Check Engine Light when Generator Running

[MarkK10]

We just took our brand new Sunseeker 3270 out for its maiden voyage and stayed in a campground with full hookups for the weekend. On the way home, I decided to run the generator for a while under load (refrigerator) since we did not use it all weekend. We were told by the dealer that running the generator (Cummins Onan 4000w) while driving is not a problem.

Shortly after we got under way, however, the check engine light came on. I turned off the generator right away, but the check engine light stayed on. Upon returning home, I hooked up my code reader (Bluedriver - plugs into OBD port and connects to iPhone via bluetooth - highly recommended) and pulled the following codes:

1. P0455 - EVAP System Leak Detected (large leak)
2. P0457 - EVAP System Leak Detected (fuel cap loose/off)

Note that I had checked the fuel cap earlier. It was NOT loose. I cleared the code with my Bluedriver and drove my Sunseeker about 15 miles with the generator NOT running. The check engine light did NOT come back on.

Since I do not believe in coincidences, I think the the check engine light was caused by the generator running while driving. Possibly, the fuel being drawn from the RV gas tank by the generator was incorrectly interpreted by the ECU/PCM as an EVAP problem.

Has anyone heard of this happening? I will ask the dealer to look at it, but I predict a runaround. They will say that the check engine light is a Ford problem, not a Forest River problem.

Any help is much appreciated.

Thanks,

Mark

[Reverse_snowbird]

Very strange.

There is a 'break in' process for the generator and maybe that had something to do with it? When we broke ours in, there was a guide as to how much load to put in it at first.

[Secarider]

[QUOTE=MarkK10;1804125]We just took our brand new Sunseeker 3270 out for its maiden voyage and stayed in a campground with full hookups for the weekend. On the way home, I decided to run the generator for a while under load (refrigerator) since we did not use it all weekend. We were told by the dealer that running the generator (Cummins Onan 4000w) while driving is not a problem.

Shortly after we got under way, however, the check engine light came on. I turned off the generator right away, but the check engine light stayed on. Upon returning home, I hooked up my code reader (Bluedriver - plugs into OBD port and connects to iPhone via bluetooth - highly recommended) and pulled the following codes:

1. P0455 - EVAP System Leak Detected (large leak)
2. P0457 - EVAP System Leak Detected (fuel cap loose/off)

Note that I had checked the fuel cap earlier. It was NOT loose. I cleared the code with my Bluedriver and drove my Sunseeker about 15 miles with the generator NOT running. The check engine light did NOT come back on.

Since I do not believe in coincidences, I think the the check engine light was caused by the generator running while driving. Possibly, the fuel being drawn from the RV gas tank by the generator was incorrectly interpreted by the ECU/PCM as an EVAP problem.

Has anyone heard of this happening? I will ask the dealer to look at it, but I predict a runaround. They will say that the check engine light is a Ford problem, not a Forest River problem.

Any help is much appreciated.

Thanks,

Mark[/QUOT

Generator has nothing to do with this issue, From my experience I had same faults and it ended up being a broken vent line on top of fuel tank, dealer blamed it on factory, chassis is delivered full up and then built up, either someone stepped on vent elbow before MH was built or hit during buildup. They found it by pumping up the system and heard the hissing at fuel tank. Ford would not repair because they said rear jacks needed removed and fuel tank removed. My dealer did it without dropping tank or jacks no issue.

[MarkK10]

Reverse_snowbird, thanks for your suggestion. I don't believe that it has anything to do with break in, however. I think it has something to do with the way that the generator is drawing gas from the main RV fuel tank. This probably would not change based on break in.

Secarider (as in Yamaha Seca?), I appreciate your input also. I understand where you are coming from. However, since the check engine light only came on with the generator running and no other time, I am still inclined to believe it is generator related.

Thanks all for your input.

[jk510]

The only way to tell is to drive for a while with no generator then then turn the generator on and see if the code comes back.