Been trying to get the old 751 with Pug motor running....special props to Tazza for helping me with lots of things to check. Here is what I know so far.... Was running, throttled back to idle to check something and it died. Would not start again. Coolant level low, but temp gauge never went out of 'good' range... Checked timing, all right on, crank, injector, cam... Checked compression,#2 cylinder a little low, 285psi, but rest above 350psi... Checked fuel solenoid...operating.... Replaced glow plugs with new. Verified they are getting voltage and are red hot on ends Pulled injectors, cleaned and checked. Did not mix up parts, all pins were moving when put back together.... Verified good spray pattern on injectors before re-installing. Did not buy new copper seals, but they seemed pretty good, reinstalled with existing just to see if we could get it to run.... Bought new battery and starter spins motor better than ever before... Replaced primer bulb... Bled fuel system of air through bleeder on injector pump... Installed clear hose to watch fuel, no air bubbles... Sprayed wd-40 in intake while cranking, didn't help... Still won't start. At a total and complete loss as to what it might be. I've searched and read every thread on 751's here to see if it could be anything else. Got reasonable compression, glow plugs working, cranks, getting fuel. Shouldn't anything run with that? About to sell it for parts and chaulk up the $8K I payed for it as a lesson learned..... Any and all suggestions would be much appreciated. TIA, Mike
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7LBSSMALLIE
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hard to sell if it dont run,,sound like all bases covered fuel air and compression. .and timing? all checked sound s good. but as is typical of this eng the cam is probally snapped in half. pull valve cover and inspect
I'm pretty well out of ideas.
You tried WD40, it should have kicked a little, even if there is a fuel supply issue. There is just nothing that i can think of that could cause the problem that would prevent it from showing even a hint of life.
If the pump was to fail, which is possible, the WD40 should have at least kicked. The timing must be right or else you would have low compression.
Can you grab a can of engine starter? It has ether in it and is far more combustible. Disconnect the glow plugs, spin the engine and give it a good snort of it. You really have little to loose, it is not good stuff, it makes a horrible clang when it fires. If it does kick, it sounds like the pump could be bad.
When you crank with the injectors in, does it smoke at all?
Are you getting fuel to the injectors?
Can you hook up an injector to the pump with a line out the back and see if you get a spray?
You tried WD40, it should have kicked a little, even if there is a fuel supply issue. There is just nothing that i can think of that could cause the problem that would prevent it from showing even a hint of life.
If the pump was to fail, which is possible, the WD40 should have at least kicked. The timing must be right or else you would have low compression.
Can you grab a can of engine starter? It has ether in it and is far more combustible. Disconnect the glow plugs, spin the engine and give it a good snort of it. You really have little to loose, it is not good stuff, it makes a horrible clang when it fires. If it does kick, it sounds like the pump could be bad.
When you crank with the injectors in, does it smoke at all?
Are you getting fuel to the injectors?
Can you hook up an injector to the pump with a line out the back and see if you get a spray?
7LBSSMALLIE
Well-known member
- Joined
- Feb 2, 2012
- Messages
- 1,294
keep in mind the french hate us. the pukeo the versa handler etcI'm pretty well out of ideas.
You tried WD40, it should have kicked a little, even if there is a fuel supply issue. There is just nothing that i can think of that could cause the problem that would prevent it from showing even a hint of life.
If the pump was to fail, which is possible, the WD40 should have at least kicked. The timing must be right or else you would have low compression.
Can you grab a can of engine starter? It has ether in it and is far more combustible. Disconnect the glow plugs, spin the engine and give it a good snort of it. You really have little to loose, it is not good stuff, it makes a horrible clang when it fires. If it does kick, it sounds like the pump could be bad.
When you crank with the injectors in, does it smoke at all?
Are you getting fuel to the injectors?
Can you hook up an injector to the pump with a line out the back and see if you get a spray?
They are an excellent engine... when they are running that is.keep in mind the french hate us. the pukeo the versa handler etc
I am not saying compression is your problem , but I will say that 285 is not good compression , my spec book is out in the truck so I don't know what the compression should be on your engine but would guess it should be above 400 , probally some where between 425-450 , also compression between cylinders should be no more than 10 percent between cylinders --------I really think the engine should run with 285 on one as I have seen them run with none on one --------- the low compresion could be from a bent rod , when you tested compression did you do a wet test on that cylinderThey are an excellent engine... when they are running that is.
Tazza, Will try Starter Fluid. Cranking with injectors....it does smoke some, not belching, but some. Yes, getting fuel to injectors. After cleaning them, they were connected to fuel lines from injector pump, engine turned over and good spray verified from all 4 injectors. Before cleaning, only #1 injector had good spray, #3 and #4 were dribbling/little spray. #2 was bound up....which, coincidently was the low compression cylinder. Haven't run another compression check, but wonder if that would have any bearing on pressure reading. So, we have verified fuel to all cylinders, and glow plugs are working....just can't see how it could'nt start. Regarding broken cam.....wouldn't the compression readings be affected by that? I know they are on the low side, but they aren't non-existant. I'm going to try fresh diesel tomorrow. The fuel has been in the tank for awhile. It's pretty full, so I'm not scraping the bottom of the barrel. Think that might be it? Ughh!!!A Pug!!!I'm pretty well out of ideas.
You tried WD40, it should have kicked a little, even if there is a fuel supply issue. There is just nothing that i can think of that could cause the problem that would prevent it from showing even a hint of life.
If the pump was to fail, which is possible, the WD40 should have at least kicked. The timing must be right or else you would have low compression.
Can you grab a can of engine starter? It has ether in it and is far more combustible. Disconnect the glow plugs, spin the engine and give it a good snort of it. You really have little to loose, it is not good stuff, it makes a horrible clang when it fires. If it does kick, it sounds like the pump could be bad.
When you crank with the injectors in, does it smoke at all?
Are you getting fuel to the injectors?
Can you hook up an injector to the pump with a line out the back and see if you get a spray?
Fish, Did not do a wet test. Tazza suggested that, but since they were kind of OK, we kept looking. The fact that it was running, basically stalled, them we couldn't get running again, made me think compression, pistons, rings, etc. wasn't the problem. Seems much more like a fuel or electric problem. It has always been hard to start first thing, even in the summer. But, I have got it started on 35 degree winter days before. Thanks for thinking about it.... MikeTazza, Will try Starter Fluid. Cranking with injectors....it does smoke some, not belching, but some. Yes, getting fuel to injectors. After cleaning them, they were connected to fuel lines from injector pump, engine turned over and good spray verified from all 4 injectors. Before cleaning, only #1 injector had good spray, #3 and #4 were dribbling/little spray. #2 was bound up....which, coincidently was the low compression cylinder. Haven't run another compression check, but wonder if that would have any bearing on pressure reading. So, we have verified fuel to all cylinders, and glow plugs are working....just can't see how it could'nt start. Regarding broken cam.....wouldn't the compression readings be affected by that? I know they are on the low side, but they aren't non-existant. I'm going to try fresh diesel tomorrow. The fuel has been in the tank for awhile. It's pretty full, so I'm not scraping the bottom of the barrel. Think that might be it? Ughh!!!A Pug!!!
Was going from memory last night, but here's what was done, by my brother , who is a much more experienced and talented wrencher that the hack that I am....."We checked the compression and found the following. All checks require 3 pulses. Fuel solenoid was denergized and spun over prior to compression test to be sure the cylinders were clean. Test was preformed dry with no oil added to cylinders. Cyl 1 350 psi Cyl 2 225 psi Cyl 3 350 psi Cyl 4 350 psi We spun the motor over with the glow plugs out and fuel solenoid open and the following was observed. Cyl 1 and 2 spray fuel out the glow plug hole. Cyl 3 and 4 had no spray out glow plug hole. Removed Cyl 4 injector line at top of injector and fuel would dribble out. Reconnected line and cranked again and no fuel spray out of glow plug hole." Based on this info, he pulled the injectors and cleaned them out. Not sure if this helps or not. UGH!! PUG!!Fish, Did not do a wet test. Tazza suggested that, but since they were kind of OK, we kept looking. The fact that it was running, basically stalled, them we couldn't get running again, made me think compression, pistons, rings, etc. wasn't the problem. Seems much more like a fuel or electric problem. It has always been hard to start first thing, even in the summer. But, I have got it started on 35 degree winter days before. Thanks for thinking about it.... Mike
I felt 285 was dead , 225 is a stone dead cylinder , and even 350 isn't much to be happy with , time for a rebuild or replacement -------- you noted it has been hard to start ---compression is what fires the fuel on a diesel engine ------when it gets light outside I will go get the Bobcat spec book out the truck and see if your engine is listed -------- if you want to try something that won't cost a lot , get some Rislone ring sealer , put a quart in the engine oil and put a squirt in that 225 psi cylinder and see if the compression comes up a bit and gets you running ---that stuff really works , I had a Chevy 350 that one cylinder was bad and it smoked when acclerating and keep fouling out that plug , with the stuff in there it quit smoking and I drove the truck for another year and sold it ----------Was going from memory last night, but here's what was done, by my brother , who is a much more experienced and talented wrencher that the hack that I am....."We checked the compression and found the following. All checks require 3 pulses. Fuel solenoid was denergized and spun over prior to compression test to be sure the cylinders were clean. Test was preformed dry with no oil added to cylinders. Cyl 1 350 psi Cyl 2 225 psi Cyl 3 350 psi Cyl 4 350 psi We spun the motor over with the glow plugs out and fuel solenoid open and the following was observed. Cyl 1 and 2 spray fuel out the glow plug hole. Cyl 3 and 4 had no spray out glow plug hole. Removed Cyl 4 injector line at top of injector and fuel would dribble out. Reconnected line and cranked again and no fuel spray out of glow plug hole." Based on this info, he pulled the injectors and cleaned them out. Not sure if this helps or not. UGH!! PUG!!
The strange this is it just stopped all of a sudden, there needs to be something in common that caused it. Even with one pot really low on compression, i'd suspect it would still start, or at least pop with WD40 or starting fluid.I felt 285 was dead , 225 is a stone dead cylinder , and even 350 isn't much to be happy with , time for a rebuild or replacement -------- you noted it has been hard to start ---compression is what fires the fuel on a diesel engine ------when it gets light outside I will go get the Bobcat spec book out the truck and see if your engine is listed -------- if you want to try something that won't cost a lot , get some Rislone ring sealer , put a quart in the engine oil and put a squirt in that 225 psi cylinder and see if the compression comes up a bit and gets you running ---that stuff really works , I had a Chevy 350 that one cylinder was bad and it smoked when acclerating and keep fouling out that plug , with the stuff in there it quit smoking and I drove the truck for another year and sold it ----------
I guess a cam shaft is possible, but i would have thought that compression would be non existant on some of the pots if that was the case....
7LBSSMALLIE
Well-known member
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- Feb 2, 2012
- Messages
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15 mins to pull muff and check cam. or two months down time,?The strange this is it just stopped all of a sudden, there needs to be something in common that caused it. Even with one pot really low on compression, i'd suspect it would still start, or at least pop with WD40 or starting fluid.
I guess a cam shaft is possible, but i would have thought that compression would be non existant on some of the pots if that was the case....
