Intermittent Loss of Power-help
#1
12-24-2006, 07:53 PM
Intermittent Loss of Power-help
Recently I have been plagued with an intermittent flat pedal. It typically does not occur in the first 5 minutes of driving but after that it can happen at any time.
On the tach the flat spot typically represents a 300-400 rpm drop (ie. 1,700 drops to 1,400 and after about 1 second goes back to 1,700).
It does not matter what gear the tranny is in the dip is about the same.
Acceleration at WOT is very good except that above 40 mph every 4 to 5 seconds during acceleration the power goes flat for about 1 second and then comes back. This continues up to 90 mph. Fuel pressure stays about 12/13 psi.
Same thing can happen while at steady throttle. Even at moderate speeds it may still occur and at times may recur repeatedly at 7 to 8 seconds intervals and then it will clear up only to return again in a few minutes.
It is not unusual to drive 10 or so miles with no symptoms.
Using a Vulcan wet test gauge the pressure is consistantly at 13/14 PSI at all speeds. When accelerating from 40mph to 75mph at WOT the pressure only drops to 12/13 psi for a very brief moment.
I tried several WOT events to try to evoke a problem code but all I ever get is "P doNe". Even repeating the call for a code several times I still get the same "P doNe"
Through all of this the fuel pressure stays at approx. 13/14 psi so I don't think it is a fuel pressure problem (FASS 150 and Drawstraw)
I never get a stall situation but am concerned that it may quit altogether when I least need it to.
Tried calibrating the throttle position twice by turning key on and slowly depressing pedal and slowly releasing and turning key off but no change in problem. Then pulled the APPS cover and adjusted to spec on APPS label. No change in problem.
Suggestions would be appreciated.
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On the tach the flat spot typically represents a 300-400 rpm drop (ie. 1,700 drops to 1,400 and after about 1 second goes back to 1,700).
It does not matter what gear the tranny is in the dip is about the same.
Acceleration at WOT is very good except that above 40 mph every 4 to 5 seconds during acceleration the power goes flat for about 1 second and then comes back. This continues up to 90 mph. Fuel pressure stays about 12/13 psi.
Same thing can happen while at steady throttle. Even at moderate speeds it may still occur and at times may recur repeatedly at 7 to 8 seconds intervals and then it will clear up only to return again in a few minutes.
It is not unusual to drive 10 or so miles with no symptoms.
Using a Vulcan wet test gauge the pressure is consistantly at 13/14 PSI at all speeds. When accelerating from 40mph to 75mph at WOT the pressure only drops to 12/13 psi for a very brief moment.
I tried several WOT events to try to evoke a problem code but all I ever get is "P doNe". Even repeating the call for a code several times I still get the same "P doNe"
Through all of this the fuel pressure stays at approx. 13/14 psi so I don't think it is a fuel pressure problem (FASS 150 and Drawstraw)
I never get a stall situation but am concerned that it may quit altogether when I least need it to.
Tried calibrating the throttle position twice by turning key on and slowly depressing pedal and slowly releasing and turning key off but no change in problem. Then pulled the APPS cover and adjusted to spec on APPS label. No change in problem.
Suggestions would be appreciated.
[/align]
#2
12-24-2006, 08:32 PM
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