We have replaced a LBZ that had issue with a low mileage LLY that we had on hand. Left all LBZ electronics in place, installed the 06 crank and cam sensors, change the cam reluctor wheel and front covers. Have good fuel rail pressures but the computer will not fire the injectors ( they are the 06 injectors that we had trimmed off .010'' to fit the 05 heads). Any ideas as to why they will not fire. We have switched out the computer with no luck, installed all new wiring harness, no luck. Can the 05 turbo be keeping this from firing? Is there a way to disable the anti-theft side of the computer? Any and all ideas would be greatly appreciated. Naturally GM says I have to replace all parts with the exact year model on every part.
Replace LBZ with LLY
- Thread starter Leaddog
- Start date
Did you change the crank reluctor wheel? Didn't have to change the cam reluctor but absolutely have to change the crank
The lbz is a different injector they use a different ECM that identify each injector individually. Both lb7 and lly identity the injectors in pairs 1&4. 2&5. 7&6. 8&3. So you need an lly ECM.
Don't know then??? Are they the original injectors and are they in the same position as they were in the lbz? Is the ECM giving off any codes other than from the power interruption?
I also misstated injetor arrangement with ECM the lbz is in pairs as stated above for lb7 and lly and the lb7 and lly are arranged in two groups of four.
Not that it matters for your problem but I don't like giving incorrect info.
Not that it matters for your problem but I don't like giving incorrect info.
I did misstate the reluctor wheel, it is the crank one that was replaced with the 58 tooth off of the lbz. And no codes are showing up at all. They are the original injectors but do not know about original location. We also tried to get a new injector to fire/vibrate out of the head with no luck.
Answers
Cannot turn off the VATS with stock program. We have had it relearn the VATS twice now with no luck and yes we do have cranking RPM's being registered on the scan tool.
Cannot turn off the VATS with stock program. We have had it relearn the VATS twice now with no luck and yes we do have cranking RPM's being registered on the scan tool.
What are you considering good rail pressure? What was wrong with the truck originally? How long have you cranked on it?
If you have good pressure (IIRC they need 1,500-2,000psi (10-15MPa) to open the injectors when cranking). If you have that pressure and have good crank and cam signal then make sure you have fuel at the injectors. How long you been cranking it? some of these bitches take forever to get going. Crank lines and make sure fuel is at the injectors.
When you say its not firing the injectors, is that based off holding the one or a scan tool parameter?
Ben would know more about the electronics side. If the above is all good then its something with the electronics. Security light on? The emergency relearn doesn't always work. I don't know if anything else in the computer would reject the LBZ ECM.
The injector position shouldn't matter. The "programming" people speak of is the flow rate code for each injector that you enter. You can enter it when you replace them, but its not going to make the truck run drastically different like in this case. You say you swapped the ECM? Was it a new one? that is where the issues come into play as you need to copy the injector flow rates from the GPCM into the ECM as there wont be any in it to begin with IIRC. Are you running the LBZ or LLY GPCM? The LLY GPCM cannot store the codes AFAIK because they did not use them back then.
When you say its not firing the injectors, is that based off holding the one or a scan tool parameter?
Ben would know more about the electronics side. If the above is all good then its something with the electronics. Security light on? The emergency relearn doesn't always work. I don't know if anything else in the computer would reject the LBZ ECM.
The injector position shouldn't matter. The "programming" people speak of is the flow rate code for each injector that you enter. You can enter it when you replace them, but its not going to make the truck run drastically different like in this case. You say you swapped the ECM? Was it a new one? that is where the issues come into play as you need to copy the injector flow rates from the GPCM into the ECM as there wont be any in it to begin with IIRC. Are you running the LBZ or LLY GPCM? The LLY GPCM cannot store the codes AFAIK because they did not use them back then.
engine
I swapped the lly in because we had one on hand from a totaled truck, no engine compartment damage. In hind site made a mistake doing this, could have sold lly and just found a lbz, (maybe where I am still headed). The injectors not firing was based on holding it in your hand, told this was ok, (should vibrate a little) is this wrong. Engine will actually run on minimal shot of ether the one time we tried it. ECM changes where from another 2006 with reprogram to truck that will not run to one that does. ECM from running truck was also reprogramed for the truck that does not run. In each case both ecm worked for the donor truck. Have not tried to bleed each fuel line separately.
I swapped the lly in because we had one on hand from a totaled truck, no engine compartment damage. In hind site made a mistake doing this, could have sold lly and just found a lbz, (maybe where I am still headed). The injectors not firing was based on holding it in your hand, told this was ok, (should vibrate a little) is this wrong. Engine will actually run on minimal shot of ether the one time we tried it. ECM changes where from another 2006 with reprogram to truck that will not run to one that does. ECM from running truck was also reprogramed for the truck that does not run. In each case both ecm worked for the donor truck. Have not tried to bleed each fuel line separately.
we do have good rail pressure right at 2100 psi, have fuel showing up in the return line, so assuming fuel is at the injectors, scan tool is also showing that the injectors are not firing.
So are you running the LLY injectors or LBZ injectors? Since the LBZ's dont fit in the LLY without machining I assume you are still using LLY injectors? But you are using the LBZ electronics correct? You need to swap the injectors, I dont think the LBZ electronics will fire them because they operate at different voltages. LLY's run higher volts and use an FICM in conjunction with the Delphi ECM. LBZ's run lower volts with no FICM, everything go through the Bosch ECM.
Once ether is gone motor quit. I know we have fueling issues. The injectors are not firing, trying to figure out why.