LS2 conversion hard to start, when it does runs great?

[1965 ssvert]

After over a year on this 69 Camaro LS2 conversion we finally got her to fire up and run! Unfortunately it is hit and mostly miss on getting her to fire off. Once she fires...good idle, oil pressure, communication with the pedal, sounds good, no codes other than some emissions ones that are taken care of now.

First fire was cranking, cranking, cranking....randomly fired up and purred.

Second fire, removed intake elbow open throttle, sprayed some starting fluid, after cranking finally fired at some point, replaced elbow and it ran great. Shut her down....no fire.

Third fire, charged battery (from cranking so much) removed intake elbow in preparation for spray. Turned the key and it fired, struggled for a second and idled great, ran it for 20min. or so, tapped the throttle a few times and all seems well. Shut it down and it just cranks and cranks and cranks.

My thoughts are cranking timing too retarded for the cam (240ish duration, .640ish lift), bad or failing cam sensor. We have a gauge on the rail and have tried between 56 and 65psi of fuel pressure. When running it is a constant 58psi at the moment. Vats 1&2 disabled, Maf patched, idle rpm raised to aid in starting although I manually idled it down to 700 with the scanner while running with no issues. It just will not start easily or consistently. I am attaching the second start scan and the current tune file. Ideas?

[Widebody06]

E40 or E38? If E40 I can point you to the tables and ball park setttings. Are you cranking with no throttle or have you tried a variety of positions?

[1965 ssvert]

Widebody06, that would be fantastic! I believe it is an E40...2005 GTO LS2 with 3 connectors on it. From what I can find pictures of an E38 would only have 2 connectors on it. I am all ears...

[1965 ssvert]

Just checked a plug, bone dry after cranking. Checked for power at the injector with a noid light during cranking...no flash. Sprayed starter fluid in the intake and it almost lights off. Now I need to figure out how to get the power to the injectors during cranking and hopefully that is it.

It must be starting off of transient fuel under perfect conditions and the injectors are powered once it is running so it stays running.

[1965 ssvert]

Anybody have a wiring schematic for the Current Performance SA-1000 fuse block? It only had little label tabs on the ends of the wires that got cutoff. It seems that the injector circuit my not be providing 12V cranking power to the injectors. I believe the coil circuit is.

Anybody know if I will hurt anything by jumping a 10amp fused wire directly from the battery positive to the injector power wire to confirm that this is in fact the problem and the motor will start with powered injectors before I start tearing into the harness?

I have an email into Current Performance and am going to call in the morning.

[1965 ssvert]

Where does cranking power for the injectors begin? I must have missed a wire, apparently the injector cranking power does not come from the SA-1000. Thinking about using a 5 pin automotive relay triggered by the cranking wire from the ignition switch to power the injectors while cranking.

[Widebody06]

http://www.ls2.com/boggs/dtcs/DTC%20P0206.htm
I think you'd be throwing a code if the injectors werent responding
Just for giggles try adding 50% to your idle/airflow/startup table, its far lower than my car would start on.

[1965 ssvert]

The injectors were not getting power during cranking. Jumped power from the battery to the coils and injectors....fired right up. It ended up being a bad relay.

[1965 ssvert]

I added 25% to that table and increased the cranking timing and idle timing a bit. I will upload the current file when I am on the computer with HPtuners. It almost doesn't start 1 out of about 6 times and throws a 340/341 cam sensor code when it does that. It throws the code regularly while it is idling as well. I dielectric greased the connection with no improvement. Idling pig rich too, as to be expected I guess. Off to the stealership for a replacement tomorrow....

Widebody06, any chance I could take a peek at your tune file?

[1965 ssvert]

I replaced the offending cam sensor and the other relays that shared the brand of the two that were new and faulty (Omitron) and it starts every time! I added another 25% to the idle airflow and upped the cranking timing a bit more. Idle timing is up at 20 degrees and it seems to idle happy at 925rpms. I scaled the MAF and VE up by 10%, it now has -5% fuel trims at idle and doesn't smell as rich as it did before.

It almost falls flat on its face for a second right at startup and then picks back up again and idles nice. It is throwing a P0106 for the MAP sensor. It did it once intermittently while idling as well....almost died and then picked back up. Is this a symptom of a failing MAP?

[Widebody06]

Maybe....
2006 Pontiac GTO RA6 V2a3_EOIT90d.hpt

[1965 ssvert]

Cool, I will try to open that up when I get to the laptop. We went out and put a mile on the odometer a couple nights ago. Pretty peppy old Camaro now.

[1965 ssvert]

Widebody06, what are the specs on that Track Max cam. I can't seem to find them anywhere. I will keep looking. Your VE table looks like a good place to start for what I have.

[Widebody06]

Trick Flow sells the cam...tricky to find stuff on their site
Pn# TFS-30602004 238/242 112 @0.595"

[1965 ssvert]

Yeah, that is a tough cam to find the info on..... Sweet the duration and lsa is right on. Mine has a bit more lift and a couple degrees ground in. I noticed you have still have cats and have a better intake and heads than this one. I am tempted to flash the VE and MAF tables into this one and go out and check it against the wideband.

How is that tune working out for your car? I am mainly trying to gain some drivability down low (the clutch is like an on/off switch) and get it in the ballpark so we can wideband tune it or take it in for some dyno time.

Does your car come back down to idle smoothly or does it almost act like it is going to die and pick back up again?