I have a question about a 2000 GMC bifuel CNG truck. The truck is a factory IMPCO conversion that was done in 1999.
I am looking at buying this truck. I am trying to determine if the CNG is operable. I believe the CNG tank was empty (I cannot find a presure guage on the truck). I have filled the cng tank for 3 hours with a FMQ2. The truck has a push button switch on the dash to the right of the steering wheel. When I push the button it rocks upward and springs back to the original position. I noticed that the gas guage changes level when I push the switch (I think to reflect how much CNG is in the CNG tank). The gas guage stays to this position for about 30 seconds and then reverts back to the original level (I think the gasoline level). I think it switched over to CNG after the engine was warmed up. The gas guage would then stay on the CNG level. At this time I pushed the switch again and the gas guage displayed the gasoline level for 30 seconds and then reverted back to the CNG level. I thought that if I removed the fuel pump relay that if the truck was running on CNG it would keep running. When I remove it the truck shuts off even when I think it is running on CNG. I then decided to remove the CNG fuse when I believe it is running on CNG and the truck quit running but would start back up without the CNG fues installed.
Does anyone know how these factory CNG kits are supposed to work?
Does the above sound correct? There is a little green light on the rocker switch but it never lights up. When should it light up? I did find another cng switch that has been removed laying in the truck (or maybe it is a new switch?).
I think that the truck runs like below.
It seems that the truck starts on gasoline and will switch over to CNG if the engine is up to operating temp after pushing the button (as long as there is ample CNG in the tank). It also seems that the truck wil then run on CNG until the CNG tank is run out of CNG. It will then automatically switch over to gasoiline. There is no missfire or change in RPM when it switches over though.
The original owned has passed away and left the truck to the daughter so she does not know anything about the CNG. he stickers on the truck refer to a CNG manual supplement. Does anyone know where I can get a copy of this manual? I have searched the internet with no sucess.
Thanks
Art
[email protected]
907-892-1630
I am looking at buying this truck. I am trying to determine if the CNG is operable. I believe the CNG tank was empty (I cannot find a presure guage on the truck). I have filled the cng tank for 3 hours with a FMQ2. The truck has a push button switch on the dash to the right of the steering wheel. When I push the button it rocks upward and springs back to the original position. I noticed that the gas guage changes level when I push the switch (I think to reflect how much CNG is in the CNG tank). The gas guage stays to this position for about 30 seconds and then reverts back to the original level (I think the gasoline level). I think it switched over to CNG after the engine was warmed up. The gas guage would then stay on the CNG level. At this time I pushed the switch again and the gas guage displayed the gasoline level for 30 seconds and then reverted back to the CNG level. I thought that if I removed the fuel pump relay that if the truck was running on CNG it would keep running. When I remove it the truck shuts off even when I think it is running on CNG. I then decided to remove the CNG fuse when I believe it is running on CNG and the truck quit running but would start back up without the CNG fues installed.
Does anyone know how these factory CNG kits are supposed to work?
Does the above sound correct? There is a little green light on the rocker switch but it never lights up. When should it light up? I did find another cng switch that has been removed laying in the truck (or maybe it is a new switch?).
I think that the truck runs like below.
It seems that the truck starts on gasoline and will switch over to CNG if the engine is up to operating temp after pushing the button (as long as there is ample CNG in the tank). It also seems that the truck wil then run on CNG until the CNG tank is run out of CNG. It will then automatically switch over to gasoiline. There is no missfire or change in RPM when it switches over though.
The original owned has passed away and left the truck to the daughter so she does not know anything about the CNG. he stickers on the truck refer to a CNG manual supplement. Does anyone know where I can get a copy of this manual? I have searched the internet with no sucess.
Thanks
Art
[email protected]
907-892-1630
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