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Air in Fuel, Filter head or in-tank pump?
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Author:  painemann [ Mon Jan 30, 2012 10:43 am ]
Post subject:  Air in Fuel, Filter head or in-tank pump?
Well I have the dreaded air in the fuel and hard start after a long sit.
I do plan on doing the in-tank pump soon but I don't have the parts or the time right now. If the block heater is plugged in over night (its cold here) it starts with much less hesitation but with out the heater it takes excessive cranking to start. It also sounds like crap and has a raw diesel small after a cold start w/o the block heater.
I have the old filter head (with heater unplugged), would that be a good place to start?
I found the new filter head online for around $86+ shipping.
Is there a good way to pressurize the system and check for leaks?
Thanks.
Author:  papaindigo [ Mon Jan 30, 2012 11:13 am ]
Post subject:  Re: Air in Fuel, Filter head or in-tank pump?
There are a number of possible "leak" points in the system:
1. the quick disconnect fittings in the fuel line between the tank and the inlet on the fuel head - as far as I know those don't leak fuel out but they can leak air in as they were designed for the gasser KJ which puts pressure on the system with an in-tank pump.
2. around the fuel head (lines in/out, loose bleeder screw, double inner gasket on filter, loose filter, loose WIF sensor). IMHO best check is to bleed the fuel head (see the video on Sam's NOOB guide although I use a clear vinyl tube leading to a plastic jar to catch the fluid for less mess and I can see when air bubbles stop) until you get a hard bleeder pump and then use paper towels to look for leaks which will show instantly as a damp spot on the towel. The new fuel head generally runs ca. $125 including the new wiring pigtail and a new filter installed with WIF sensor. If you have found the whole deal for $86 I'd grab it as good preventive maintenance. Note - when I had air problems on a 1s gen head the source was a really tiny leak at the heater plug which you could barely see under pressure.
3. lines to the CP3 and injectors, around the base on each injector (the "O" ring and crush washer at the injector base can go if the injector clamp(s) get loose) and return lines that send excess fuel back to the tank - again the paper towel trick is useful but I suspect checks of these areas need to be done with engine idling especially "downstream" from the CP3.

As to fuel pumps. I know lots of folks like/love the in tank pump and that's fine. However, I'm not a fan of the in tank pump. Our system uses a "puller" pump mounted at the engine much like back in the old days when most all gas engines had a mechanical cam driven fuel pump on the engine block. In those days if you wanted an electric pump you installed same AND removed the mechanical pump with a plate to block the hole in the engine block to avoid haveing 2 pumps in the system. You cannot remove the fuel pump from the CRD engine if for no other reason than its pulley is an integral part of the timing belt routing hence whatever option you choose will have 2 fuel pumps (stock and the one you add). Because of that it's imperative that whatever you add fails "open" so that fuel can continue to flow pulled by the stock fuel pump in the event the other pump fails to operate - I think the intank pump may allow this but I'm not sure. The common in line pumps (Facet 40109, pump for 6.5L GMC TD Kennedy, etc) all do flow if not operating. I like the in-line pumps for several reasons 1) no need to drop the fuel tank, 2) inexpensive with the 1st 2 options being about $60 with hardware, 3) extremely easy to install in the engine compartment (seems to take like 30 minutes) but can be installed back near the fuel tank by splicing into the existing harness for power, 4) regardless of install location easy to replace if need be. I will agree that the in tank pump probably does a better job of preventing air intake through those quick disconnects but they can be removed and replaced with hose and hose clamps.

Look around for how too's on both types of installs or if you drop me an email I can reply with attached examples.
Author:  warp2diesel [ Mon Jan 30, 2012 11:36 am ]
Post subject:  Re: Air in Fuel, Filter head or in-tank pump?
Lift pump works great for bleeding out the air. Airtex sells a great pump, check Sir Sam's posts and check some of the older posts in the CRD Tech section.
Even a Facet or Carter pump slapped onto the line and wired into the wires that go to the pump under the rear seat works better than the suck system cobbled together by the Bean Counter Engineers. In the tank is best close to the tank is second best, fewer connections the less chance of air leaking into the system (may Isac Newton Rest In Peace).

Ignore all the Fear Mongering from the Descendents of the Flat Earth Society who try to scare you away from lift pumps or pull their Bean Counter Engineering Talking Points about how pressure on the inlet side of the CP3 will trash the pump (they need to put Exlax investments into their 401Ks). On Cummins Common Rail Engines that use a larger version of the CP3 have jacked up their inlet pressure to ~20PSI with no problems and report great results.

As far as the Bean Counter Engineers go, tell your HR managers they should get you the latest generation of beans that have GPS transponders in them so your Spread Sheet Crunchers can micro manage every move you make. :ROTFL: :ROTFL: :ROTFL: :ROTFL: :ROTFL: :ROTFL:
Author:  Joe Romas [ Mon Jan 30, 2012 12:59 pm ]
Post subject:  Re: Air in Fuel, Filter head or in-tank pump?
Mine had a stubborn air leak that showed up on it's maiden voyage home from the dealer in May of 2006 :banghead:
Since it was not a constant problem and dealers knew little about our CRD I got the "could not duplicate" rubber stamp :furious:

Others were having the same problem and I installed one under the hood using Black Liberty's methode to verify air in the fuel was the problem, there were two problems that caused similiar symptoms pre f37 :roll:
I considered under the hood faucit pump a test or a temporary solution :)
About that time I installed trailer wiring and discovered a "prime pump" relay and fuse already in the power distribution box in front of the battery :ALONE:
Another traced the wire to under the rear seat :shock:
Yet another, maybe GMCTD, discovered the pump from a Cummins powered Dodge fit our application :BANANA:
So for many that was a clear sign of what should have been :BINGO:

Air was the problem and the jeep ran much better so I installed a intank lift pump and have never looked back. That was 6 years ago :-)r

It sure makes filter replacement easy :POPCORN:

Some think the new style fuel head is a cure all for air in the fuel :?

Others look further and view the fuel head as a victim of another problem and cure that problem instead, yeah if it's melted it needs replaced :wink:

If you keep the air from building up in the filter head it will not overheat and then leak. I still have my original fuel head :JEEPIN:
Author:  BlackLibertyCRD [ Mon Jan 30, 2012 1:15 pm ]
Post subject:  Re: Air in Fuel, Filter head or in-tank pump?
Joe Romas wrote:
Others were having the same problem and I installed one under the hood using Black Liberty's methode to verify air in the fuel was the problem, there were two problems that caused similiar symptoms pre f37 :roll:
I considered under the hood faucit pump a test or a temporary solution :)

Some think the new style fuel head is a cure all for air in the fuel :?

Others look further and view the fuel head as a victim of another problem and cure that problem instead, yeah if it's melted it needs replaced :wink:

If you keep the air from building up in the filter head it will not overheat and then leak. I still have my original fuel head :JEEPIN:


I been running the faucet pump for about five years now and it hasn't missed a beat. So it's not a temporary solution unless you want it to be. You are right about the fuel head replacement of treating the symptoms and not the problem. If the heating element is not submerge in fuel it will overheat no matter how big the connector is. I still have original fuel head also and don't plan on replacing it.
Author:  jeepdan [ Mon Jan 30, 2012 7:26 pm ]
Post subject:  Re: Air in Fuel, Filter head or in-tank pump?
Joe Romas wrote:
Mine had a stubborn air leak that showed up on it's maiden voyage home from the dealer

Air was the problem and the jeep ran much better so I installed a intank lift pump and have never looked back. That was 6 years ago :-)r

It sure makes filter replacement easy :POPCORN:

Some think the new style fuel head is a cure all for air in the fuel :?

Others look further and view the fuel head as a victim of another problem and cure that problem instead, yeah if it's melted it needs replaced :wink:

If you keep the air from building up in the filter head it will not overheat and then leak. I still have my original fuel head :JEEPIN:

Hi Joe, What pressure is your older Cummins lift pump delivering at the filter head? I would REALLY like to know to help settle my
Flat Earth Society fears of reinstalling the Airtex pumps that I bought.
Author:  Greasey Bob [ Mon Jan 30, 2012 10:32 pm ]
Post subject:  Re: Air in Fuel, Filter head or in-tank pump?
It sounds like a clogged filter to me. When was the last time the filter was changed. It should be changed every fall before it starts to get cold. The CP3 pump sucks thought the filter creating pressure. When you turn it off it releases the pressure and when the filter is clogged it creates an air pocket. Most of the time it will start and then die and have to be re-preimed. The cold weather makes it worse. Lift pump makes it much better. Just my experiance.
Author:  painemann [ Tue Jan 31, 2012 1:32 pm ]
Post subject:  Re: Air in Fuel, Filter head or in-tank pump?
It does get worse with cold weather and I did just replace the fuel filter. I can bleed air out every time it sits for a good period of time. I haven't tried to re-bleed it since I put the new filter on, maybe I'll try that tonight.
I think I'll try and pick up a new filter head, I found the one for $86 at jeepcarparts1.com but I am not sure if it comes with the wiring harness pigtail or now.
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