MPG/Air/Fuel Issues since Installing Racor

PathFinder7 · **Posted:** Wed Dec 05, 2012 2:43 pm

So, my issues continue. It all started with replacing the OEM filter. After I put the new one in, the mileage dropped off significantly and I smelled fuel constantly, even after a full degreasing. I figured like many, my filter head was no leaking so I followed the awesome instructions here and replaced the filter head using the Racor 245R with the Omega temp sensor. The CEL was on, but then cleared and all seemed ok. However, the smell of diesel is still prominent and my MPGs are GARBAGE! I have a bad speed sensor so it's hard to tell, but it seems like I'm getting between 10-15 MPG. A trip around town and I can see the gauge move, and it's a very small town. I'm assuming air in the system is what is killing my MPGs?

I've checked my connections and clamps and they all seem good. I removed and reseated several, including the output line from the filter into the injector input. I used a hydraulic sealant on all the new connections and they are seated tight. I'm not sure where else the leak could be.

Does any one have any ideas, tips or suggestions? This is my first diesel and I'm still learning the basics. Is it possible I messed up a line somewhere? It doesn't seem to be actually visually leaking fuel, but that oil is going somewhere....

Thanks

warp2diesel · **Posted:** Wed Dec 05, 2012 5:43 pm

I don't see a Lift Pump in your Signature, Amazon was selling the Airtex for $122 a couple weeks ago and Rock Auto has had them for ~$137. The Airtex in tank pump will get rid of air leaks that are getting sucked into the fuel system and can cause running and loss of fuel economy issues.
Outside of Academia Theory and the Bean Counter Engineering Water Cooler talk, air leaks into the fuel system of a Common Rail Diesel engine, retards injection timing resulting in power loss and fuel economy at the same time. Excess EGR, stuck open EGR, or an intake clogged up with carbon crud will cause a loss of fuel economy too. Since the BS about having pressure on the inlet side of a CP3 pump has less truth to it than other forms of Mythology, Serious Common Rail Diesel Owners have increased their down stream fuel pressure to 20PSI or more with only positive results. Since all the line fittings on the CRD were designed for pressure and not Vacuum, the Airtex pump used also on the Dodge Cummins is a great improvement. Adding another inline pump in addition will increase the performance and reliability even more.
Excess soot from an over active EGR (personally any EGR is excessive to me) in your oil will trash out your rockers, clog up the oil passages in the cylinder head, and can trash out your Turbo Bearings as well causing Turbo Failure. Using a good high zinc CI4+ oil along with a bypass filter or centrifuge will keep the soot from trashing out the engine.

4.10 gears are for climbing trails and having fun, not getting great mileage. Looking at the list of your mods, they are not the ones for peak fuel economy either.

You might want to fix the problems with your CRD, enjoy it on the trails, and use it in bad winter weather if that happens in your neck of the woods. Then, pick up a daily driver that gets great fuel economy like an ALH engine VW TDI.

papaindigo · **Posted:** Wed Dec 05, 2012 6:12 pm

My personal experience with air in the fuel filter head is that the engine simply won't run. Less air in the fuel lines may let the engine run but poorly at best and would certainly hurt mpg. Of more concern to me though is your constant smell of diesel fuel which to me is indicates a fuel leak not an air in the fuel problem. I'd start as close to the fuel tank as possible and look for a fuel leak. Possible locations include:
1. fuel line quick disconnects.
2. at the filter head and around the filter even if new.
3. between the filter head and the CP3 pump, not sure how accessible the fittings to the pump are but check if possible.
4. same for the other side of the CP3 up to the injectors.
5. leaks in the injector rail, supply from the rail to each injector, etc.
6. leaking at the injector base - makes the area filthy, fix is to remove injector(s) reinstall with new crush washer and "O"ring.

Best thing I've found for looking for leaks is a dry paper towel as moisture shows immediately.

PS. Warp is right about the 4.10 gearing. Prior to my GDE tune my in town short cycle driving mpg was like 18-19 on summer fuel. I'd expect 4.10 gearing to cut that to more like 16-17 and winter fuel maybe a bit more but that still doesn't explain the smell which worries me.

warp2diesel · **Posted:** Wed Dec 05, 2012 7:15 pm

To address the smell, also check the return line junction fitting where the injector return line, return line to the tank, and CP3 return line join together, it may have cracked. I made a replacement for mine out of brass fittings from the local Hardware Store. Also check the return line fittings on your injectors, they can fail and leak. Since the eturn line is not under a vacuum, it can leak.

papaindigo · **Posted:** Thu Dec 06, 2012 6:40 am

warp did you ever post a how to or pictures of your brass fitting replacement?

PathFinder7 · **Posted:** Thu Dec 06, 2012 1:08 pm

Thank you both for outstanding replies, it is greatly appreciated. I may not have explained things as well as I should have. I need to be clear that it is not a general MPG issue. I have had the gears and all other parts in place for a long time and I have been quite happy with my 24 MPG average. I have found a great balance in daily driving and off road capabilities and have no desire to sway to either side of the line while sacrificing the other.

As to mods, I cleaned my MAP sensor about a year ago and the MAF has been disconnected since I bought it, no issues there and the EGR should be a non-issue. I would love to get the lift pump, but I just don't have the time to put it in right now with a full time job, school, two boys 50% of the time and the holidays. Maybe next spring...

My concern is simple: Before I changed my stock fuel filter, all was well. I was getting about 24 MPG average and there was no fuel problems. The change was a simple filter change, that's when I started smelling the fuel and I figured I had a bad seal with the filter or some such. I removed it all, then refitted it. After driving it for a while, I would bleed the system and constantly get a LOT of air out of the bleeder. After some research, I figured the filter head had brown stinkies the bed so I decided it was Racor time. I followed the directions on here and replaced that without major issue, bleed the system, then power washed the engine bay. Since then, the smell of fuel is still quite strong and the MPG is total crap now, estimated from a pre filter install of 24 MPG to about half that now. Not sure if this is relevant, but when I pump the Racor primer and the pressure builds up, I can hear a release of pressure where the outlet hose from the filter head enters the hard fitting under the CAC hose. I removed that line, inspected it, trimmed it and reinstalled, but that persists. I never noticed that before with the factory head. Pressure would build and the primer would be near impossible to pump with your hand until it was bleed off.

Papaindigo, I will check out the list of leak locations you provided, I greatly appreciate that. Some of those locations are unknown to me, do you have any pics of where they are? I would imagine that if there is a leak in the system, it was caused by my removing and reinstalling the original filter since that is when it began. I tried to be gentle with the lines, but I am a bit of an ogre and finesse is not my thing. I would speculate that the leak is somewhere on the hard fuel lines from the tank and the injectors based on this. However, that is just guessing...

Thanks again to warp and papa, you guys are why I love this board.

-Rob

dgeist · **Posted:** Thu Dec 06, 2012 1:24 pm

I had lots of issues with the factory head as well which were mitigated various ways, except for the smell from seepage out the heater port. I eventually replaced the head with a stanadyne (similar dimensionally to the Racor) and had some leakage at the fittings. I resolved it with teflon tape even though the manufacturer says not to. One thing that was a constant was that I could ALWAYS tell where the leak was by simply spraying a little simple green all round, hosing it off, letting it air-dry and then running it. Diesel leakage is easy to spot with a flashlight (really shiny). One thing to mention though is that the mileage never got as bad as you describe, so it might be good to see if the pressure washer might have gotten water in other bad places and if there are any engine error codes that might be making the computer control things badly.

Dan

papaindigo · **Posted:** Thu Dec 06, 2012 1:55 pm

I don't have pictures of the locations but you should be able to get a decent idea if you go to Sir Sam's NOOB guide and download the Factory Service and Parts manuals (FYI I recommend getting both the 05 and 06 FSMs as the 05 lacks diesel cooling system info and diagnostics but has illustration keys while the 06 is the reverse).

Thoughts:
1. FYI the 1s gen fuel head was prone to leaking due to burnt insulation at the fuel heater connection. Some found an obvious leak others, myself included, could barely detect the leak by sticking a "Q" tip into the fitting. Other leak points for both OEM fuel heads include a bad seat for the bleed screw; a bad seal on the primer pump shaft; mismatch between hose ID and OD of fittings; and when changing the filter failure to remove the small inner seal from the shaft the filter screws onto (doubling up that seal prevents the outer seal from seating) or not seating the water in fuel sensor correctly. How or if any of this translates to a Racor install I don't know.
2. I'm not totally sure what hard fitting you are referring to under the CAC hose and don't feel like digging into my engine bay to check but I suspect it's the feed to the CP3 in which case I would think there should be zero release of pressure at that location. That sounds like a fuel leak point that could be significant; perhaps the fitting itself is loose; you might take a look at Figure 14-430 in the 06 parts manual.

Comments:
1. very bad idea to pressure wash the engine bay. As dgeist suggests this can induce water into electrical connections and cause all sorts of issues. At minimum you might want to unplug your ECU connectors and check for moisture. When cleaning engine bay IMHO it's much better to warm the engine (not hot), apply an engine degreaser (I use GUNK spray), wait a bit, and rinse (very light spray) off being carefull to avoid any direct pressure spray on electrical connections.
2. lift pump. Installation of a Facet in the engine bay (see part 2 at viewtopic.php?f=5&t=24527&hilit=automatic) is like a 1 hour job. Helps with air in the lines and might apply enough pressure to help find what appears to be a significant fuel leak. An in tank pump or a lift pump install back by the tank may be better but the engine bay install is quick and easy and seems to work.

PathFinder7 · **Posted:** Thu Dec 06, 2012 5:34 pm

That inline pump sounds like a much better plan, at least for now. I see talk of using the bigger Facet @ 42 GPH, is there any benefit to this? Also, I see the operating temperature is potentially an issue, have you heard of any problems with that?

papaindigo · **Posted:** Fri Dec 07, 2012 9:11 am

There has been a lot of discussion on the forum regarding psi. Keep in mind that the CRD already has a fuel pump (the CP3) but it "pulls" fuel from the tank (just like old style engine block mounted pumps) rather than pushing fuel from the tank (like newer style intank pumps). The CRD fuel system was cribbed from the KJ gasser which has an intank pump so the gasser fuel system is under pressure from the tank forward in contrast to the CRD fuel system which is not under pressure in that area which is likely why air leaks into the system between the tank and the CP3 as fuel is pulled from the tank. The consensus seems to be that any added lift pump or intank pump should be relatively low psi and should also be a flow thru design so if the pump fails the CP3 can still pull fuel from the tank.

So, I think that you need to look for a low psi Facet like the 40109 which is a 4-7psi/32gph pump that can be obtained from http://www.yachtsupplydepot.com/mechani ... t_697.html . Operating temp. should not be an issue at least I've never seen a post that it's an issue. Of course it cannot be an issue mounted back near the tank. As to an in the engine bay mount doing so on the driver's side away from the exhaust/turbo should keep it well away from any really hot areas.

PathFinder7 · **Posted:** Fri Dec 07, 2012 8:43 pm

Great input brother. Thanks so much for taking the time to educate me on the ins and outs of all this, I really appreciate it.

I'm gonna go ahead and order the Facet pump you recommend as well as poke around a bit to see if I can find the leak. Since I suspect the leak is before the CP3, I doubt I'm gonna find it until I put the pump on, but it's worth a look. I'll post my findings on here if I sort it out.

Thanks again.

-Rob

MPG/Air/Fuel Issues since Installing Racor

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