Onan 5500 Marquis install 2009 36Max1

Onan 5500 continuing saga.

I have done too many projects in between so lost track.

Finally got enough semi original pipes for the exhaust got it working but the bend in the exhaust that fit the proper downtube (I ordered a lot of different ones) was 5in too long going down (it would have hit something eventually) and 4in too short to properly get out from under the coach..sigh..

Proper exhaust downpipe 1/1/2in and Cummins pipe from the parts manual was 1 ¼. Bought “the other one” listed and it was the right size and could use 1 ½ size EMT to fit over the outside of the cummings 1 ½ … yeah confusing but 4 trips the muffler guy and pipe supply, and we have legal and not going to break or kill us with CO from the gas exhaust.

All the while testing, the combination of the new carb worked well and ran properly… until… over 100-degree weather. The genset dies within about 45 minutes to an hour of running if running both ACs. There were no more issues with the governor; now it just plain dies, error code 36.

Cool down ½ hour and it restarts but repeats within 15-30 min

Here is the error code sequence, for I could not find it documented anywhere. Just in videos

Onan Error Code reading

Stop or Prime button 3 times in 5 seconds.
Series of blinks (3)
Press prime button one more time
Then get a series of blinks
First series of blinks, then pause, then second series of blinks
Reset and erase code, press the prime button 2 times
Ie:  blink 3 times, pause and blink 6 times, error code 36

Had already ordered a “replacement” Carbole pump (Ebay) with 4075 good reviews rather than purchasing a Cummins $244 fuel pump. Amazon will not ship “replacement” auto items to where I live in California.

The “perfect” replacement was less than perfect, but changed the oil and replaced the broken heat spacer between the carb and engine. Had ordered the new original Cummins gaskets for the carb replacement. But they had not arrived when I replaced the carb.

Needless to say, the fuel pump did not fit, and I had to hacksaw off part of the mounting tabs, but I got it installed. It fired right up and really sounded good, but the same issue, only shorter now, would not start until it cooled off for at least an hour. I ran it with the doors closed, Both AC’s on, outside temp 107.

I went into the Victron because I had temp sensors taped to the Onan, top of the shelf, and the normal one on the Lithium batteries. It gets hot in there.

I was also not happy with the fit and using a hose clamp between the pump and the carb (it needs the crimp type) to fit properly (I made a wire clamp). I was also concerned I might be boiling the fuel by adding the extra fuel filter, but that was probably not a problem. So I went down to the local NAPA and bought a real $90 FACET pump, fuel lines, and fittings to see how they worked. They works perfectly. Generator put out more KW, ran both AC’s and ran the whole afternoon in 108 temps, with the front bay doors open but I think this is how it is supposed to run.

The Facet is noisy but I may just find a place to mount it on a pad or wood, to lessen the decibels. I did order a 12V 14” radiator fan for the front bay cutout to exhaust heat buildup.

I have looked everywhere for the Airtex E11015 Electric Fuel Pump that is the OEM, but nothing comes up. I will make some calls to RV parts places claiming to have “OEM” but somehow I think Cummins has pulled all the gross profit into their coffers. I don’t even mind paying $150 but $250…huh

In a week of on and off testing the FACET has kept the gen running perfectly. Temps 115 to a balmy 108 today. Ran the gen non stop for 11hrs and not a hiccup.
I did order a factory “rebuilt” E11015 off Ebay for $32 and will give it a shot tomorrow.Hopefully NOS stock.

Got the 14in fan and it would not fit if using the stock “mounting ears” so ordered a 10 in “reversible flow” fan and a 12V 10 amp PWM controller to slow it down.
You have to change the polarity and flip the fan around, but easy. Tested the PWM and installed it in the vent area of the forward compartment pushing air out of the front generator compartment.
Blows a LOT of heat out. 11 hrs of running and the little 16 gauge wire is hot. (only 6.6 amp draw)

The gen temp got to 200, battery temp to 135 and tray temp to 145, which is only 20 degrees higher than not running the gen. Yes 120 degrees F in the front compartment, no gen running.