DW400 starting problems

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Installed a DW400 on my gen2 and having starting problems that started immediately after install.
On a full tank of gas I get very long cranks before it fires up. Like 5 to 6 seconds. As the tank empties, the crank times shorten but are very weak. This occurs on hot and cold starts. Once started there are no ill effects.
From my research this seems to be a check valve problem. Reached out to DW and they want me to send them the pump back for testing.
Has anyone else had this problem?

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[Zrussian13]

All new DWs "should" have a check valve I believe. I've seen some cases like yours where the dw struggles to start the car at battery voltage even though nothing is really wrong. You may try installing a bap. That pump likes 18v and seems to function better at that voltage.

 

[slime_bullet]

All new DWs "should" have a check valve I believe. I've seen some cases like yours where the dw struggles to start the car at battery voltage even though nothing is really wrong. You may try installing a bap. That pump likes 18v and seems to function better at that voltage.

Correct. I think the DW's for the 11-14 cars do not come with internal check valves. Ive only come across one thread with issues similar to mine and new pump solved the problem.

 

[5doorsoffury]

That fuel pump does not have a internal check valve. without one it will take time to build pressure. try a key on engine off for 2 seconds before cranking.
you can add a inline one after the fact iirc.

 

[slime_bullet]

That fuel pump does not have a internal check valve. without one it will take time to build pressure. try a key on engine off for 2 seconds before cranking.
you can add a inline one after the fact iirc.

I have the one that supposed to have a check valve

 

[5doorsoffury]

The check valve was added in recently even their website still lists it as no check valve. When you go into the tech document it does mention the check valve is new so you need to check whether the manufacturing date lines up with the change. Can you confirm rail pressure during cranking?

 

[PC_GUARD]

I bought my car used, but I assume my pump is OE. I always push the clutch in and the pump fires up, it stops I crank. I'd assume an auto car it would come on when the brake is applied in a start scenario?

I guess my point is, I always let the pump prime, before I spun up the car.

The only other thing is maybe it needs a different starting strategy?

 

[1badrz28]

I have the same issue, except the long start happens after a full pass at the track and the rest of the day in the staging lanes. Then after driving it for a while, it starts normally again. I just added a Glow Shift fuel pressure combo gauge inside the car. This year I'll be able to see what the fuel pressure is during cranking when I get it out after winter storage.

 

[PC_GUARD]

I have the same issue, except the long start happens after a full pass at the track and the rest of the day in the staging lanes. Then after driving it for a while, it starts normally again. I just added a Glow Shift fuel pressure combo gauge inside the car. This year I'll be able to see what the fuel pressure is during cranking when I get it out after winter storage.

Thats all due to bleed off? Why dont they prime when you hit the key? Is it heat?


I know nothing about the bigger volume pump setups like this

 

[Cory S]

Thats all due to bleed off? Why dont they prime when you hit the key? Is it heat?


I know nothing about the bigger volume pump setups like this

It primes, but air gets trapped between the pump and injectors. Without the check valve, as the car sits and cools down, fuel makes its way backwards towards the pump. then the air gets trapped in front of fuel fuel upon startup creating longer occasional cranks before ignition.

All DW400’s have come with check valves installed in the outlet nipple since Nov of around 2019.

 

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UPDATE:
Recieved a new pump from deatchworks and all is well. Either it didnt have a check valve or it was faulty.

 

[daSNAK3]

UPDATE:
Recieved a new pump from deatchworks and all is well. Either it didnt have a check valve or it was faulty.

Nice that you got it figured out, I just installed mine the other day, I was nervous but thankfully its starting and running good.

 

[Scat2018]

I’m have a problem restarting car after u shut it off for a few mins. When I shut my car off and go to restart it.It starts up, then just dies. Then I start it again and it starts right up.I just did the whipple install and I did drive it a little before install pump.I had to get Intercooler system bleed.and didn’t have any problems until I install the DW400 then I got gas then it did fire right up again.I just got the whipple stage 2 back in Feb

 

[Samantha Soule]

I used to be on the same boat. Then, the staff advised me to install a bap. I tried and the problem is solved.

 

[Scat2018]

I used to be on the same boat. Then, the staff advised me to install a bap. I tried and the problem is solved.

. DW staff? Did u need a tune change to run the BAP ?I have not got a reply from whipple these I since a email them last week

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