Help With First Start on a 911 Swap

[lowlow4g64t]

Back again after some help with my previous swap on a Gen3 car.

I bought the PCM online and made some of the basic changes I could remember for VATS and then changed the injector (85lb injectors) data and MAP (3bar MAP) data. The Gen3 to Gen4 stuff looks considerably different. I was just hoping to get it started to confirm no engine issues before having the rest of the turbo hotsides made and then sent off to be actually dyno tuned.

It is a GEN IV 5.3. It has an LS9 cam with supporting valve springs. 85lb injectors. Radium FPR set to 58psi. LS2 intake manifold. Gold Blade throttle body.

I do not have a MAF, so i did the MAF fail settings, but I do NOT get the P103 CEL when i read in the scanner. The VVE instead of VE tables have me way over my head, but was hoping you guys could help get me to at least get the car to idle.

The car cranks, will sputter once like its catching, then nothing.
The car has right at 58psi from the radium FPR.

With the Scanner, a couple things i noticed that didnt seem right.
TPS sits at 28% with KOEO... if i put the pedal to the floor it only goes to about 85%. Not sure if thats relevant, as one thread I read said that PID could read that way.

the MAP sat around 85kpa with KOEO.

The injector PW in the scanner never changes from zero.

Tried to provide all pertinent information in the first post. And of course, the "tune"

Again, any help is appreciated, THANKS!2.4.FLASH.INJECTOR VOLTAGE.NEW.MAP.DATA.hpt

[blindsquirrel]

What '85lb injectors'? Part number? Do you have complete data for them in GM format? If you do, why is the sheet not posted here?

At Engine Diag > Airflow, you still have a 300 RPM & 400 count threshold before the MAF fails out, best to change those to something less than cranking RPM, and 1/1 counts so it fails ASAP.

Are you checking for the P0103 by looking in the logs afterward? Because the MAF codes only appear in the 'Details' tab of a saved log after the second run cycle. You should log the PID for Mass Airflow Sensor State, that will tell you in real time.

[blindsquirrel]

58psi from the radium FPR

And is there a vacuum hose from the manifold to the top of the regulator, or is it being used 'non-referenced' style with no hose, as your injector data would suggest?

TPS sits at 28% with KOEO

Normal, because the throttle blade does not close to 0% basically ever, except as a position check at initial key-on.

if i put the pedal to the floor it only goes to about 85%

Probably because you probably used the generic SAE PIDs for the throttle stuff. Don't. Use the non-SAE for GM Gen4 throttle PIDs.

the MAP sat around 85kpa with KOEO

It'd help a bunch if you could give a general hint as to what part of the world you're in. Like altitude. Could be totally normal if you're in Denver, not so much if you're in Pensacola.

The injector PW in the scanner never changes from zero

Did you do Write Entire the first time after you disabled VATS?

[lowlow4g64t]

What '85lb injectors'? Part number? Do you have complete data for them in GM format? If you do, why is the sheet not posted here?
Dont kill me for this, but FAST Injectors. I later realized they do not provide injector data apparently. I used a reference from someone with them that was able to get their car to run. I will most likely end up changing these, I assumed FAST wasnt so shit in this aspect, but I was wrong

At Engine Diag > Airflow, you still have a 300 RPM & 400 count threshold before the MAF fails out, best to change those to something less than cranking RPM, and 1/1 counts so it fails ASAP.
Got it. Changed the RPM to 50. Changed the counts to 1.

Are you checking for the P0103 by looking in the logs afterward? Because the MAF codes only appear in the 'Details' tab of a saved log after the second run cycle. You should log the PID for Mass Airflow Sensor State, that will tell you in real time.
I checked using the Vehicle>Diagnostic drop down in the VCM Scanner. Ill add that PID


And is there a vacuum hose from the manifold to the top of the regulator, or is it being used 'non-referenced' style with no hose, as your injector data would suggest?
It is non-referenced currently.



Normal, because the throttle blade does not close to 0% basically ever, except as a position check at initial key-on.



Probably because you probably used the generic SAE PIDs for the throttle stuff. Don't. Use the non-SAE for GM Gen4 throttle PIDs.



It'd help a bunch if you could give a general hint as to what part of the world you're in. Like altitude. Could be totally normal if you're in Denver, not so much if you're in Pensacola.
Sorry, Im in Indiana.



Did you do Write Entire the first time after you disabled VATS?
Yes sir, I did the VATS patch 1 & 2 then Write Entire. Since then Ive just done Write Calibration

Just did a quick flash with those, it still just does a quick catch and then nothing. Just enough to know there was combustion for a second, but then immediately stops.

[blindsquirrel]

What's the part number on the MAP sensor?

Does it run if you spray it with brake/carb cleaner? That should be the #1 very first step in a cranks-no-start. Jut make it run. If you can do that it rules out a bunch of stuff you don't have to waste brain cycles on anymore.

[lowlow4g64t]

What's the part number on the MAP sensor?

Does it run if you spray it with brake/carb cleaner? That should be the #1 very first step in a cranks-no-start. Jut make it run. If you can do that it rules out a bunch of stuff you don't have to waste brain cycles on anymore.

12614970 but it also says 3 bar on it.

yeah it really felt like fuel supply was the issue. i dont have any cleaner, will probably try this through the week.

[blindsquirrel]

That is NOT a 3-bar sensor, if that part number is what it really is. What is it, where did it come from? Is it some aftermarket thing with different innards inside a 1-bar housing?

[blindsquirrel]

Is there a reason why there is no log file posted yet?

[lowlow4g64t]

That is NOT a 3-bar sensor, if that part number is what it really is. What is it, where did it come from? Is it some aftermarket thing with different innards inside a 1-bar housing?

The latter is what I was told and it was on the engine. Thats why I questioned the 83kpa reading with KOEO. If that seemed right, then I was going to look for issues elsewhere, if its not, then Ill just replace it.

Ill have a log file posted tomorrow. I spent most of the day trying changes with the "tune" to see if it would start. Ill record one tomorrow and have it posted.

[blindsquirrel]

83 kPa is not correct for, what, 800ft elevation?

If it really is a 12614970 and hasn't been monkeyed with inside then the linear/offset should be 94.43/10.33. If someone modified it with a new sensor element I don't know why it would still have the GM number on it anywhere, because it'd no longer be that part.

[lowlow4g64t]

EFI Source is where the MAP came from... with this info I updated the MAP info in the tune, tried to crank and now it doesnt act like it wants to fire at all. However, I noted the voltage was only at like 10v while cranking as well... So we'll be getting a new battery tomorrow :facepalm:

Ill get the new battery in and try again from there. Im still not getting the MAF showing as failed though.

2.6.CORRECTED.MAP.SENSOR.DATA.hpt
LOWVOLTAGELOG.hpl

[gtstorey]

Get a good known source GM Map sensor. This stuff is too hard to do to mess around with unknown senors.

[Alvin]

2.6.CORRECTED.MAP.SENSOR.DATA.2.hpt

Try this.. Do a Write entire with it.



Is the cam sensor stuff all ok? The little jumper harness that comes on GEN 4 has some pins switched around on it. IF you plug directly ino the cam sensor you'll have a cam sensor issue.

Traditionally if you have a bad cam sensor the car will start at least every OTHER time but I've ran into several GEN4's that act like a vats issue with a cam sensor issue. It fires and quickly shuts off.

[edcmat-l1]

The injector PW in the scanner never changes from zero.

This right here sounds like you didn't do a "write entire" after you disabled the VATS system.

And the voltage is way too low in your data log.

[obthomas]

you probably need to disable the starter diag and starter fault items as part of the VATS disable.

[lowlow4g64t]

Get a good known source GM Map sensor. This stuff is too hard to do to mess around with unknown senors.

I have the one referenced from EFI Source, I do not believe the MAP to be the issue, with the correct data in it is reading correctly it seems.

2.6.CORRECTED.MAP.SENSOR.DATA.2.hpt

Try this.. Do a Write entire with it.



Is the cam sensor stuff all ok? The little jumper harness that comes on GEN 4 has some pins switched around on it. IF you plug directly ino the cam sensor you'll have a cam sensor issue.

Traditionally if you have a bad cam sensor the car will start at least every OTHER time but I've ran into several GEN4's that act like a vats issue with a cam sensor issue. It fires and quickly shuts off.

I tried that one, it runs for like 2 seconds now. I bought cam sensor extension that should plug directly into the cam sensor (not into the little harness in the bracket) so I "think" this is done correctly and didnt need to swap any wires. However, what youre describing makes sense and sounds like whats happening. With the way its running now, it sounds like something is shutting the car off. It does NOT sound like its too lean or rich and kind of sputtering then dying (i had this when i was tuning my RX7 with a Gen3 PCM).

This right here sounds like you didn't do a "write entire" after you disabled the VATS system.

And the voltage is way too low in your data log.

I definitely did the write entire. But as I mentioned above it sounds like a VATS issue, I 100%. Because it sounds like its being "shut off", not like its sputtering then dying.
I 1000% agree with the voltage thing. Ill finally have the battery tomorrow, I posted the tune to see if someone could show me what i may have missed in the tune.

you probably need to disable the starter diag and starter fault items as part of the VATS disable.

As stated above, this was definitely an improvement. My current concern is the MAF is STILL not pushing the P0103 code. So I dont think Ive failed the MAF properly. I watched a video with the steps, but obviously Ive botched something there.

[blindsquirrel]

I still wouldn't trust a MAP sensor that was marked as '3-BAR' but still had the original sticker on it.

Try 2/1 instead of 0/0 for MAF Fail High/Low.
Put the stock numbers back in the MAF table, not the 12.5/0/0/0/0[...] it has now.
Add this PID to your logs:
screenshot.09-02-2024 21.01.21.png

[blindsquirrel]

And... when you've changed stuff, and it still doesn't work or does something different, post a new log showing it doing/not doing the thing with the new settings. With only an older log to look at from however many changes ago it leads people like me to make guesses and suggestions that may no longer apply. Please provide the information we need to help you.

[lowlow4g64t]

I still wouldn't trust a MAP sensor that was marked as '3-BAR' but still had the original sticker on it.

Try 2/1 instead of 0/0 for MAF Fail High/Low.
Put the stock numbers back in the MAF table, not the 12.5/0/0/0/0[...] it has now.
Add this PID to your logs:
screenshot.09-02-2024 21.01.21.png

Sorry, forgot to correct this earlier in the thread when you mentioned it. It does not have the oem sticker on it. Its a blank, black plastic top that has that part number (i believe to note which vehicle fitment it is) and also "3 bar" printed on it.
Not sure how important it is, but the first 5 cells of the MAF table were negative numbers on my OEM read of the PCM, but it wont let me put those values back in as it says 0 is the lowest range... so i just put those first five cells as "0"
Added that PID.

And... when you've changed stuff, and it still doesn't work or does something different, post a new log showing it doing/not doing the thing with the new settings. With only an older log to look at from however many changes ago it leads people like me to make guesses and suggestions that may no longer apply. Please provide the information we need to help you.

Yeah that makes sense. I tried to start the car twice with those changes. I also made a few other changes that I found on a "failing the MAF" video.

Im still a little unsure why the car thinks its going 158mph :facepalm:
The injector data looks a little odd, says theyre at like 100+lb/hr of flow which should be wrong. However, the car still feels like it is being shut off, not like too much fuel then dying. Im probably going to have to sell these FAST injectors though, them not supplying injector data is mind boggling to me.

I did note the PID you had me add, still shows the MAF as NOT being failed. Not sure what Ive missed there.
2.10.CHECKING.MAF.FAILURE.hpt
MAFFAILTRY2.10.1.hpl
MAFFAILTRY2.10.2.hpl

[blindsquirrel]

Unknown injector data, and a questionable MAP sensor, and it's a crank/no-start. Amazing. There are too many known-unknowns here left unresolved to be able to diagnose any of the unknown-unknowns that come with an everyday no-start in a swap vehicle. You have a real nightmare here and I do not envy you, I would walk away from one like this in a hot second if someone tried bringing it to me. You need to take a step back and go through this thing and get rid of anything that shouldn't be there. I am sorry.