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Replacing Injector Pump

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Replacing Injector Pump

Postby kiwiguy » Sat Sep 20, 2014 9:05 pm

Hi All,

I own a much loved 1996 Bighorn 4JG2 3.1TD with a very leaky Injector Pump.

Here in NZ to get it removed, reconditioned and reinstalled is approx. $900!
I've managed to pick up a second-hand one for $100 which appear to be in great condition and I'm thinking of installing it myself.
However while I do have some mechanical experience and a workshop manual, it suggests I need to strip out the radiator, belts, gears etc. etc. in order to remove the pump and replace.
If this is the only method can anyone give me some tips to confirm and make this as easy as possible... especially if there is someway to duplicate the current setup and avoid readjusting the timing as the manual requires a gauge and other equipment I don't have.

Much appreciated in advance!

Thanks - Mike.
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Re: Replacing Injector Pump

Postby isuzurob » Sun Sep 21, 2014 5:51 am

yes remove radiator, belts, covers, time the motor as per the book, the hardest bit will be getting the gear off the pump, loosen nut while the cambelt is still on, you will have to time it with a dti gauge to get it to run properly, if efi its not so important
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Re: Replacing Injector Pump

Postby kiwiguy » Sun Sep 21, 2014 7:04 am

Thanks very much isuzurob, your answer confirmed my suspicions!
It was probably a dumb question but I had to ask as I know with experience there's sometimes an easier way.

It is an Efi model so I'm hoping I can set up and position the unit as close as poisible to the one I'm taking out so it will at least run. (More wishful thinking?)

Can you give me any indication on how long you think this job should take me and if there are any parts I will need to replace as part of this process as the manual is basically a series of steps and assumes these things.

Thanks again. Mike
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Re: Replacing Injector Pump

Postby isuzurob » Sun Sep 21, 2014 8:09 am

you should get it done in a day easy, yes if you line it up with old marks it will run, just wont be spot on but will be fine, just replace the cambelt and check idlers and tenioner pulleys while you are in there
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Re: Replacing Injector Pump

Postby kiwiguy » Sun Sep 21, 2014 1:45 pm

Thanks for that. Having a crack at it in a few days!
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Re: Replacing Injector Pump

Postby mudslinger » Mon Sep 22, 2014 6:58 pm

if you remove the cover over the inj pump pulley, you will find a couple holes in the pump pulley, on the backing plate that the pump bolts to are a couple of threaded holes. line pulley up with the threaded hole and find a bolt that is long enough and same thread. wind the bolt in, it holds the pulley in place. now undo the nut holding pulley onto pump and now you can remove the pump and not loose the timing or nothing. bolt new pump on and job done. i have used that trick a few times works a treat.
obviously radiator and and everything needs to come out to gain access. also take note of where the pump bolts as the holes are slotted.
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Re: Replacing Injector Pump

Postby whitetroopere » Mon May 06, 2019 3:51 am

Hi, My name is Harry and I owned a trooper with a 4jg2 diesel engine. The problem is that my fuel pump is not responsive to the throttle. It has only one idle speed, and cannot be driven. I was told that fuel pump needs to be replaced. I bought another fuel pump online, and now trying to learn all I can how to replace the pump.

I was very happy to see mudslinger's post here about replacing a fuel pump by locking the pump pulley in place and removing the old fuel pump. I removed the cover over the inj pump pulley and I have some questions before begin doing the job.

1) is there more than one threaded hole(s) on the backing plate for the inj pump pulley bolts to?
2) if I can find only one threaded hole behind the pump pulley, will that be enough to secure the pump pulley in place and start removing the old pump?
3) will the new inj pump shaft be fitted to the old pump pulley only one way and has the same fuel pump timing?

Looking forward to your reply. Thank you very much for your help,
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Re: Replacing Injector Pump

Postby whitetroopere » Mon May 06, 2019 4:10 am

Hi all, My name is Harry and I own a trooper with a 4jg2 diesel engine. The problem is that my fuel pump is not responsive to the throttle. It has only one idle speed, and cannot be driven. I was told that fuel pump needs to be replaced. I bought another fuel pump online, and now trying to learn all I can how to replace the pump.

I was very happy to see the post here about timing belt replacement. However, since I am not replacing the timing belt, I do not wish to complicate the matter by removing more things than i need to. I removed the cover over the inj pump pulley and I believe I can find the one (1) threaded hole on the backing plate behind the inj pump pulley.

1) is there more than one threaded hole(s) on the backing plate for the inj pump pulley bolts to?
2) if I can find only one threaded hole behind the pump pulley, will that be enough to secure the pump pulley in place and start removing the old pump?
3) Will the new fuel pump shaft key way slot be fitted to the old fuel pump only one way? and cannot be fitted any other way? (i have not seen the shaft keyway slot but I was told that it can only fitted one way to the pump pulley?)
4)If the new fuel pump can be fitted to the old pump pulley, will the new pump timing be the same as the timing of the old fuel pump?

Any comments are greatly appreciated.
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Re: Replacing Injector Pump

Postby whitetroopere » Wed Jun 26, 2019 6:32 am

Mudslinger, a member her on this forum, never got back with my question. I went ahead and dove into the problem. I was able to secure the pulley in place and remove the pump. The pump will be sent off for rebuilt.
I wonder if anyone else has a similar problem.
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Re: Replacing Injector Pump

Postby isuzubighornnz » Fri Aug 30, 2019 7:34 am

Hi I also have a leaky fuel pump and I am needing advice as to how difficult it is to replace and a list of what tools are required for the job or better yet a manual of how to do it, as i bought a second hand pump on Trademe and yes i understand this pump might also fail.

Alternatively I would consider paying a mechanic to do it however the first quote i received was nearly $2,200 to do the job. From memory it $1200 to rebuild the pump and $1000 in labour to install it which is absurd imo.

Looking for recommendations on where to have the pump rebuilt and installed?

@whitetr
whitetroopere wrote:Mudslinger, a member her on this forum, never got back with my question. I went ahead and dove into the problem. I was able to secure the pulley in place and remove the pump. The pump will be sent off for rebuilt.
I wonder if anyone else has a similar problem.
- How much did this cost you?

Any help would be much appreciated.
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Re: Replacing Injector Pump

Postby Smurt2010 » Tue Oct 01, 2019 7:39 pm

Hi just wondering if I could get some help on how to get timing on my 1999 tf 4jb1t engine fuel pump timed correctly as I removed mine to replace front seal which I have done and reinstalled pump but can’t get the timing rite it just won’t start tried everything I could so far what makes it worse is my harmonic balancer is free spinning so trying to workout where the Tdc markings sit over the key and which mark I need to try set the timing
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Re: Replacing Injector Pump

Postby stardog » Tue Oct 08, 2019 2:43 pm

I had same problem on a 4jb1t I ended up buying a new harmonic balancer on eBay and installed it found the timing mark 12degrees 0.5 on dial gauge before TDC one thing reinstalling the pump make sure you line it up using the 0 mark not the V on the pump gear wheel this fixed the problem.
There was a video on you tube with some clowns using the v mark this is wrong mark its the 0 mark then bleed the injectors should start then.
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Re: Replacing Injector Pump

Postby Smurt2010 » Sat Oct 19, 2019 9:40 pm

thanks for the help stardog just wondering if you can help me again
Just wondering what may cause my Ute to rev really high while cruising on highway and make a really loud shuttering sort of noise in the direction of the pump then hiccup a couple of times then blow a big puff of black smoke out the exhaust
Thanks in advance
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Re: Replacing Injector Pump

Postby stardog » Sun Oct 20, 2019 5:50 am

Could be the turbo seal but if it was it would be popping and farting all the time with thick black smoke.
With out seeing and hearing it I wouldn't really know.
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