[YellerFeller]

Hello everyone, first post here but I’ve been a lurker for a few years lol
I’ve got a 2018 ZL1 1LE and I am having some issues with the DSX aux low side kit.
To summarize, 99% of the time it works great. Low side 78-80psi WOT and high side rock solid as well.
But if I get stuck in traffic or am running the car for awhile (driving all day), two things begin to happen:
1. The low side falls off, as if the aux system isn’t even kicking in
2. The pump whines after any accelerations or even aggressive downshifts, and sometimes for 5-6 seconds after the event. Not just WOT, it also occurs aggressively pulling away from a light and hitting a bit of boost.

It’s very rare that it happens, and if I just go out for a highway blast it might not ever do it.
But when the pump doesn’t kick in and I’m running E40-E50, the fueling plummets dangerously.
Any ideas?? I’ve been reading on other platform forums that these Ti Auto 255s don’t like to be ran externally because they are heat sensitive and more “pushing” pumps than “pulling” pumps. But I can’t find anyone else on the internet using this kit with my issues so…. Lol
I could just run 93 but the gains are noticeable going to E and I wouldn’t have bought the $1000 dsx system if I was just running pump gas so I’d like to actually reap the benefits.
Anyways, any ideas would be much appreciated!

Relevant Mods:
-BTR Stage 2 Cam
-18% Lower
-ARH 2in Headers
-RotoFab
-Mamo Ported TB
-Dsx Aux Low side
-Dsx Flex Fuel

[KingLT1]

Sounds like a thermal problem with the fuel pump itself. I would try swapping it out.

[laynlo15]

Call Dave at DSX and let him know what's going on.

[BunnyBoy]

Weren't there an issue with a few of these pumps failing and going bad? I think even J speed on youtube had one go bad on his ZL1.

[radz28]

I think that issue was for the bigger pump.

I just installed this system, with the bigger pump, and so far it seems okay. It's a new controller, though, so...

I did call speak to Dave about a power question I had, and they were good at answering my questions. As already stated: I'd give them a call.

Is the pump connected as they describe in the manual? They state it should just have constant 12V all the time.

[YellerFeller]

I emailed Dave and he suggested that the pump shouldn’t be pushing 78-80psi constantly as they don’t like to run up there. This could have caused some damage or is causing the pump to have heat issues. Waiting til tomorrow to see what he suggests next.
Oddly enough, my pump primes up during flashing which is something he said it should not do. So I’m not too sure why that is… More suggestions from him to hopefully follow up on tomorrow. The system was installed by a shop so I’m not sure of all the install details but from what I can see it’s nothing out of the ordinary. And it typically works perfectly… Just something to do with heat.
I’ll probably pull the trigger on a new pump since they’re relatively cheap.
I will keep you guys posted!

[laynlo15]

Good luck man, need to get that resolved soon. You have a good build and wouldn't want something like that to cause a failure.

[radz28]

Originally Posted by YellerFeller

I emailed Dave and he suggested that the pump shouldn’t be pushing 78-80psi constantly as they don’t like to run up there. This could have caused some damage or is causing the pump to have heat issues. Waiting til tomorrow to see what he suggests next.
Oddly enough, my pump primes up during flashing which is something he said it should not do. So I’m not too sure why that is… More suggestions from him to hopefully follow up on tomorrow. The system was installed by a shop so I’m not sure of all the install details but from what I can see it’s nothing out of the ordinary. And it typically works perfectly… Just something to do with heat.
I’ll probably pull the trigger on a new pump since they’re relatively cheap.
I will keep you guys posted!

Mine did this, too. It did it 1 time out of 2 flashes... Please report back.

[YellerFeller]

So Dave is going to send a new pump for me to try out which is awesome! Great customer service, and very impressed he was even willing to look at logs and suggest some settings.
The old pump is working fine currently (as it usually does) but I haven’t had the opportunity to get it really hot in stop and go traffic during the day with little pulls here and there. That’s usually when it acts up. I’m not sure why it runs during a flash and it has me worried it could be a wiring issue, but it’s pretty PnP so I’m not sure how that could be. Let’s just pray it’s a faulty pump and all is well after the new pump lol

[YellerFeller]

Something odd as well, do you guys know why this noise would be occurring after a downshift? In the log I see no boost being built when I downshift... so what gives?

[YellerFeller]

I’m blowing up my own post, but now I’m wondering, where is the low side sensor located? If it’s pre aux pump, how would the information I’m receiving about low side pressure be valuable? There would I have to be a sensor near the engine bay, likely just before the HPFP… ahhhhhh. There’s not much info on this, it’s making my brain hurt.

[Jamyzd44]

Originally Posted by YellerFeller

I emailed Dave and he suggested that the pump shouldn’t be pushing 78-80psi constantly as they don’t like to run up there. This could have caused some damage or is causing the pump to have heat issues. Waiting til tomorrow to see what he suggests next.
Oddly enough, my pump primes up during flashing which is something he said it should not do. So I’m not too sure why that is… More suggestions from him to hopefully follow up on tomorrow. The system was installed by a shop so I’m not sure of all the install details but from what I can see it’s nothing out of the ordinary. And it typically works perfectly… Just something to do with heat.
I’ll probably pull the trigger on a new pump since they’re relatively cheap.
I will keep you guys posted!

My pump prime shard during flash and is very inconsistent with coming on as it should. It works maybe 75% of the time, and other times is delayed to kick on. Almost like a bad MAP signal. Didn't kick on until 4th gear the other day