Questions on converting Izusu gen4 6.0l 6l80e from CNG fuel to Flex Fuel e38 ecm

[John H]

Hello I have a 2012 Izusu NPR HD with a stock gen4 6.0l with 6l80e transmission with a e38 ecm. This truck had been running on CNG Fuel (compressed natural gas). I am converting this truck to run on E85 and gasoline. I have done all the mechanical work and taken all the CNG tanks and stuff off the truck and added all the gasoline and E85 to the truck. New tank fuel pump PTFE lines and Flex Fuel sensor in the return line. The last 2 things I need to do is wire the flex fuel sensor wire to the e38cm and the fuel pump trigger wire to either a switched 12+ or somewhere in the ECM if there is a correct wire for the fuel pump. I have GM delphi 50lb flex fuel injectors installed. The wire harness did not seem to be diffferent for the CNG other then the different injectors it had and little injector conversion pigtails I removed. I have purchased HP tuners and the pro cable and will be using a innovate LM2 for wide band 02 and will try to get the wide band 02 signal back to the hp tuners this way. My questions are many because I am brand new to tuning a GM ecm with hp tuners. I have purchased 2 credits also. I also have another LS3 t56 engine harness and e38 ecm that came out of a wrecked 2015 camaro ss 1le for another vehicle swap going into a 69 camaro at a later date and another 6.2l 6l80e engine with e38 ecm out of a wrecked 2008 caddilac escalade for a swap going into a 72 nova at a later date. Can I use any fueling information from these other ecms and copy the fuel trims or configurations into my Izusu e38 ecm to help with this? I know the caddilac engine had DOD or VVT originally and the LS3 did not and I am pretty sure the Izusu does not have DOD or VVT. I need to get this vehicle up and running soon and any help will be appreciated. I do have some experience tuning but with after market stand alone setups. I have tuned a BBC on a FAST XFI a bit also a SBC on a ACCEL DFI and 13B turbo rotary on a Electromotive TEC2 and then a Haltech 1000 on E85. But I am humble and definitely not a professional by any means. Also I have replaced the heads that were damaged on the motor and did a rocker trunnion upgrade and hardened pushrods and arp head bolts on the Izusu engine but otherwise it is bone stock.

[GHuggins]

Off subject I know, but do you mind posting the OE CNG calibration?

[John H]

Off subject I know, but do you mind posting the OE CNG calibration?

I wish I could It is looking like HP tuners has bricked my ECU on trying to read the stock calibration file. It got half way through reading it and stopped saying too many failed attempts. It did this about 3 or 4 times and then it says detect protocol failed. That's all it will do now and I am stuck. Upon doing research this happening to other people but usually not the first time reading a file. I am really not a fan so far. I have now paid $500 for a replacement E38 ECM that is blank with only my VIN number on it. I am now stuck not knowing how to proceed and wish I Holley made a Terminator x ECU that could control a 6L80E Transmission. I was able to read 2 other ECMs just fine but am afraid to touch them after bricking This ECU without even using my credits and writing 1 file. I found a video showing a guy grounding a pin in the ECM after he took the metal off and he was able to write his original file back to it but I don't have my original file so looks like I am SOL. I was planning on selling my CNG tanks and complete setup but looks like that ship sailed.

[John H]

Anyone with a stock flex fuel tune for 6.0 ly6 6l80 Engine is stock it does not have VVT or DOD though. How do I use my credits? Why wont Hp Tuners connect to the replacement ECU? Still Detect protocol failed. Wire harness looks good. I only added 1 wire to pin 40 now for the flex fuel sensor. Also I have a external adjustable fuel pressure regulator now. Do I need to hook up a vacum line to it or do I need to change settings for that? I set the fuel pressure at 58 psi for now. Stock GM delphi 50lb injectors installed.

[2xLS1]

It's pretty damn hard to brick an E38 and even harder just trying to read it. I bet it's not really bricked.

[GHuggins]

AND to add to that, usually the big trucks don't run the same calibrations as what you would find in a chevy truck for example. That cal file will be unique - usually anyway - to those Isuzu trucks. This is another reason I was curious about it

Unfortunately - if for whatever reason it is bricked - you'll most likely have to get it flashed with an OE tool. You might reach out to a mobile repair guy for this, but it's going to be expensive on an Isuzu. Those guys are usually 150 or more an hour plus other fees.

[gtstorey]

Can you connect with any other devices or scanners? It wouldn’t surprise me if there isn’t wiring or other differences that you haven’t discovered.

[TheMechanic]

Related topic, I had a CNG truck I tried to get to run on gas only. P59 I believe. Struggled with it for a time. Tried different OS etc until I started looking at the added computer under the battery that controlled the CNG. Tried voltage dividers for all of the tank sensor that were missing. All it needs is the sensors signaled in the "comprehensive" test and a reading of an empty CNG tank and it starts off gas. Long story short it just didn't want to go because of the added module. Customer didn't want to go with new P59 style factory/aftermarket harness for the conversion. Got it running and it was off the the auction.