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4JG2T will not start after install

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4JG2T will not start after install

Postby Silvertrain » Sat Jun 08, 2019 5:24 am

Hey everyone, many thanks in advance for any advice you may have for me. I just installed a 4JG2T but it will not start.

Just a bit of history on this build first so as to better understand what im into or how deep in over my head I really am! I bought a used 4JG2T with 120K on it, that I installed in my 2004 Land Rover Discovery. The motor was pulled from an operating Isuzu Bighorn Trooper which came with the mechanical pump, not the fly by wire, and was delivered fully intact.

Now here's where it gets fun/miserable, I purposely bought a used motor that was intact and running in order to take the weak link out of the mechanical equation, which was me. I say that not because I don't know how to turn a wrench but because this will be my third failed attempt to build a successful 4JG2T; more like four attempts actually. I feel like im stuck in some parallel Monty Python scene where "I built that castle/motor, that one sank into the swamp, so I built a second one, that one sank into the swamp, so I built a third one, that one burnt down, fell over, then sank into the swamp"!

With that said, the last motor I bought was new from China and felt, as did the first one, like it was in "limp mode". I made a slight adjustments to the IP pressure, advanced the timing a bit, and installed an electric lift pump in order to get it to start. I drove it a quarter mile down the road and the turbo blew up, sending the equivalent of a bucket of sand through the engine that absolutely destroyed the bearings/crank! Not knowing the full extent of what just happened, I watched the oil pressure drop from 85 to 7psi in a matter of seconds as I idled out of traffic to a safe place on the side of the road. (copper bearing within the "new" turbo was pummeled without explanation, though failure to lubricate is the culprit). after teardown, I checked to see if the camshaft oil galleys were restricted by the bearings causing the oil supply to the turbo to be compromised, but no, they were correct. :cry:

So heres what I'm working with now. I put my new/used engine i just got from a UK yard and placed it on a shop stand, replaced the timing belt and front main seal, which was leaking and Installed a brand new IP pump which I timed, via dial gauge, to 1.04 BTDC. (due to high altitude operation, about 5400ft above sea level, I gave it .04 increase above the recommended degree described in the Isuzu manual). I then Installed the motor into my 04 Land Rover Discover that I had set up for this with.

Once installed, I depressed the fuel filter diaphragm to prime the Pump, bled the pump from the bleeder valve located at the return line fitting. The diaphragm will stiffens up after about 7 or 8 pumps and then after about 10 seconds it relaxes a bit so I don't know if thats an issue. I opened the injector lines at the injector to bleed off any air as i turned to motor a few time, closed all but the #1 cylinder at second start up but didn't notice any "squirt". I placed a section of clear fuel line post the filter canister to observe potential air that might be contaminating the system but no air was observed traveling through the fuel line. However, i've not been able to get the engine to start so the volume of fuel is a bit limited. I understand that these iP's pull fuel directly from the tank without a lift pump? Thats a very rare thing to see on any Diesel in US, but then again, most mechanics here look at this engine as if it were a pink unicorn so no surprise if it doesn't use one. I should mention that the original land Rover in-tank fuel pump was gutted and only the housing remains modified with a brass bulkhead that pulls fuel directly and uninhibited through a 3/8" fuel line.

So, no start, some popping to signify the shutoff solenoid is working, which I also check with an independent 12V source just to be sure...Did a compression test that showed 425 pounds across all four cylinders (cold) so its probably a bit lower then that at temp but I imagine still well within tolerance. Replaced two failed glow plugs and confirmed the valve lash. I've run all new fuel lines and check for breach in fitting, reinstalled the original IP pump and still nothing. Their is no ECU, oil level sensor, or an immobilizer that would otherwise prevent the motor from starting. I've installed an aftermarket electric oil pressure gauge, independent ignition switched 12v source to the solenoid, bypassed the neutral safety switch, which is more land Rover anyway, and considered making a visit to the liquor store this morning.

One thing im not sure how to do exactly is reset the wax CSD (part of timing adjustment) described in the manual as "with a screw driver" which I used to depress the spring loaded valve maybe 90 degree or so. ???

So im leery, very leery of making any adjustments to the IP pressure or incorporates any fuel assisted components that my manipulate or mask the real problem, in which case I don't want to deviate too far from the original working order of the Trooper in fear of losing another engine! Im out on my own with this one so any help would be greatly appreciated!!!
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Re: 4JG2T will not start after install

Postby geeves » Sat Jun 08, 2019 7:37 am

Check the timing on the pump and cam. This and the injector pump are the only things that are different to the running engine. Its easy to get the timing out. Also why did you replace the injector pump. That could also be a failure as it is unknown. Could try refitting the original pump. After that a squirt of easy start might kick it into life although it might run on easystart but still not fire the injectores.
Did you see the engine running before buying?
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4JG2T will not start after install

Postby Silvertrain » Sun Jun 09, 2019 1:31 am

i was concerned of the timing as well so i did revisit it. Took off the cover, with the main crank timing mark aligned with the pointer just above it to indicate TDC, I locked down the cam with an 8mm bolt, at about the 3 o'clock position, and the IP pump gear looked good as it lined up nicely with its 8mm pin too. belt tension is set to the manual spec, sound correct?
Because I have three Injection pumps, one of which was brand new, I went ahead and replaced it; thought it would be one less thing the give me grief in the long run. I did refit the original IP too for exactly the reason you suggested, to eliminate any unknowns and I didn't see the engine running while it was in the trooper, yup, thats hard to admit, my optimism is often the bane of me...
Ill give it some easy start this morning and let you know what i come up with. I noticed the #1 injector line, when crack open a bit, does not squirt when i turn the engine over as do the rest of the lines. Im going to recheck the fuel system for air leaks. Would you suggest that i hook up an electric 9psi lift pump or would that potentially cause damage to the IP or motor?


seemed like a good idea at the time.
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Re: 4JG2T will not start after install

Postby Silvertrain » Sun Jun 09, 2019 6:23 am

Its gotta be a timing issue..??.just sourced the pump with fuel straight from a liter bottle, pre primer canister so that I could depress the diaphragm and observe through the clear fuel line if any air are present...but nothing, barely runs at fully depressed throttle. it seems the IP just isn't producing enough pressure to the injectors or is out of time?
To reference, I followed this procedure to the T: http://www.itocuk.co.uk/forums/viewtopic.php?t=27458
Silvertrain
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Re: 4JG2T will not start after install

Postby stardog » Sun Jun 09, 2019 7:22 pm

www.itocuk.co.uk/forums/viewtopic.php?t ... highlight=
This will show you how to do timing with the csd I would do the timing at TDC 0.5mm not BTDC are you sure the diaphragm in the filter where you bleed the fuel isn't stuffed.
Are the fuel line from the tank to the inlet pipe on the filter isn't put on back to front if you connect a electric fuel pump 9 psi is to much pressure should be around 3-4 psi.
Also could be a injector problem .
But I am suspecting your timing is not set right just a few thoughts on the no start problem .
Regards Stardog
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Re: 4JG2T will not start after install

Postby Silvertrain » Fri Jun 14, 2019 1:30 am

Thanks for the link SD, very helpful! I reinstalled the brand new injector pump and timed it to .5 at TDC, (referenced link that you provided) changed out the injectors with a new set that i ran in my last 4JG2, fuel rail and lines looked good and clean and still no go.
When i remove the return line to the tank from the IP, the fuel stream is faint/nearly a dribble and fuel stream post filter/pre IP is a bit underwhelming too (fuel assisted with an 9psi electric lift pump coupled with a fuel regulator set to 4 pounds). I'll swap the filter, even though it's new, and see if that changes anything. Curious why these engines were not equipped with an electric or mechanical lift pump, just a diaphragm/fuel filter? Even my old 4BTA Cummins used a lift pump that produced at least 9psi and had a similar Bosch V-pump design.
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Re: 4JG2T will not start after install

Postby stardog » Fri Jun 14, 2019 7:16 am

After all that has been tried maybe its electrical try running a wire from positive on battery to the fuel cut off solenoid but fit a cut off switch on the wire so if it fires up you can turn the engine off .
Have you got the TPS connected up right if its a auto and the park and neutral switch's by passed on the gearbox.
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Re: 4JG2T will not start after install

Postby Silvertrain » Sat Jun 15, 2019 12:00 am

The Neutral safety and the TPS have been removed. Their is no computer or wiring harness for this rig since it is not in a Trooper anymore. I built a switch panel to select the transmission solenoids in sequence and shift through the gears that way, kinda like using paddles, except not as cool.
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Re: 4JG2T will not start after install

Postby stardog » Sat Jun 15, 2019 8:17 pm

Some thing isn't right going through your posts you say you have the 8mm bolt at 3 o clock on the pump it should be at 1 or 2 o clock like in the photo I have attached.
Just wondering what do you set the dial to when you screw it in at the back of the IP before timing 1 or 2 mm lift before you rotate back wards before setting it to 0 then going clock wise to set at 0.5 mm at TDC the trick is to disengage the csd before you screw the dial into the IP these motors are pretty easy to work on when you understand them but why yours wont fire up is ????.
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Re: 4JG2T will not start after install

Postby Silvertrain » Sun Jun 16, 2019 1:37 am

Yes, to clarify, my original description of the timing was a bit general but it was done exactly as the attached photo describes. I reset the CSD by placing a 12mm shim between the piston/plate to simulate "operating temp". I gave the dial gauge 2 mm lift before rotating the crank backwards before setting it to 0, turned it clockwise to 0.5 mm at TDC. Turned the crank full 360 degree and checked it again, all looks good. I did noticed a bit of play between the timing mark and indicator pin. With both the cam and pump gears static, the indicator pin over the main crank pulley lands directly on the first of two hash marks, right hand hash, but not between the two? i fooled with this for a while, exploring the idea that maybe the crank was out a tooth, but it seemed that there was really no other fitment then where i had it originally. I even went as far as to order a new timing belt from a UK source if in the event the one I was sent may be out of spec or something crazy. I've learned that a lot of parts from China are not exactly the same, ie, the gasket sits look as if they are for a forklift of something but not the same as the Bighorn UK or AU sets. With that said, I don't remember from whom I ordered the my T-belt from; it was well over a year ago, so another is on the way.
I did also check the 12v ignition source to the solenoid, all is good there too.
im going to try and run a new high efficiency fuel filter/canister and lift pump this morning and see if that makes any improvement. Thanks again for all your impute on this!!
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Re: 4JG2T will not start after install

Postby stardog » Sun Jun 16, 2019 4:09 pm

The belt drive engine injector pump should be 1mm lift with the dial after the csd is disabled then set at 0.5 mm TDC .
I hope you get it sorted out I don't know anything about the Landy discoveries I once had a old Landover series 1 or 2 about 37 years ago with 4cyl petrol engine and ended up putting a Holden 186s 6cyl conversion in it went well until I got up to the gulf country engine would over heat every 20 minutes on salt pans.
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Re: 4JG2T will not start after install

Postby Silvertrain » Tue Jun 18, 2019 1:39 am

ok, I'll install the new belt this week once it arrives and time it accordingly. Even the last two motors I assembled, with the same belt, had no trouble starting?? a bit out of time in relation to 6000ft Alt I imagine but at least it started.. :? I did install a new high efficiency fuel filter (3 microns) with a universal housing and the new lift pump; pressure regulator and check valve included. It's pretty much the same set up on most all US diesel motors, Cummins, Duramax etc. The stream of fuel looks steady, no air bubbles.
As for the Land Rover, there isn't much left of her but the shell and brakes, Ha. Even those I upgraded and added line lockers since the Isuzu transmission doesn't support the LR E-brake system utilized from transfer case. BUT, I would not do this type of conversion again simply because the drive train. Specifically the rear diff, It does not line up well with the output shaft of the Isuzu Auto gearbox, which is more centered. The solution, have a new rear end/axel housing fabricated for $5000.00.. eesh. Thanks again for you input SD! will keep you updated.
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