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I have a 2015 E450 motor home with the V10. Had a pack rat do some damage in the engine compartment but I found it before it became massive damage. Appears no wiring was damaged, engine runs. While cleaning up the mess of mesquite bean pods and a few cholla cactus pieces, I found the remains of a vacuum check valve on the right valve cover with short section of tubing. It has chewed remains of hoses on 2 of the connections.
Problem is I cannot find what vacuum lines are missing, no obvious ends hanging open. It is not the vacuum line to the dash vents as I can follow that and it is all intact and working. I looked everywhere I could but see no places to connect tubing to. Engine idles OK, I have no error codes from the OBD II, have not driven it on the road.
How can I identify where the missing lines should connect?
check valve, short section of tubing, chewed tubing
I've not seen that type Ford check valve used any other place than the HVAC air flow change system. I wonder if any or all of the original parts were replaced with a re-routed system and the old stuff just left in place?
I have run the engine and could not hear any hissing sounds. With the engine shroud off there is more engine noise than I'm normally hearing but it still is a fairly low noise engine. When I tap the accelerator there is a slight hesitation that I did not notice before but maybe I'm just more critical now that I'm looking for something. Just not sure if the idle is what is normal, again may be overly critical.
I did have to reroute the dash vent line about 2 yrs ago. Thought it was the common reservoir leak so I did the bypass, put a new reservoir inside behind the glove compartment along with a new check valve. When doing that I found the original vacuum line was cut somewhere down under the heater/AC box where the original reservoir and check valve is located. I did not tear in to the box so did not actually see what is in there. For that mod I used the original vacuum line and ran it through a new hole in the firewall, connected the new components inside. That line is now very easy to follow and is not damaged, the dash vents work correctly. I didn't modify the original vacuum line at the engine, it all seemed very straight forward when I did it. Do not remember anything about other vacuum components around that area.
Do an engine vacuum test at idle and at maybe 1500-2000 RPM---if its around 22" I'd not worry about the chewed parts. If the HVAC system is working and you have 22" or so of vacuum it would appear you don't have anything more to check for rat damage.
I checked the vacuum using the OBD II, getting a reading right at 22" at idle and also at 2000 rpm. Reading does drop when tapping the accelerator so I believe the readings to be good. So that indicates no vacuum leak. I will take it out for a test drive next week just to verify there are no other issues. Still can't explain the chewed parts. Thanks for the help.
Frankly I'd check vacuum with a dedicated gauge---not sure the OBD-ll reading would be a usable value as it might be measuring relative vacuum rather than what the engine is actually experiencing. IMHO anyway..................
Frankly I'd check vacuum with a dedicated gauge---not sure the OBD-ll reading would be a usable value as it might be measuring relative vacuum rather than what the engine is actually experiencing. IMHO anyway..................
Did the test with a dedicated gauge and there is a slight difference, 21" at idle and 23" at 2000 rpm vs. the OBD II reading around 22" at idle and 2000 rpm. There are small variations in the digital values from OBD II readings.
For a test I disconnected the vacuum line to the dash vents at the check valve I rerouted 2 yrs ago and found no difference in the vacuum readings at the engine. The vacuum leak is too small to notice on the vacuum gauge but I can feel the vacuum at the end of the line. This is a very thin vacuum line so not much volume.
So this tells me there is no major vacuum leak.
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