Switched to 2 Bar OS, now car doesn't want to start

[gtstorey]

You could try plugging the values I posted above into you current 2 bar tune and see what happens. Decent chance it’s the correct numbers, although not 100%.

[blindsquirrel]

Those are not off enough to cause a no-start. I would be suspecting a defective sensor or not wired correctly. Plugging the known-good old sensor back in and using the known-good linear/offset that matches it would eliminate the physical items and leave only the changes made to the tune file as possible causes.

[gtstorey]

Those are not off enough to cause a no-start. I would be suspecting a defective sensor or not wired correctly. Plugging the known-good old sensor back in and using the known-good linear/offset that matches it would eliminate the physical items and leave only the changes made to the tune file as possible causes.

10-4. I wasn’t able to review his tune to see what values he had in.

[David94TA]

OK, so first of all, many thanks to everyone's input.

Reinstalled the 1 Bar map sensor and loaded in my NA tune. Car cranked right up and ran fine. Interesting side note--since the supercharger was reconnected, I had to go back and add fuel. Scanner showed that it was running a little lean throughout. I guess the air filter that I had placed on the intake when I had the supercharger disconnected was a little more restrictive than I thought it would be. Didn't do any heavy throttle runs, just normal driving and maybe holding it in gear a little longer. In any case, I added to the entire table and last scan showed pretty good afr throughout the mapped cells. Did not add back any of the fuel trims just yet.

Created a new 2 Bar OS tune but left the 1 Bar map sensor in place so as to not change too many variables. No luck. After loading the new 2 Bar tune in, car didn't want to start. Sounds like it wants to for a second, but never cranks up. So I'm stumped for now. Has to be something in the tune that I'm not seeing.

I'm posting the 1 Bar final tune and new 2 Bar tune if anyone wants to review and tell me what I'm missing.

Thanks

VE Tune Final.hpt

2 BarTune-1.hpt

[blindsquirrel]

Created a new 2 Bar OS tune but left the 1 Bar map sensor in place so as to not change too many variables. No luck.

screenshot.01-04-2023 13.08.26.png

If you plug in a MAP sensor that has actual linear/offset of 94.43/10.33, but in the tune file it says 200.00/10.33, then no, it's not going to start.

If you have the 1-bar sensor plugged in it has to use the linear/offset for that sensor - not the linear/offset that gets auto-applied when the OS is patched.

[David94TA]

Blindsquirrel, I misread your response in window #15--my apologies. Your last response cleared it up.

I left the 2 Bar OS in place, reinstalled the 1 Bar map sensor and adjusted the linear and offset values in the tune to what was correct for that sensor.

Car cranked right up. My luck to get a bad (brand new) 2 Bar map sensor.

Thanks for sticking with a noob.

Thank you all.

[blindsquirrel]

These days, every new electrical part should be assumed defective until proven otherwise.

[David94TA]

That's what my friend who works at an auto parts store says. He said the amount of returns is unbelievable these days.

[David94TA]

That is an old one. The data I can find online would indicate a linear of 201.9 per 5 volts and an offset of +2.3828. This is based upon data found here; https://sites.google.com/site/sloppy...identification
If this is correct, you should have a map value in the scanner with key on/engine off of less than 100kpa or 14.5psi.

You should be able to find this under an airflow tab.

You also might find a stock file for an early 2000's Grand Prix or Regal to compare this too.

Do you have a part number for a newer map sensor?

[Bill@HPTuners]

Those are not off enough to cause a no-start. I would be suspecting a defective sensor or not wired correctly. Plugging the known-good old sensor back in and using the known-good linear/offset that matches it would eliminate the physical items and leave only the changes made to the tune file as possible causes.

EXACTLY my thinking.

[Bill@HPTuners]

Blindsquirrel, I misread your response in window #15--my apologies. Your last response cleared it up.

I left the 2 Bar OS in place, reinstalled the 1 Bar map sensor and adjusted the linear and offset values in the tune to what was correct for that sensor.

Car cranked right up. My luck to get a bad (brand new) 2 Bar map sensor.

Thanks for sticking with a noob.

Thank you all.

Awesome, renews my faith in my minimal diagnostic ability

[blindsquirrel]

Do you have a part number for a newer map sensor?

What pressure range do you need? You can use any sensor with any OS as long as the linear/offset are correct for the physical sensor. Connector pigtails are readily available for everything. The Cobalt SS BARO sensor is pretty common, linear/offset of 200.00/8.00. Or the LSA/LS9 3-bar, though that one is harder to adapt to a hose-style vacuum source, though not impossible.

[David94TA]

Just 2 bar. I'll be running about 9-10 pounds of boost. Prefer one that just replaces my stock map on my LT1 manifold.

[blindsquirrel]

https://www.rockauto.com/en/moreinfo.php?pk=87029

[David94TA]

Thank you!