Air in fuel line after changing filter

[1ciderdog]

I've put over 100K miles on this motor home and have changed the fuel filter numerous times but this time I am unable to get it to run. It did start after the filter change, ran good, then ran rough and then quit. I do have the batteries on a charger to keep them up for starting. I've given it about 6 or 7 tires but no start and it doesn't seem to be trying to start.

My questions are:

How long can I run the starter motor without overheating it?

How long between starting attempts do I wait for the starter motor to cool?

Any idea of the number of attempts I'll need before it purges the air out of the injectors?

Any thoughts or suggestions appreciated.
Bob

[t55watson]

I had a similar prob and I dropped the filter again and found it not full of fuel. I filled it before installing the first time but it sucked some out on the initial start and then didn't pull fuel from the tank. A air pocket now at the top of the filter. I refilled the filter (topped it off) reinstalled and the motor started and ran fine.

[1ciderdog]

Originally Posted by t55watson

I had a similar prob and I dropped the filter again and found it not full of fuel. I filled it before installing the first time but it sucked some out on the initial start and then didn't pull fuel from the tank. A air pocket now at the top of the filter. I refilled the filter (topped it off) reinstalled and the motor started and ran fine.

Thanks for the reply. I changed the filter yesterday and filled it about halfway with diesel from my tractor. I removed the filter this morning and as you say it was way down on fuel. I filled the filter (again through the little holes) and tried starting it again about four times but no success. Will be giving it another try in the morning.

[bdpreece]

Remove the fuel cap and put an air hose in the inlet. Pack a rag around it and put about 40 lbs pressure to the tank while cranking the engine. You will need someone to hold the rag and trip the air hose but this will work.

[stuhly]

Fill the filter all the way. Every time. Don't listen to the Rocket Scientists and Brain Surgeons. Fill the filters and save your self a lot of grief, Just keep it clean.

[Family Time]

I always install the filters dry. I use a Mityvac MV7400 fluid extractor suck the fuel through the filters and purge the air. It works perfect every time with no mess. There is a threaded plug in the top of secondary filter housing that I remove, and pull the air out there.

[1ciderdog]

Originally Posted by bdpreece

Remove the fuel cap and put an air hose in the inlet. Pack a rag around it and put about 40 lbs pressure to the tank while cranking the engine. You will need someone to hold the rag and trip the air hose but this will work.

Thanks, I remember reading that this could work but didn't know how much pressure to use. I'll give this a try this morning.

Originally Posted by Family Time

I always install the filters dry. I use a Mityvac MV7400 fluid extractor suck the fuel through the filters and purge the air. It works perfect every time with no mess. There is a threaded plug in the top of secondary filter housing that I remove, and pull the air out there.

I wasn't aware of these devices. They sell for about $60 on the internet. I'll take a look at this as an option for future use. Also could use (I think) a hand vacuum pump to remove air from the filter but that won't help with my current problem. If this were a recurring problem I'd probably add a small electric fuel pump between the fuel tank and the filter. I did that with a diesel boat I used to have and that worked well on Perkins diesel.

[Skip426]

30 secs. of crank time then a minimum of 2 mins of cool down for the starter and batteries.
Is you coach only equipped with one filter?
Doesn't your Cat have a manual prime pump?

[loisjop]

Originally Posted by bdpreece

Remove the fuel cap and put an air hose in the inlet. Pack a rag around it and put about 40 lbs pressure to the tank while cranking the engine. You will need someone to hold the rag and trip the air hose but this will work.

X2 but I would start out with about 20 psi. You can't hold enough pressure with a rag to hurt the tank.
Also you can loosen the outlet line from the filter until you get fuel out then crank the engine after tightening the line. This will save a little crank time on the starter.
It does work!

[1ciderdog]

Originally Posted by Skip426

30 secs. of crank time then a minimum of 2 mins of cool down for the starter and batteries.
Is you coach only equipped with one filter?
Doesn't your Cat have a manual prime pump?

Thanks for the crank time and cool off time. This only has the one filter and it does not have a manual prime pump. I stopped by CAT a couple of years ago and they did not have a manual pump for this filter.

Originally Posted by loisjop

X2 but I would start out with about 20 psi. You can't hold enough pressure with a rag to hurt the tank.
Also you can loosen the outlet line from the filter until you get fuel out then crank the engine after tightening the line. This will save a little crank time on the starter.
It does work!

Thanks for the information.

[Family Time]

Originally Posted by 1ciderdog

Thanks, I remember reading that this could work but didn't know how much pressure to use. I'll give this a try this morning.



I wasn't aware of these devices. They sell for about $60 on the internet. I'll take a look at this as an option for future use. Also could use (I think) a hand vacuum pump to remove air from the filter but that won't help with my current problem. If this were a recurring problem I'd probably add a small electric fuel pump between the fuel tank and the filter. I did that with a diesel boat I used to have and that worked well on Perkins diesel.

This will work, I was in a similar situation as you the first time I used the fluid extractor. Now I use it every time I change the filters.

[bdpreece]

Bob,
Where is your filter located? You stated that you could not find a priming pump for your filter. When I had my 04 Cat C6 350 (same as the 330) I installed a priming pump on the engine itself. It was a fairly easy job only entailing the removal of two bolts taking off a cover plate and putting the pump in it's place. Not all coaches have room for the pump so you would have to pull the access cover in the bedroom and look but you can purchase the pump on ebay 1052508 Caterpillar Fuel Priming Pump Cat | eBay
Picture of plate to remove.
https://onedrive.live.com/redir?resi...nt=photo%2cJPG

[1ciderdog]

The filter is located aft of the radiator in the rear compartment. It is visible when standing behind the motorhome. It would be kind of a pain to have the pump located on the engine. That would require removing a part of the bedroom floor when changing filters.

[bdpreece]

Agree. My coach had two filters and one of them was located just below the pump so it was necessary to remove the access panel to change the filter.