brambleberry
Active member
- Joined
- Sep 2, 2020
- Messages
- 25
I had posted a year ago about my '91 743ds that had engine troubles, compression was too far gone to even start.
In the meantime, I found a 743 in pieces that had a rebuilt engine with it. I bought it for the engine, but it had a full set of brand new bobcat brand hydraulic hoses in boxes, brand new bobcat instrument panel and wiring harnesses, and loads of other new stuff.
I started off by running the engine outside of the machine, to be sure it was indeed in working condition. It has the Engine Rebuilders Inc plate and stamp on it, so I know it was rebuilt. Just not sure when
I used a suspended funnel with diesel for fuel feed, and disconnected the belt to water pump and alternator. After sounding awful for about 5 seconds, the engine purred beautifully and I felt great about it (I had to stop it with a thick rubber flap over the air intake because the kill switch was stuck, could this have damaged something?). So removed my old engine and put in the new one.
Unfortunately, I have not been able to get it to start again. The wiring is all correct to my knowledge, the starter cranks it no problem. All that comes out is white smoke. Not even a try at catching on a few compressions.
I assumed there was something wrong in the fuel line so I disconnected the hose from the filter and put the funnel back in, and removed the return line, and had it go into a jar. That didn't change anything. I opened up the kill switch to make sure it was moving freely in there and not still stuck, and it was moving fine. I even left it in the open position and didn't touch it after replacing the cover.
I have tried cracking the injector nuts to let air out at each stage, and fuel definitely is seeping out of those. So it seems that the pumps are moving fuel. The only things that are different from when I had it running on the ground are that the coolant system is hooked up (is there a chance that coolant is leaking into the cylinders?), the wiring is hooked up, and it's now connected to the hydraulic pump. To my knowledge, there's no electronic valves or anything in this engine that would be preventing fuel from getting to the cylinders. There is a second solenoid in back of the starter solenoid, that is labelled as a "fuel shutoff solenoid (optional)" in my parts manual. I can't imagine what this would do to shut off fuel but maybe that's what's keeping it from happening?
The only other things I can think of are that somehow the injectors all got clogged at once, but that seems so unlikely since it was just running great. The next steps I would go to are pulling an injector, and putting an endoscope down into the cylinders, see if maybe coolant is leaking in there? Maybe send the injectors off to get checked for spray pattern?
I also don't know for sure that the glow plugs are working, the relay clicks when I engage them, and I checked for power going to them which it is, but I haven't checked the plugs for resistance yet. Seems though that with all the times I've tried cranking it for 15 sec, it would have at least tried to catch on a few of the compressions.
Anyways, thought you all with more experience than I have would have some good thoughts or ideas about this. I still feel like there's something incredibly obvious that I'm missing, but can't figure out what it could be.
TIA
In the meantime, I found a 743 in pieces that had a rebuilt engine with it. I bought it for the engine, but it had a full set of brand new bobcat brand hydraulic hoses in boxes, brand new bobcat instrument panel and wiring harnesses, and loads of other new stuff.
I started off by running the engine outside of the machine, to be sure it was indeed in working condition. It has the Engine Rebuilders Inc plate and stamp on it, so I know it was rebuilt. Just not sure when
I used a suspended funnel with diesel for fuel feed, and disconnected the belt to water pump and alternator. After sounding awful for about 5 seconds, the engine purred beautifully and I felt great about it (I had to stop it with a thick rubber flap over the air intake because the kill switch was stuck, could this have damaged something?). So removed my old engine and put in the new one.
Unfortunately, I have not been able to get it to start again. The wiring is all correct to my knowledge, the starter cranks it no problem. All that comes out is white smoke. Not even a try at catching on a few compressions.
I assumed there was something wrong in the fuel line so I disconnected the hose from the filter and put the funnel back in, and removed the return line, and had it go into a jar. That didn't change anything. I opened up the kill switch to make sure it was moving freely in there and not still stuck, and it was moving fine. I even left it in the open position and didn't touch it after replacing the cover.
I have tried cracking the injector nuts to let air out at each stage, and fuel definitely is seeping out of those. So it seems that the pumps are moving fuel. The only things that are different from when I had it running on the ground are that the coolant system is hooked up (is there a chance that coolant is leaking into the cylinders?), the wiring is hooked up, and it's now connected to the hydraulic pump. To my knowledge, there's no electronic valves or anything in this engine that would be preventing fuel from getting to the cylinders. There is a second solenoid in back of the starter solenoid, that is labelled as a "fuel shutoff solenoid (optional)" in my parts manual. I can't imagine what this would do to shut off fuel but maybe that's what's keeping it from happening?
The only other things I can think of are that somehow the injectors all got clogged at once, but that seems so unlikely since it was just running great. The next steps I would go to are pulling an injector, and putting an endoscope down into the cylinders, see if maybe coolant is leaking in there? Maybe send the injectors off to get checked for spray pattern?
I also don't know for sure that the glow plugs are working, the relay clicks when I engage them, and I checked for power going to them which it is, but I haven't checked the plugs for resistance yet. Seems though that with all the times I've tried cranking it for 15 sec, it would have at least tried to catch on a few of the compressions.
Anyways, thought you all with more experience than I have would have some good thoughts or ideas about this. I still feel like there's something incredibly obvious that I'm missing, but can't figure out what it could be.
TIA
