Check engine light

[gtschulz]

I have a 2007 Damon Tuscany on a (2006) Freightliner chassis with a Cat C7. I recently added 65 gallons of fuel and when leaving the pumps to get to the road, about a hundred yards travelled, the check engine light came on and although the engine was running it had no power. I shut the engine off and checked the engine area for anything obvious and found nothing obvious. I started the engine and no check engine light came on so I proceeded to the entrance ramp to the E-way. Half way down the ramp the check engine light came back on so I pulled over to the shoulder and shut the motor off again. This time I got under the motorhome to give the motor area a better examination. No leaks, no drips and all belts where they belong. I restarted the engine with the intent to get to a safer area but the check engine light didn't reappear so I continued down I-75. 120 miles later I was home with no additional events.

I took the motorhome in to get the codes checked and they found a low fuel pressure warning so they ran tests on the system. Fuel pressure readings were in spec, all 6 injectors passed the cylinder cutout testing, all ECM sensor values reading properly.

They found no reason for the check engine light and power loss.

Any Ideas as to what the cause was? It seems to be tied into adding fuel.

[gtschulz]

The fuel cap was not the issue. The entire fuel system was tested from the pumps to the injectors and all passed. The only connection to the check engine light coming on was that it came on right after fueling.

[LittleBill]

lack of a gas cap is not going to cause a power loss, it will throw a evap large leak code, and it may take a while for that code to set, evap systems do not constantly test for leaks, nor are they sealed except for testing.

no idea on diesel, my comments are based on gas.

[was_butnotnow]

Is gas different than diesel in DP MH for the gas cap?
I was in Eugene OR and they left off the gas cap and had to go back to get it. But it didn't cause andy check engine alarm.
Is there a difference in diesel and gas for fuel tank pressure.
05 Monaco Cayman 36 PDQ

[wolfe10]

Gas cap issues with a DIESEL???

New one on me.

You don't say who you took it to. Was it a Caterpillar dealer. That is who I would take it to!

[77rollalong]

If its coming up with and small Evap leak the best thing to do if you have already checked the gas cap is have the system smoked, where they inject smoke into the system and see where it comes out. Other wise just ignore the light if thats all its on for as it does not affect the engine running at all..

[Harvey51]

Last spring I got an engine light on the Ford E350 for the code that means gas tank vapour leak, something like environmental leak, very small. In the past I have got rid of it with a wee bit of grease on the gas cap rubber ring seal. But that time I had to buy a new gas cap to clear the code. Now, I have the light and code again. Grease doesn’t solve it. What is the next step?

[wa8yxm]

I think you should have the fuel in your tank checked for contamination. but other than that.. Might be something else entierly

Codes come in 3 flavors
Some turn the light on till the problem clears then turn it off and go away
Some turn it on. till it clears up then off but REMAIN in the Computer memory where a Technician (I no longer call 'em mechanics) can read it with a reader
}
Some turn the light on and a technician has to turn it off.

Suggestion is ask the engine control computer if it knows what the problem is.

NOW.. I drive a gasser. not a Big D. but there is this lovely OBD (OBD II) connector.. I have a Blue Tooth adapter plugged into it and an APP (Torque) on my phone.. another BT adapter in my car.. I can read and RESET the codes FROM THE PHONE.. Live and in color a it were. plus even if it is a "Vanishing" code the PHONE logs it in memory for me so I can show the technician.

[gtschulz]

The fuel cap is tight and there are no fuel leaks.

[naturist]

Agree with checking fuel cap first.

Recently had the same error code on my BMW X5 diesel. No loss of power, could have been. Turned out the fuel filter had started leaking. The leak just hadn’t yet gotten big enough to cause power loss. Sorry your issue/leak has proven harder to find and fix.

[donn0128]

Always ALWAYS check this first with a check engine light. Especially after refuling.

[newman_fulltime]

Loose fuel cap might cause it