pikkashoe

Noticed today, that my dash logic threw out a "Low Fuel pressure warning".I was on boost and i have that alarm set to go off when ever fuel pressure drops below 55 psi.

First question, shouldn't the BAP kick in and increase the fuel pressure when in boost?

I couldn't see what it actually dropped too since the warning came on, but if it drops to 55, is that ok? Or should I be looking for a more significant drop, lets say to 40 psi?

Unreal

Hard to say. Tune could take into account dropping fuel pressure, then it isn't an issue. 3-4psi drop isn't uncommon in high HP builds. Most stock pump BAP combos do drop pressure, but you just make up for it in the tune. What you need to monitor is drops from what it was tuned/safe at and go from there.

pikkashoe

Well the fuel pressure usually reads between 62 to 64 psi, so its dropping almost 10 psi.
Im only at 617 hp, so its not really a high hp build.
I would imagine when i go into boost, the BAP would kick in, increasing the Fuel Pressure, but I am not seeing that.

Unreal

No, it doesn't increase pressure. There is still a regulator that regulates pressure so any more flow will just get dumped back into the tank.

Like I said, 10psi drop maybe normal, or it may not be, without AFR and seeing tune/etc it is hard to say.

pikkashoe

Thanks unreal for clarifying that. I didn't know the fuel pressure would not go up with the BAP. At least thats a relief. I sent out an email to Matt at FSP to see what he thinks.

Unreal

What is the afr? If it is flat and where it should be, you are good. Plenty of people have dropping FP and don't even know it.

pikkashoe

Unfortunately, I don't have a wide band to check afr. Maybe it's time to get one. They all run off the rear o2 bungs in the exhaust right?

Streetk14

Honestly, a wideband is WAY more important than a fuel pressure gauge. That's my opinion at least. I wouldn't do an FI build without one.

And yeah, pressure dropping is "normal". By that, I mean common. BAP or not, once the fuel requirements exceed a certain percentage of the pump's output, pressure will start to drop. It's not ideal, but isn't the end of the world either.

Your car was likely tuned with the fuel system in this condition, so it's being compensated for. The flip side of that is that your fueling won't be as consistent as a car with rock steady pressure. My experience with pressure drop is that it varies based on fuel/ambient temperature. So it might drop more in some conditions than others.

And lastly, I had a stock C6 pump with a BAP and Racetronix harness on my old build. Even with 100% meth helping take a load off the fuel system, I still got noticeable fuel pressure drop at 660 rwhp. Even upgrading to a Z06 pump and a 20 volt BAP didn't stop it when I added a little more power. No surprise you're getting some drop without meth.

And get a wideband. I really like my PLX AFR module & touch gauge combo. I like it better than the AEM failsafe gauge I had before.

schpenxel

Need to be placed before the cats, if you're running cats. If no cats, rear bung should be fine.

Some can output a simulated narrowband signal.. so you can replace one of your O2's with a wideband, connect wideband to controller, then the controller can output a simulated narrowband O2 signal back to the computer. That's what I'm doing, but getting everything right to make it work was a pain. I wanted to try that before adding another bung and so far it has worked fine.

Probably easier to just add another bung (if necessary) and run a wideband by itself and leave the narrow band ones alone, but there are options I guess is my point

If you do decide to go the route I did let me know and I'll get you the formula I ended up using to make it work

pikkashoe

Well I have no cats. My cats got gutted. I will look into it today. New project!

Street, I am running meth on my system, alky control single nozzle.

schpenxel

That makes it easy then. Use rear bung as you had originally mentioned

Leave front o2's alone in that case

pikkashoe

Any particular wide band recommended for use with the dashlogic?

schpenxel

I have one of the innovative motorsports ones, but Palmer has some great prices on plx ones which are supposedly the best option right now

So, if I were doing it over I'd get the one from Palmer

schpenxel

Also, Innovate Motorsports has the LC-2 which just has the controller and no gauge.. sounds like you don't want a gauge, so there is another option

pikkashoe

Tuner responded. (love FSP, they are so quick).
Last night the lowest i saw it drop was to 55.4, so it probably just dropped right under 55 when the alert went off. Could have been ambient conditions, yesterday was pretty hot down here (close to 90 degrees) and my car sat idling for a while waiting for someone.

FSP said that is normal what I am seeing, he has seen even bigger drops for fuel pressure.
So for now it seems everything is ok.

I am still going to get the wideband for the car.

Looking at AEM Uego (Tuner recommendation), the pLX and LC-2. Gonna do some research over the next few days and pull the trigger. I think the AEM is a gauge, which I don't really want, having a dash logic.

schpenxel

If I was buying again I'd get the PLX. Everyone seems to agree it is as accurate as they get in this price range and don't have a gauge to bother with since you have dashlogic

pikkashoe

Just saw this thread:

https://www.corvetteforum.com/forums...endations.html

PLX set up and I could just hook it up to the Dash logic.
Anyone else experience what he mentioned in that thread, about slow response times?

telly444

get a seperate wide band gauge. its basically like you heart monitor. I couldn't imagine not having one after getting one installed. saved me many times when my fuel pump was dropping pressure.

pikkashoe

Telly, I have the Plx afr with dm6 gauge coming. Going to install this week.

realcanuk

I use a Zietronix ZT3 which I bought without a gauge and connected it to my aeroforce gauge. It has worked flawlessly for 3 years now and they have a very good reputation. Mine reads almost dead on to what the one on my tuners dyno does.
I suppose the new generation sensor might be better but see no problem with what I have for now.