Changing Fuel Filters on ISL 425 (Smog Engine)

[kraig]

I am referencing the HPCR (high pressure common rail), CM 2150, smog engine, with the exhaust pipe on the right side on the 08 and 09 and maybe some 2007 like mine. I learned the hard way on these new engines are different from changing filters and starting engines than in the past. The bottom line it wouldn't start, and I had to get Cummins service truck out to get it started. Luckily I did this in my garage and not along side the road.

Changing the suction filter which on mine was when you open the door on the back of the motor home and is on the right side and is easy to get to. Since it is located high, no fuel siphons from the tank. When you change the filter, you should fill the filter with clean diesel to top and install it making sure you removed the washer on the threaded shaft first. There are two different filters you could use. The standard is a Fleetguard FS 1003 (10 micron 98.7%) There is a better upgraded filter Fleetguard FS 19596 (7 micron 98.7% first pass with a 5 micron 88.0% on second pass) I did call Fleetguard to get this info since the dealers don't have it. I am using the FS 19596 since that is the easiest filter to get to and I am filtering as much I can before my pressure filter. The water Sensor plug still plugs in fine.

On the outlet of the suction filter, I did in Tee in Cummins fuel filter minder (3925199S) which does show when a filter is plugged. I feel this actually saves money, because you actually know the how much the filter is plugged and you are not changing filters when you don't need to. It can only be used on the suction filter. I don't know how to post a picture.

Changing the pressure filter is what is different. There is only one filter which is the FF5488 and is a 5 micron. This is the one that is over the starter and a little hard to get to. One word of warning even with the both battery disconnects off, the positive wire to the starter is hot all the time, so you should disconnect at the battery wires. I also disconnected the ground wires to the block, so I had access to get to the filter with a filter wrench reaching in from the end. Even if you have a 36 footer, I don't think it would be easy to to from the top. When you loosen the filter, you can't take it out upright, so stay clear and dump the fuel into a drain pan. Make sure you get old washer off the threaded shaft. The Cummins tech told me it is important to NOT to fill the filter at all, since you putting unfiltered diesel into your injection system. He says puts a light coat grease on the gasket of all fuel filters. Also he said not to over tighten them. I always use a Sharpie pen so I know how far I tightening them. Since you broke the suction in the system you have to get all the air out before it will start. The ECM (Electronic Control System) won't let the engine start till you get all the air out.

One word of warning is you NEVER WANT TO CRACK OPEN INJECTOR LINES TO GET AIR OUT. These HPCR (High Pressure Common rail) engines are 30,000 psi pressure. Cummins shows a training video to employees cutting through a hot dog. No way would you want your hand in there. There is not a problem as long as you never crack open the fuel lines.

To get the air out you need to turn the key to the on position, not cranking the engine over for about 20 seconds to run the fuel transfer pump to fill the pressure filter. Since the pump does shut off after about 20 seconds, you must repeat this about 3 times. This still does not get all the air out. Then turn on the key and let it crank over to get all the air out. The ECM (electronic control module) will not let the engine start until the air is out. I never looked at my watch, but I had to crank quite a bit before it started. The older engines would run a little rough until all the air was worked out, but these when they start, run good.

As far as the brand of filters, Cummins Tech would only recommend Fleetguard or Baldwin. He has cut them all apart and these were the best. I have used both them over the years and never had a problem.

One more thing on oil filters Cummins said you should only use LF 9009 on these engines, don't use the LF 3000.

The other thing is WRV gave me 2003 Cummins owners manual (earlier ISL) 4021427-00, which is the wrong one for the CM2150. On the Cummins web site you can download the right one for free. The new manual does cover DPF and lot other useful information on these engines.

In my opinion, like anything else, it is easy to do the fuel filters once you know how, and the first time it is better to do at home. I did ask questions first, but I didn't get all the information. Hope this helps.

[76dc]

I changed my own oil filter and the larger of the two fuel fiilters. The small one I could not get to because of lines coming out the top and running down the sides. I need to find fiilter wrench for that one. I understand this is a micro fiilter and does not need to have fresh fuel put into to it before putting on. I also have the cm2150 engine. I filled large filter about 3/4 full before installing.

[TerryM]

I just did the fuel filter changes last week. The small filter over the starter was easily changed with two people...one underneath and one (me) from the top, working together. You do have to spill the fuel to bring it out. It took us about 10 minutes at most to change. Note...I do have a 36 footer, 425 engine. The filter is in the exact same difficult location as my previous 2006 34 footer, 400.

[76dc]

Forgot to ask in my post. What site did you find manual. They gave me a three year old one when I purchased coach. still waiting for correct one they were goi ng to send me. I checked cummins.com and could not find any download for free.

[kraig]

The manual you want is #4021580. Go to store.cummins.com and if you want you can purchase it for $18.90 plus shipping or call 1 800 diesels and they will tell you how you can log in for free one time to download the manual and then you can print it.

As as for the wrench, just buy good qualitity metal strap wrench that fits the filter. When Cummins built the engine they had my filter on so tight, I use cheater pipe to get the filter off and it crushed the filter. That is why you want to get a good wrench.

[EngineerMike]

Kraig- in another post I can't find, you mentioned WRV installed a bleed screw on the 425's presumably for air release on initial assembly. Did you ever figure out where?

[kraig]

Mike-Mike Young told me WRV installed them on the 425 because they had trouble starting them at the factory. It is a small brass ball check valve. It is on the fuel pump on the back side of it. If you open the back access door, you can't see it. You have climb in and look over the top. I just used a small punch to push on the ball check while cranking the engine over. It doesn't hurt your hand, but it does have pressure. I will see if I can find a picture of it.