs is new. Jets, needle valves. Everything is set to factory specs outside temp etc also makes no difference. The harder you crank on it the more noticeable it is.
 
I wouldnt place my bet on the CDI QUITE yet. Have you checked out the reeds and cages? 1st thing I would check next.

Do all cylinders seal up good on pistons and rings? Is there something wrong with your fuel pump or pulse line?? (Noticed you swapped carbs)
 
You could swap the fuel lines around and see if the miss moves, spray around the crank seal area when running and see if there is a change, check compression or leak-down test too.
 
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