Lml fuel/boost issues

[drperry]

So I'm thinking my CP4 might be on the way out.... But looking for other options.

I can be cruising at highway speeds and my fuel pressure will drop 2 - 3k and a couple psi of boost... Or at least, you can hear the turbo change pitch, and possibly a small rpm drop as well.

I'm running Idao Rob's tuning, FASS 150, and 5" DP back exhaust... The issue has been on and off since I've had the truck, but it's starting to get worse...

 

[Awenta]

You don't want to have a cp4 let go

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[drperry]

I'm aware... But it's a big chunk of change to swap out, so I want to make sure before I do a CP3 conversion. That's around 5k, give or take.

 

[kiwilml]

When you say your rail drops pressure does the desired rail stay the same or what?

 

[drperry]

I'll double check after work, but I think so.

I got my first fuel filter warning since the FASS last week or so... The filter is only a month or so older than my lift pump.

If the demanded fuel pressure drops as well, what could cause that? It's done it since day one, even on stock tuning/pre-deletes...

Could it be detecting transmission slip? I've never had any transmission codes pop up, but that doesn't always mean anything.

 

[Harbin_22]

I'm aware... But it's a big chunk of change to swap out, so I want to make sure before I do a CP3 conversion. That's around 5k, give or take.

Cp3 conversion is no where near $5k. It will be if you let the CP4 grenade and kill everything in its path though.

 

[drperry]

Cp3 conversion is no where near $5k. It will be if you let the CP4 grenade and kill everything in its path though.

It is in Canada... It's 2 - 3k for the kit with pump... Plus labour @ 100/hr or so, give or take. The exchange rate is killer on parts, lol.

 

[drperry]

Well, it looks like my fuel pump is doing it's business just fine... Rail pressure is always within spitting distance of commanded rail pressure...

It appears to be the turbo vanes opening that's doing it... I'm just not sure what would cause that, as it did it when it was on stock tuning.

What other PID's can I look at to determine possible causes?