Have I missed any steps when priming/changing fuel filters?

CCousins · 11-24-2019, 01:14 PM

Hi, I’m about to prime these fuel filters (unfortunately I have let the tank run too low and the engine is spluttering and not running right before bogging down and stalling) I kick myself for this!

So I’ve decided to get some new fuel filters and go from there (just put 2 brand new batteries in to help)

I will half fill the tank this week, then as far as I’m aware do I need to screw that white valve in that says “lock”?
It appears stiff to turn.. is that normal?

Once that’s in, I’ll unscrew filters and fill them with clean fuel and put back on with a nip of oil on the seal, then unscrew the valve?

Few more questions.

I’ve read about some priming pump but not sure where that would be? If my bus has one (1983 internal Wayne 9.0 diesel)

If I have an airlock and the bus starts up but rough, would that push any air through or would an airlock still stop the engine running right and idle rough?
In which case would cracking the fuel rail at the block until fuel comes out be okay to bleed it?

Once again everyone on here thank you so much for any advice.

o1marc · 11-24-2019, 01:37 PM

I have heard a lot of people say priming the filters is not good. They have yet to convince me. Their reasoning is by pouring nasty clutter filled fuel into the filter can glog the system. I wonder where they are getting their fuel from. Some say it is not an issue. I have heard that if you must (I do), fill them, use clean fuel and pour it into the small holes around the perimeter of the filter. This way it will filter as it reaches the center of the filter.

Brad_SwiftFur · 11-24-2019, 04:39 PM

I've always seen the shops I visit prime the fuel filters - prefill the spin-on versions, or (partly) fill the reservoir on the cartridge types. I've always seen them use clean, fresh fuel. Usually no more priming is needed, they simply start the engine and let it do its thing to purge any remaining air.

CCousins · 11-25-2019, 12:58 AM

Thanks! Yeah I will for sure fill the filters with clean diesel, would anyone know where a possible priming pump would be located on the engine?
Looking at the second photo with the black filter, if I took that square plug out would I need to adapt and buy a pump or something to fit into that to prime up some fuel?
Thanks!

Native · 11-25-2019, 02:13 AM

In the first photo, on the left ... there is a large light blue cylinder with a white top. I believe the white top is the pump handle and the light blue thing is the priming pump. It is similar in design to the one I put on my CAT 3126. To use it you will need to unlock the handle then move the handle out and in ... many times. Do this until it gets so hard to pump that you just gotta quit. On the last push in, lock the handle.

Warning: I do not have the same engine as you do ... but it sure looks like a priming pump.

banman · 11-25-2019, 09:09 AM

Quote:

Originally Posted by CCousins

Thanks! Yeah I will for sure fill the filters with clean diesel, would anyone know where a possible priming pump would be located on the engine?
Looking at the second photo with the black filter, if I took that square plug out would I need to adapt and buy a pump or something to fit into that to prime up some fuel?
Thanks!

I couldn't find my pic of when I went through this but -- get a hose plug of the correct size to thread into the center hole of your filter. Then you can easily fill the filter without getting any dirt in -- all fuel will go through the filter. After doing that I didn't even need to use my priming pump -- I tried it, and it was immediately stiff! Started right up!

Quote:

Originally Posted by Native

In the first photo, on the left ... there is a large light blue cylinder with a white top. I believe the white top is the pump handle and the light blue thing is the priming pump. It is similar in design to the one I put on my CAT 3126. To use it you will need to unlock the handle then move the handle out and in ... many times. Do this until it gets so hard to pump that you just gotta quit. On the last push in, lock the handle.

Warning: I do not have the same engine as you do ... but it sure looks like a priming pump.

Weird -- mine came with a priming pump -- assumed it was standard...

CCousins · 11-27-2019, 01:12 AM

Quote:

Originally Posted by Native

In the first photo, on the left ... there is a large light blue cylinder with a white top. I believe the white top is the pump handle and the light blue thing is the priming pump. It is similar in design to the one I put on my CAT 3126. To use it you will need to unlock the handle then move the handle out and in ... many times. Do this until it gets so hard to pump that you just gotta quit. On the last push in, lock the handle.

Warning: I do not have the same engine as you do ... but it sure looks like a priming pump.

Interesting that I wasn’t 100% sure what the purpose of it was for I assumed it may have been a bleed screw but I’ll have a look tonight and see what it’s about. Great! Thank you!

CCousins · 11-29-2019, 12:52 AM

For anyone wondering, Yep it was a priming pump as above,, we just brimmed the filters and screwed them on, we gave the pump about 100 pumps but didn’t appear to get any more difficult to pump, so braved it, air box off with some QuickStart ready sprayed down the intake and gave it some throttle before turning it over on new batteries. Started straight up! When unscrewing the old filters they biased air out and were only partly full of fuel, so must of been full of air.. thanks

Native · 11-29-2019, 01:59 AM

Excellent! Glad to hear your motor is running again.

EastCoastCB · 11-29-2019, 04:11 AM

Quote:

Originally Posted by o1marc

I have heard a lot of people say priming the filters is not good. They have yet to convince me. Their reasoning is by pouring nasty clutter filled fuel into the filter can glog the system. I wonder where they are getting their fuel from. Some say it is not an issue. I have heard that if you must (I do), fill them, use clean fuel and pour it into the small holes around the perimeter of the filter. This way it will filter as it reaches the center of the filter.

https://www.youtube.com/watch?v=P6MLDH0zTpw

Truthseeker4449 · 11-29-2019, 07:43 AM

I believe fuel filters should always be prefilled with the cleanest source of fuel available poured down the outside holes. Many fuel filters, even Fleetguard ones, come with caps on the centers to enable this. If you don't on a 6.7l Cummins you probably will burn the starter up before you get the engine to run and idle smoothly. Even if you prefill, it can take a while before the engine will run.

I didn't know about that fuel fitting though, definitely need to check and see if my CAT has one.

Booyah45828 · 11-29-2019, 08:32 AM

I almost never prefill filters. The only time that I do is when there is no primer pump or electric lift pump. Then, and only then, do I plug the inner hole with an appropriately sized threaded plug and o-ring, and fill from the outer holes.

When you're dealing with pumps and injectors that have such tight tolerances, the particles that can cause damage won't be visible to your eye. So I really don't care how "clean" you think your fuel is. It's dirty compared to what they want it filtered to.

As you've found out, the white handle is your priming pump. There is sometimes a schraeder valve to depress or a pipe plug you can remove to let the air out while you pump.

The 6.7 cummins should have an electric lift pump that does the priming for you. Most cummins engines from about 1998 have had one. I can go through the procedure if you'd like, just let me know what vehicle it is in.

CCousins · 11-29-2019, 11:45 AM

Yeah I figured I would always prime the filters, it kind of proves it that they were half full when I unscrewed them and it was equally struggling to start. If it meant less pumping for the engine for it to start than surely that’s a better thing.
We prime everything at the Exxon refinery I work at as per OEM instructions.
I didn’t fill the filters from the outside of the holes either, it’s clean new fuel and brand new Jerry’s and when I think that I’ve read that people run these busses and old machinery on all sorts of things including old engine oil and a mix of diesel, or old cooking oil etc. It’s kind of incomparable in terms of the quality of fuel going into an engine which I had put in. Not to mention the quality of the diesel that was around 40years ago compared to today. The bus most likely has a lot looser tolerances than anything of today’s standard, and less sensors to block up or trip. But it’s always good to get different opinions and ideas as it’s a talking point to say the least. Cheers!

CCousins · 11-29-2019, 11:49 AM

I will add that I got some ether start from the mechanics at work and when it cranked over you could see it suck straight in. Started over like it was on dynamite! Hopefully won’t need to use it again will only keep it for a rainy day/low battery’s or something

Booyah45828 · 11-29-2019, 02:44 PM

Quote:

Originally Posted by CCousins

I didn’t fill the filters from the outside of the holes either, it’s clean new fuel and brand new Jerry’s and when I think that I’ve read that people run these busses and old machinery on all sorts of things including old engine oil and a mix of diesel, or old cooking oil etc. It’s kind of incomparable in terms of the quality of fuel going into an engine which I had put in. Not to mention the quality of the diesel that was around 40years ago compared to today. The bus most likely has a lot looser tolerances than anything of today’s standard, and less sensors to block up or trip. But it’s always good to get different opinions and ideas as it’s a talking point to say the least. Cheers!

If you're prefilling, fill through the outside holes.

It doesn't matter what fuel they use, as long as it's clean and filtered. People run into reliability issues all the time using wvo and wmo when it isn't filtered or heated to a level that it should be.

Yes new diesels are more sensitive, and there may not be sensors to block or trip up on an old diesel, but the manufacturing tolerances are still tiny in the injection pump between the barrels and plungers. Delivery valves also take a beating due to dirty fuel.

You may not screw it up immediately by doing it wrong, but it was obvious when I was rebuilding pumps which places changed filters correctly and which didn't.

Truthseeker4449 · 12-01-2019, 08:31 AM

Quote:

Originally Posted by Booyah45828

The 6.7 cummins should have an electric lift pump that does the priming for you. Most cummins engines from about 1998 have had one. I can go through the procedure if you'd like, just let me know what vehicle it is in.

Ok sure, I like learning.

2016+ Freightliner with the black fuel filters
2013-2015 F-650

Also we have 2013 Maxxforces that give us fits trying to prime them, I've seen some of the older guys reach for the ether more than once.

Booyah45828 · 12-01-2019, 07:54 PM

Quote:

Originally Posted by Truthseeker4449

Ok sure, I like learning.

2016+ Freightliner with the black fuel filters
2013-2015 F-650

Also we have 2013 Maxxforces that give us fits trying to prime them, I've seen some of the older guys reach for the ether more than once.

Every Cummins should run the lift pump for a few seconds when the ignition is turned on. What many don't know is that if you bump the starter, the ecm will run the pump for a minute or so, bleeding the system of air and priming the filters. So, on the freightliner, bump the starter with the key returning to ignition on, and the pump should run and prime the filters. I think the fords are the same.

If you have an auto-crank feature(some do), you'll just have to key on, wait 10 seconds, key off, wait 10 seconds, and repeat that a bunch of times.

Maxxforce 7 or one of the inline versions?

Truthseeker4449 · 12-05-2019, 01:39 AM

Quote:

Originally Posted by Booyah45828

Every Cummins should run the lift pump for a few seconds when the ignition is turned on. What many don't know is that if you bump the starter, the ecm will run the pump for a minute or so, bleeding the system of air and priming the filters. So, on the freightliner, bump the starter with the key returning to ignition on, and the pump should run and prime the filters. I think the fords are the same.

If you have an auto-crank feature(some do), you'll just have to key on, wait 10 seconds, key off, wait 10 seconds, and repeat that a bunch of times.

Maxxforce 7 or one of the inline versions?

Sorry for the belated response. Thank you, I'll try that on the next Freightliner I PM.

We have Maxxforce 7s and 9s, about 13 of each. God what a pile of junk they are, but they are paid for and make enough to keep fixing them. The 7s are in our IC ACs, which resemble Terrastars. The 9s are in IC HCs, I think we've had to put a new engine in every one of those. Nearly all of the 9s sound terrible and are very loud while they are idling.

EastCoastCB · 12-05-2019, 06:00 AM

Quote:

Originally Posted by Truthseeker4449

Sorry for the belated response. Thank you, I'll try that on the next Freightliner I PM.

We have Maxxforce 7s and 9s, about 13 of each. God what a pile of junk they are, but they are paid for and make enough to keep fixing them. The 7s are in our IC ACs, which resemble Terrastars. The 9s are in IC HCs, I think we've had to put a new engine in every one of those. Nearly all of the 9s sound terrible and are very loud while they are idling.

Everyone I talk to with a fleet of later Navistar products seems to hate them.

How do you like the 3126. I like it a lot. Seems to be really well put together. Mines is smooth and quiet.

Truthseeker4449 · 12-05-2019, 11:02 AM

Quote:

Originally Posted by EastCoastCB

How do you like the 3126. I like it a lot. Seems to be really well put together. Mines is smooth and quiet.

I'm pretty satisfied. Mine does vibrates a bit at idle, especially cold but as soon as I kick the rpms up it smooths way out. I am told it sounds like a trash truck from the end of the street but at speed its fairly quiet at the front of the bus.

Starts easier than the 7.3 in my pickup. Got an oil seap on intake side of the motor. I think the fan setup on this bus will give me more fits than the engine will.

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