496 HO - hesitation/miss/lost rpm
08-13-2008, 11:32 AM
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Location: Owensboro, KY
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496 HO - hesitation/miss/lost rpm
DId a lot of searching and reading before I posted, but there are never any real clear answers.
On my 496 HO I recently started having a hesitation or a miss when under a load. ALso lost about 400-500 rpm. Idles great, and i can pop the throttle and hit the limiter without a load with no hesitation or miss. There are no audible alarms going off. No, I do not have access to a scan tool.
Most folks said they found trash in the screen of the booster pump. I had no trash there.
All plug wires were on securly. I did have one plug that was a little more "burnt" looking than all the others. Could this cause the symptoms?
I will test the fuel psi on the rail today.
Any suggestions would be much appericated.
On my 496 HO I recently started having a hesitation or a miss when under a load. ALso lost about 400-500 rpm. Idles great, and i can pop the throttle and hit the limiter without a load with no hesitation or miss. There are no audible alarms going off. No, I do not have access to a scan tool.
Most folks said they found trash in the screen of the booster pump. I had no trash there.
All plug wires were on securly. I did have one plug that was a little more "burnt" looking than all the others. Could this cause the symptoms?
I will test the fuel psi on the rail today.
Any suggestions would be much appericated.
08-14-2008, 06:27 AM
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Update:
I did 3 things:
1) I changed the one plug that looked a little more burnt than the others.
2) I changed the water seperator/filter
3) Switched batteries
After the changes I had a static fuel psi of 40-41 psi, I never checked it before, just got the guage yesterday.
Put it in the water, had good fuel psi thru all rpm. It ran up to just over 5000 rpm and ran as fast as it ever has.
What fixed it????? I do not know. I will undo all changes except the fuel filter. I do not think one slightly burnt plug caused it to run bad. The old fuel filter was basically new (6 hours).
Could be very possible it was a low voltage situation. My battery setup is a 2 batt set up where basically i can switch the starting battery only. All other accessories are ran off the same battery all the time (the battery I eliminated). I do not know how the fuel pumps get there power. I am just not sure, I did changed the battery switch when I first had the symptoms, but condition did not improve. I will switch back to the old battery set up and see what happens.
I did 3 things:
1) I changed the one plug that looked a little more burnt than the others.
2) I changed the water seperator/filter
3) Switched batteries
After the changes I had a static fuel psi of 40-41 psi, I never checked it before, just got the guage yesterday.
Put it in the water, had good fuel psi thru all rpm. It ran up to just over 5000 rpm and ran as fast as it ever has.
What fixed it????? I do not know. I will undo all changes except the fuel filter. I do not think one slightly burnt plug caused it to run bad. The old fuel filter was basically new (6 hours).
Could be very possible it was a low voltage situation. My battery setup is a 2 batt set up where basically i can switch the starting battery only. All other accessories are ran off the same battery all the time (the battery I eliminated). I do not know how the fuel pumps get there power. I am just not sure, I did changed the battery switch when I first had the symptoms, but condition did not improve. I will switch back to the old battery set up and see what happens.
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