Diesel Fuel Pressure

Phil №❶ · **October 07, 2011, 06:53:28**

Can anyone tell me what pressures exist in the fuel line at the entry to the fuel filter. I want to add a glass filter, before the factory filter, so I can see contaminants & purge easily. The factory one will remain due to warranty issues and the water sensor, which I don't want to compromise at all.

**Reply #1: October 07, 2011, 07:57:34**

I'm reasonably certain that there is no pressure at all. I believe the diesel fuel pump resides directly on top of the filter and sucks from the fuel tank at the back of the car. This is why if you run out of fuel you have to re-prime the pump manually. If the pump was in the tank then it would self prime. The inlet to the fuel filter is also above the tank height. Also proven by the fact that when I took the inlet pipe off the filter no fuel poured out.. Remember too that if you get a proper sight glass to view contamination it will be quite robust.

2i30s · **Reply #2: October 07, 2011, 08:03:02**

as far as i know a diesel engine has a mechanical fuel pump and not an electric one. [but i may be wrong about the i30] the fuel pump is on the engine block and not in the fuel tank.

2i30s · **Reply #3: October 07, 2011, 08:06:19**

Quote from: Steve R on October 07, 2011, 07:57:34

I'm reasonably certain that there is no pressure at all. I believe the diesel fuel pump resides directly on top of the filter and sucks from the fuel tank at the back of the car. This is why if you run out of fuel you have to re-prime the pump manually. If the pump was in the tank then it would self prime. The inlet to the fuel filter is also above the tank height. Also proven by the fact that when I took the inlet pipe off the filter no fuel poured out.. Remember too that if you get a proper sight glass to view contamination it will be quite robust.

you just beat my post Steve.

[i own 2 petrol i30's]

**Reply #4: October 07, 2011, 11:06:33**

Well just to confuse further I believe there is an electrical pump mounted on the fuel filter which feeds low pressure fuel to the mechanical high pressure fuel pump driven directly by the engine. It is a recirculating system whereby any fuel that the high pressure mechanical pump doesn't need is returned via a bypass back to the tank. The electric pump is recirculating a loop of fuel round and round returning to the tank any excess. This is how any diesel or petrol fuel system has worked for years.

Phil №❶ · **Reply #5: October 07, 2011, 12:01:33**

So when we run out of juice, the electric pump will deliver fuel to the filter from the tank & we hand pump from there to the HP pump, right!

**Reply #6: October 07, 2011, 12:05:04**

I don't think there is a pump in the tank. The recirculating electric pump on top of the filter sucks the diesel from the tank (once it's been primed) and delivers it to the HP pump, the excess returning to the tank via the return line.

Phil №❶ · **Reply #7: October 07, 2011, 12:15:04**

Lakes · **Reply #8: October 08, 2011, 21:58:30**

hi 847563, i've seen people mount the second glass filter on diesel's b4, but were all old style diesels not common rail. & all on trucks not small car's. i think you might have a problem finding a good mounting point. also to purge the diesel to remove any water you see in the glass filter, you have to drain diesel fuel out ( very messy also it damages bitumen ). it is not that often you have trouble with water in fuel. i have not had any problems with water in diesel personally & have driven millions on killometers over the years. but i know people who have had the missfortune to fill up with contaminated diesel, but only one or two i know who damaged there motors. & the oil company covered the costs. ( not saying oil companys always cover those costs, just the few i know had that covered by the oil co's ) the others i know that never had damage & got contaminated fuel, just kept having the fuel waning come on to indicate water in filter, they just had to keep replacing the fuel filter.
i don't think i would worry, as the way i look at it is the glass filter is just one more thing that could give you trouble & they are very messy & a problem on a small car to mount. but if you go through with it , it would be interesting to see pictures.

Another thing i thought i might mention is, never attemp to drive your car through a flood, a guy i worked with had a two tonne Toyota diesel truck, that had the exhast pipe exit low like our i30's not up like a normal truck. he drove through a flood to get home, once as the detour was 80k, water went into the motor via exhast & Hydraliced the motor. just thought i would mention this.
good luck what ever you do.

Phil №❶ · **Reply #9: October 08, 2011, 22:26:30**

lakes

Thanks kindly for your detailed reply, I will take the info under advisement.

Paolo5 · **Reply #10: October 09, 2011, 06:50:53**

I too have thought about the logistics of fitting a glass bowl filter to the fuel line of my diesel and went to my local auto parts store and looked on ebay but never took it any further than that.

Let me know how you fare with this pursuit, 847563.
Cheers,
Paolo

Phil №❶ · **Reply #11: October 09, 2011, 09:13:26**

paolo5

Thanks for your interest.

The 1st problem I have is it is actually my wife's car, so convincing her to do mods will be difficult. We should consider the response from "lakes" as to just how necessary this mod actually is. I wish there was a clear option for the existing filter.

Why I want to do it.

The filter & it's fitting cost is far too high in my opinion, unless you do it yourself. Fitting a glass filter separator should cancel any requirement to change the factory filter, saving money.

Through normal use, depending on your climate (humid /dry) there will inevitably be a build up of water in the tank, this could take years, months or weeks but it will be there. 1 bad fill from contaminated fuel adds to the problem and it can be a lot in 1 fill. A glass gauge will show water easily and will continue to show until all the water is purged. The factory option would be to see the water indicator come on, replace the filter, (a lot of work / money) drive the car & have the light come on again, repeat, repeat repeat, until finally all the water is gone, no thanks I'm not doing that!

Even the busiest garage tanks will condense water inside them when they are nearly empty from the air inside the tank, so to me sucking up water is like playing Russian roulette.

Water in the breeds things apparently, and we don't want that.

I have a post asking about the breather pipe location for our tanks (no reply yet), I intend to silica gel the air into the tank making it dry & I think eliminate tank condensation from that area as well.

Funky · **Reply #12: October 09, 2011, 23:13:02**

The 2.0 CRDi has an electric priming pump in the fuel tank. This will supply around 3bar of pressure at the filter housing.

The 1.6CRDi U & U2 has no electric pump. The fuel is pulled from the tank via a geared pump that is incorporated in the High pressure pump.

Phil №❶ · **Reply #13: October 09, 2011, 23:55:48**

funky

**Reply #14: October 18, 2011, 09:54:08**

Quote from: 847563 on October 07, 2011, 06:53:28

Can anyone tell me what pressures exist in the fuel line at the entry to the fuel filter. I want to add a glass filter, before the factory filter, so I can see contaminants & purge easily. The factory one will remain due to warranty issues and the water sensor, which I don't want to compromise at all.

i have a 05 hilux ute diesel that has a glass bowl fuel filter before the factory one after i had the car a year it die took it to toyota they said i had water in the filter and it was going to cost me $7500 to fix no warranty now my i30 is dead and in the shop it is the fuel pump

Dazzler · **Reply #15: October 18, 2011, 10:31:26**

Hi Lindlake .. Nice to see you back (first post for 3 months) but sorry to hear about your car...

Just the fuel pump? Hopefully no other damage? (sounds like you've been hit with the unlucky stick)

Phil №❶ · **Reply #16: October 18, 2011, 10:43:48**

lindlake

Like the others, sorry to hear about your troubles. If you had a glass filter how come water got into your engine, didn't you see it in the glass

**Reply #17: October 18, 2011, 11:31:37**

i put it on my hilux after the water got in to late my i30 went to the shop today i hope it is only the fuel pump it was getting harder to start and blowing black smoke now it will not start and there is no smoke when it turns over

Phil №❶ · **Reply #18: October 18, 2011, 11:35:28**

See, this is my whole point, I30's need glass filter housings. How did the water get in, bad fuel or long term condensate.

**Reply #19: October 18, 2011, 11:47:27**

in my hilux i put in a long range tank 140 lt that is made of steel that condensate. from the hot diesel from the fuel pump in the i30 it is plastic i looked in side the fuel tank very clean and no water before i sent the i 30 to the shop ang change the fuel filter

**Reply #20: October 19, 2011, 08:58:30**

just a update on my i30 it looks like a cracked fuel filter housing and two glow plugs dead just waiting on parts

Phil №❶ · **Reply #21: October 19, 2011, 09:00:26**

Could have been worse!

**Reply #22: October 26, 2011, 10:37:36**

look like my i30 needs a new fuel pump now it is still blowing black smoke the service man said have not been offer a loan car yes my i30 will not be back for to next fri if i am lucky new fuel pump and rail new fuel filter housing

**Reply #23: November 07, 2011, 07:34:21**

i am still waiting for my i30 we might get it by fri at less now i have a loan car for free

Phil №❶ · **Reply #24: November 07, 2011, 07:39:21**

Good, hope it comes back ok.

**Reply #25: November 11, 2011, 09:02:37**

still waiting for my i30 new fuel pump new fuel filter housing and still not running ok blowing smoke

Phil №❶ · **Reply #26: November 11, 2011, 09:54:30**

So what's going on

**Reply #27: November 14, 2011, 07:45:30**

ok got phone call today looks like it is number 3 injector is jamming open causing the smoke and hard to start so i have a new fuel pump for free

Dazzler · **Reply #28: November 14, 2011, 07:49:00**

**Reply #29: November 17, 2011, 06:54:50**

got my i30 back today it is the same as before it went in to get repaired blowing heaps off black smoke

they now saying that it is the injector that are blocked which i have to pay for up to $900 each