Isuzu 6bb1 no start

[Lbb]

I have a 1985 linkbelt with an isuzu 6bb1. Starts great cold needs starting fluid warm and wont start at all hot. Any ideas? It runs great otherwise.

 

[Delmer]

When it's nice an hot, take the fuel return line off the tank and put it into a clear jar so you can see if there's bubbles coming out.

Is this an inline injection pump? standard pump, line, nozzle system.

 

[heymccall]

You didn't say how many hours, but without actually being there, I'd hazard a guess at clogged/ worn injectors.
With my experience, poor hard starts with good cold starts, it has always been injector performance.

With that said, there are a myriad of fuel related reasons it could be.

 

[uffex]

Good day
Taken from the manual it may help if you do not have the information
Kind regards
Uffex

 

[Lbb]

It's an inline type a I am unsure what type of injectors it's an older motor designed in the 70s everything of course is mechanical. I will try the return line at some point it's going to be raining all day. Who knows the hours on the engine I am sure it's high. The injection pump was rebuilt a couple years back. I have the manual and it shows how to test the injectors but I do not have the high pressure testing tools. Anyone know some cheap basic ways to test them. I was also wondering if it could be the feed pump that's a cheap part.

 

[Delmer]

Yes it could, and it sure wouldn't hurt to clean out the screen inside the banjo bolt inside the inlet to that priming pump. It's pointing straight down so it will be easy for you to access

 

[thepumpguysc]

That pump SHOULD have a hand primer on the supply pump.??
Loosen the return line bolt on the pump & work the HP until u get fuel there & tighten it up..
Loosen ALL the lines AT THE INJECTORS & crank the engine until theres fuel THERE & tighten the lines back up..
U can remove the injectors & hang'm w/ the tip up or just exposed & hook the line back to them & crank the engine to SEE if they're spraying..
DO NOT get near the spray.!!! it WILL penetrate your skin & then its off to the hospital..
it could be a faulty/worn out supply pump.. but using the hand primer should solve that problem, short term..
BUT if the piston in the supply pump is THAT WORN, so aren't the pumping plungers in the inj. pump..
TRY to clean out the INLET banjo bolt fitting on the supply pump.. its the line BELOW the HP..
I think theres 1 at the filter too..inlet side.. check'm both..
Good luck..

 

[John C.]

I don't recall ever seeing a 6BB1 Isuzu engine. There were plenty of 6BD1 engine in that time period. What is the model of your Link-Belt?

 

[Lbb]

I wanted to update this a bit. It is in fact a 6bb1. My excavator is a LS-2650. It wasnt the feed pump or the screens looks like it is not making enough pressure to pop off the injectors when it gets hot. Pump must be worn out. I will have to have it rebuilt this winter. Anyone taken one of these zexel pumps apart. I can find the barrels and plungers for cheap. $10-12 a piece. I found a video of a tear down but its in hindi. I am not sure I want to tear it apart. Thanks for your help

 

[thepumpguysc]

Yea, I've done thousands of'm.. it's something that requires special tools to disassemble & reassemble..
Quality P&Bs aren't that cheap.. more like 100.00 apiece.. They wear out from dirty fuel.. Period.
I keep saying to anyone that'll listen.. "A couple of 20.00 fuel filters a year, will save u thousands in pump & injector repairs."..

 

[Tags]

Yea, I've done thousands of'm.. it's something that requires special tools to disassemble & reassemble..
Quality P&Bs aren't that cheap.. more like 100.00 apiece.. They wear out from dirty fuel.. Period.
I keep saying to anyone that'll listen.. "A couple of 20.00 fuel filters a year, will save u thousands in pump & injector repairs."..

I would probably send it to the guy that’s taken thousands of them apart to get it fixed… Probably send him a private message and I’m sure he would be happy to guide you through removal, he’s one of many guys on here that makes this forum so great....

 

[heymccall]

looks like it is not making enough pressure to pop off the injectors when it gets hot. Pump must be worn out.

Based on symptoms, I'd have the injectors tested before pulling that pump.

How did you determine that the pump is suspect?
It's a lot easier (read cheaper and faster) to have the injectors removed and tested.

 

[thepumpguysc]

YUP.. most people just yank the pump & leave the injectors in the head.. {not good}
It SHOULD BE, yank the injectors & THEN the pump.. or do them at the same time..
I would hang # 1 injector outside the engine & see if it "pops off"..
I say #1 because that's where all the dirt & contaminates hit 1st..

 

[Delmer]

...wasnt the feed pump or the screens looks like it is not making enough pressure to pop off the injectors when it gets hot. Pump must be worn out...

What makes you say that? Not exactly the most common outcome, how long has the engine been acting like this?

 

[LACHAU]

I don't recall ever seeing a 6BB1 Isuzu engine. There were plenty of 6BD1 engine in that time period. What is the model of your Link-Belt?

ISUZU 6BB1 is older than 6BD1 but the fuel system is same (even 6BG1), my dear.

 

[uffex]

Compliments that is clear and helpful info
RE
Uffex

 

[LACHAU]

I wanted to update this a bit. It is in fact a 6bb1. My excavator is a LS-2650. It wasnt the feed pump or the screens looks like it is not making enough pressure to pop off the injectors when it gets hot. Pump must be worn out. I will have to have it rebuilt this winter. Anyone taken one of these zexel pumps apart. I can find the barrels and plungers for cheap. $10-12 a piece. I found a video of a tear down but its in hindi. I am not sure I want to tear it apart. Thanks for your help

You can refer to this manual. Good luck.

 

[LACHAU]

and also refer to follow video.

 

[thepumpguysc]

I believe he has an A pump..The videos are showing a P pump..
I think he might have used the info in post 7 to figure out it was the pump.??
Hang an injector outside the engine & spin it.. no fuel from the injector, more than likely means, bad plunger & barrels..