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Rhanagar Lifetime member
Joined: 12 Jan 2010 Posts: 4861 Location: Preston, Lancs.
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Posted: Fri Mar 26, 2010 20:08 Post subject: Removing EGR Valves and vacuum pipes - Mk.1 2.8 - 4JB1T |
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Ok so you have blanked off your EGR Valves and all is fine and dandy. I did this mainly due to a replacement Exhaust manifold that didn't have the outlet that fed them. Now I also never use the quick warm up feature as she seems to be spot on when its chilly out there. I was looking at various things and thought to myself I have an awful lot of vacuum pipes and solenoids sitting there probably doing nothing. I have done some research and asked a few questions about a couple of forums and finally came up with this resolution. In essence if you have blanked off the EGR Valves and have no use for the quick warm-up system you can do this to get rid of un-necessary clutter in your engine bay.
First off this is what you are looking to remove:
Right old birds nest. Moving to the drivers side you need to unplug the following vacuum hoses. First off the the hose on the intercooler, then the one on the secondary warm-up valve shown below:
Then there is the one on the main warm-up valve bolted to the exhaust:
Finally the one thats attached to the vacuum pump on the back of the Altenator has been disconnected, and then the outlet on the Altenator has been blanked off. You can just use a bit of hose with a 4mm screw in the end. I actually had a blanked piece of hose that I put on there as you can see in the photo below:
Pull all the hoses accross to the passenger side. Now you need to look at the fuel pump. There are two hoses attached. You need to pull them both off.
Now its the two EGR Valves themselves that need disconnecting.
Now thats all done and dusted, you can go about removing the birds nest from the car itself. Four of the solenoids have electrical connectors. Which can be unplugged and then the ends tucked away. Now with all that out of the way find the longest piece of hose you have spare. The fuel pump requires a feed from the inlet manifold to detect the turbo boost. Without this you will find that the car will underfuel and will not rev much past 2000rpm. Not good unless you don't want to go much above 30mph. To rectify this you need to put a length of hose from the outlet in the intercooler (position 1 in the first photo below) to the fuel pump (position 5 in the second photo below). I happened to have a length of brand new hose in the garage to make sure it wasn't perished and used a couple of the little metal clips to make sure it was on tight.
When your done you should have something like this which is much neater:
Took mine out for a test drive and did actually notice a marked improvement. Seemed smoother and perkier. Not much but a definate improvement. I can only assume that the 20 year old hoses that were on there were leaking slighly hampering peak performance Now with it all out of the way and the fuel pump getting a direct feed with a fresh new hose it must be doing the right thing now.
I have some stainless steel in the garage and will be making some blanking plates out of it and totally removing the EGR Valves from the engine to clear up even more space under the bonnet. But that will be another day. Eventually I will remove the two warm-up systems entirely as well. There is no need to have them on there now, and to be honest the drivers side of the engine bay could do with having more space to work with. _________________ 1990 Isuzu Bighorn LWB Mk.I 2.8TD Manual Lotus Edition
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto Lotus Edition
Deceased
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto LS
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Posted: Fri Mar 26, 2010 20:08 Post subject: Google Ads keep this community free to join! |
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:::Matski::: Lifetime member
Joined: 27 Dec 2005 Posts: 5181 Location: York
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Posted: Fri Mar 26, 2010 21:07 Post subject: |
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The only ones you need are 1 and 5. These are for the boost pressure to the fuel pump, it gives more fuel on boost.
I did away with the entire vac system on mine, blanked it at the alt, fitted a plate where the EGRs were and ran a hose from the plate to the pump and blanked it at the inter cooler. _________________ Front Aussie Locker - Rear LSD - Petrol Diffs
2" Lift - 1" Body lift - +2" shocks - 32" KL71s
2.5" free flow stainless system - TMIC - 20psi Boost
Suckin' Diesel Baby!
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Rhanagar Lifetime member
Joined: 12 Jan 2010 Posts: 4861 Location: Preston, Lancs.
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Posted: Fri Mar 26, 2010 22:22 Post subject: |
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Mentioned the pipe between the positions 1 and 5 just before the second and third to last photos. Also said about the blanking of the altenator just before the forth photo. I only took it off the intercooler as there was a port there for convenience.
In time I will probably take off the EGR valves altogether replace the studs, and cut two proper blanking plates. Then put another port one one of them either to have a shorter length to the fuel pump, or to attach a boost guage. Have to say that the idea of putting a port on one blanking plate for the boost guage was your idea Matski.
Either way I hope it helps others to get an idea of how to do this mod on their trucks. _________________ 1990 Isuzu Bighorn LWB Mk.I 2.8TD Manual Lotus Edition
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto Lotus Edition
Deceased
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto LS
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:::Matski::: Lifetime member
Joined: 27 Dec 2005 Posts: 5181 Location: York
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Posted: Fri Mar 26, 2010 22:58 Post subject: |
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Doh, didn't read it properly
One plate to span both works fine for blanking the EGRs. The only down side to removing the vac system is that the little arm that raises the idel when you first start it cold will not work now (No6). _________________ Front Aussie Locker - Rear LSD - Petrol Diffs
2" Lift - 1" Body lift - +2" shocks - 32" KL71s
2.5" free flow stainless system - TMIC - 20psi Boost
Suckin' Diesel Baby!
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Rhanagar Lifetime member
Joined: 12 Jan 2010 Posts: 4861 Location: Preston, Lancs.
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Posted: Fri Mar 26, 2010 23:44 Post subject: |
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Lol, I did wonder if I had missed it. Was a couple or few shots down by the end of it
As for the arm on the throttle, that is true ... but I reckoned its offset by the hand throttle on the dash _________________ 1990 Isuzu Bighorn LWB Mk.I 2.8TD Manual Lotus Edition
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto Lotus Edition
Deceased
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto LS
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claypot75 Newbie
Joined: 31 Jul 2013 Posts: 6 Location: Australia
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Posted: Fri Oct 25, 2013 4:39 Post subject: |
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What do you do with the vacuum ports on '2' and '6' ? |
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Siraniko *
Joined: 16 Jul 2011 Posts: 10 Location: Philippines
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Posted: Thu Jan 02, 2014 3:11 Post subject: |
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So connect a hose from 1 to 5, blank off everything else and plug the vacuum? |
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Rhanagar Lifetime member
Joined: 12 Jan 2010 Posts: 4861 Location: Preston, Lancs.
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Posted: Mon Jan 06, 2014 13:12 Post subject: |
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Ports 2 and 6 you can leave open.
Just run a new line from 1 to 5 and plug the vacuum on the back of the alternator. This of course is for all non-SOTF models. _________________ 1990 Isuzu Bighorn LWB Mk.I 2.8TD Manual Lotus Edition
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto Lotus Edition
Deceased
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto LS
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Siraniko *
Joined: 16 Jul 2011 Posts: 10 Location: Philippines
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Posted: Mon Jan 06, 2014 16:58 Post subject: |
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Hmm. My Bighorn 3.1 4JG2 is a 4x4 with SOTF I think. What should I do then? To be honest I don't do any off road travel and I have no pl;ans of doing so. I may get the 4x4 system inspected but since I have had no use for it nothing is pushing me to get it done. |
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Rhanagar Lifetime member
Joined: 12 Jan 2010 Posts: 4861 Location: Preston, Lancs.
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Posted: Tue Jan 07, 2014 1:14 Post subject: |
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If you have SOTF then you will need the vacuum hoses in the picture in this thread
http://www.itocuk.co.uk/forums/viewtopic.php?t=23620
Essentially run a feed from the vucuum pump on the alternator to the 4WD system. Then ditch the rest.
Personally if you are unsure then the quick and brutal method is to pull the vacuum pipes off the EGR'S and plug them. Don't take this the wrong way but it sounds as if you are hesitant. My advice is to leave well alone. If the truck is running fine then change nothing. This mod often sounds like it does wonders, but it does vary truck by truck. You might fond it does nothing beneficial, and your stuck with no 4WD on the potential coming snow. _________________ 1990 Isuzu Bighorn LWB Mk.I 2.8TD Manual Lotus Edition
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto Lotus Edition
Deceased
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto LS
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Rhanagar Lifetime member
Joined: 12 Jan 2010 Posts: 4861 Location: Preston, Lancs.
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Posted: Tue Jan 07, 2014 1:16 Post subject: |
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Oh Philippines .. swap snow for monsoon _________________ 1990 Isuzu Bighorn LWB Mk.I 2.8TD Manual Lotus Edition
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto Lotus Edition
Deceased
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto LS
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claypot75 Newbie
Joined: 31 Jul 2013 Posts: 6 Location: Australia
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Posted: Tue Jan 07, 2014 1:24 Post subject: |
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Thanks Rhanagar,
This fix is also applicable to the 4jg2. Fixed mine using the same principles. I had masses of vac lines with nothing attached (egrs and quick warm lines but no hardware to attach to), only to find that someone had put them back together in the wrong order and caused all kinds of mayhem. Pulled all hoses out, replaced with the main one, all good.
One note that should be mentioned, may not be applicable to the 2.8's, is that on the 3.1 there is a fast idle thingo on the injector pump, which goes through a solenoid to the back of the vacuum pump, quite often the solenoid is cactus and stays open, causing the engine to idle up. I bypassed the solenoid and decided it would be better to plug the line anyways, all good now!
Thanks again |
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claypot75 Newbie
Joined: 31 Jul 2013 Posts: 6 Location: Australia
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Posted: Tue Jan 07, 2014 1:24 Post subject: |
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Thanks Rhanagar,
This fix is also applicable to the 4jg2. Fixed mine using the same principles. I had masses of vac lines with nothing attached (egrs and quick warm lines but no hardware to attach to), only to find that someone had put them back together in the wrong order and caused all kinds of mayhem. Pulled all hoses out, replaced with the main one, all good.
One note that should be mentioned, may not be applicable to the 2.8's, is that on the 3.1 there is a fast idle thingo on the injector pump, which goes through a solenoid to the back of the vacuum pump, quite often the solenoid is cactus and stays open, causing the engine to idle up. I bypassed the solenoid and decided it would be better to plug the line anyways, all good now!
Thanks again |
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Siraniko *
Joined: 16 Jul 2011 Posts: 10 Location: Philippines
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Posted: Tue Jan 07, 2014 7:04 Post subject: |
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Thanks Rhanagar!
My mechanics (I have consulted three) and I are of two different minds about it. I want to follow your advice but they always want to put a line from the vacuum to the fuel pump #5.
Will try your advice once I get a new vacuum hose.
So it appears that if I want to utilize 4-wheel drive I will have to invest in more hoses to make sure it works when I want/need. Have so far been fortunate not to need it. Have appreciated the Trooper's high ground clearance though a lot when the floods come about.
Monsoon season is almost over around here, but the feeling is it will keep getting worse every year. |
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Rhanagar Lifetime member
Joined: 12 Jan 2010 Posts: 4861 Location: Preston, Lancs.
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Posted: Tue Jan 07, 2014 8:33 Post subject: |
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Your mechanic is very wrong about putting a vacuum to the top of the fuel pump. The way it works is the pressure built up in the intercooler by the turbo pushes air down the hose from port "1" to the fuel pump port "5". This PRESSURE pushes down a diaphragm in the pump to allow more fuel into the injectors. More air and more fuel means more power. If you put a vacuum into the pump on port "5" at best you will starve the engine of fuel as it closes the feed. At worse you will damage the the diapragm and need a new pump.
Pump manual:
http://www.itocuk.co.uk/forums/viewtopic.php?t=25151&highlight=bosch++pump _________________ 1990 Isuzu Bighorn LWB Mk.I 2.8TD Manual Lotus Edition
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto Lotus Edition
Deceased
1994 Isuzu Bighorn LWB Mk.II 3.1TD Auto LS
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