after i get staged for a launch, shortly after i let the clutch out and hit WOT the AFR leans way out 17-19 until i shift to second. AFR goes to 12-13 at first when i let off but, after the shift & Im back on the throttle it leans out again & the same thing happens in 3rd also. I have done a compression test & got 140-150 on all cyl. I have new plugs at the factory 0.050 gap. new wires, new MSD coil and my dist cap and rotor are also MSD but they are about 4 months old. I have a new fuel pump relay & have done a fuel pressue test at idle 36-42 lbs. I have the TWEECER RT and have my timing at WOT set to 33 deg max timing. I think i am having a fuel volume problem. I tried to acc in 3rd from cruise to WOT. At first the AFR would go to13 but the longer i held it at wot it would eventually start to lean out again. what do you guys think?
WOT going lean
- Thread starter 90stang5speed
- Start date
Try increasing the fuel pressure if the problem is across the entire RPM range.
Get one of your buddies to ride along with you. Find a level stretch of road where you can do some testing. Watch for the wind speed and direction, it can have a definite impact on your test results.
Don't choose a speed range that will make you shift gears, the shift quality & speed will affect your results. Use 2nd or 3rd gear and do a run from 2000 RPM to 5800 RPM. Call out the RPM as it increases and have your buddy record it and the elapsed time. If you have one of those cheap digital watches like I do, a stop watch is built in.
Start the fuel pressure at 38 PSI, vacuum off and make a run. Turn it up to 40 and make another. Be sure to reconnect the vacuum every time you set the pressure. Keep turning up the pressure in 2 PSI increments and making runs until you notice a drop off in time. If your bud was careful to record the results, you'll have a nice chart to use to find the optimum pressure.
Get one of your buddies to ride along with you. Find a level stretch of road where you can do some testing. Watch for the wind speed and direction, it can have a definite impact on your test results.
Don't choose a speed range that will make you shift gears, the shift quality & speed will affect your results. Use 2nd or 3rd gear and do a run from 2000 RPM to 5800 RPM. Call out the RPM as it increases and have your buddy record it and the elapsed time. If you have one of those cheap digital watches like I do, a stop watch is built in.
Start the fuel pressure at 38 PSI, vacuum off and make a run. Turn it up to 40 and make another. Be sure to reconnect the vacuum every time you set the pressure. Keep turning up the pressure in 2 PSI increments and making runs until you notice a drop off in time. If your bud was careful to record the results, you'll have a nice chart to use to find the optimum pressure.
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