07 Z06 long term fuel trim issues

[Guy With A Chevy]

I think its fair to say edcmat was trying not to mislead people in general with the scanner fuel pressure values but thanks for some of the info smokeshow always on point and spicy

[blindsquirrel]

There is no fuel pressure PID in that log. The PID that IS there, does not mean that it is delivering 63.5 lb-hr. It is simply looked up from the pressure delta table.

screenshot.25-09-2023 21.42.24.png

[Camaro68]

Here is another scan a few minutes after the one in OP that shows fuel pressure. If that is not correct, please let me know.

Jon

[blindsquirrel]

It's a known issue that the 'fuel pressure' PID is not an actual measurement from the FPCM's sensor. It's not live data.

[Camaro68]

Thank you for the clarification blindsquirrel and your input to this thread.

We will be putting a pressure transducer at the fuel rail to check fuel pressure. Weather is really wet here now so replicating the fault condition may take awhile.

Thanks to everyone for their help with this problem.

Jon

[edcmat-l1]

I think its fair to say edcmat was trying not to mislead people in general with the scanner fuel pressure values but thanks for some of the info smokeshow always on point and spicy

Yeah that guy LOL

[edcmat-l1]

People can use this
eBay item number:364492084876

0-100psi 0.5-4.5v Pressure sensor

Bring into EGR just like a wideband, 0-5v signal , analog offset in maths to calibrate

They can also do this with 0-300psi sensor for the transmission pressure to log wideband, fuel press, and trans pressure

Never say something can't be done because there is always a way

Everything up to an including the post of mine you quoted, was in reference to the vehicle not having a factory fuel pressure sensor. Please try to keep up.

[blindsquirrel]

A loggable-type electronic sensor is not a substitute for verifying the rail pressure with a mechanical gauge, like everybody else in the world does when diagnosing a possible supply pressure issue. A mechanical gauge does not need any math, or transforms, or conversion before it tells you what the pressure is. You screw it on and the needle tells you what it is and then you fix stuff.

[blindsquirrel]

And did I see someone confuse smokeshow for... that other guy? How is that even possible? I must be missing a joke somewhere, please tell me I'm just missing a joke somewhere.

[edcmat-l1]

A loggable-type electronic sensor is not a substitute for verifying the rail pressure with a mechanical gauge, like everybody else in the world does when diagnosing a possible supply pressure issue. A mechanical gauge does not need any math, or transforms, or conversion before it tells you what the pressure is. You screw it on and the needle tells you what it is and then you fix stuff.

I totally agree even the cars with factory sensors get a mechanical gauge to the rail and taped to the windshield, and it stays there until completed. Do the same thing, the same way, every time, without fail and you'll have repeatable results.

[edcmat-l1]

And did I see someone confuse smokeshow for... that other guy? How is that even possible? I must be missing a joke somewhere, please tell me I'm just missing a joke somewhere.

I guess I'm late to the party. Don't know a smoke show but that kind of describes a couple guys on here.

[blindsquirrel]

https://forum.hptuners.com/showthrea...ynamic-airflow

Compare that to the other one's posts and you'll see why my gob was so smacked by someone mistaking one for the other. Polar opposites.

[edcmat-l1]

LOL I love the guy's sig that's for sure LOL

[Alvin]

In case anyone hasn't noticed.. If the vehicle came with a FPCM or at least a FP sensor than the PID will log like it should. Else it just reports what the fuel pressure is defined to be.. It will always read 58 psi on these. If he was logging it anyway.


I agree to check fuel pressure. And there are times will fuel pumps will only act up when they get hot. Especially if you have little gas in the tank.

[blindsquirrel]

Sure have been a lot of threads where there was a FPCM and a sensor and the pressure reading sat there and did nothing related to actual pressure.

[Alvin]

Sure have been a lot of threads where there was a FPCM and a sensor and the pressure reading sat there and did nothing related to actual pressure.

Might have been the wrong pid. I use it often... like daily. Seems to work as expected. But this year Z06 did not have either for sure.

[edcmat-l1]

Might have been the wrong pid. I use it often... like daily. Seems to work as expected. But this year Z06 did not have either for sure.

I don't think any C6s had either with the exception of ZR1s.

[Alvin]

I don't think any C6s had either with the exception of ZR1s.

Yes...

Also most GEN4 trucks do not.. some do.

[edcmat-l1]

Yes...

Also most GEN4 trucks do not.. some do.

I started seeing a lot of them in 12s and 13s (trucks) like right before they switched over to GEN5. Not sure if that was the reason or what just started noticing a lot more had them.

[obthomas]

There is no fuel pressure PID in that log. The PID that IS there, does not mean that it is delivering 63.5 lb-hr. It is simply looked up from the pressure delta table.

screenshot.25-09-2023 21.42.24.png

Blindsquirrel

I have been following posts about fuel injectors for a while and have a sense that of all the tuners on the forum you may be most proficient with fuel injectors. I have a question for you. If the car and ECM have no sensor to monitor fuel pressure then it most likely has to work from the flow rate versus pressure table. It follows that the ECU most likely can go up and down the table within limits.

Using the HP Tuners conversons, injector calculator, changing pressure changes flow based on the orifice formula Q=CD(sqrt P).

I concede that there are several offsets possible but most of the offset tables in my tune contain Zeros or small multipliers.

In my ECM I have specified the fuel pressure to be 55 psi at all times. How does the ECM calculate a new fuel pressure and flow that is outside the range of 55 psi plus or minus offsets?

Regards,
O.B. Thomas