Whipple 4.6 Eletrical issues/ bogging over 3500 rpm

[Whipple3v]

I recently bought a 2007 Mustang S197 with a 4.6L engine and a Whipple supercharger, 92,000 miles, and a 2000-watt amp in the back. The car drove perfectly on the test drive and on the way home.

The day after I bought it, the car started cranking for a long time to start, and while driving, all electrical components went out. I first thought it was a bad battery, so I replaced it. The battery wouldn't hold a charge and eventually died completely.

Assuming it was the alternator, I replaced that with a remanufactured unit. After installation, it kept the battery charged, but it had a weird "smoky" smell initially.

Now, the car behaves strangely under load:

• When driving, it bogs at around 3,500 RPM and won't go past that.
• At idle or when revving in neutral (not under load), it can rev past 3,500 RPM just fine.
• No check engine light is showing.

Other relevant details:

• I previously unplugged a thick wire near the battery that I thought was for the amp — it had a bracket at the end, so it may actually feed the amp or the Boost-A-Pump/fuel system.
• The bog only happens under load, not at idle or in neutral.

I'm wondering if anyone has experienced something similar, or has any ideas about what could cause this. Any advice or suggestions would be greatly appreciated!





Thanks in advance for any help!

 

[MrBhp]

I suggest getting a good scanner, something to datalog with.
@DieHarder is the grounding nazi around here. He can tell you about that.
I would pull the fuel pump to determine what it is. I don't like the boost-a-pump scenario. Too many people using it as a bandaid, leaving a tired old factory pump in the tank and expecting an electronic device to cure a problem. They do work, but there are much better solutions. The big wire kit is awesome. Along with a big pump.

I would be very careful with the car. A supercharged car with a bad tune or timing/fueling problem is a bomb, and your foot is the fuse.

 

[86GT351]

If the wire you unplugged is for a Boost A Pump you need to trace that down and OHM it out to make sure it is good. No Boost A Pump could be a huge issue

 

[DieHarder]

I recently bought a 2007 Mustang S197 with a 4.6L engine and a Whipple supercharger, 92,000 miles, and a 2000-watt amp in the back. The car drove perfectly on the test drive and on the way home.

The day after I bought it, the car started cranking for a long time to start, and while driving, all electrical components went out. I first thought it was a bad battery, so I replaced it. The battery wouldn't hold a charge and eventually died completely.

Assuming it was the alternator, I replaced that with a remanufactured unit. After installation, it kept the battery charged, but it had a weird "smoky" smell initially.

Now, the car behaves strangely under load:

• When driving, it bogs at around 3,500 RPM and won't go past that.
• At idle or when revving in neutral (not under load), it can rev past 3,500 RPM just fine.
• No check engine light is showing.

Other relevant details:

• I previously unplugged a thick wire near the battery that I thought was for the amp — it had a bracket at the end, so it may actually feed the amp or the Boost-A-Pump/fuel system.
• The bog only happens under load, not at idle or in neutral.

I'm wondering if anyone has experienced something similar, or has any ideas about what could cause this. Any advice or suggestions would be greatly appreciated!





Thanks in advance for any help!

Hmmm... Funny that it ran fine and only started acting up after you got it home.

Off the bat doesn't sound like your issue is grounding. To check do a simple voltage check w/a VOM (on DC volts) across the battery terminals with the engine running. If you're seeing 14.2 vdc - 14.7 vdc your charging system is likely fine. If you want to read up more on grounds see: Finally found the cause of my low voltage - Beware the all important grounds.

Your symptoms mirror a recent issue I had with my car after replacing plugs. From what you're describing it sounds more like you have one or more bad COPs. No fault codes in my case either. I run a DOB kit w/M122.

By chance did the previous owner recently remove plugs for any reason? If so, it may be the case that the pigtails for the COPs have retreated up into boots so far that they're not making good contact anymore with the top of the plugs. The car will idle fine and accelerate at low levels but if you try anything past 20% - 30% throttle she'll bog down and act like she's starving for fuel (because the spark is now having to jump a gap). You'll need a decent scanner (or take it to the dealer) to tell exactly which one/s are at fault or you can buy a complete set (all 8) on feebay for ~$65 - $90. Get OEM Motorcraft (black boot version) for your year.

Pardon Our Interruption...

If you do change out the COPs you might as well get a set of Brisk plugs. Expensive but the Best plug out there for supercharged applications.

 

[Whipple3v]

Thanks for the responses. A couple things I should add. Looking at the cord now I’m pretty positive it’s just a cord to my amp. Not even sure this car has a boost a pump. Also, none of this was happening before the electric issue. The alternator is now keeping the battery charged, I will still try to do a voltage check. I also was thinking maybe of getting a scanner just to reset the ecu

 

[Racer45]

I don’t know to much about sound systems but a 2000watt amp kind of sounds like a lot. I wouldn’t be surprised if the factory alternators output aint enough. I’d maybe look into upgrading the alternator to a 200 amp version. Also if the car is cammed as well some people will set it up to idle very low rpm’s so it sounds better better @ idle. Only issue is the crank may not be spinning fast enough to charge the battery effectively. Issue may be amplified if there’s a underdrive pulley on the crank all though I don’t think many people would run a UDP with a blower

Not to say this is your issue but may be some extra things to consider looking into

 

[Whipple3v]

More updates. Battery died overnight. Maybe a parasitic drain? Or faulty alternator out the box? It was remanufactured

 

[JC SSP]

Most remanufactured alternators are done in China and are of poor quality.

Put in a good alternator and disconnect the amplifier (for now) see what happens…

 

[MrBhp]

Do you have the factory audio head unit? I'm thinking not, if you have a 2k amp. If you leave it switched on (the factory head unit) when you turn the ignition off, they can randomly drain the battery.

 

[DieHarder]

Thanks for the responses. A couple things I should add. Looking at the cord now I’m pretty positive it’s just a cord to my amp. Not even sure this car has a boost a pump. Also, none of this was happening before the electric issue. The alternator is now keeping the battery charged, I will still try to do a voltage check. I also was thinking maybe of getting a scanner just to reset the ecu

I would Not reset the ECU. Your car has a custom tune in it to deal with that supercharger. If it was a standard installation the ECU was probably sent off to be tuned separately. To be sure I recommend you contact the seller to verify. Regarding that thick line connected to B+. Check to see if it runs to the FPDM (Fuel Pump Driver Module) in the trunk. If so, it needs to be hooked up as it provides increased current to drive an upgraded fuel pump that you should already have sitting in the gas tank. If it was a standard installation a new fuel pump was part of the installation package that came with the whipple. Until you can chase down the history and verify a few things be careful with it as MrBhp cautions.

Not sure which installation you have but here's a link to Ford's instructions for a Whipple installation on a 2005 - 2010 3v:

https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-6066-05-10_GT.pdf

 

[jlmotox]

I've recently had similar issues with a similar setup... I stomp on the skinny pedal, rpm's hit 3500-4000 and it sounds like a 2 step, sputtering and popping, if I stay in the throttle it will clear out after a few seconds and will continue to build rpm like normal. My car sits in the garage more than I would like so I assumed it was bad gas... I drove it until near empty then refilled with some non-ethanol 93 and then everything is back to normal. This has happened now two times over the last year and both times just new gas seems to fix it...Guess I need to drive it more LOL! Next step is new plugs since I have not replaced them since the Whipple install. I have googled this problem and never saw anything that was similar to my problem until I ran across this thread, I installed the Whipple back in 2017 and have had zero issues since install except for this... As of a few weeks ago when I drove it last all was well and the car was acting normal. If you find a solution report back!

 

[Whipple3v]

I've recently had similar issues with a similar setup... I stomp on the skinny pedal, rpm's hit 3500-4000 and it sounds like a 2 step, sputtering and popping, if I stay in the throttle it will clear out after a few seconds and will continue to build rpm like normal. My car sits in the garage more than I would like so I assumed it was bad gas... I drove it until near empty then refilled with some non-ethanol 93 and then everything is back to normal. This has happened now two times over the last year and both times just new gas seems to fix it...Guess I need to drive it more LOL! Next step is new plugs since I have not replaced them since the Whipple install. I have googled this problem and never saw anything that was similar to my problem until I ran across this thread, I installed the Whipple back in 2017 and have had zero issues since install except for this... As of a few weeks ago when I drove it last all was well and the car was acting normal. If you find a solution report back

It was low on gas so I filled it with gas and charged it on a trickle charge and the bogging issue stopped. However the battery still wouldn’t hold charge. I took it to a shop they told me the alternator I had just put in was bad. They told me that vintage of alternator sucked so they put a 2010 style alternator in and replaced my serpentine belt. Everything was smooth then a couple days later I did a small pull and it bogged back at me once, the fuel cut, engine slowed down then turned off. Assuming it’s fuel pump issue now