I'm working on a Bobcat T650 s/n ALJG18685. It starts very hard. can't hardly get it started without either. I know that is bad. It will set code P0087 Injector Rail Pressure Sensor. I did an injector buzz test and number 1 sounds alot different than the rest. I don't know much about that test. I did not have it running today ( too cold to start ) to do a cut out test. I'm thinking that number 1 injector may be bad. I want to check the bleed off of the injectors next and compare them. I may check the resistance of the injector coils and compare them also. Probable should check the glow plugs to but I don't think that is the problem. I think it is something bigger than that. Would be glad for any input.
Is it possible to read fuel rail pressure? check how much it reach when you are cranking. What diagnostic tool areyou using?
Injectors return flow will probably give you your answer. A very common problem on those. To be bad enough to set a code while cranking will be quite evident, as most will fail to hard/ no start and still build enough pressure to avoid coding. If you have access to a rail cap off fitting you may be able to start it on 3 cylinders. If return flow is not very high on at least one injector, I would look at fuel supply, jncluding the cold weather bypass valve.
I am using a Jaltest diagnostic tool. I should be able to read fuel rail pressure with it. I'll check that when I get it running. Do you know the range it should be in?
I don't think it was setting the code while it was cranking. That was an inactive code from when it was running before. Now that I am working on it, I have not got it to start yet. Too cold and don't like to use either on it. I was just observing some of this while someone else was messing with it, and now it is my job to fix it. I have some rail caps ordered but it will be a couple of days before they get here. Can you explain more about the cold weather bypass valve? I know where it is, and what it looks like, but would like to know how it functions.
Just a question as I have not worked on one, but does it have an Air Intake Heater or Glow Plugs and if it does, do they work. Something that cost nothing to try is 2 good heat guns shooting into the air intake with it cranking. Of course, you would blow out the housing before removing the first filter and clean housing after second filter if it has an inner filter. That combined with a super heavy spray of WD 40 would give a bit of an idea about cylinder condition. Of course it will not fix the injectors if they are not putting out sufficient fuel. I would test that if you feel like it. Just to let you know a Komatsu D155 Engine will start the first time on the second injection line being closed when the cylinders were heavily lubed with oil just before installing the heads. The excess oil causes a heavy spike up in compression and ignition of the fuel. Simon C
I liked those ideas. I'll have to try them on some engines. So this is what I found today. It has three bad glow plugs. The fuel bleed off on two of the injectors was bad and not real good on one so three bad injectors. Also not sure that the cold weather fuel bypass is working right. I used an electric fuel pump between the primer bulb and the filter to make sure that it was getting good fuel flow. I could not get it to prime up until I clamped off the line from the bypass.
Is this a newer 650 with a Doosan? Maybe you already know this, but common issue with them is fuel delivery. The pump goes, sends shavings through the whole system to wreck the injectors. To repair properly, need 4 new injectors, rail and pump. Have seen people skip the rail replacement and wreck a new set of injectors. Not saying this is your issue. But without proper fuel supply, paired with a doosan- It’s quite possible. Hopefully you have a Kubota, but I suspect not, because you likely wouldn’t be having this problem if so…
It is the Doosan. In taking it apart I did not see any glitter in the fuel lines. Maybe I need to look farther though. How do I tell if the pump is shredding?
At least you found 3 faulty glow plugs. That is a good start. Problems often accumulate and then a person has big problems like no start or no power. There is a guy on You tube that does a lot of Doosan engine repairs, his you Tube name is " HowIDidIt ". He is heavy into Bobcat Repairs and one of his videos may help. Simon C
As Simon C said, let’s hope minor problems are leading to no start conditions, if your injector 1 is bad, that’s no ideal, but doesn’t sound like we can confirm that yet either. Would be good to know fuel pressure as well. Check out this thread. T650 crank but no start I'm working on a T650 2014 year model with bobcat/doosan engine in it. It currently will not start and has no codes displayed other than an m0116 air filter not connected code. Will this code cause a no start? I wouldn't mind knowing a bit about the fuel pump as well. It appears to be a... www.skidsteerforum.com Also, avoid the either if you can..
Basically is supposed to be a temperature activated valve that recirculates fuel to help prevent cold weather filter issues. We routinely remove them completely. If I'm not mistaken Bobcats "update" is simply a solid tee, ie does nothing.
An update on the T650. I replaced the three bad injectors and three bad glow plugs. I did not see any glitter in the fuel rail or lines. That always makes me alittle nervous hearing the horror stories. Coded the injectors, primed up the fuel system, and it started right up. The kid messing with it before me had already drained the fuel and put in new. He also replaced the fuel filter. Talked to the costumer today and he said it has been starting good.
3 bad glow plugs will definitely put a slow down on compression ignition. Glad it is working, with new injectors if you keep fuel clean it may be good for a while. They all break down. Simon C