Casper’s Hotwire Kit Issues

[Amab145]

Hey guys, i’m having a pretty big issue lately with my Caspers hot wire kit. I installed this kit back in 2015 when I put in a double pumper set up I had zero issues from 2015 until last spring. I parked the car after going for a cruise, and when I went to restart it, the pumps weren’t turning on. through the process of elimination in a parking lot, I started with the fuse that is on the power wire, and when I opened up the fuse holder, everything was completely melted. I was able to scrape out the melted plastic, jam a 25A fuse in its place and get the car home. I ordered a new fuse holder and installed it along with a 30A fuse.

Drove the car all summer last summer after repair with what seemed to be zero issues. Upon dropping the fuel tank yesterday to mess with the sending unit because the fuel gauge in the dash isn’t working properly, I figured I would inspect the rest of the wiring for the fuel system. Couldn’t believe it but the fuse and holder melted again. In neither scenario did the fuse blow, it just melted everything to hell…

Any ideas what would cause this? The power wire is connected directly to the back of the alternator, fuse holder mounted to the inner LF fender, power wire run all the way to the relay mounted back by the fuel tank. Dual DW300 pumps run in tandem at all times. Amp draw on the pumps is 12A at 40psi and 13.7A at 70psi (per pump). Like I said, I’ve run this exact set up since installation in 2015 with no issues until the past few months, I’m completely stumped…

 

[RUQWKNF]

A few of things that come to mind.
Do you mount that fuse holder anywhere next to the headers or another possible heat source?
How long has it been since you serviced the factory fuel filter, or aftermarket filter/filters?
Close to where you mount the fuse holder, are there any other wires or connectors that are showing similar signs of melting?

I'm suspecting a few things.
You have a rather high heat source that is radiating enough to melt the connector, or your pump / pumps are working overtime due to a clogged fuel filter or filters.
IMO, 2015 is a long time to be running the same fuel pump socks, especially with ethanol blended pump gas. Almost 8 years old and I have seen the pumps start to degrade in less than 6, as well as pump filters get clogged and nasty.
Short of putting a fuel pressure gauge in the car and monitoring it while driving to see if your pressure is decreasing when fully up to temp, I don't know how you could monitor/replicate it tbh.

Maybe some others can come up with some ideas as this is very odd, but I think you've got something going on with the pumps and filters due to age and fuel.

- Patrick

 

[Chuck Leeper]

Bad grounds will add to the issue.
Do a volt drop test on both sides of the system + and -.

You have both pumps running all the time, so the draw at the low end is 24A, the hi end 28.
That's too close to the fuse limit. We like to fuse for the operating load not to exceed 80%
So, 28A on a 30A fuse is too close. On the 25A it's upside down.
Add in Patrick's comment on pump wear, filters degrading, and the system is on edge.
{IMO, 2015 is a long time to be running the same fuel pump socks, especially with ethanol blended pump gas. Almost 8 years old and I have seen the pumps start to degrade in less than 6, as well as pump filters get clogged and nasty.}
Cheapo fuses will not survive either. Cheap Ho Chi Min junk is not a good choice.
Buss fuses here.
I would suggest a new set of pumps, filters and a Hobbs sw to run the 2nd pump.
If the system is using the stock return line, that's a contributor to the heat/load on the system.

 

[SCOOBY DOO]

Kills me how long guys leave fuel pumps in for. I swapped mine out every spring including fuel filter. Cheap insurance against head gaskets. It's a 2 beer job.

 

[dynoman]

The current draw for the pumps as you stated are factory specs. and probably not what you are seeing . Any restrictions such as fuel sock and / or filter and the pump goes past full load current . If you had a clamp on DC Amp Probe it would be easy to see what they are drawing ( an HVAC friend might have one ) . Like Chuck said check grounds and install a hobbs switch so you're not running both pumps all the time . I never had an issue with double 340's & a hobbs switch .

 

[Mr.Spool]

Those pumps cant just sit in the ethanol fuel.
In most cases it will cost the owner.
Not sure how these companies say the pumps a good for ethanol
I've seen so many take a shit I dont run that style pump anymore unless it's a race gas car or non ethanol.
I've monitored fuel pressure on a lot of them and they go away and they never really had enough for high psi to begin with.
I've seen them even with low miles throughout say a 3 year span sit in ethanol fuel and go away.
So even if you use them or let them sit it's a timebomb some get longer than others.
They heat the fuel up as well.
If you have a double pumper setup and aren't leaning on it there is alot of fuel cushion and you may not have an issue,for instance 2 pumps that can supply 1500hp of fuel but your only making 800.
On the other side of things if your leaning on it and have the right monitoring equipment in the car you may be able to see it go away if your paying close attention,for instance your running e85 and have a base fp of 50 and running 30psi should equal 80psi,but you start seeing 76psi.
Now your afr may not change due to having enough at 76psi but if you add in 3psi of boost of go into a cold air situation now the car really leans out and fast enough where it cooks things and the computer wont save it due to the % of loss so quickly.
So watch for 1to1 fp.
G forces are a factor as well as well as the entire fuel system like patrick and chuck have said.
My advise is to overfuel these cars with a great pump like a aeromotive brushless spur.

 

[SCOOBY DOO]

@Mr.Spool

Are Aeromotive brushless spur fuel pumps available in a 255 for bums like me not making any HP.

 

[dynoman]

Are Aeromotive brushless spur fuel pumps available in a 255 for bums like me not making any HP.

I believe the smallest is a 3.5 gpm , and that's what I'm running . I put in a cell in the trunk and mounted the pump in the spare tire well below the level of the cell as it needs to be gravity fed .

 

[BEATAV8]

For a double pumper you will want to run a "double hotwire" setup with a fused cable for each pump and a relay for each pump.

 

[Mr.Spool]

@Mr.Spool

Are Aeromotive brushless spur fuel pumps available in a 255 for bums like me not making any HP.

Since your smart enough to run race gas on your 255 or 340 you'll be fine
But.....
Inmo double pumpers,modified tanks,hanger mods, wiring turn on points and hoping the 2nd pump comes on.
By the time that's all said and done anyone could be on a brushless spur for not much more money and have 0 matinence and pump failures for a very very long time
And they know the pump is moving the fuel
I've seen magnafuel,aeromotive,Weldon all outlast these walboro/turbine style in tank pumps most of us have been running 5 to 1 or better in terms of time.
The brushless spur is even better.
Think how many beers you could save

 

[Mr.Spool]

I believe the smallest is a 3.5 gpm , and that's what I'm running . I put in a cell in the trunk and mounted the pump in the spare tire well below the level of the cell as it needs to be gravity fed .

And it can run off the stock ecm
And doesnt overheat the fuel and rely on a hotwire kit to flow fuel.
And can work off the tps to curve the fuel flow

 

[Amab145]

Lots of good info here, thanks guys!

Let me try and answer some of the questions asked. So yes, they have been installed since 2015, however, likely less than 3000mi on the car since installation. I run VP C12 race fuel all the time so they wouldn't have any exposure to ethanol fuels to potentially ruin the pumps. The car hasn't seen regular fuel since I built it. Last spring I dropped the tank and pulled everything out because the fuel gauge wasn't working properly, so while I was at it I changed the socks on both fuel pumps before reinstallation, so they are less than 1yr old. As far as fuel lines, I'm running -8 braided line for feed and -6 line for return to the tank.

I also have an Aeromotive in-line fuel filter mounted on the frame rail under the car that is cleanable, so I'll definitely take apart and inspect, good thought for sure.

I do have a FP gauge mounted inside the car visible to me at all times and haven't noticed any decrease in pressure over the past few months. Still cruises around at around 40psi and climbs 1:1 with boost. Do you think 10AWG power wire is good enough to come off the back of the alternator to power the pumps or should I go with 8AWG?

 

[Mr.Spool]

Lots of good info here, thanks guys!

Let me try and answer some of the questions asked. So yes, they have been installed since 2015, however, likely less than 3000mi on the car since installation. I run VP C12 race fuel all the time so they wouldn't have any exposure to ethanol fuels to potentially ruin the pumps. The car hasn't seen regular fuel since I built it. Last spring I dropped the tank and pulled everything out because the fuel gauge wasn't working properly, so while I was at it I changed the socks on both fuel pumps before reinstallation, so they are less than 1yr old. As far as fuel lines, I'm running -8 braided line for feed and -6 line for return to the tank.

I also have an Aeromotive in-line fuel filter mounted on the frame rail under the car that is cleanable, so I'll definitely take apart and inspect, good thought for sure.

I do have a FP gauge mounted inside the car visible to me at all times and haven't noticed any decrease in pressure over the past few months. Still cruises around at around 40psi and climbs 1:1 with boost. Do you think 10AWG power wire is good enough to come off the back of the alternator to power the pumps or should I go with 8AWG?

I hope you are running the pumps staggered.
Where is the 2nd pump turning point?

 

[Amab145]

I’m not running them staggered, they have been running parallel. I know it’s overkill but I did upgrade the rest of the fuel system to handle the additional volume etc.

 

[Mr.Spool]

You may be your own problem

 

[TType85]

If you are running an regular hotwire kit that only had a single 12ga feeder wire running 2 DW300's that seems like a bad idea to me. The newer heavy duty kit is 10ga with a 40a fuse which I still wouldn't run 2 pumps off of personally. I ran 2 separate 10ga feeder wires to my dual DW300 setup.

 

[BEATAV8]

Something like this would do the job. This particular kit may not have the compatible bulkhead connector for a stock hanger but they are available. Racetronix has the stuff but getting it all identified can be a chore.

Dual Pump Wiring Kit, MP150/280 F99 GSS (DPWK-001): Dual Pump Wiring Kits | Racetronix

Purchase Dual Pump Wiring Kit, MP150/280 F99 GSS or shop other Dual Pump Wiring Kits and Racetronix products from Racetronix.

www.racetronix.biz

 

[SCOOBY DOO]

So what exactly does the ethanol wreck in the pumps like I was running.

 

[Mr.Spool]

So what exactly does the ethanol wreck in the pumps like I was running.

There is a host of things.
From impeller deformation to seal swell.
To the rest of the fuel system breaking down due to the ethanol fuel reaction.
One of the reasons why the spur was designed with not much to go wrong inside the pump in mind.
In the alky diaphragm pumps its usually the seals even with the viton but m1 is even more corrosive.

 

[TIMINATOR]

I have never in over 50 years of running high HP street/strip cars and high HP boats had a mechanical fuel pump failure that left me stranded. But I have had several electric pumps leave me walking, or swimming!
Why? Mechanical pumps are driven at engine rpm, so at low speeds/rpms, the pumps aren't doing much work. The electrics on the other hand, don't know what the engine speed or load is, so they are running wide open, full bore ALL OF THE TIME! They are puking their guts out making max pressure and flow all of the time! Even at idle!
Replace them, often! Once a year anyway, sell the old one to a race car guy that doesn't drive the car except once a week, or less at the track. It will last him for years!
The OEMs have solved these wear and fuel heating issues by pulse width modulation of the pumps supply amperge to drop pressure and volume in low load situations.
Until someone, MSD? Comes up with one of these modulation units for us, pump replacement is our only option.
Someone, perhaps MSD, had a resistor based unit that dropped pump voltage and current to carburated electric pumps, about 15/20 years ago. I had one on my blown BBC, 9 second Nova back in the 90s. Those worked in a carburated situation because carbs have float bowls to keep the flow constant pretty much regardless of fuel pressure. A full throttle switch bypassed the resistor stack at WOT. This won't work with FI. A Hobbs switch in the manifold could be used to shut off one of the double pumper pumps, but the main pump would still wear quickly. AND, if the system croaked, so would your engine!
Perhaps one of our computer ECM gurus might work on this! To my knowlege, the oem modulator systems are built into the ECM, and not capable of stand alone operation, nor capable of modulation of the current requirements of our large pumps.
Food for thought from the
TIMINATOR