Got a call yesterday about one of our Bobcats "Smoking and doesn't run good". I went over today and started it... At first it ran pretty smooth (maybe a little miss) and smoke from the exhaust. After about five minutes to warm up (was about 35 degrees) I ran it and when I put it under a load (lift/tilt or forward/backward with full bucket) it would miss and there was a quick puff of smoke out of the exhaust. Seemed like white smoke at that time, but was hard to see from the cab. When it missed, it sounded like a large chain riding up on a miss-aligned sprocket then dropping back down... kind of a popping noise. I shut it down and checked the air filter which looked good. After it sat a few minutes while I went over stuff, I started it again. This time it ran very rough and smoked heavily. Smoke seemed like fuel (more blackish). I didn't run it very long as I was worried it might be an internal engine problem and didn't want it to disintegrate in the customer's small backyard. I took a short video...but looks like I can't upload videos. I uploaded a snapshot, though. I shut it down and checked for error codes. point there were no error codes other than the V8520, which I figured was the version of firmware or something. The inside of the exhaust pipe was somewhat sooty, but not wet with oil or anything. The oil level was within the marks, maybe a half quart low.... though was due a change. I fired it back up and it ran for a few seconds and died. The I got an error code 157-21 ("Fuel Rail Pressure Control" I think. Tried to start it a couple more times and it would just die and throw the above code. It seems to me it's getting too much fuel or maybe an air restriction. I talked to another guy the works for us and said it sounded like the turbo had failed. Unit has only 751 hours on it (2016). Any ideas, guys? Thanks!
Popping and smoking under a load is classic fuel starvation.. Either clogged filters or a weak supply pump or garbage in the tank outlet.. Good luck
Thanks, thepumpguysc! I'll replace filters and fuel first. Then I'll address the pump. I'll let you know what I fine. Again, Thanks!!!
What year is the machine. Doosan motor ?? No codes ?? There have been a lot of issues with fuel filtration through out the line up. They are very particular about fuel quality. We go through filters like crazy. Ours are rental units and they get filled up with old buckets/ god knows what mixed with diesel. Plus we have had a lot of doosan injectors fail. They return rate is high when.you remove the return line off the injectors they shoot fuel all way to the frame bulked. They don't always through a code either. Might be worth checking out if a fuel filter change doesn't get you square
Thanks, Txhayseed! It's a 2016 model. I think that unit has a Doosan motor... I could not find a tag on the engine with the model, serial number, etc. I have trouble with our operators maintaining fuel quality and quantity. They seem to run them nearly empty much of the time. I keep telling them to fill them up at the end of the day, but as I only see them during servicing or when somethings wrong it's difficult to monitor. I replaced a fuel meter inlet valve a few months back that was rusted from all the water in the fuel. Thanks for the advice on the injectors and testing them. I'm going to go back to the job site tomorrow and pick it up. I keep filters in stock. I'll drain the tank, fill it with fresh clean diesel, then replace the filter. Hopefully, that'll fix it. I'll post as soon as I have done that. Again, thanks for the help.
Oh, the only code (which just popped up after 20 minutes of running rough) was the 157-21.
Went over Sunday to retrieve the T-450. As the unit was in the customer's back yard and no way to get to it with the trailer, I had to get it running enough to drive it about two hundred feet. At first, I could not get it run for more than a couple of seconds (lots of gray/white smoke). It had a little less than a half tank of diesel, so I added another five gallons and used starter fluid to get it going. Pumped the fuel bulb up until it was hard and hit it with either…. it finally started and ran enough to get it on the trailer. It died three times, but was able to get it going again with the either and pumping bulb. There are no longer any in mosquitos in that neighborhood… I smoked them out. Did not have any fuel filters in stock, so had to get one from Bobcat Monday. Drained all the fuel from tank, but it really didn’t look bad. Changed fuel filter, vented the air from the filter cap, added four gallons of clean diesel. Tried to start, but could not get it to run more than about a second. Used either and still would not run more than a second. I then filled the tank with clean diesel and (using starter fluid and lots of pumping bulb) got it to run for four of five seconds. Pumping once started didn’t help keep it running either. I’ve had trouble with the inlet metering valve on this Bobcat and our other T-450, so I thought that might be it. Removed it and inspected. Looked OK, but when tapping it on my palm I could not feel any movement from inside. Check resistance and found five ohms +/-. Tapped housing on a hard surface a few times, but still could not feel any movement inside. As I remember, I could feel the plunger moving inside when tapping on my palm. I did get another error code (157-10) which appears to be fuel rail pressure with a #1 injector fault. I ordered another inlet metering valve to try that… if that’s not it, I can keep it for future use. We get them from mydieselpro.com for $209.00… Bobcat wants upwards of $900! I would appreciate any advice on where to go from here. Thanks!
Update: Checked the fuel injectors. Removed the return lines and found the #4 (furthest from the alternator) was putting out much more fuel than the other three injectors. I connected some clear hose to each injector and the #4 hose was filled to about a foot after craning a couple seconds. The #1 injector had about an inch and the other two maybe a ¼ inch. After another crank (about three seconds) the #4 filled the line (about three feet) and the #1 was about three inches. The other two were about a ½ inch. So… looks like I definitely need a #4 injector and maybe a #1. Bobcat dealer has them for around $1100. Diesel Pro has them for about $400 (Delphi remans – 1 yr warranty). Questions: --- I can’t decide if I need to order one (for #4) or two (for #1 also). Or maybe four and keep a couple in stock in case the other two follow suit? --- I’m leaning toward the Delphi remans as I can buy three for what the Bobcat units cost. Is this a bad idea? --- These injectors each have a unique code set from bench testing (at the manufacturer) that is supposed to be entered into the ECM to get full performance from the injector(s). Does everyone do this? And if so, I don’t have a Bobcat computer interface/software… so what’s the be way to get this done once installed? --- Anywhere to get the interface for a cheaper? --- My manual is a .pdf and doesn’t have a search function, so it’s really hard to find stuff in it. Does anyone have a T450 manual that is text searchable? --- Can I get room enough to take that valve cover off by just removing the airbox? --- I understand Bobcat wants me to replace the fuel line for each injector too… is this necessary? --- Any other parts I should order? --- Any other tips for replacing these? Thanks thus far for the help from thepumpguysc and Txhayseed! You guys are really helpful. I owe you a steak dinner. Thanks in advance for any advice from them and anyone else. THIS FORUM IS AWESOME! I took some pics and will post them soon.
Injectors 1-4 (from top to bottom). Hard to tell from the bottom picture, but that line if full.
Had to wash the engine before I was brave enough to work on the fuel system... this is after scraping out about 20 pounds of mud/sand from under the engine and fuel filter.
Got the track loader fixed and it was an injector. For a time, it seemed that I had two or three injectors that had failed as there was a lot of fuel coming out of the returns. I decided to just replace the one that was originally bypassing (and the worst). As I already had all the tools out, the engine clean and airbox removed I figured it wouldn’t be too hard to go back in and change other injectors later. Once I had it back together, it faired right up. But it did still put out a bunch of gray/white smoke. No popping or missing, though. I let it idle for about twenty minutes while the engine warmed up and the smoke decreased considerably. I then ran it pretty hard for about another thirty minutes and it quit smoking completely. Started fine the next couple of days and no smoke at all. I guess the other injectors maybe were clogged a little bit from being ran with low fuel pressure to them (as the #4 injector was returning so much fuel). If someone else has a better explanation, it would be good to know. I ended up buying the injectors from Diesel Pro in Pa ($409 ea). I bought two and am keeping one for stock since I had so much trouble recovering that unit. The folks at Diesel Pro have always been very helpful… Thanks, Dylan!!! Was not a difficult repair overall. I took a bunch of pictures throughout… I’ll try to post them later with some text explaining what was going on. Thanks for the advice from thepumpguysc and Txhayseed.
Glad you got it fixed. They are pretty easy injectors to R&R wich is good since we do so many. Ideally the new injectors need to be coded into the cylinder they where installed into to help the ecm create a new fuel map. If you don't code them after installation and before starting your going to see that smoke since the system is working on information that it already knows and has not been told its changed. New injectors verse old with current fuel map smokes a little till the system balances out.
Thanks, Txhayseed. That's good to know. The injectors were pretty easy... would have been easier had I removed all the "tube-lines" (fuel lines) between the common rail and injectors. That would have made it easier to get the valve cover out of the way. From Bobcat Manual: "NOTE: Both the high pressure fuel lines and return fuel line are a one time use line. Replace the fuel lines with new fuel lines after removal." Does everyone replace this lines when replacing injectors?
I don't. I usually blow through with carb cleaner and air. There is no orifice or anything just straight through hard line. They are flared ball ends like old school injector lines. Not at like fuel tubes that you see on Cummins etc. That should absolutely be replaced. If you push cleaner through with the straw and it comes out the other side the line is clear. Since we have not got any factual data back on what's causing the issue we are just assuming the injectors themselves are getting hung and bypassing likely to manufacturing. If it was contamination you would have most likely lost the high pressure pump as well. I also usually take the rail pressure sensor off and purge the rail with brake clean and air also. I have read online a lot of people are loosing fuel systems on these units due to contamination but I have not ran across one out of the 15 or so I have done this year that pointed to fuel contamination. Modern fuel filters are made to a pretty high standard these days. I would think it would be straight neglect on owners part to crater the pump, injectors and the rail in one shot from foreign material in the fuel supply. Im know it happens but your good just swapping injectors if its running good. Any fuel pressure issues from the pump, rail or injector would other wise get flagged quickly and trigger a code.
Thanks for taking the time to answer that question. As those lines are $75/ea (and really simple), I couldn't see replacing them unless there was a good reason. And it will make it a lot easier to get the valve cover off next time. I like what you said about cleaning the rail with brake cleaner and air (sans pressure sensor)... I will do that from now on. I use only Bobcat brand fuel filters. They're expensive, but I figure cheap compared to the pump, etc. Unless you know better, anyway. Thanks again for taking the time to reply.