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Air in fuel ideas?
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=86919		 Page 1 of 1
Author:  its1louder [ Mon Jul 24, 2017 8:22 pm ]
Post subject:  Air in fuel ideas?
I've been dealing with air in fuel problems lately. The long story is that when I first got the jeep around 2012, I replaced the fuel filter housing with the upgraded one, it fixed a recurring air in fuel problem that we were having. A few months ago, my wife drove the jeep to Mexico and couldn't get it to start. It seemed like fuel delivery problem because it cranked strong. I have shown her how to bleed it and keep a couple spare 11mm wrenches in the car for just such an emergency. She was not able to get it running and some good samaritans not knowing what they were doing smoked the electrical system trying to jump it. A very expensive tow across the border ensued. We took it to the dealership in national city and they decided it needed a new fuel pump in the tank. Expensive, but they did it.

IT's run fine for a couple months since then but every now and then it gets air in the fuel line and stops. We have been doing a lot of priming at the fuel filter. It has been ok but I wonder if the hose got damaged where it attached to the new fuel pump at the tank. Anyway, after opening the bleed valve and tightening it so many times in the last month I think we have damaged it. It is a metal part screwed into abs plastic and I think horking it down too tight has dmaged the threads and made it so the bleed valve won't seal. I can't get it to start at all now even when I bleed extensively.

So the first thing I am doing is ordering a new fuel filter housing. It's easy to replace and not too expensive and It just seems like the bleed valve doesn't tighten up like it should, so my first question is has anyone else done this, I've never heard of it happening. Once I do that I should be back in the situation where I have been the last couple months, where if it has sat longer than a couple days I need to bleed it and then it runs fine all day. I will want to figure out where the smaller leak is tho, and if there are suggestions about replacing the fuel line back to the tank as I suspect that's what I will have to do.

THX!
Author:  papaindigo [ Mon Jul 24, 2017 9:18 pm ]
Post subject:  Re: Air in fuel ideas?
Not that I'm overly cynical but my initial suspicion is the dealership in National City (San Diego) area took you for a ride and did NOT install a fuel pump in the fuel tank. A) the CRD never had a fuel pump in the tank and B) while a fuel pump can be installed in the tank it requires adding wiring under the back seat. If I had to guess if the idiots did anything in the fuel tank they simply replaced the CRD fuel tank insert which contains a fuel level sending unit only but lacks the fuel pump. Further if in fact they installed a fuel pump in the tank when you first turn the ignition "ON" without cranking the engine you a) should hear the pump run and b) if it in fact runs if there are any leaks in the system (only way air can get in) there would be diesel spraying out of those same points (for example a bleed screw that no longer seats) and c) is a corollary of b) in that a fuel system pressurized from the fuel tank forward CANNOT "ingest" air short of fuel in the tank being extremely low.

Could be wrong but....
Author:  its1louder [ Tue Jul 25, 2017 12:52 pm ]
Post subject:  Re: Air in fuel ideas?
I think I misunderstood how the fuel system works. I thought there was a lift fuel pump in the tank but after reading more online it looks like there is not unless someone puts it in aftermarket. I need to dig up the paperwork from the visit to the dealership because I am not sure now what they did.
Author:  papaindigo [ Tue Jul 25, 2017 4:16 pm ]
Post subject:  Re: Air in fuel ideas?
Nope, hence my reply. The CRD's fuel pump is the CP3 (fuel injection pump in the parts fiche) located on the front of the engine and driven by the timing belt. It's designed to a) "pull" fuel from the tank thru the filter and b) pressurize the fuel rail that feeds the injectors. The CRD in tank unit is similar to, perhaps identical to, the gas unit EXCEPT the CRD unit lacka the fuel pump and only serves as a fuel gauge sending unit. Nothing inherently wrong with an engine mounted pump, they have been around for decades, but DCJ went cheap (no surprise) and fitted the CRD with the gasser fuel lines that have a couple of quick disconnect fittings back by the tank. Those fittings are designed to seal best under internal pressure which is lacking due to the front pump hence they can allow air to be sucked into the system back by the tank.

A common "fix" to air in the system is to retrofit a combination fuel level/fuel pump (ex. Airtex E7181M) in the fuel tank which serves to "lightly" pressurize the fuel system all the way to the CP3. Good and maybe in the short term bad. Good = no air leaks. Short term bad = any leaks between the tank and the CP3 will immediately start leaking fuel and need to be fixed.
Author:  TKB4 [ Wed Jul 26, 2017 8:31 am ]
Post subject:  Re: Air in fuel ideas?
I agree with everything papaindigo stated. However, much easier quicker and cheaper to at least temporarily put external tank lift pump in easiest is in engine compartment put under battery tray. I have 3 CRD with the Kennedy lift pump mounted underneath on frame with no problems whatsoever that are fuel related since installing them over 5 years ago. I have one that I did the lift pump in the engine compartment about a year ago and no problem with it and much cheaper and easy to install ( about $40 to $50 ).

I also totally agree theoretically that pressurizing whole fuel system is better but for more money and several hours more time and messy I haven't seen any practical need for it. If the crd had an easily accessible access plate in back floor above tank I would probably do it that way or make one as some have. Then at least if you had to replace in tank pump again it would be simpler and quicker.

I would definitely replace the fuel head but you might want to change to rakor or other head up to you I haven't but many have.


I did have one fuel head that the bleeder valve would not seat in my threads were not stripped. I removed the bleeder and looked in thinking there might be an o ring or something replaceable in it . The bleeder valve is just a kinda cone shaped end that screws in to block off opening i didn't see anything replaceable or fixable and still can't figure out why that one wouldn't seal. no trash etc was in it.

Temporarily if you needed to run it immediately you could get a filter meant for a diesel lawnmower such as a Wix 33972 the hose connections are smaller but will work. of course you won't have the water separator function while using it. i keep this one as a spare in vehicle glove box as a spare in case needed on the road. You could probably prime it by using wd 40 to run engine till air out of system or just fill filter and line with diesel holding both above fuel head and also fill line toward engine fuel pump then connect the fuel pump line to the filter.

Unless you put an in tank pump in you definitely need to run a fuel line from tank to front lift pump etc though it may work without it. I used 3/8 inch fuel injector line I believe i bought 12 feet though 10 probably enough. I left a foot or so extra so I can remove filter head from bracket and pull it up to easily to change the filter.

If you need any help or other info feel free to pm me.

I think many might want to keep this little filter Wix 33972 in jeep for failed fuel head temporary fix it will keep you on road while waiting for permanent fix and filter the fuel ok. Of course, you could just use barb connector to connect without a filter but I would definitely not want to chance this and if you had recent water in fuel I wouldn't even do either way temporarily.
Author:  papaindigo [ Wed Jul 26, 2017 1:41 pm ]
Post subject:  Re: Air in fuel ideas?
FYI the fuel head bleeder screw is identical to brake bleeder screws (pointy end; holes just above that end; bottoms in an inverted "V" in the head to seal) but it has a functional problem in that it screws into an, IIRC, aluminum filter head. Given repeated bleeding the aluminum threads and or seat are going to get boogered and the bleeder won't seal.

Cheap fix - pop the bleeder off and head to a parts store or good hardware store. You are looking for an adapter that will thread into where the bleeder screws in that will allow installation of a valve like in this picture (not the saddle thingy but the valve) https://www.google.com/search?q=refrige ... QQwJDhluTM: . The adapter and valve should total less than $10. Screw adapter into fuel head; screw valve into adapter; add a bit of vinyl hose so bleeding can be directed to catch can and you are done. Back when the CRDs were new you could buy a kit to do this but I don't recall the vendor and they stopped selling the kit some years ago anyway.

In line pump works if quick disconnects are not leaking air too bad. Facet 40109 is fine and cheaper than Kennedy.

My underlying issue though goes back to I suspect he got screwed by the dealer, whether he can collect for the screw job is another question.
Author:  its1louder [ Mon Jul 31, 2017 6:45 pm ]
Post subject:  Re: Air in fuel ideas?
Thanks for all the support.

So the vehicle seemed to be working for a while and I did a long 130 mile trip with no problems. Then after sitting 2 days at that destination I again experienced intermittent stalls. So I towed it home and now I am about to put a replacement filter housing in. I don't think it was the original problem but I've messed up the bleeder valve after so much fiddling. After I get it out I may look at modding it with a valve similar to the suggestion below. Since I don't expect the new filter head install to fix the problem I had with intermittent stalls, here are some observations and maybe the brain trust can throw up some suggestions.

    1) after it has sat for a while, it will often start right up and run fine. If I leave it idling, it will run for like 5-10 minutes and then stall.

    2) once it stalls I open the bleeder and lots of two phase bubbles spray out. It takes many pumps to get a good clean air free flow coming out.

    3) then I hork down the bleeder valve and try to start. Usually, I can't get it to start. Sometimes I can but it will run for less than a minute or so.

    4) sometimes while it is idling I will go to turn on the a/c and it stalls. I think this is a coincidence, but it has happened twice so it seems worth watching.


I suspect the problem is that these quick connects I read about at the gas tank are leaky, dependent on temperature/thermal expansion. It seems like the solution folks recommend is to put another fuel pump in line but shouldn't it also be possible to replace/upgrade the fuel lines to the fuel tank? Or even just slather a bunch of RTV on the quick connects? if I put the rear end on jackstands can I reach the tank quick connects?

as far as getting screwed by the dealership, I guess they just replaced the fuel pump at the engine. As far as I know that was in need of replacement. IT worked reliably for a month or two after. Current problem may not be related or it may be a stronger newer pump has started sucking harder on weaker quick connects. I just moved and it's hard for me to find my docs right now so I can't dig up any receipts just yet.

THX!
:5SHOTS:
Author:  WWDiesel [ Mon Jul 31, 2017 10:21 pm ]
Post subject:  Re: Air in fuel ideas?
Do your vehicle and yourself a huge favor, install an in-tank lift pump and all your air in fuel problems will be gone forever. It will put the entire fuel system under pressure from inside the fuel tank all the way to the back of the CP3 injection pump. Air cannot leak into a pressurized system!!!
Any leaks that were air ingestion leaks will immediately become external fuel leaks and become self-evident so they can be repaired.
There is no better mod than adding an in-tank lift pump to your Jeep CRD!!! :roll:

See these two threads for additional information:>
viewtopic.php?f=5&t=85697

viewtopic.php?f=5&t=26385
Author:  its1louder [ Thu Aug 03, 2017 11:35 pm ]
Post subject:  Re: Air in fuel ideas?
OK. It is definitely correlated with turning on the air conditioner. When I bleed it and get it running, I can let it sit there idling and reliably, if I turn the AC on it will stall within a second.
Author:  WWDiesel [ Fri Aug 04, 2017 8:50 am ]
Post subject:  Re: Air in fuel ideas?
its1louder wrote:
OK. It is definitely correlated with turning on the air conditioner. When I bleed it and get it running, I can let it sit there idling and reliably, if I turn the AC on it will stall within a second.

If you are still getting air in fuel, that needs to be addressed first and rule out that problem before trying to address others! One bite at a time...
and if you still have the stalling when turning on the AC after resolving the air in fuel issue, then you need to look at the AC compressor and see if it is locked up or if it is not, then is there is an electrical problem...

:5SHOTS:
Author:  its1louder [ Tue Oct 03, 2017 3:22 pm ]
Post subject:  Re: Air in fuel ideas?
For completeness, I'll record the end of this tale here. So the pump in the gas tank didn't fix the stalling problem, much to my surprise. I took it in to a diesel specialist who determined that the crank shaft sensor was failing. He replaced the part and it seems to have fixed the problem, but I'll have to put more miles on it to be sure. Anyway turns out I didn't need the lift pump, but maybe it's a good thing to have anyway.
Author:  APC9199 [ Tue Oct 03, 2017 5:06 pm ]
Post subject:  Re: Air in fuel ideas?
its1louder wrote:
For completeness, I'll record the end of this tale here. So the pump in the gas tank didn't fix the stalling problem, much to my surprise. I took it in to a diesel specialist who determined that the crank shaft sensor was failing. He replaced the part and it seems to have fixed the problem, but I'll have to put more miles on it to be sure. Anyway turns out I didn't need the lift pump, but maybe it's a good thing to have anyway.


I've thus far not installed a better modification to my CRD. The only things that compare to the usefulness of the in-tank pump are the EGR delete and GDE tune. Maybe the ARP studs also? You didn't waste any money doing the in-tank pump is what I am trying to say.
Author:  WWDiesel [ Tue Oct 03, 2017 8:53 pm ]
Post subject:  Re: Air in fuel ideas?
its1louder wrote:
For completeness, I'll record the end of this tale here. So the pump in the gas tank didn't fix the stalling problem, much to my surprise. I took it in to a diesel specialist who determined that the crank shaft sensor was failing. He replaced the part and it seems to have fixed the problem, but I'll have to put more miles on it to be sure. Anyway turns out I didn't need the lift pump, but maybe it's a good thing to have anyway.

It is a very good mod, right there with EGR delete, so you did good! Be happy, your Jeep will thank you for it in the long run!!! :BANANA:
Author:  its1louder [ Sun Nov 26, 2017 1:59 pm ]
Post subject:  Re: Air in fuel ideas?
another thing I noticed since getting the gas tank lift pump installed, the fuel gauge is not calibrated correctly now. The mechanic who did it for me said he followed the instructions on line and replaced the float arm. However, the gauge always reads 25% higher than it really is. It seems to work fine at a full tank except the computer guesses that there is about 75 miles greater distance to empty than usual. When it gets down to quarter tank, the gauge will suddenly go to zero and the low fuel alarm will sound. I can live with this since I know how to read the gauge now, but I'd rather recalibrate it if that is possible. Maybe putting a series resistor in the sensor wire?

As far as the stalling problem, I've got about 1000 miles on it since the crank sensor was replaced and it seems to have solved the problem.
Author:  GordnadoCRD [ Sun Nov 26, 2017 3:09 pm ]
Post subject:  Re: Air in fuel ideas?
Putting a resistor inline with a rheostat of unknown range of value, with current of unknown value, sounds like an exercise in frustration of unknown value.

The only things that could cause the gauge to read off as you describe after doing this is, EITHER, he used the wrong float arm, OR he didn't get the unit in lined up with float arm perfectly side to side, and the float arm is contacting the front of the tank and hanging up a little. This could happen if he didn't trim the locating tab to align it correctly.

The rheostats are the same, so it's one or the other of those two.

Seriously, it's really less of a problem to do it, or have it done, right, than to cut up a perfectly good wiring loom and experiment with resistors.

EDIT: There is perhaps a way you could check this without pulling everything clear apart. This is based on the fact that a properly installed lift pump float and arm should never contact the tank.
1)Drain the tank completely (this is REALLY easy with your newly installed lift pump.
2)If you have a tank skid it needs to come off.
3)Loosen the tank straps so it hangs loose just a little.
4)Take a rubber mallet or if you've got a pretty good fist, you get the idea. You will see a molded in set of curves that look a bit like ( ). The pump is held under spring pressure right in the middle of those. You want to give a nice stout thump directly under those curves. If you hear something inside bounce, then they used the wrong float arm. If they use the right one, it will be up high enough that the curves won't contact them and won't bounce.
Author:  WWDiesel [ Sun Nov 26, 2017 3:44 pm ]
Post subject:  Re: Air in fuel ideas?
its1louder wrote:
another thing I noticed since getting the gas tank lift pump installed, the fuel gauge is not calibrated correctly now. The mechanic who did it for me said he followed the instructions on line and replaced the float arm. However, the gauge always reads 25% higher than it really is. It seems to work fine at a full tank except the computer guesses that there is about 75 miles greater distance to empty than usual. When it gets down to quarter tank, the gauge will suddenly go to zero and the low fuel alarm will sound. I can live with this since I know how to read the gauge now, but I'd rather recalibrate it if that is possible. Maybe putting a series resistor in the sensor wire?

As far as the stalling problem, I've got about 1000 miles on it since the crank sensor was replaced and it seems to have solved the problem.

Sounds to me the unit is not clocked correctly in the tank and the float arm is making contact with the side of the tank. :roll:
When installing the new unit with a pump, it is important to trim the index tab and clock the unit in the same position as the OEM unit was!
Sounds like a tank drop may be in your future???? :(
Author:  95Z28A4 [ Sun Nov 26, 2017 3:53 pm ]
Post subject:  Re: Air in fuel ideas?
WWDiesel wrote:
its1louder wrote:
another thing I noticed since getting the gas tank lift pump installed, the fuel gauge is not calibrated correctly now. The mechanic who did it for me said he followed the instructions on line and replaced the float arm. However, the gauge always reads 25% higher than it really is. It seems to work fine at a full tank except the computer guesses that there is about 75 miles greater distance to empty than usual. When it gets down to quarter tank, the gauge will suddenly go to zero and the low fuel alarm will sound. I can live with this since I know how to read the gauge now, but I'd rather recalibrate it if that is possible. Maybe putting a series resistor in the sensor wire?

As far as the stalling problem, I've got about 1000 miles on it since the crank sensor was replaced and it seems to have solved the problem.

Sounds to me the unit is not clocked correctly in the tank and the float arm is making contact with the side of the tank. :roll:
When installing the new unit with a pump, it is important to trim the index tab and clock the unit in the same position as the OEM unit was!
Sounds like a tank drop may be in your future???? :(


I had to trim a tab on the Carter pump assembly to clock it to prevent the arm from contacting the inner tank wall. The float arm isn't exactly parallel with the tank like the factory float arm, but it easily clears the tank wall. I used the float and float arm that came with the Carter pump. The fuel gauge is accurate.
Author:  its1louder [ Fri Jan 19, 2018 6:52 pm ]
Post subject:  Re: Air in fuel ideas?
So the mechanic who did it left town so I can't ask him any of these questions. I guess I will just live with it until I have some time to drop the tank myself. Time is something I don't have lots of, unless that govt shutdown happens...
Author:  GordnadoCRD [ Fri Jan 19, 2018 7:01 pm ]
Post subject:  Re: Air in fuel ideas?
It's easy to check the clocking of the pump unit.
Basically the fittings that come through the top piece need to be pointed straight towards the rear of the vehicle (oem clocking) or the front of the vehicle. Either way works fine as long as it's parallel to the direction of the vehicle.
If you choose front of the vehicle, the OEM plastic push-lock lines will not work. I just replaced them with good all-fuel grade hose. (silicone) That's a mod I really recommend no matter which way it's installed so you can use diesel, bio-diesel, etc without causing problems.
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