Priming the fuel filter/system

Probably this applies to all Sprinters. I know it works on my 2002. When changing out a fuel filter, you can pressurize the fuel tank at the fuel cap and fill the filter and lines. An air compressor set to 15 psi and a seal on your air nozzle (even a rag wrapped around the air nozzle) will readily fill the lines and the filter. Unscrew the bleed valve on top of the filter, pressurize the tank, and you'll see overflow on the top of the filter. Tighten the bleed screw and you're set to start.

Blisspacket.
15 psi is way to high, you could split your tank open. I have used this method but only about 1 PSI max. Eric.

Eric Experience said:

Blisspacket.
15 psi is way to high, you could split your tank open. I have used this method but only about 1 PSI max. Eric.

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all i do is put hand primer on return pip off filter pump till you get fuell pipe back on start simple

blisspacket said:

Probably this applies to all Sprinters. <snip>

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I know that NCV3s are self-priming (one or two cycles of 30 second key on/don't start) will prime the fuel system.

Yeah, this is the T1N section.

I thought 2004-2006 US/Canada Sprinters were (also) self-priming.

-Jon

jdcaples said:

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Yeah, this is the T1N section.

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YES IT IS BUCKO!!!!

Oops. Hormones again.

jdcaples said:

I thought 2004-2006 US/Canada Sprinters were (also) self-priming.

-Jon

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Yep. All NAFTA (I know it isn't a correct term, but we all understand the geographic area it refers to.) Sprinters from MY 2004 up have in tank fuel pumps and are therefore self priming. I suppose that there are some MY 2004 (2005?) RV's that have older running gear, but normal NAFTA Sprinters don't need fuel priming after MY 2004. vic

I just changed my fuel filter this past weekend. I did the self-prime method (turn key on/off numerous times), but decided to see if I could prime it myself.

With the WIF sensor out, I tilted it back and forth and had fuel trickle out of the old filter to the new.

I didn't get it all transferred (like two tablespoons worth), but what level of fuel is considered primed?

Even if we use the method stated in the first post, I would guess there would be some (compressed) bubbles left in the system. Does the method evacuate all air pockets within the system?

sikwan said:

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Even if we use the method stated in the first post, I would guess there would be some (compressed) bubbles left in the system. Does the method evacuate all air pockets within the system?

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Sikwan,
You don't mention your model year. Many of the longer term members here add that info to the signature. If you're not sure of how to do that I'm certain one of the moderators can help you.

The few times I've had my fuel system apart (mostly for filter changes) on my 2004 I've noticed a slight lag on starting for the next day or so. Not a big difference, just maybe a half crank extra time. After the first day (related to # of starts?) it's back to normal. My theory is that not all the air bleeds out right away so there's a bit of a starting lag while that air compresses until it's all gone. So my answer is, "No. All the air is not gone by bleeding." Just observation and theory though. vic

I prime the system by pumping diesel through the filter using a syringe, or a blister pump on the supply line, to prime the whole system. Other wise you can crank forever. You can watch the bubbles in the plastic lines and prime until they are clear.

Aqua Puttana said:

Sikwan,
You don't mention your model year. Many of the longer term members here add that info to the signature. If you're not sure of how to do that I'm certain one of the moderators can help you.

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Added above my avatar.

sikwan said:

Even if we use the method stated in the first post, I would guess there would be some (compressed) bubbles left in the system. Does the method evacuate all air pockets within the system?

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Don't the 647 fuel filters have a bleed screw like the 612s do?

hkpierce said:

Don't the 647 fuel filters have a bleed screw like the 612s do?

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There is the water in fuel drain if that's what you mean. The in-tank fuel pump pushes the fuel and air around and eventually back to the tank so there's no real reason to bother with air bleeding based upon my few experiences with my 2004. vic

On my '02, the bleed screw allows the filter to be drained when the WIF sensor detects water (or, when replacing the filter). How do you drain water (or fuel) from an '04's filter?

talkinghorse43 said:

How do you drain water (or fuel) from an '04's filter?

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You have to turn the key to the ON position (no engine start or run) with the water valve open at the top. The electric pump in the fuel tank will start pumping away. The water valve is connected to a straw extended to the bottom of the filter where the water sits (if any).

I just tried this method, and it does not appear to work (2002). Maybe my seal was not good enough, but I suspect that there is a pressure relief valve of some sort in the fuel tank that prevents if from working (at least for me). I started with very low pressure (barely felt any air coming out of the compressor, and slowly got it up to 20 psi - no fuel flow at all. I used a foam rubber block to seal the hose / fuel filler port with. I did manage to drop a nipple from my compressor hose into the fuel tank (brass, so I am not sure how I will get it back out).

I did get a new fuel filter in, but I now need to get the prime back.

Did you crack the vent screw on the top of the filter?

Yes. - I also popped the fuel intake hose off - nothing came out (I sealed up the opening on the filter with my finger tip) I will play with this tomorrow (it was getting dark when I stopped). I will also get some Diesel to try to manually prime it.

I did get it to work, but I never got much fuel flow. I ended up at 30 PSI (My compressor is one of those that you use to run a nail gun with, so its not real high output to begin with).

I fully prefilled the fuel filter (using 1 foot of 3/8 inch hose with a funnel on one end to pour Diesel into) at the fuel intake. I unscrewed the bleeder and made sure fuel was bubbling out.

I cut a larger chunk of foam in a circle (about 4 inches in diameter - ie. approx 100 mm) and cut a small slit in the center - enough for the nozzle to fit thru. It was all very sloppy, but the intent was to seal much as possible at the fuel tank filler.

My van is parked on a slight incline - which may also have some effect.

When I lifted the fuel hose up higher than the fuel filter I got very little Diesel flow, so I took a small funnel and primed that hose (while the fuel tank was getting pressurized), then attached the hose to the filter and clamped it on. I waited until I got fuel dribbling out of the bleeder vent then started the van.

I did this a few times (it started each time, but the fuel never pulled from the tank and eventually stalled). The last time, I left the air pressure hose in the fuel tank - started and let idle for 10 minutes with the added air helping. Afterwards, I pulled the pressure hose and restarted. All is good now - I don't see any air in the lines (2002) and its running fine.

I suspect that the foam I used leaks quite a lot of air, which required the extra air pressure.

I'm an expert at running out of fuel.

I can confirm that my 2003 313 is a self primer!

I fill with diesel, turn ignition on for 40'secs and switch off. Do thisn3-4 times then try tonstart pumping accelerator. If it dosnt start after 15 secs max STOP! Any longer and battery may start to die. Repeat 40 second theory and it should then work.

I have had to do this a few times and it works

My 313 is an Australian version if that's any help.

Even now, my '02 with no in-tank pump will start unprimed (my last change was on the side of the road with no access to extra fuel), but the total cranking time (I go 10 sec at a time) could be up to 1 minute - just like my owner's manual says. I usually fill the new filter with fuel after changing through the recycle port (dirty side of the element) and that greatly reduces the cranking time (usually starts immediately and then dies, but sometimes starts as normal and continues to run (at idle, missing from time-to-time) while air is cleared).

So, the fact that a T1N will start unprimed doesn't necessarily mean it's fitted with an in-tank pump.