CAV Filters for Nissan Patrol 3 lt TD
Submitted: Tuesday, Aug 21, 2007 at 23:12
ThreadID:
48924
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3847
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4
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wet feet
Hi Guys,
This concerns problems with pulling fuel thru to the original nissan fuel filter.
A couple of weeks ago I posted some queries in relation to the Delphi CAV filter 296, as a prefilter to the original nissan unit.
I have reinstalled, checked air tightness and still cannot get the unit to "vac" up. Read some posts from 2004 and a Peter with a Hummer suggested the Walbro pumps, somebody suggested a fitting into
tank filler neck to pressurise and force fuel thru. I have removed outlet from plunger side as per Roachie's comments (thanks), but still no go.
Also noticed the direction arrows are/seem incorrect (see other archive threads on this site) on filter head.
As you can appreciate ideally I would love to have an additional filter but fast running out of patience.
Should I have to pressurise
tank to get fuel up????
I have dissassembled, reassembled checked seal integrity by pressurising and still cannot vac up the units.
I have also checked the new hoses for their integrity.
It appears as though if the unit was a secondary unit to the existing I may be able to pressurise the unit as pump is still able to pressure line between filter and fuel pump.
Would appreciate any words of wisdom on this,
Thanks in anticipation.
Wetfeet
Reply By: mattche - Tuesday, Aug 21, 2007 at 23:53
Tuesday, Aug 21, 2007 at 23:53
Are you trying to use the hand primer on the CAV filter head or are you using the original nissan hand primer.
Now you have the filter head between the fuel
tank and the original nissan filter housing ???
I would be checking the direction of flow on top of the CAV filter housing first,then check the operation of the hand primer if using the nissan one.
Matt
AnswerID:
258400
Follow Up By: wet feet - Thursday, Aug 23, 2007 at 22:25
Thursday, Aug 23, 2007 at 22:25
Hi Matt,
Mine is just the filter without CAV primer, so I am reliant on the nissan plunger.
Direction is opposite to that on filter head, fuel goes into bowl first, allowing crap and
water to settle then rise up thru filter and out to Nissan. Other way leaves crap inc
water on top of filter defeating purpose of glass bowl. Tried both directions and still no difference.
Thanks
Wetfeet.
FollowupID:
520058
Follow Up By: ross - Friday, Aug 24, 2007 at 01:07
Friday, Aug 24, 2007 at 01:07
Ive seen this problem elsewhere. You will need to put the cav filter in between inj pump and OEM filter or otherwise get one with a built in primer.
The way you have it set up ,you are trying to fill the cav filter by vacuum.
Also I thought the fuel was drawn through the centre.
Any
water just sinks to the bottom .
Some filter heads have valves inside the inlet/outlet nozzles so they should be set up the recommended way.
Ive been using a single Delpi 296 with built in primer for 2 years and it works perfect
FollowupID:
520075
Follow Up By: ross - Friday, Aug 24, 2007 at 01:09
Friday, Aug 24, 2007 at 01:09
Having to pressurise the fuel system not a good recipe for filter changes in remote areas.
FollowupID:
520076
Reply By: Voxson - Wednesday, Aug 22, 2007 at 08:03
Wednesday, Aug 22, 2007 at 08:03
This year we had a similar problem on our Cape Trip.
But it was a hairline crack in alloy housing of cav filter.
Anyway, we had trouble like you are having and we cracked an easy injector, then we filled the
tank with compressed air and it started.
Whilst someone is feathering the throttle because it will run like crap, someone needs to do up the injector.
If it doesnt start again next after all that hassle then it means you have a vacuum leak my dear sir.
AnswerID:
258411
Follow Up By: Voxson - Wednesday, Aug 22, 2007 at 08:04
Wednesday, Aug 22, 2007 at 08:04
Thats if you have the flow directions right as already stated.
FollowupID:
519701
Reply By: Leroy - Wednesday, Aug 22, 2007 at 11:42
Wednesday, Aug 22, 2007 at 11:42
'Also noticed the direction arrows are/seem incorrect '
Like others have mentioned and you yourself!
I haven't gone down the extra filter path as others have posted about additional strain on the pump leading to failure. I personally carry an extra filter for the way out trips.
Leroy
AnswerID:
258433
Follow Up By: Shaker - Thursday, Aug 23, 2007 at 22:44
Thursday, Aug 23, 2007 at 22:44
I doubt very much if the arrows are incorrect.
FollowupID:
520065
Reply By: Gimp35 - Wednesday, Aug 22, 2007 at 21:05
Wednesday, Aug 22, 2007 at 21:05
Hi Wetfeet,
I have the same 4b with a cav pre filter.
My filter is mounted very close to the original filter and it is plumbed in before the original filter.
That is from fuel
tank to cav filter, from cav to Nissan filter and then from Nissan filter to injector pump.
Mine has been on for about 60000Km know with no problems to the the injector pump.
I have to say when I do change the filter it does take a bit of time to prime it up, I can usually get fuel to the cav bowl by pumping on the factory plunger, this will take some effort more than usual as it needs to suck the fuel through the cav filter, but be patient.
Then I try to start the engine and she usually stalls and prime again until the plunger is firm. This time it will start a bit rough but will clear up after a few seconds.
Please let me know if this helps.
Paul
AnswerID:
258505
Follow Up By: Gimp35 - Wednesday, Aug 22, 2007 at 21:59
Wednesday, Aug 22, 2007 at 21:59
Forgot to mention make sure the nissan filter is primed first before connecting the cav filter.
FollowupID:
519842
Follow Up By: wet feet - Thursday, Aug 23, 2007 at 22:38
Thursday, Aug 23, 2007 at 22:38
Hi Paul,
Mine is mounted just off guard in front of brake booster, pretty close. Fuel hose length doubles plus some, plus filter. I have pumped that plunger up to 100 times with no result, yet when I reapply the factory hose about 6 -8 pumps and up the fuel comes.
I might try the compressor and carefully apply pressure to push fuel thru to the nissan filter. I reckon the nissan plunger is good for lifting fuel thru a 10mm tube of length 300-400mm but when you ask it to do 1000mm plus filter volume plus bends etc etc it just can't cope.
I have drilled the plug (finger blade) at bottom and wired it to one of the outlets for safety sake and would recommend this.
Thanks
Mark
FollowupID:
520063
Follow Up By: Gimp35 - Friday, Aug 24, 2007 at 20:34
Friday, Aug 24, 2007 at 20:34
Mark
Mine is mounted on the same bracket as the original filter bracket, facing the brake booster.
The main metal fuel line coming from the
tank has a rubber hose at the end that goes to original fuel filter this hose was only extended by 40mm, and the hose going from the cav to the original filter is about 300mm.
It sounds like maybe this is where your problem lies.
If you would like I could send you some pics of my set up, just send me your email address.
Paul
FollowupID:
520202