HPFP rail pressure raising while engine not running!

Now this is strange.

Two logs included. Other one when engine is not yet running and rail pressure keeps climbing, until it goes down rapidly to around low side fuel pressure when the engine starts.

Other log is vice versa. Engine is running, rail pressure is too low and after the engine is shut down, pressure keeps rising on rail.

Now, that's pretty much impossible. So something is clearly wrong here. Tune attached.

Car details:

- 2014 LT1 with:
- LT4 supercharger kit, breakout cable, LT4 MAP, etc.
- LT4 HPFP
- LT4 injectors

No visible leaks.

Error codes P0089, P228C.

Then some screen shots:

https://img.aijaa.com/b/00760/14891836.jpg
https://img.aijaa.com/b/00869/14891837.jpg
https://img.aijaa.com/b/00869/14891839.jpg
https://img.aijaa.com/b/00421/14891840.jpg
https://img.aijaa.com/b/00560/14891842.jpg

Finally, very first log where rail pressure rises for some second or so.

i have seen this before issue with cap for HPFP, is the camshaft changed and fuel lope lash

Quote:

---

Originally Posted by SultanHassanMasTuning

i have seen this before issue with cap for HPFP, is the camshaft changed and fuel lope lash

---

Thanks!

This is with stock LT1 cam and stock LT4 pump. I've not done installation by myself.

Is there a specific procedure to follow, or perhaps different from LT1 with LT4 HPFP?

Did you copy over the LT4 high pressure tune tables over to your LT1 tune?

Quote:

---

Originally Posted by Joshinator99

Did you copy over the LT4 high pressure tune tables over to your LT1 tune?

---

Yes, as well as LT4 injector data.

Forgot to mention that it also has Dsteck aux fuel pump for the low side, as we're going to use E85 later.

https://img.aijaa.com/b/00251/14892135.jpg

Nothing in the tuning side seems to help with the fuel rail pressure issue.


Next we'll try original LT1 HPFP pump with original settings for the high pressure side.

Quote:

---

Originally Posted by Pekka_Perkeles

Nothing in the tuning side seems to help with the fuel rail pressure issue.


Next we'll try original LT1 HPFP pump with original settings for the high pressure side.

---

Well, with LT1 hpfp no more fuel rail pressure problems!

Is there some kind of quality issue ongoing with LT4 hpfp pumps?

Damn. With brand new LT4 hpfp, the rail pressure drops very soon after the start. But with LT1 hpfp it works fine.

This must be a tune issue. Anyone?

Quote:

---

Originally Posted by SultanHassanMasTuning

i have seen this before issue....

---

Now getting towards the root issue, since rail pressure is as it should be with latest changes with the tune. Very good, finally!

I've changed some axis values back to stock, as well as using imperial values instead of metric ones. Don't yet know why it works now, but will be testing gradually to find out more.

Quote:

---

Originally Posted by Pekka_Perkeles

Now getting towards the root issue, since rail pressure is as it should be with latest changes with the tune. Very good, finally!

I've changed some axis values back to stock, as well as using imperial values instead of metric ones. Don't yet know why it works now, but will be testing gradually to find out more.

---

Any update on this-running into the same issue

Bump again.....Im having the exact same issues as the OP with 2 Different LT4 HPFPs. Installed one, had low rail pressure, removed, warrantied it, and installed another brand new one and same exact low pressure condition and codees. I can watch the pressure rise with the truck off, but once the truck is started it immediately drops to Low Side Pressure, and pops the P0089 and P228C

Quote:

---

Originally Posted by 1993 sle

Bump again.....Im having the exact same issues as the OP with 2 Different LT4 HPFPs. Installed one, had low rail pressure, removed, warrantied it, and installed another brand new one and same exact low pressure condition and codees. I can watch the pressure rise with the truck off, but once the truck is started it immediately drops to Low Side Pressure, and pops the P0089 and P228C

---

Sorry, haven't been here lately until now.

Compare against attached tune.