Does HP Tuners Offer Access to These Engine Parameters???

[GrannySShifting]

Can break out wiring and set up for a stand alone baro sensor so its always sampling

[pannetron]

OK, now to find a wiring diagram for my E67 and hope that the crate engine OS (12638778) has code to sample a separate baro sensor.

[GrannySShifting]

OK, now to find a wiring diagram for my E67 and hope that the crate engine OS (12638778) has code to sample a separate baro sensor.

I would THINK it would have to be set up with the Supercharged Fitted switch set to yes maybe a couple other, and CTSV/ZL1 wiring diagram should tell you what you need. It is a funky OS though so....

[pannetron]

Thanks! I found E67 pinouts and a part number (12591290) for an ACDelco baro (aka MAP) sensor. I don't see a table for baro sensor cal values in HPT so I'll assume that the OS is expecting an OEM sensor and it hopefully will work.

[NotSure]

Good luck with wiring one in separately, maybe the crate motor OS has a provision? I have the E38 in a Yukon, same ecm as the cts-v and Camaro, and the pinouts for map OR baro are completely different from my truck's map (doesn't have separate baro), as in not even in the same connector. I would bet that it has to be turned on in the OS as well. For now I have fudged the lower right numbers in the baro fuel multiplier chart (forget the name) so that when it readjusts to 103 kpa after a boosted WOT, it doesn't skew the fueling from my actual 98 kpa. I put 1.0 in those cells, the ones at operating temp and at or above my typical true atmospheric pressure seen in my area. I believe the chart was ECT vs Baro. Not the best, but the only way I came up with.

I mis-spoke, looks like the N/A Camaro uses the E38 but the same year with LSA uses the E67.

[pannetron]

Thanks. I wouldn't sweat the baro sensor except that here in Colorado, I routinely drive between 5,000' and 11,000' elevation so my ambient air pressure varies a LOT! Fortunately the O2 sensors and closed loop control adjust for the worst of it! Still beats tuning a carb out here!

[NotSure]

So I changed my "Supercharger Fitted" to Yes this morning, and the baro stayed at 90 kpa for the whole log, before and after a WOT, though I was not logging with the engine off to see if it was a map issue. Weather says it is 101 kpa here today. WTF. As far as I know the E38 isn't used in any boosted applications, so I don't think I can add a pin for a separate baro.

[NotSure]

I tried it again on key up with "Supercharger Fitted" = Yes, baro was 90 kpa. Put it back to "Supercharger Fitted" = No, and baro was 98 kpa on key up. Just an oddity I thought others should be aware of. E38 ecm, not E67. Still, looks like I am screwed with the baro updating to 103 kpa after a boosted WOT, and have to resort to fudging my baro fueling adjustment table, under Engine/Airflow/Dynamic/VE Correction Factor-Initial. I put 1.0 in baro columns 95,100,105 kpa for 159.8F ECT and up.

There is also something else weird going on. I tried adjusting my map offset to get the baro in line just for grins, and that got it to 100 kpa key on engine off instead of 98 kpa, but after a short bit of driving it updated baro in the log to 100.5 kpa even though I never went over 22% accel pedal or 45 kpa map during that time. Then later in the log (same drive cycle) it updated the baro to 102.5 after hitting 145 kpa map and 83.6% accel pedal peak (not throttle position, just what my foot was doing), then later it updated the baro yet again to 104 kpa after hitting 128 kpa map at around 53% accel pedal, so that is 3 updates and I never hit WOT at all for the whole drive cycle/log. I don't know what is going on inside that E38 brain. I'll just leave my fudged VE Correction chart as it is and stay out of the mountains, I guess.

[pannetron]

I tried this again with Supercharger fitted and not fitted. My local atmospheric pressure is typically 75 kPa, which it was this morning. With the "not fitted" setting, I logged 75 kPa, which was correct. With the supercharger "fitted", I logged 90 kPa and it never varied throughout my drive. With supercharged set to not fitted, my log shows the recorded value starting out at 75 kPa and ratcheting upward to 81 and then 82 kPa as the blower built some boost and ended up at 105 kPa, even though I never went WOT at any time. Once latched upward, it didn't seem to come back down until a key off, key on transition. But I never opened the throttle fully so maybe the ECU only latches lower pressures at WOT?

I ordered a MAP sensor and connector and will wire it into the ECU as the "supercharger inlet air pressure sensor" to see if it behaves as desired with the supercharger "fitted" setting. My ECU is a E67 for a 430 HP crate engine with a custom tune on the OEM 12638778 OS . Will report back after wiring it in...

[07GTS]

have u guys enabled the "manifold vacuum/boost" patch ? it may or may not help but just came to mind as a test

[NotSure]

have u guys enabled the "manifold vacuum/boost" patch ? it may or may not help but just came to mind as a test

I did, but am not really clear as to what that does. Says it is to allow the injector flow rate table read into boost, but I applied this patch right from the start (the day I bought the truck, lol), months before I boosted it.

[pannetron]

My crate OS has tables appropriate for boost and big injector flow rates so I decided against "upgrading" it. And my usual drives cover almost 5,000' elevation changes so I'm hoping wiring in a real inlet air pressure sensor will be good to track my significant ambient baro changes.

[pannetron]

re: post #49 -- I wired in a "supercharger inlet air pressure" (SCIAP) sensor and now my "barometric pressure" PID agrees with my actual barometric pressure, typically 75 kPa. No idea yet if this additional sensor input will make any difference in the ECU's calculations but I feel better now that the data point is at least correct instead of stuck at 90 kPa. And it was a good garage project for a rainy day :-) Here are the part numbers I used:

sensor: A/C Delco 213-4681, GM 55573248
connector: A/C Delco PT2798, GM 13585850
ECU connector pins: Molex 334680002 (for 22 AWG wire, 334680003 for 22 AWG)

The sensor's signal lead (pin 3) goes to pin 46 of the 56 pin (blue) connector on my E67 ECU. I used ECU connector pin 9 for the sensor low reference (sensor pin 2) and ECU pin 34 for 5V reference (sensor pin 1). ECU pins 9 and 34 are defined for a CTS-V "fuel tank pressure" sensor but were unused in my GMPP crate engine harness blue connector. Doing surgery on the ECU's connector was fussy but doable. I'd operated on another connector years ago to wire in the "reverse lockout solenoid control" for my T56 Magnum so I still had some notes on how to dissect the connector.

In VCM Editor, I set Airflow->Supercharger->Fitted to True, Sensor Linear to 128.13, and Sensor Offset to -0.13 for the sensor I used. Hope this helps!

But now I'm wondering if this sensor should be measuring ambient barometric pressure or s/c inlet air pressure *behind* the throttle blade? That would make it read engine vacuum at idle and light cruise up to (almost) ambient baro at WOT. There are other inputs for a baro sensor but VCM editor doesn't show that PID explicitly. Do I need a baro sensor *and* the SCIAP sensor?

One of you senior tuners out there must know the real deal on the SCIAP and actual BARO sensors and what they're used for in ECU calculations?

[pannetron]

Follow up to my SCIAP sensor -- sorry if I've totally thread jacked this! I plumbed the sensor into the supercharger inlet behind the throttle vs. open to the atmosphere. The barometric pressure PID still reads my correct ambient atmospheric pressure and does not vary with the s/c inlet air pressure changes. From reading other (Gen V) threads, I believe this is now the correct plumbing for this sensor and that the ECU must be smart enough to record barometric pressure from the SCIAP at key on and engine not running. So maybe a separate baro sensor is unnecessary? Now to do some driving and logging...