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4JB1T cranks but won't start

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4JB1T cranks but won't start

Postby manders » Thu Jul 18, 2019 4:25 pm

Hello to all!

I have nearly completed a swap of a 4JB1T into a 1989 Trooper II, with the last step being to get the darn thing started!!! ;)

A little bit of back-story ...

I purchased this engine from a gentleman who relocated back to the US from Australia and returned home with a half-dozen 4JB1T engines to fill up the empty space in the shipping container of all his worldly possessions.

The engine I received was from a 94-95 Holden Rodeo but it was completely rebuilt. (He worked as a diesel mechanic for a good portion of the decade or so he was in AU.) It has a gear-driven IP.

Here's where I'm currently at:
  • The engine cranks ... strongly ... but does not start.
  • The fuel "flow" is Tank -> Water Separator -> 3psi "lift pump" -> Fuel Filter -> Injection Pump.
  • Using a clear hose, I verified that fuel is flowing from Fuel Filter -> Injection Pump, and also from the return line to the tank.
  • Thinking that I have air in the fuel system, I opened each injector while cranking - verifying that fuel "splatter" occurred for each cylinder - and then tightened the injector while still cranking to ensure no air wormed its' way back in.
  • I used brand-new injectors and have had a "local shop" verify the adjustment and pressure.

WRT the "local shop" ... from my reading of other posts, even if the pressure was set incorrectly, the engine very likely would start but blow smoke and/or run rough. Am I understanding that correctly? Putting it another way ... if the pressure or spray pattern was wildly inaccurate, could this prevent starting of any kind?

I chatted with the gentleman from whom I purchased the engine, and he is "highly confident" that he got the timing set correctly, but he is not 110% certain. If the timing is wildly inaccurate, could this prevent starting of any kind?

Locating a mechanic hereabouts that is familiar with this engine is going to be ... challenging :smile: ... so I appreciate any advice/guidance/hints/etc., that y'all can toss my way to help me figure out what the heck is going on.

Thanks.

MAnders.
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Re: 4JB1T cranks but won't start

Postby geeves » Thu Jul 18, 2019 6:34 pm

As long as you have fuel and compression the only thing left is timing. Fuel at the injectors proves fuel. Rough and ready test for compression is hearing the engine change on each compression stroke but a proper compression test would prove it better.
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4JB1T cranks but won't start

Postby dieselguy86 » Fri Jul 19, 2019 7:11 am

Could always try a puff of ether. If it fires compression is good.

You swapped it into an 89 trooper, did check that the fuel shutoff solenoid on the pump is on with key on? Sounds like it is since you say you have fuel to the injectors, but might be worth checking
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Re: 4JB1T cranks but won't start

Postby manders » Fri Jul 19, 2019 5:50 pm

geeves wrote:As long as you have fuel and compression the only thing left is timing. Fuel at the injectors proves fuel. Rough and ready test for compression is hearing the engine change on each compression stroke but a proper compression test would prove it better.


I ran a compression test and got 320-340 psi on all cylinders. The service manual I have says that the "limit" compression pressure value is 313. My tester is brand-new-but-a-cheap-one, so I hope the values I got are within the acceptable margin-of-error ...
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Re: 4JB1T cranks but won't start

Postby manders » Fri Jul 19, 2019 5:55 pm

dieselguy86 wrote:Could always try a puff of ether. If it fires compression is good.


Considering that my other truck is a 5-Ton 6x6 "retired" Army vehicle that I have to from time-to-time douse with a bit of ether to get it started ... youda thunk that I woulda thought of that!!! :wink:

dieselguy86 wrote:... did check that the fuel shutoff solenoid on the pump is on with key on?


I verified that when I redid the wiring harness and added another circuit tied in to the gas engine ignition coil circuit; it makes a pleasing "thunk" sound, and coupled with fuel at the injectors ... I believe it to be working correctly.
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Re: 4JB1T cranks but won't start

Postby Roderunner » Fri Jul 19, 2019 9:41 pm

You must be pulling your hair out by now :cry:
Not that I can offer much.....I did have an injector pump partially seize up a few years ago, I left it sit dry for a year or 2 and when I went to use it some of the internals had stuck together, and I'm guessing that any engine that gets packed into a shipping container would have to have all fluids drained from it. My pump somehow got stuck in the full throttle position, that was fairly entertaining when it finally fired up! :lol:
Another thing that crossed my mind was the injector lines. I have seen someone replace the injectors and then put the injection pump lines onto the wrong holes in the back of the pump, so there is somewhere else to look.
If I had a 6 ton truck I would hook up your vehicle to it and tow start it rather than burn out the starter motor, for a reasonable distance so that any residual air in the pump might get pushed through the system. That's about all of the "possibles" that I can think of at the moment!
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Re: 4JB1T cranks but won't start

Postby manders » Sat Jul 20, 2019 4:56 am

Roderunner wrote:You must be pulling your hair out by now :cry:

Ain't that the truth!!! 8-)

Roderunner wrote:Another thing that crossed my mind was the injector lines. I have seen someone replace the injectors and then put the injection pump lines onto the wrong holes in the back of the pump, so there is somewhere else to look.


I double- and triple-checked the injector lines with the gentleman who rebuilt the engine, so I'm fairly confident those are correct.

Thank you for info, and your brothers-in-arms support!!! :wink:
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Re: 4JB1T cranks but won't start

Postby dieselguy86 » Sun Jul 21, 2019 3:37 am

Is valve lash adjusted?
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Re: 4JB1T cranks but won't start

Postby manders » Wed Jul 24, 2019 11:40 am

dieselguy86 wrote:Is valve lash adjusted?


Per the guy that rebuilt it ... yes.

I tossed in my hand today and had it towed to an Isuzu Truck service center with a supposed "Isuzu God" :wink: on staff, I'll let y'all know the verdict.
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Re: 4JB1T cranks but won't start

Postby stardog » Wed Jul 24, 2019 1:21 pm

There was a guy on the site not long ago had same problem engine wouldn't start but his was a 4jg2t not a 4jb1t let us know what was wrong why no go.
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Re: 4JB1T cranks but won't start

Postby Roderunner » Wed Jul 24, 2019 2:36 pm

I would also consider checking the voltage at the cut off switch while cranking the engine, there may not be enough juice left to keep the switch open if the starter is stealing most of it, hence my previous suggestion to try tow starting it.
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Re: 4JB1T cranks but won't start

Postby manders » Wed Jul 31, 2019 11:33 am

Roderunner wrote:I would also consider checking the voltage at the cut off switch while cranking the engine, there may not be enough juice left to keep the switch open if the starter is stealing most of it ...


For more than a handful of my troubleshooting attempts, I had a second "jump-starter" battery hooked up to ensure that I had sufficient CCA.

But I'll also admit to skipping past the potential of insufficient juice once we were able to verify fuel spattering from the individual injectors when we bled them; I am assuming that the solenoid is truly on/off rather than partial-but-still-insufficient-to-start fuel flow.
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Re: 4JB1T cranks but won't start

Postby geeves » Wed Jul 31, 2019 12:47 pm

if they were spattering under cranking the solenoid is ok. Its sounding like timing. An easy mistake is to set the cam or pump 180 degrees out.Then everything happens on the wrong up stroke
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4JB1T cranks but won't start

Postby manders » Mon Aug 19, 2019 3:46 pm

Sorry for the delayed follow-up ... I've been traveling.

As y'all rightly suspected, the local mechanic also diagnosed the issue as incorrect timing, likely because of "... several white paint marks on the vibration damper that someone must have thought was TDC because it looks like the gears marks (sic) line up with those marks".

He tinkered a bit more and got it to work. Here's the comments he left on the final invoice:
I removed the front cover and idler gears again then lined up cam, crank and fuel pump gears so all alignment marks on the gear teeth meshed. I tightened
both idler gears down then re-installed front cover and vibration damper tight. I cranked engine and it started right up, sounds good and there is good throttle response.


I've been baby'ing it for the 25+ miles since picking it up and everything seems to be running just fine! :D

Thanks for the assistance, advice, and good cheer!

MAnders.
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Re: 4JB1T cranks but won't start

Postby geeves » Mon Aug 19, 2019 5:38 pm

Good result. Now remember the 4jb1 likes to rev. (by diesel standards at least) Peak power is between 2500 and 3500 and its not going to complain if it hits 4000 from time to time. Dont baby it like a big American diesel.
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4JB1T cranks but won't start

Postby manders » Tue Aug 20, 2019 3:03 am

geeves wrote:Good result. Now remember the 4jb1 likes to rev. (by diesel standards at least) Peak power is between 2500 and 3500 and its not going to complain if it hits 4000 from time to time. Dont baby it like a big American diesel.


Thank you VERY MUCH for that insight. The only other diesel I've ever had is a 6-cyl Cummins, which is just about the size of the Trooper ... not the engine ... the whole vehicle!!! :lol:
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Re: 4JB1T cranks but won't start

Postby geeves » Tue Aug 20, 2019 6:10 am

Cummins are very good engines but they are designed like truck engines and will pull from idle but never rev. Small Jap diesels are not like that. The old cummins would run out of revs about the same place as the 4jb1 wakes up yawns and starts working. I think Cummins are making a few small high speed diesels now
Sanding your knuckles before starting work can help. That way you cant skin them
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