Gotta be something I'm missing

[neps_automotive]

Hey guys and gals... trying to get some help here... I've scoured the forums hoping to find a solution, but I think this is the only way to go at this point. A little bit of background about me: I run a small auto shop and I specialize in LS swaps, rebuilds, and performance stuff... I recently got into tuning as its so difficult to find good tuners here in MI, and I hated having my customers have to wait to get their newly swapped LS stuff while I'm trying to find or waiting for a tuner. So, here we are. I'm a beginning tuner, and I think for the most part I understand the directions I need to take due to reading, and Goat Garage's YouTube videos, on top of doing my own research and paying for a few beginning tuning courses. Ultimately, I'd like to maybe find someone who can kind of show me some of the deeper ins and outs (and I'd have no issue paying for your time also), but in the meantime, trying to get this LS swap outta here.

So, off to the specs. Gen IV 5.3, with a BTR Stage 3 cam, everything is brand new, timing is right on spec, fuel pressure is 58psi. AC Delco Sensors for all the importants (cam, crank, oil pressure, MAP). Engine has been completely rebuilt down the mains, using an E38 Corvette computer, with a 700r4 trans. It's sitting in a 90 Caprice. Crazy thing is, I was able to get it to run 2 or three times for about 45 seconds while I was trying to dial everything in, then it just died. I haven' been able to get it started since. After it first ran, it would fire and run for about 3 seconds and shut off. VATS has already been disabled. I'm posting the latest tune file, hoping to get some insight. As I said, I have no issue paying for a little bit of tutelage, so let me know if anyone out there would be interested. I also have no issue paying anyone who would help me dial in this tune if necessary. As I run a shop, and do it all, I know how precious time is. I'm uploading the most recent tune (as I have 6 drafts). Thanks wonderful people...

[TheMechanic]

Did you do a write entire when you disabled VAT's and you forgot starter fault checks. Disable that

[neps_automotive]

I did indeed my friend. I did a full write this time with the Start check disabled. Still nothing.

[TheMechanic]

Hook up the scanner. Verify cranking RPM.
Verify MAP KOEO is above 90kpa 98-100 is usually about right depending on altitude.
Verify Throttle is closed or below 15% or so.
Check for battery voltage on supply side of injector harness.
Let me know the results

[Alex14SS]

I had the same issue with my swap on my Camaro; my issue was the injectors making it crank for a bit and then fail. Since you have a bigger cam you may need to revisit air/fueling and see where you can fix it. Have any logs?

[neps_automotive]

Hey Alex14SS... thanks for the info. I didn't log anything as I couldnt get it started, but I definitely will. I'll upload a log tomorrow. TheMechanic, thanks for all your help my friend... I got sick there for a couple of days, so I was down... this damn Michigan weather has been the absolute worst. We broke a record for the coldest temperature in June the other day. Our high was like 58... in freaking June. Voltage is between 11.6-11.8. Cranking RPM is good, between 160-195. Throttle is at 0% (unless of course I press it). The battery was trash, got a new one in there now... I am getting a backfire thru the exhaust currently. Im definitely thinking I need to revisit air/fuel, but I'm not sure where to adjust currently.

[TheMechanic]

Hey Alex14SS... thanks for the info. I didn't log anything as I couldnt get it started, but I definitely will. I'll upload a log tomorrow. TheMechanic, thanks for all your help my friend... I got sick there for a couple of days, so I was down... this damn Michigan weather has been the absolute worst. We broke a record for the coldest temperature in June the other day. Our high was like 58... in freaking June. Voltage is between 11.6-11.8. Cranking RPM is good, between 160-195. Throttle is at 0% (unless of course I press it). The battery was trash, got a new one in there now... I am getting a backfire thru the exhaust currently. I'm definitely thinking I need to revisit air/fuel, but I'm not sure where to adjust currently.

Yikes 58 as a high. Must be global warming.
It is pretty cold here in Coronado too. It will be 71 sunny with a slight onshore breeze.
Maybe pin out your injectors real fast and make sure you don't have any swapped injector pigtails. Also I would pick up a noid light for verification of injector drive. They are cheap and very effective for diag purposes. Last is 11.6 should be during cranking I hope. If it is your current voltage with KOEO then that is bad.

[blindsquirrel]

92*/74% humidity here yesterday (State Motto is 'That's not sweat, it's condensation'). Before the regular afternoon tornadoes rolled through, at least. Looking forward to a few weeks from now when overnight lows will be in the mid 80s with 100% humidity. Nothing like getting heat stroke at night.

But sure, if it still gets cold anywhere, then that proves scientists are lying.

[Alvin]

Hey guys and gals... trying to get some help here... I've scoured the forums hoping to find a solution, but I think this is the only way to go at this point. A little bit of background about me: I run a small auto shop and I specialize in LS swaps, rebuilds, and performance stuff... I recently got into tuning as its so difficult to find good tuners here in MI, and I hated having my customers have to wait to get their newly swapped LS stuff while I'm trying to find or waiting for a tuner. So, here we are. I'm a beginning tuner, and I think for the most part I understand the directions I need to take due to reading, and Goat Garage's YouTube videos, on top of doing my own research and paying for a few beginning tuning courses. Ultimately, I'd like to maybe find someone who can kind of show me some of the deeper ins and outs (and I'd have no issue paying for your time also), but in the meantime, trying to get this LS swap outta here.

So, off to the specs. Gen IV 5.3, with a BTR Stage 3 cam, everything is brand new, timing is right on spec, fuel pressure is 58psi. AC Delco Sensors for all the importants (cam, crank, oil pressure, MAP). Engine has been completely rebuilt down the mains, using an E38 Corvette computer, with a 700r4 trans. It's sitting in a 90 Caprice. Crazy thing is, I was able to get it to run 2 or three times for about 45 seconds while I was trying to dial everything in, then it just died. I haven' been able to get it started since. After it first ran, it would fire and run for about 3 seconds and shut off. VATS has already been disabled. I'm posting the latest tune file, hoping to get some insight. As I said, I have no issue paying for a little bit of tutelage, so let me know if anyone out there would be interested. I also have no issue paying anyone who would help me dial in this tune if necessary. As I run a shop, and do it all, I know how precious time is. I'm uploading the most recent tune (as I have 6 drafts). Thanks wonderful people...

Post a log if you can.

Traditionally GM stuff would run without a cam sensor. They would run with just a hard start. But I've had a handful of swaps (my own included) that would either no start or act like VATS was still on where it would fire one cylinder and then have no fire. Triple check the cam sensor wiring. Some harnesses use a jumper harness between the cam sensor and the rest of the harness. Other harness guys make it go right to the cam sensor. That jumper crosses a two of the wires.

They often will not throw a code either.

[neps_automotive]

Just wanted to post a log file... hopefully I can get some insight from you guys.

[blindsquirrel]

119 kPa with engine not running... not possible. Diagnose the P0108.

[Alvin]

Try this file but do a "WRITE ENTIRE"

Sixth Draft WRITE ENTIRE.hpt

[neps_automotive]

Alvin, not sure what you changed my friend... but now, It starts, runs for about 2 seconds, shuts off. But she fires everytime. The MAP sensor is brand new, I've tried starting with it unplugged, and with it plugged in, still same issue. But i'm getting closer. I'm attaching a log file with your tune. Thanks again for all your help.

[Alvin]

Alvin, not sure what you changed my friend... but now, It starts, runs for about 2 seconds, shuts off. But she fires everytime. The MAP sensor is brand new, I've tried starting with it unplugged, and with it plugged in, still same issue. But i'm getting closer. I'm attaching a log file with your tune. Thanks again for all your help.

Its going to be because of this code

P0341 - Camshaft Position Sensor A Circuit Range/Performance (Bank 1 or single sensor) (Pending)


See my reply below.

Post a log if you can.

Traditionally GM stuff would run without a cam sensor. They would run with just a hard start. But I've had a handful of swaps (my own included) that would either no start or act like VATS was still on where it would fire one cylinder and then have no fire. Triple check the cam sensor wiring. Some harnesses use a jumper harness between the cam sensor and the rest of the harness. Other harness guys make it go right to the cam sensor. That jumper crosses a two of the wires.

They often will not throw a code either.

[neps_automotive]

Alvin, took a break from this one for a bit. Now I'm back at it. Had to order a brand-new OEM camshaft sensor, took me a couple days to get it. Got it in, cleared the code out, now I can't get it to start and of course I have a backfire out of the exhaust. The crazy thing about this, is I got it to run and it ran great. It shut off on me due to a faulty fuel pump, got that resolved. Now I can't get it running at all.

[GHuggins]

I don't see any airflow on your MAF once it does fire. Is it installed correctly? It keeps showing 0hz on top of low airflow too.

[neps_automotive]

MAF is installed correctly my friend. And it's an AC delco MAF, so I'm not sure why it's not showing anything.

[GHuggins]

Just to be sure try failing the MAF only set the test parameters to 1 rpm, .1 seconds and fails to 0. Should fail the second you go to crank. You need to be logging a lot more like injector pulse widths, torque pids, cut types and so on as well. I know when I look at logs for a start/stall and they show no airflow there's usually something wrong there. May just be the scanner and/or your computer causing it to not pick up, but needs to be double checked just to be sure.

[Pekka_Perkeles]

Alvin, took a break from this one for a bit. Now I'm back at it. Had to order a brand-new OEM camshaft sensor, took me a couple days to get it. Got it in, cleared the code out, now I can't get it to start and of course I have a backfire out of the exhaust. The crazy thing about this, is I got it to run and it ran great. It shut off on me due to a faulty fuel pump, got that resolved. Now I can't get it running at all.

Log also cam counts to verify it works as inteded.

I had a very similar problem with a muscle car LS3 swap and it was all about a bad wiring that killed 2 cam sensors until it was finally resolved.

[Alvin]

Alvin, took a break from this one for a bit. Now I'm back at it. Had to order a brand-new OEM camshaft sensor, took me a couple days to get it. Got it in, cleared the code out, now I can't get it to start and of course I have a backfire out of the exhaust. The crazy thing about this, is I got it to run and it ran great. It shut off on me due to a faulty fuel pump, got that resolved. Now I can't get it running at all.

Triple check the cam sensor wiring. Some harnesses use a jumper harness between the cam sensor and the rest of the harness. Other harness guys make it go right to the cam sensor. That jumper crosses a two of the wires.

They often will not throw a code either.