Runaway Isuzu 4JB1 help ... yikes that was scary

[kilohertz]

Just bought a mid 90's Bobcat 853 with the Isuzu 4JB1 4 cylinder Diesel, not running. It's been sitting for at least 2-3 years and had some minor parts removed for other machines so I decided to just get the engine going first, and figure out what may be missing later. I completely disconnected the electrical system and just hot wired the engine, shut off solenoid and starter was all I had connected. Fresh fuel into the tank, checked oil and water level, all good, gave her a crank and it sounded good cranking, no bad noises, but wouldn't fire. Tried a few times with the glow plugs and still nothing. Let it rest, cranked again, and gave it a little sniff of ether and she coughed, yeah, we have compression, another little shot and away she went, idled fine for about 2 seconds then went to full throttle....scared the crap out of me so I yanked the IP shut off solenoid and it kept running...:confused2::confused2: Thank the good Lord I had the foresight to have my trusty tennis ball ready so I stuffed it into the intake tube and killed the engine. After I regained my composure, tried it again, same result, this time I used the tennis ball to control the engine speed and let it idle for 30 seconds or so, all the while it was pumping out black exhaust smoke, hoping it would clear up, but it didn't. It sure wanted to eat that ball. :laughing: I tried moving the throttle lever and it didn't make any difference, then while it was running mid speed I tried yanking the IP solenoid and this time it quite. Fired it again and let it get to high RPM and now pulling the IP power wouldn't kill it, I had to stuff in the tennis ball.

So it's an Isuzu 4JB1 4 cylinder with a ZEXEL (Bosch VE4) injection pump.

Any and all help would be greatly appreciated....I would love to get this off my trailer and get working on other things. I have attached a picture of the pump, assuming that is the problem.

Cheers!

 

[RPW]

My first thought would be a problem in the injector pump.

 

[kilohertz]

My first thought would be a problem in the injector pump.

Mine too. I have spent the past hour searching the web and found that Bosch VE pumps have been know to have the governor collar stick, at wide open which is where they rest when not operating. They start at wide open and the rotating speed pulls in the governor weights to idle after it gets its' first big shot of start up fuel. I am thinking best case, just sticky collar which I may be able to get to under the top cover (while still in the machine) worst case, the little knob that goes to the throttle linkage has broken off (also seems to be common failure on these) in which case, new pump time, or at least rebuild.

Am I on the right track?

 

[kilohertz]

Made a video tonight..after all, 10,00 pictures are worth a 1000 words.

[video]http://www3.telus.net/radioboy/Bobcat%20running.wmv[/video]

Not sure what format to make the link so I tried both.

thanks for any help.
Cheers

 

[Kioti Paul]

Hi kilohertz,

I found your post because (almost) the exact same thing just happened to me, & I was searching for answers. Mine is a Kioti DK45S with a DaeDong 45hp engine, and (I assume) a DaeDong injector pump.

I was brush hogging my property, & stopped for lunch with everything operating properly. After lunch, when I started it, it idled normally for a few seconds then slowly died. It had never acted like that before (I bought it new, 6 years ago). I had considerable trouble restarting it, & when it did start, it went BERSERK!! It seemed to be at full throttle, and the governor didn't seem to be working at all. The throttle position had no affect, & when I turned the switch off, nothing happened. That REALLY gets your attention, doesn't it!!! I was able to stop the (run away) engine by putting the trans in high gear, & 'popping' the clutch. I feel very fortunate that I don't have a hydrostatic trans (it would probably still be running!)

After some soul searching, I decided to try to restart, & load the engine down by continuing my mowing chores. This time the engine started right up, & I was ready for it, as it began to speed up (I had the throttle at idle). I engaged the PTO, & began mowing. After a short time I concluded it was actually not developing full power (at the idle setting), perhaps it was developing 1/2 to 3/4 power. I could advance the throttle, and it would perform as always, including the governor maintaining the RPM, it just would not slow below a certain power level.

The next day I pulled off all the "inspection" covers, & found the governor, throttle linkage, & shut off solenoid all working properly. After studying the system (mine is incredibly simple), I have come to the conclusion, that what ever is wrong with it, it is contained in the injector pump (that's really the only thing left)

I thought that probably 1 (or 2) of the metering ports must be stuck open, allowing 1 (or 2) of the cylinders to always develop full power. To test my theory, with the engine cold, I started & ran it for 15-20 seconds with the shut off solenoid disconnected. I figured with the solenoid "off", only the cylinders with the 'stuck open' ports would be firing. After shutting the engine off (popping clutch technique), I was disturbed to find that all 4 exhaust stacks were warm (seemed to be about the same temp) That shoots a hole in my theory! (I think??) I just can't think what would happen to affect all 4 cylinders at the same time (& instantly), and not be controlled by either the throttle position, or the shutoff solenoid. Perhaps my system is not so 'simple', or perhaps I am just 'more simple'!

Anyway, that is where I stand right now (this all happened April 15th). The injector pump does not seem to be serviceable; at least Kioti doesn't list parts for it. Unless someone does shed some light on our situation, I guess I will pull the pump off, & see if I can find a shop that can overhaul it. Otherwise I guess I have to shell out $1,500 for a new one, (& hope that's the problem).

I am sorry I can't (presently) point to the problem you (& I) are having; but I will repost when I discover what fixes my problem.

Surely someone else out there has had this problem & could advise us??? If it ever has happened to you, you WILL remember it... it is quite an eye opener!

Finally, for what it's worth, I feel certain your 'smoke' is caused from the injector pump injecting a considerable amount of fuel into the cylinder, while at the same time you are restricting the airflow with the tennis ball, causing an extreme over rich mixture being burned. Mind you, I am NOT suggesting you test my theory by NOT restricting the air flow!!! ha ha.