Cummins 8.3 ISC Lift pump replacement

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RonPatt

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Joined
Nov 15, 2007
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Mamers, NC
My coach has changed from starting as soon as the key is turned, to having to crank on it for several seconds.  This remains constant regardless of the temperature.  There is no decrease in power once it is started.  I have changed out the fuel filter.  From most of my reading it appears to be the lift pump.  How hard a job is it to change out and where can I find one?  Google searches have resulted in numerous hits on the 5.9L Cummins but not the 8.3.  Thanks for any help or suggestions.

Ron Patterson
'99 American Tradition w/8.3 Cummins ISC
 
Ron,
I have a 99 Country Coach Allure that has 154,ooo+ miles.  In december of last year,  the engine would stumble on take off if it had been idyling as for waiting for a light to change.  turned out to be the gasket in the lift pump was leaking.  At my age,76, I did not want to tackle the job even though I usually do my own maintance.  We were on our way south so took it to cummins Coach Care in Bakersfield,CA  and had them do it.  Could have had a new gasket put in but chose to have a new pump installed because of the milage. The new pump was $200+ the best I remember.

Bill Dane
 
Thanks for the info Bill.  It is probably more than I want to tackle as well, so the pricing was informative.

Ron
 
I have attached a picture of the "fuel transfer pump".  There are two wires entering the pump but the wires are not connected to anything.  Anyone know how that works?
 

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That's a picture of the fuel filter, not the pump. At a guess, the wires may be for a water sensor that may be part of the filter. If water appears in the sensor, the wires wold trigger an alarm on the dashboard.

What is the number on the fuel filter - cannot read all of it?
 
The filter is a Baldwin BF957.  I have attached a picture from the Cummins parts catalog for my fuel pump.  It appears to me that the filter attaches to it. 
 

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I found the pump.  It at the back of motor.  Verified that the job looks too big for me.  I assume that it is a mechanical pump?  Thanks for listening.
 
I thought all the "I" engines (e.g. your ISC) had electric lift pumps, but do not know that for a fact. The non-electronic engines all had mechanical lift pumps that are physically attached to the engine. The parts diagram you showed seems to be that way.

But your first photo does not look like the part in the diagram, which does indeed seem to have a filter on it.  Could the first photo be the second stage filter and there is also one on the pump (called the primary filter)?
 
His is a 99 Trad. probably a 98 engine, as such could be ether the mechanical or the common rail engine. Cummins changed to the common rail for 98 but sold out the mechanical thru 98.>>>Dan ( His description of the pump being on the rear left side makes me believe its a pre-common rail engine)
 
utahclaimjumper said:
His is a 99 Trad. probably a 98 engine, as such could be ether the mechanical or the common rail engine. Cummins changed to the common rail for 98 but sold out the mechanical thru 98.>>>Dan ( His description of the pump being on the rear left side makes me believe its a pre-common rail engine)
Click to expand...

The engine is a '98.  The Cummins parts catalog that showed the transfer pump with a filter attached confused me (I confuse easily).  I did follow the fuel line back to where it
attached to what appears to be a mechanical pump.  There is only 1 fuel filter.
 
That was a transition year for that engine,, both the pre-common rail and the ISC where sold that year,, it could be either. If the engine has individual fuel lines originating from the left front of the engine and going to each of six cylinders,, its a C8.3 "pre" and the lift pump will be on the left rear of the engine right next to the filter.>>>Dan
 
AS you alluded to the 5.9 lift pump is junk.  The rest of the motor is great.  see: http://fassfuelsystem.com 
I didn't like the price but the mechanic at work talked me into it.  I'm glad I went this way for the following reasions: 1 does the job.  2. Can change filters very easy. 3 Has a petcock that you can drain and do a visual on what has been in your tank, like algae.  4 Priming is a piece of cake.  just screw on new filter and back off just 1 or 2 turns then turn key and pump fills up filter, when it starts to leak out screw tight. 
But I would also recommend a light known as "low fuel pressure" in your dash, about the size of an eraser. It is like getting an EKG on your fuel system.  Nothing is worse than low fuel pressure.
Having said all that I thought only the 5.9's had that problem.  And a big reader of www.turbodieselregister.com 
 
utahclaimjumper said:
His is a 99 Trad. probably a 98 engine, as such could be ether the mechanical or the common rail engine. Cummins changed to the common rail for 98 but sold out the mechanical thru 98
Click to expand...

The '98 ISC used a computer controlled injection pump, with individual lines running from pump to each injector.  In 2003 the ISC became the common rail variety.
 
After farther research I find I'm wrong,,(imagine that)  Common rail was continued until 03 as rtluft indicates but went to electronics in 98.>>>Dan
 
Well I bite the bullet and replace the fuel transfer pump myself.  The pump is indeed electric with what I thought was a filter the electrical part.
I removed the air filter and exhaust pipe.  That made it fairly easy to access the pump.  The most difficult part of removing the pump was disconnecting
a fuel line that was installed on a barb connector with a screw clamp.  The space issue made it difficult to work it off.

I ordered the pump from Cummins Charlotte for $306 and had it delivered to my shop.  Engine now starts quickly as before.  Let me know if I can provide any additional information to anyone who is considering this repair.  Ron
 
I'm glad you did the job, it is not that difficult. Be grateful you have the electric pump. We went through a long odyssey of bad replacements, leaky gaskets and repriming the motor to finally get our mechanical pump replaced. As others have said, it is the Achilles heel of the 5.9.
 
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