Won't start, what am I missing?

[Curby50]

All,

I have a stock LS2 (2005 GTO) except for a decent sized street NA cam. Car ran great until I recently made the following mods: Holley Lo-ram intake, Nick Williams 103mm TB, 3 bar MAP sensor (only one available at the time to work with new intake), and 42lb Holley injectors.

Car ran for about 5 seconds on initial fire up after the mods were made. No abnormal mechanical sounds to indicate mechanical failure. Car just continues to spin without trying to fire. Here is what I have done so far:

Replaced cam sensor
Replaced crank sensor
Confirmed I have spark and fuel pressure
Set Flow Rate vs Pressure table to 42lb injectors (just to get them in the ballpark...down and dirty)
Set ETC Area Scalar to 7298 (pi x 51.5 x 51.5) - (103 x 10) = 7298
Set MAP Sensor Linear to 305

Let me know where else I should be looking to get this thing to fire.

[eXo3901]

Scalar should be closer to 6317.

Holley injectors (522-428) are rated at 43psi. If you are running 58psi, you need to adjust the flow rate for that. The whole table will not be the same value if you have a stock fuel system, it will will have slope like the stock table does. I have never seen HP Tuners data for Holley injectors (never really looked for it either), so maybe think about getting different injectors with specific data for HP Tuners.

For starters, if KOEO MAP does not equal your local BARO the data input is wrong. Try to track down actual Offset, Scalar, Linear data for the sensor. Or fudge it for now if you want to get it idling. Why can you not run the stock MAP sensor temporarily?

[Curby50]

Scalar should be closer to 6317.

Holley injectors (522-428) are rated at 43psi. If you are running 58psi, you need to adjust the flow rate for that. The whole table will not be the same value if you have a stock fuel system, it will will have slope like the stock table does. I have never seen HP Tuners data for Holley injectors (never really looked for it either), so maybe think about getting different injectors with specific data for HP Tuners.

For starters, if KOEO MAP does not equal your local BARO the data input is wrong. Try to track down actual Offset, Scalar, Linear data for the sensor. Or fudge it for now if you want to get it idling. Why can you not run the stock MAP sensor temporarily?

Thanks for the quick response eXo!

You are correct that I am running ~58psi for fuel, so I'll adjust those parameters. Regarding the Scalar, where did I go wrong on my calcs? Is the butterfly that much more restrictive?

Regarding the MAP, you are correct, I could run the stock unit temporarily to get it fired up with one less variable. I had to go with a new one because the stock unit is a clip on style whereas the new intake requires a bolt on style. I'm outside Atlanta at ~1100 feet, so BARO shouldn't be radically off I wouldn't think.

Thanks again!

[eXo3901]

There are a bunch of different values people use. You may end up needing something different.
Stock 90mm TB: (pi*45*45)-(90*10) = 5462
New 103mm TB: (pi*51.5*51.5)-(103*10) = 7302
Ratio New/Stock: 7302/5462 = 1.33687294
Reference stock scalar adjusted by ratio: 4725*1.33687294 = 6316.72

It would probably be easier to just use the stock MAP sensor with the stock sensor data for now. A hose barb fitting, some vacuum line, and small hose clamps should work for now.

Also, you should post the tune and a log trying to start the car so others can help.

[Curby50]

Thanks again eXo for the quick response. I see what you mean with the different TB area calcs. I'll figure out a way to rig up the stock MAP to get the car to fire along with updating the TB area scalar and the injector flow rates.

Below are links to the current tune and a data log of the car cranking. The data log is on the original tune not the current one because I didn't get a log when I cranked with the new tune.

Tune:
https://1drv.ms/u/s!AmAMRfcA5ju3iGqX...GMTD5?e=LYVdS0

Log:
https://1drv.ms/u/s!AmAMRfcA5ju3iGs4...8KlDe?e=eZsbWF

Thanks again for the assistance, I truly appreciate it.

[Curby50]

Below are links to the updated tune and log of the test fire after downloading the tune. It wanted to fire "slightly" more than previously...I could hear a cylinder or two lighting every other revolution or so whereas on the last couple tunes it would only fire a single cylinder every 3-4 revolutions.

I didn't put the stock MAP sensor back in yet, that is a project for the weekend. Let me know if you guys see anything in the files or have any other suggestions. All input is appreciated.

Tune:
https://1drv.ms/u/s!AmAMRfcA5ju3iGy3...MvkzD?e=kngR0L

Log:
https://1drv.ms/u/s!AmAMRfcA5ju3iG3_...dJVuf?e=hZbbZn

[eXo3901]

This is not a 2005 GTO, is it? Glad I ASSumed it was... Hopefully smarter people can chime in, I do not have experience with GMPP stuff. This is mostly low hanging fruit. (The MAP and flow rate stuff)

You have a GMPP E67 running an LS2 pulled from a 2005 GTO and then swapped into something else. The LS2 is allegedly stock except for a NA cam and ran before the new mods.
-When it did run, was it still in the 2005 GTO?
-Did you change the LS2 from 24x to 58x?
-Where you using the stock MAP sensor from the 2005 GTO or do you have an LS3 MAP sensor? The original MAP data in your tune suggests the former. The GMPP instructions I found call for the latter on the presumption the tune would not be altered. Should be a non-issue as long as the correct data is entered.
-Your BARO at KOEO is 90KPa. ATL area should read 96KPa-99KPa. Not sure if that is related to your MAP sensor situation or not.
-Your MAP now shows 117KPa at KOEO. I did some searching and the Holley MAP sensor might just be basic GM 3bar sensor? Not really sure... Maybe try Linear 315 and offset .34. Again, KOEO MAP should equal BARO, if BARO is accurate. So, if you have a newer cell phone, download a BARO app and compare.

When I said the flow rate table should look like stock, I was thinking this was a GTO tune. Your stock table on the GMPP tune is not what I was picturing in my head. Since we have no injector data for Holley injectors, go to your flow rate table:

1. Expand the decimal points to 3 places.
2. Set the lowest KPa column to 29 lb/hr.
3. Set the 400Kpa column to 49 lb/hr.
4. Set the highest KPa column to 59 lb/hr.
5. Select from 29 lb/hr to 49 lb/hr and click the interpolate button.
6. Select from 49 lb/hr to 59 lb/hr and click the interpolate button.
7. You should have a sharp transition at 400KPa and 400KPa should still show 49 lb/hr.
8. Now, select the entire table and click the smooth button until the 400KPa column shows ~48 lb/hr. It should only take a few smoothing clicks.

We do not have voltage offsets or short pulse information so those should remain as is.

Log some additional channels also, like Injector pulse width, Injector flow rate, cylinder airmass/pressure ratio, dynamic airflow, volumetric efficiency, timing sources, cranking related stuff, torque related stuff, coolant temp, manifold air temp.

[Curby50]

Exo, thanks again for you response and at this point patience!

You are correct, it is not a GTO, the engine and trans were pulled from an '05 GTO with only 5 miles on it back in '06, and put in a 1963 Splitwindow Corvette with an SRIII tube chassis to accept the drivetrain and C5 Corvette front and rear suspension. It is running a stand alone GMPP harness and ECU (E67). It was running very well after being initially tuned in 2010/11 (can't remember exactly), made ~390 hp at the wheels and has ~5k miles on it since then. When it was tuned the intake and TB were swapped for ported units (a custom cam, long tube headers, and 3" duals with x-pipe were all initially installed and still on the car). Apparently at the same time the injectors where switched to 36 lb "truck" style injectors (taller). Original MAP part # is 16212460 42752, new MAP part number is 12592525 Chevy Perf 3bar.

My local BARO is 101.7KPA. I'll dig up the 3bar conversions and compare that to what you have recommended.

I'll update the injector values and do the smoothing as you recommend as well as add the additional channels to log.

Thank you again for your input and time, it is greatly appreciated. I am a competent shade-tree mechanic, and fairly computer savvy, but new to the tuning game...I agree that what I am dealing with should be relatively low hanging fruit, but also don't want to bury people with way to much info.

[blindsquirrel]

2005 GTO LS2 had a 24x crank reluctor. E67 will only work with a 58x crank reluctor.

I think the question is, did it ever run with the E67?

[Curby50]

I meant to respond to that in my last post….The motor was converted to a 58x reluctor and has been running on the E67 for the past 10+ years.

James

[FASSTRUK]

Are you able to check for codes with just the ignition being on?

[Curby50]

Are you able to check for codes with just the ignition being on?

Unfortunately it?s not throwing any codes at the moment?

[eXo3901]

Original MAP part # is 16212460 42752, new MAP part number is 12592525 Chevy Perf 3bar.

My local BARO is 101.7KPA.

That seems high unless you are below sea level. Local needs to be station pressure.

Quick search on these forums for #12592525 returns numerous threads stating MAP data to be: Linear = 312.5 Offset = -11.25