Lift pump location on isc350

[crah]

Anyone know where he life pump is located in an ISC 350? I see a small new drip in my driveway and hard to tell what it is, but its not oil. It looks like the exhaust is in the way from the source.

Thanks in advance

[Ken C]

It is located on the curb side above the starter motor

[HeapBigEngin]

Originally Posted by Ken C

It is located on the curb side above the starter motor

Yup....and you should be able to also spot the main fuel line that goes into the pump.

Surely don't know if your lift pump is leaking. If the spot smells of diesel fuel, then there is a problem somewhere. Unfortunately, early ISC lift pumps have developed a reputation for internal seal failure...just ask a tech at your local Cummins Dealership. Some say it's the result of the new ultra-low sulphur diesel fuel now required. Cummins no longer offers a re-seal kit for the lift pump, and they have "updated" the seal material in the last couple, three years. That says something.

Perhaps you already know this. If not, maybe this will help. The lift pump only operates for about 30 seconds with "key on", with or without start up, and then shuts off. It ensures that the low pressure fuel lines are fully primed before fuel enters the high pressure injector pump. If the pump seal(s) are bad, the pump will drip then....but usually (not always) stop dripping after it shuts off. If you can raise your bed in your coach and access the top of the engine, you should be able to see the pump, although with some difficulty. If you can't determine that the pump is leaking, I suggest you "key on" to activate the pump....no need to start the engine. You might see a pump drip right away. If not, after the pump shuts off and with "key off", hand check the bottom of the pump for diesel fuel. If it's wet, it's leaking. In either case, it will require replacement.

If you can't easily get to the top of the engine, you and your trusty flashlight should be able to spot the lift pump from underneath, again with some difficulty. You should be able to determine if it is leaking after your "helper" does the "key on" thing....and no start. Wear eye protection. If the lift pump is not leaking, you might want to check the individual high pressure fuel lines at the injector pump. Number 5 & 6 are the usual suspects here. And please....don't ask me how I know this!! Thanks!

Good luck. And please let us know what you find out....it will help many of us. Thanks!

[crah]

Thank you for the info. The leak does smell like diesel and it seems like it trips in the exhaust and steams a little ad well. The leak is closer to the road side. Hope it's not the injectors. Where is the injectors located?

Thank you

[HeapBigEngin]

Originally Posted by crah

Thank you for the info. The leak does smell like diesel and it seems like it trips in the exhaust and steams a little ad well. The leak is closer to the road side. Hope it's not the injectors. Where is the injectors located?

Thank you

Am unclear where your exhaust exits. Ours is on the passenger side, and the lift pump leak on our ISC was on the passenger side of the engine/coach.

Re your question, the high-pressure fuel injection pump is located further up and nearer the top of the engine. As I recall, it is about 12 inches or so to the rear of and above the lift pump which feeds it. You really cannot miss the fuel injection pump if you have access to the top of your engine. The six individual high pressure fuel lines go from the fuel injection pump to the individual cylinders. There are no individual fuel injectors...just the high-pressure pump. There can be leakage at the high-pressure fuel line fittings at the fuel injection pump. Of course, the fuel injection pump could also be leaking....just dunno' Hope that makes sense....

The fuel leak you are describing is most likely at the lift pump based upon the age of your ISC and where these leaks ususally develop. IMO, do the easiest things first. Suggest you do the lift pump test thing mentioned above. If you don't have easy access to the engine from above, do the underneath test as described. It is quick and not difficult to do. If the drip starts at "key on" and then goes away after the pump shuts off, it is the lift pump. That does not mean you don't have an injector line leak as well....but you must get to the top of the engine to determine that. And I sure wouldn't jump off that bridge until I came to it...right? Just be careful and do wear eye protection if you go underneath.

Again, good luck, and please let us know how you make out...thanks!

[HeapBigEngin]

Really not trying to "beat" this thing, but your comment about your leak being "closer to the road side" is puzzling. If the leak is on the driver "half" of the engine/coach, maybe you are just seeing normal spotting from the slobber tube. IF that is the case, jump for joy 'cause all is well!!

[crah]

Originally Posted by HeapBigEngin

Really not trying to "beat" this thing, but your comment about your leak being "closer to the road side" is puzzling. If the leak is on the driver "half" of the engine/coach, maybe you are just seeing normal spotting from the slobber tube. IF that is the case, jump for joy 'cause all is well!!

That would be good news. The exhaust exits the passenger side but its the main trunk it drips on. I probably won't be able to get to it until this weekend but will definitely report back. It did not drip before so that is not good news.

[crah]

Ok update everyone. From the bedroom lookin down, the drip is on the right hand side while looking back at the engine. No signs of dripping from the top. Looking up from the ground, the slobber tube is almost above which is placed right next to the oil filter. The slobber tube was slightly wet. Another line near that location is a tube that goes from the front side of the turbo back to the crankcase. That tube has a splice in the middle with a connection fitting with band clamps on both sides. Evidence of this area shows oil has accumulated through the years. I cleaned it up and checked the clamps which were tight. Looks like the slobber tube was the culprit which means its normal.

Thanks all.

[HeapBigEngin]

Thanks for getting back with your findings. That is great news re the drip. When you said the drip was closer to the "road side", that indicated to me something other than lift pump. Sounds like the slobber tube is doing what it is supposed to do.