coolin the diesel with a cooler and or using pre pump before injection pump NEED HELP

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motojunkie86

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Im wondering if anyone has used an oil cooler or anything else to cool the diesel before it gets to the injection pump, and im also wondering if anyone on here has used a pre injection pump, in other words an intank low psi pump to supply the injection pump with cooler fuel and take some load off the injection pump, I have heard a pre injection pump can give your IP a lot longer life or even assist a worn IP......
 
It greatly depends on your engine. CR engines run pumps at phenomenal pressures, with high flow rates. A lift pump has to be able to deliver enough flow so that the IP never starves (any pump in a hose is a restriction unless it's operating faster than the flow needs).

There are some people here that have two pumps, usually those that run a pair of filters and/or having an even finer filter than factory installed (fine filters are also restrictions).

As for cooling the fuel, 4WD models already have a fuel cooler but I think what you're looking for is something that cools the fuel before combustion.

Consider the scale involved here: the ability to reduce volume from a thermal change in two different substances will be more noticeable in the less-dense substance, and diesel is 540-something times denser than air. If you're going to chill something for performance benefit, do the air - that's what intercoolers are for, and there are better intercoolers out there than Nissan supply. Water to air, for instance.

If you're going to the expense of chilling the fuel so that you get more fuel in, a pressure raiser or injector duration extender would be more cost and power effective - you need motive power to drive the compressor to chill the fuel enough to get any benefit, and the chip uses a tiny amount of electricity.

If you're doing it for safety, consider something like a transmission oil cooler placed somewhere out of the way of general damage and away from the exhaust. It'll have enough flow rate to not impede things enough to bother the system.
 
its a zd30 d22, im having issues with power loss, so im covering all basis, the ute has been to a couple of very reputable diesel performance places with no proper diagnosis.

im going to add an intank pump to supply the injection pump, im thinking something around 6-7psi intank pump with a free flow valve if the intank pump fails so the injection pump can still pull up through it. it will help ease the IP and help cool the fuel.

I heard something about using coolers between the tank and IP, i have been searching and searching for info but there is very little, i know that 70 percent of the fuel gets recycled and warmed up, perhaps an oil cooler or transmission cooler would recool the fuel for the better combustion and benefit of keeping the IP electrics cool.

thankyou for the extra info Tony, do you think any of what im saying has any merit or its not worth a squirt of goats....?

it would be cheap to get a cooler and intank pump so that's why i thought its a mask up type fix :) ??
 
I have no idea if what your thinking will help, but surely this is a complicated solution to what surely should be a solvable problem.

Its a bit worrying though that 2 diesel specialists couldnt pin point anything.

How many kms? Could a compression test be in order?

Apart from that Im guessing youve done all the basics, Air filter, fuel filter leaks etc, cleaned/reset tps, nuetral position switch, lack of boost (turbo,waste gate related), maybe run some injection cleaner through, im running out of ideas.
 
have a look on patrol forum. quite a few use lift pumps on the zd30 engine. be aware that you have to mod the spill line.
the zd30 IP uses fuel as hydraulics to do the injection timing (like old VE pumps) so restriction on the fuel lines causes injection timing to retard. hence the common blocked filter (or air in lines) causing the 0707 injection timing fault code.

there is also a thread on coolers. they fit them on the return to the tank. bit of a gain in high temps. but thats on the patrol which has larger tanks than the navara. navara may have more to gain especially if you normally drive with half fuel tank.
 
is it a must to modify the spill line? I ask only because the diesel place here in SA that was going to put a lift pump on my navara mentioned nothing about the spill line...

is the fuel return line under much if any PSI? I wonder how much and if its better to have it in the return line or between the lift pump and injection pump?
 
its EXTREMELY important to mod the spill line.
the spill line is connected to the IP inlet side. ie the IP sucks fuel from the spill line, which is a good thing. but the spill line connectors on the injectors are prone to leaking. it can mean the ip sucks a bit of air in.
however if you add a lift pump the inlet line is now under pressure which also means the spill line is also under pressure. any leak in the spill line means fuel leaks into the engine oil.
diesel in engine oil causes bearings to fail, typically the turbo is the first to go.
there is a few patrols where this has actually happened. it was misdiagnosed and the replacement turbo also failed which blew the engine.

all that needs to be done is move the spill line from the inlet side to the outlet side.

a cooler is better on the IP outlet side. not being under pressure is a minor thing.
main reason is that the fuel is at its hottest. therefore the cooler will remove the most amount of heat. the 2nd thing is if on the inlet side, any air can be trapped in it causing air lock.
 
is there a different name for the spill line? as im looking for diagrams with one on google but cant find out.

found one never mind, seems its the return line from the injectors which flows back through the injection pump.... why does it flow back through the injection pump?
 
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I did one of these mods only a few weeks ago to my nav as i thought i was down a fair bit of power when i was out wheeling about a month ago. Mainly to see if this would improve power delivery a bit. I spliced into the lines from the fuel tank and used rubber lines from the steel bunting to connect to the new low pressure lift pump and back and a brass y piece in each side with a one way valve so if i ripped a wire off while out popped a fuse it should hopefully suck past the fuel pump. What i noticed after fitting the pump power improved throughout the rev range a little bit and idle became smoother but the motor was noticeably louder i suspect the pump or the injectors or both are a bit warn and that supplying a slightly pressurized fuel to the pump now has caused either a slight increase in fuel delivery or timing for the resulting increase in power and torque and maybe a little higher boost level measured on an in cab gauge.

I would still like to find where the rest of the ponies are missing from but haven't checked out much more then earths, connections and ecu codes. One afternoon when were quiet at work i would like to run it on the dyno and check air fuel ratios and actual power output to confirm that it is down(car has been on a few dynos and i no what it should be close to).

SO hopefully this is an interesting review for you to read and please get back to us with anything else you do to your car to get some power back to it as i would be keen on some other tested input with the car and what the results were for your lift pump install.

Also on a side note carrying out the spill line mod i found the fuel line to be a unique size and was quite hard compared to the other rubber lines i would factor in the cost of replacing the whole rubber hose to be safe shouldn't be too much i had trouble clamping the line at the ip inlet and again trying to get the hose onto a small brass T without it being loose, ended up using 1/4 inch barb and a considerable amount of hot water/ silicone spray to get them all on.
 
Howdy all, grate post.. I am planing to do a diesel cooler on mine - new pump or not... yes, do go read the 4x4patrol forum... some brilliant ideas and some very nice rigs..

Well i never knew about the spill line mod, missed that one.. i brought a 6mm and a 4mm brass barbed conectors and had Wide bay hydrolics in Gympie braze them together in a weird arse "y" piece..
Also had them weld up the "in " bango fitting...
New hose lines trough out to come... waiting on delivery 😉
 

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Now regarding a diesel cooler , I'm allllll for it ! .

Anything to help these pumps... I was planning to put it on the return line up under the tray with a fan..

I was thinking an alloy one, solid with radial fins but now thinking trans cooler with fan.. next project whilst i try to work out the issue i have with a " no start" ...

It's a bit tricky trying to get "AN10" fittings that reduce to 4mm lol might have to call on wide bay me thinks!

Being that i have the standard tank and i want to try for Alice then Darwin back down to perth, i think it's a must do!
Yes, I'm scared shiteless about braking down now... The only thing good to come out of this is the knowledge and confidence of how to work on these motors and electrical sensors etc
I hate to think of the mechanics bill trying to fix this no start ! Lol or a nissan stealers, it would be in the thousands by now... I'll post pics when I start on the cooler.. cheers
 
fuel return lines are 8mm.

a transcooler is the easy option for a fuel cooler as they often have barbed fittings rather than AN. if you go radiator style just watch where the outlet is. it needs to be on the high side so air can be pushed out. the long windy tube style don't have that problem but are less efficient.

i doubt you need a fan.

you might have seen my old posts on the patrol forum about the spill line mod.
its typically done for fitting a diesel lift pump rather than heat.
 
fuel return lines are 8mm.

a transcooler is the easy option for a fuel cooler as they often have barbed fittings rather than AN. if you go radiator style just watch where the outlet is. it needs to be on the high side so air can be pushed out. the long windy tube style don't have that problem but are less efficient.

i doubt you need a fan.

you might have seen my old posts on the patrol forum about the spill line mod.
its typically done for fitting a diesel lift pump rather than heat.

Yesss, woops- i meant the spill line not return line.. the one from the bango bolt in the head to the pump, that's the part number i supplied.. Amayama parts for that one $ 20 wanna hear what nissan gympie wanted lol myyyy god...
Oh and yes i do have a lift pump, one of my first mods along with another diesel filter... wish i could access my original profile on here?

Regarding fan, yeah I had that thought also! Maybe fit it with room for one if needed.. i think I'll go that way , thanks man..

Finding a trans cooler with barbed fittings is a little tricky, i was looking at new ones but i could try the wreckers.. the ones i have found have the AN fittings, I'll keep looking..

Yes mate i see you're everywhere lol good job.. thanks for passing on your smarts man! When i get to nz the bears are on me... or keg, i like a keg!
Sounds like a utube post, two blokes and a keg...
It was that post on the patrol forum that got me onto the mod...

Yes , and you are right "I think" with what you stated on the pootrol forum..
Why he fitted it like that was out of convienence me thinks, smart bloke don't get me wrong, but he was wrong about the return line causing resistance and bleeding the air out, nice case of wishfull thinking there ;)
Sure it doesn't matter on the return line but as you say, the cooler could/would be doing half the job..
Once agian man, thanks
 
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Just an up date, the cooler i was looking at had AN fittings.. The reason i was looking at this type of cooler was of the fabrication, had it own alloy shroud and mounts. Easy to mount buuut danm tricking and ugly getting 10mm down to return line hose diameter, so went tweak'e way and went with the trans cooler. Shity'er to mount and protect but having the barb fittings makes hose reduction muuuch easier.. wanna see some pics of camp site/farm shed fabrication?
A bit from bunnings alloy section, pop rivets, micro cutting disc and this is what i came up with..
Aaaaand before you going giving me grief , it's not done yet. I have gaurds and shrouds to go, this is just the mounting of the trans cooler lol... yup mk2 ;)

Anyway there it tiz- roast away gents ;)
 

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