Dual pump set up with DW400 pump

[Tommy V]

I think I will keep the flow .
You can prime the pumps by pressing/cycling the start button 2-3 times before you start the car.
Seems to help

Hey bud trust me with dual pumps u will not have to hit the start button a few times,first time u hit it,you will see full pressure.

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[Tommy V]

Long story tell u when we talk
Vaccum line pinched. Whoopz sorry texting and talking to,to many people lol.

 

[Burkey]

For those playing at home...
I don’t think the hot start issue is related to the lack of a non-return valve.
1. My car had no hot restart issues with the DW400 pump when it was NA (tuned but stock rails). Add Whipple, hot restarts are a problem.
2. If lack of prime was the the route cause of the hot restart problem, cold starts would be terrible (zero prime)
3. When the heatsoaked car does finally sputter to life, it smells VERY rich. This isn’t the hallmark of an engine that’s struggling for fuel supply.
4. Every engine I’ve know of that’s having this drama has a PD blower running aluminium fuel rails that are directly bolted to the lower manifold. We all know that aluminium conducts heat much better than steel, but it will conduct it MUCH better when it in direct contact, where the stock rails are kinda isolated and shrouded.

We’re talking about heatsoaked engines having issues with starting. Is it possible that the fuel rails are basically boiling the fuel and the DW pump somehow changes the starting characteristics under those conditions?
It’s also worth noting that the hotter the engine is, the harder the restarts seem to be.
I don’t have the answers, just throwing out some ideas.

 

[Tommy V]

If it is truely mainly pd blowers having this issue that is a good point.

 

[TX-Ripper]

The pd F150 guys have installed external check valves and stopped the issue.

I just sent my DW400’s back to dw to have them install the internal check valve

 

[D98gt]

I occasionally have the issue as well and it can make a gas station trip quite embarrassing.

 

[Burkey]

Were they having issues with starting gernerally or just once the car is heatsoaked

The pd F150 guys have installed external check valves and stopped the issue.

I just sent my DW400’s back to dw to have them install the internal check valve

Were they having starting issues generally or only once the car was heatsoaked?

 

[TX-Ripper]

Heat soaked and if it sat unused for a long time

 

[Burkey]

Heat soaked and if it sat unused for a long time

That’s weird.
I can leave mine sit for a fortnight and it’ll start like stock

 

[olaosunt]

I had mine crank and crank till it finally ran the battery down .
I had been sitting for a week in 30 degree temps
The shop had to spray “starting fluid” - not sure what exactly-to get it started
I have made sure to drive it daily since and always prime the pumps and so far so good .

 

[olaosunt]

May be I will send the “spares” I bought , thinking then one in the car was dead , to DW for the check valve after all .

 

[olaosunt]

Also please note that the DW400 has no check valve in it. You may have issues with hot starts. I know Whipple does not include this pump in their 18 Kits any longer. Since the fuel will drain all the way back to the tank. I know they are working on an updated version.

Not sure where you got the info about Whipple not including the DW400 pumps in the stage 2 kits anymore but it’s not true .
I asked and here is what they said

 

[Burkey]

Not sure where you got the info about Whipple not including the DW400 pumps in the stage 2 kits anymore but it’s not true .
I asked and here is what they said

It may stem from some confusion.
Lund were originally willing to tune the 18-19 for e85 with the supplied DW400 pump.
I believe initial testing showed that it could be done but further testing showed some variation.
Hence, they no longer offer an e85 tune for that pump.
Could be totally wrong here.

 

[Kona 18]

It may stem from some confusion.
Lund were originally willing to tune the 18-19 for e85 with the supplied DW400 pump.
I believe initial testing showed that it could be done but further testing showed some variation.
Hence, they no longer offer an e85 tune for that pump.
Could be totally wrong here.

They will still tune for the DW400, they just wont tune e85 on a single DW400+BAP due to user-errors during install.

 

[olaosunt]

They will still tune for the DW400, they just wont tune e85 on a single DW400+BAP due to user-errors during install.

Will they tune for dual DW 400’s on a return system ?
I got the impression they would not ,when discussing my plans to do dual DW400’s in my GT 350 with a return set up .
I had wanted to go with Lund since I would only be paying the $400 “upgrade” from the NA flex tune .
Might need to find another tuner who will , as not going to be spending $3k on a fuel system this time .

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