New member to the forum, so this is my first question.

Long story short, I have a Bi-fuel E350 5.4L VIN Z. It took CNG and regular gas. I had to remove the heads to change the head gaskets and I decided while I was there to remove the last of the CNG components (regulator, compuvalve, etc.). 4 days later, I have the van put back together minus the CNG components, with a new VIN L intake, and have all of the heater hoses re-routed back the way they're supposed to be with a gasoline only van. Van starts up, but the fuel gauge is reading PAST full. Figured that out already, I had to cut and spice two wires coming from Canada's modifications. In addition to that, I had to splice a few more wires to get my fuel pump back, lol, and ALL OF MY GAUGES, lol.

Here's my problem. There is a secondary computer under the passenger side dash that belongs to GFI (the Bi-Fuel company) that I want to get rid of. When this computer is unplugged, the van runs fine, but on second start up, a check engine light shows. Not sure what the code was, but when I keep the GFI computer plugged in, the check engine light stays off.

Here's another problem, when this computer is plugged in, I found that the VIN Z PCM tries to start the van in CNG mode AS A DEFAULT, but then switches over to gas mode while the van is trying to start up. This results in delayed starts whenever the van sits for more than 10 minutes. I checked the fuel injectors, fuel pump, fuel lines, and fuel pressure regulator, and they're all functioning. Fuel pump hold pressure like it should. PLUS, I can see when I try to start the van after an hour that the gauges read, then drop in the middle of starting up as if the computer is switching modes (I can hear a relay clicking with the dashes.) This used to happen when I had CNG working if my CNG tanks were empty. It would switch back to gas mode because of the absence of CNG in the tanks. If that secondary computer is unplugged (and the check engine light shows), then the van never has a delayed start, even after waiting a few hours.

My Question. What do I replace this PCM with? I had a junkyard PCM lying around that came from a '98 Ford E350. When I plugged that one in, the van surged in rpms and ran with okay performance, but the transmission shifted erratically. This might be because my van had the 4R100, while the other van had an E40D. I went researching and found that Ford's PCMs have all these hardware codes and different part numbers. Which PCM do I replace this van's VIN Z PCM with? Do I just throw in a PCM that came from a '99 Club Wagon with the 4R100 and 5.4l VIN L engine? Or do I REALLY NEED to get this PCM reprogrammed?

 

Bump. I need an answer for this...

 

I can’t help you with your question but I do have a PCM that came on a 1 ton van with a 4r100. I believe it was a 99. If you want to try it out you can.