Hello, first timer here, I am currently working on a 1994 LT1 that I have done a 24x ignition conversion, customer purchased this system and wiring harness and computer from EFI CONNECTIONS.The problem I'm having is when I go to fire the car it starts right up and immediately dies. The security light does not stay on or flash,I went ahead and did the pass key reset to make sure this wasn't a problem. Do I need to have the new LS computer programmed? Any help would be appreciated.

 

As part of the PASS-Key system, the PCM looks for a “fuel enable” signal from the theft deterrent module (TDM). The TDM provides the signal when it verifies the key resistance. I don’t know the details of how the LS PCM is integrated into the LT1 PASS-Key System/TDM, or if it even is. But starting and running for a few seconds, then shutting down, is a common symptom of the LT1 version of PASS-Key.

Just a guess as something to look at.

 

Any install instructions with the kit? Have you called/emailed EFI to see if the LS PCM was pre-programmed with a base LT1 tune?

Maybe a small window on the '98 and up PASS key systems....on my brother's '99 Camaro V6, his cylinder lock contacts wore out. Security light was on and did flash when attempting to crank the vehicle. The engine would not turn over.

 

no instructions at all,I emailed them and they said probably VATS ,then said programming required. Don't think it's Vats no security light will start then dies immediately. Maybe not communicated with bcm?

 

Just to be sure we are on the same page..... PASS-Key = VATS.

The SECURITY light comes on when 1) there is a problem with the resistance in the key; 2) there is a problem with the circuitry from the lock cylinder to the TDM.; 3) the system detects a new, unprogrammed TDM. If you are using the vehicle’s original key, and the original TDM, you will not have any of those three problems, and the SECURITY light will not come on.

BUT.... if the TDM is not sending the 50Hz fuel enable signal to the PCM, the SECURITY light does not come on, but with an LT1 PCM it would set DTC 46. That is the only way to know what the problem is. I do NOT know the workings of that specific LSx PCM, but if it's looking for a fuel enable signal (the LS1 PCM used in the 98-02 F-Bodies is), and it’s not getting it, you would get the exact results you are describing. The fuel pump will prime, the starter will crank the engine, the engine will run for a couple seconds on the prime fuel in the rails, and then stop.

Does the wiring harness supplied with the kit include the correct circuitry to connect the pin in the TDM that supplies the fuel enable signal to the correct pin in the LSx PCM? Does that harness address the issue that the fuel enable signal passes through body connector C230, and the pinouts vary from year to year, and may not match the engine harness.

Absolute certainty that is the case - NO. But the fact your SECURITY light is not on does not rule it out. I suspect the reason you got the response that programming may be required is tied to the fact that one way to solve the problem would be to have the need for the fuel enable signal “programmed out” of the PCM.

 

The programming could be an issue. If it's still programmed for an LS engine, I'm pretty sure the injector bank assignments will not be correct....along with a bunch of other settings. One thing I did see in the threads below is that AdsoYo said his fired up but ran with a misfire.....so to Injuneer's point, need to make sure that the wiring harness is right.

To start....have a glance at this....AdsoYo has a '94, so that should help minimize year differences.
https://www.camaroz28.com/forums/lt1...ummary-880689/
...here is where we were talking about the injector assignments
https://www.camaroz28.com/forums/lt1...1/#post6966498
This might help as well....
ttps://forum.hptuners.com/showthread.php?49363-LT1-24X-411-PCM-conversion-all-of-us-please-step-inside

 

Thank you Injuneer, The new harness does have the correct wire in c230 for fuel pump,looks like programming this out should cure my problem,fingers crossed