HELP, LS2 not getting injector signal, starts on starting fluid though

[Riggs 74]

I hope this is posted in the right section.
I am at the final stage of an LS2 swap that been a real journey, compared to others that I have seen or read about.
The problem I have at the moment is, The car will start only on starting fluid. the injectors are not receiving the needed signal from the ECU.
The ECU was tuned by http://tunedbyfrost.com/ he has told me many times he has disabled the vats. I have no way of entering into the ECU to look for myself. By the way Steve is great to work with.
I have fuel pressure at the fuel rails, near 60psi and the injectors have all been tested by applying voltage to the injector coils one at a time, each time the injector opens up and the fuel gauge drops pressure quickly, showing me that there is plenty of flow (this is done with the car off, with rail pressurized) All eight test out ok, none of them are sticking.
After testing each injector for flow, I attempted to start the car to burn off the fuel that I recently sprayed into the cylinders, the car starts, but quickly stalls due to the lack of fuel.
What would cause the ECU not to send the injector signal, but allows the coils to fire? I have change the crank sensor with having the same end result that I started with.
Thanks for any help that can be given.
Riggs

[Poorhousenext]

Cam sensor or cam sensor wiring. Just went thru the same problem with 2 cars. Both had the cam sensor wires in wrong pin position. In my case LS3 and LS7 with harnesses from same builder made 1 1/2 years apart, but both had cam sensor connector wires wired like it was an LS2 engine. Swapped the pins around and both fired right up. We want talk about what it cost to trace the problem down on 1st installation. Thirty min's on the 2nd one. Hooked up the computer, saw cam sensor wasn't working and swapped the wires around so engine would get fuel...LOL

Company that made the harnesses never makes a mistake by the way. But in my case someone there did and it's my guess its because both harnesses used LS2 MAF's that confused the guy pinning out the harness. We want talk about the fact one harness's throttle pedal did not have the pins fully seated in connector to boot on 1st harness that only contributed to tracking down problem due to trying to clear all the codes that threw...LOL

My 48 year old Wide Body PT Corvette

https://static1.pt-content.com/images/pt/2012/01/DSC0063XL-1.jpg

[Riggs 74]

Thanks for the tip, I do remember now reading that in your build thread, thanks for reminding me, I am going to go look at it tonight.

By the way that is a gorgeous car you have there.

Riggs

[Nick@HPM]

Did you get this sorted out?

[Riggs 74]

NO I have not fixed it yet, I found the wires on the cam sensor to be wrong, according to the many diagrams I have looked at, made the switch, and now I don't have spark or the noid working. I am now waiting for a GM gas pedal sensor to arrive tomorrow, after reading many other post, in some, the pedal sensor was keeping the car from starting. The pedal I received from current performance looks to be an after market with no part numbers on it, so I am changing it out for the GM unit in hopes of the car starting. I have read about several after market replacement pedal/sensors failing, I think it's worth a shot at just replacing the pedal, and if it doesn't work, well at least I can cross of the pedal as being the problem.

My tuner http://tunedbyfrost.com/ sent me some screen shots of my tune to show me that the VATS are indeed turned off, so at this point its in the sensors, or possibly in the wiring.

I will test the car tomorrow after receiving the pedal and see where I go from there.


If any one has any info that may help, please post your thoughts.

Riggs

[Mike Norris]

First things first, you really need to get some data for a proper diagnosis. Are there any codes present? Is there an RPM showing on a scanner while cranking? If you can get data it will be a relatively easy diagnosis.

It is in situations like these where the one stop packages from Speartech are priceless in that John builds and runs every package on an engine before shipping them out. His packages can be more expensive but can save in the headache and time wasting department for sure.

Hope this helps and let us know on the data and perhaps we can get you going.

Mike Norris

[Riggs 74]

I have the car running at this time, but I will need to make changes. I called Current performance on Friday and was told that they just ran into this very same problem on a swap using a 2008 SS Trail Blazer drop out unit. CP said that they found a section of the operating system that is unable to be excessed with a tuning program. Circuit 625 in the ECU is part of the starting circuit that controls the injectors, since this device can not be disabled, they said they had two ways to take care of it. The first is using a 680 ohm resistor connected to a switched 12 volt source and plugged into pin 56 on the blue ECU connector. This has allowed me to run the car, Finally. The second option was to strip out the 2008 operating system from the ECU and replace it with a 2007 SS TB operating system since the 2007 doesn't have this extra hurdle to jump over and would solve the problem once and for all.

I have contacted my tuner and he want to contact HP tuners and find out why this is and if there is a way around it, I feel we need to just scram the 2008 operating program and dump in a 2007 with a new tune and call it done. I feel that this would be more reliable avoiding any future problems I would have with rewiring the ECU pin, (its wired temporary right now) or having any other problems when the car goes to a local chassis Dyno and the tuner there having problems with the ECU and the program/operating system.

Riggs