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  • SN95 4.6L Mustang Tech

Reduced power in 1st and 2nd gear

  • Thread starter Thread starter jimted79
  • Start date Start date Feb 25, 2025
J

jimted79

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Feb 25, 2025
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  • Feb 25, 2025
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Hey guys new here and lost on my problem. I have a 2003 gt 5 speed with a 2.1 kenne bell. It feels like i may have 50% power in 1st gear and same in 2nd till about 5k then it takes off, traction control is turned off through tune. 3rd and 4th pull hard through the entire rpm range. I assume 5th would pull hard all the way just havent had the runway to test in higher rpms. took it back to the tuner he said ditch the boosta pump and get a new fuel pump. did that helped a little but still doing same thing for the most part. cleaned the map and put a new tps and nothing. Has anyone had this problem? its driving me crazy. KB says its the tune and tuner says no. Any help would be huge. Thanks guys.
 

Noobz347

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  • Feb 25, 2025
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I think you may be blowing out your spark. What is your current gap? -and- I would rig up a way for you to watch voltage going to the coil when this occurs.

Also: If you have a Boost-A-Pump is should be properly installed. Even if it's set to [Zero] it will regulate power to the pump and keep it steady regardless of your electrical system dips/spikes.
 
J

jimted79

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Feb 25, 2025
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Feb 25, 2025
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  • Feb 25, 2025
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Noobz347 said:
I think you may be blowing out your spark. What is your current gap? -and- I would rig up a way for you to watch voltage going to the coil when this occurs.

Also: If you have a Boost-A-Pump is should be properly installed. Even if it's set to [Zero] it will regulate power to the pump and keep it steady regardless of your electrical system dips/spikes.
Click to expand...
when you say blowing out my spark do you mean to much fuel? I gapped the plugs to KB's recommendation which i cant remeber off the top of my head ill have to go through the paperwork. If what you say is the case why would it run so good 3rd on?
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
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Jan 4, 1985
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#4
  • Feb 25, 2025
  • #4
jimted79 said:
when you say blowing out my spark do you mean to much fuel? I gapped the plugs to KB's recommendation which i cant remeber off the top of my head ill have to go through the paperwork. If what you say is the case why would it run so good 3rd on?
Click to expand...

You not revving as fast.

I have a Kenne Bell on my Windsor Stroker.

I ended up with the following items in my efforts to get it smoothed out.

Boost-A-Pump to regulate power to fuel pump
Boost-A-Spark to regulate power to the coil
One heat-range cooler plug than OEM gapped to roughly half of OEM spec
Tune

It would "Wall" when trying to rev out on the short gears and act fine any other time.

The plugs are not blowing out because of the air/fuel mixture. They blow because all that fuel and air mass is being rammed down its throat at an accelerated rate.

I have also indexed my spark plugs but I can't say how much it helped if at all.


To test my theory: I recommend you look at all of your plugs and re-check the gap. Close them all up a bit and put them back in for a test ride to see if the issue improves. If it does, I also recommend a Boost-A-Spark regardless of any electrical system upgrades. It is nothing more than an adjustable voltage regulator. Same as the Boost-A-Pump.

Side Note: You should be running a 255L HP in-tank pump, with or without the regulator (BAP).

Other side note: Run the car at idle at night with the hood open [after] some driving around and heat-soak. You're looking for lightning leaks all around the wires and coil.
 
J

jimted79

New Member
Feb 25, 2025
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Socal
Feb 25, 2025
#5
  • Feb 25, 2025
  • #5
Noobz347 said:
You not revving as fast.

I have a Kenne Bell on my Windsor Stroker.

I ended up with the following items in my efforts to get it smoothed out.

Boost-A-Pump to regulate power to fuel pump
Boost-A-Spark to regulate power to the coil
One heat-range cooler plug than OEM gapped to roughly half of OEM spec
Tune

It would "Wall" when trying to rev out on the short gears and act fine any other time.

The plugs are not blowing out because of the air/fuel mixture. They blow because all that fuel and air mass is being rammed down its throat at an accelerated rate.

I have also indexed my spark plugs but I can't say how much it helped if at all.


To test my theory: I recommend you look at all of your plugs and re-check the gap. Close them all up a bit and put them back in for a test ride to see if the issue improves. If it does, I also recommend a Boost-A-Spark regardless of any electrical system upgrades. It is nothing more than an adjustable voltage regulator. Same as the Boost-A-Pump.

Side Note: You should be running a 255L HP in-tank pump, with or without the regulator (BAP).

Other side note: Run the car at idle at night with the hood open [after] some driving around and heat-soak. You're looking for lightning leaks all around the wires and coil.
Click to expand...
Thank you for this info i will start with the plugs this weekend and keep you posted on progress!
Also i removed my (bap) and am running a 325lph fuel pump which after reading what you said may have been a mistake. after 325 install it did pick up power somewhat. thanks again
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
43,115
21,288
234
Box behind Walmart
Feb 25, 2025
#6
  • Feb 25, 2025
  • #6
jimted79 said:
after 325 instal
Click to expand...

On a stock engine at idle, you must be bypassing a [lot] of fuel.

Can you verify your fuel pressure at idle?
 
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