60 Series Detroit help needed

[CSnyder]

Ok this could be a long ordeal but Ill keep it short for now.



I have a 1998 Freightliner Classic with a 60 series Detroit that feels very sick right now. It all of a sudden started loosing large amounts of power a few monthes ago to the point it works real hard to pull loads averaging gross of 75,000. I have had lots of work done on it at the local Cummins dealer and it still isnt coming around and Im sick of forking out huge money for these dumb mechanics. It has a 13 speed and even in a slight head wind or pulling an empty aluminum trailer I cant hardly ever run higher than 11th. This same truck used to pull 75,000 in any condition in 13th and if you didnt watch the speedo you would be pulling 90 or more MPH!



A Few things Ive done so far...



1) new head

2) new injectors

3) new fuel lines, filters, flush on the system

4) new ECM

5) new air filters

6) new air to air

7) tried another used ECM out of a good strong truck

8) new turbo



I can pull 30 PSI boost all day long with it but it struggles to keep speed now. Even when I bobtailed home this morning 30 miles it just felt sick. An example would be comparing a stock Dodge Cummins 5 speed and an identical truck running 400 HP plus. You can tell the difference! One other thing Ive been noticing is it is only averaging 3. 53 MPG down from 7. 42 since the symptoms appeared. Getting going in all the lower gears it feels like it has strong torque and power but higher gears its like someone bolted a 2x4 under my skinny pedal.



This Classic long nose is my favorite truck and used to be the strongest in my line but Im just about ready to retire it now so any ideas or help will be GREATLY appreciated!



TIA, Chris

 

[TFucili]

My brother-in-law has been driving a tri-axle with a 60 Series, and has had an incredible amount of problems with it. It may be a little newer than yours since it is an EGR engine, but that thing runs massive amounts of boost, like 50+ in a hard pull. You mentioned 30 psi, is that peak? The last time it was apart was for a head gasket problem that is caused by the head studs "pulling" the block. They had to deck the block. This is apparently a common problem since the dealer had a whole slew of fleet trucks lined up with the same failure. I hope they get you squared away.

 

[JGrefenstette]

have you had the IP checked out on it, i dont know what the lift pump, or fuel delivery system is on the 60's but it sounds like a fuel delivery problem. especially since your getting the real problems higher in the mph range.



in august im starting work as a mechanic at a Detroit Service center in NC... ill also be starting diesel tech school at the same time. man your just a few months too soon! otherwise id probly have some answeres for you...



i would check your throttle linkage or what ever the set up is. . there may be some play or a flaw with system, keeping you from the full potential.

 

[nickleinonen]

the series 60 detroit diesel has electronic unit injectors in it. . all throttle by wire. .

is there a relief valve in the system to maintain a set pressure in the fuel passage inside the head? i am not familar with the series 60 really well, but i do know how eui's react to low fuel pressure. there should be a drain plug in the head for draining the fuel out of the head [i remember that from tech school]. put a gauge on it and see what you are getting under load and try and find some numbers for what the pressure should be. .


good luck

 

[CSnyder]

I forgot to mention I replaced the fuel pressure release valve and it corrected the low fuel rail pressure. The IP was also checked out on a bench during the head R&R.



I dont have the EGR engine but the older series like mine it is next to impossible to go higher than 35 PSI boost.

 

[MRushmeyer]

What was the last thing you replaced when it happened and how long ago. I'm guessing theres no codes. Also any difference in smoke now when its doing it. Will talk to a guy I work with thats pretty good with Detroits and try to give you some ideas. We are a freightliner shop and do quite a bit of detroit work so we should be able to come up with something.

Mike

 

[TAbbott]

What are the EGT's on your truck when working it hard? If they are above 850 or so, it would indicate you have a leak in the charge air system. They're easy to test. I put a tire chuck in the inlet air piping and made a plug out of a 4" pipe cap on mine and go over it regularly. Just because the clamps are tight doesn't mean it isn't leaking. If it won't hold 40 psi though the shrader valve, which doesn't provide much volume, its got a leak somewhere. Even new air to airs can leak. It's like a death spiral when you don't have enough air, the ecm isn't gonna give it any fuel and you won't make much power but the EGT's will be high. You also mention that it has new injectors. Low power could be the result of not calibrating the injectors with the ECM properly. If they are properly calibrated (code on injector matches code for that injector in ecm), try setting the injectors with the number "75" instead of whatever they came with and see if that doesn't perk it up. You'll need the DDEC reader for that task. One other thing that Detroits are famous for when older is sucking air. apparently right thru the fuel lines. Your Detroit dealer should be able to sell you a deareator that mounts up alongside the head that will give you solid fuel to the injectors with no intrained air in it. It sounds like BS, but it works -- at least it did on mine.

 

[dieselshu]

Chris, since your replaced the major components maybe you got as bad component or incorrect component. Wrong size injector would be my guess or incorrectly programmed injector. You are getting good boost so the turbo is sat but depending where the sensor is maybe the air cooler is clogged. Check the connections on the ecm, if a pin is bent or tweaked a bit you can run into power isssue we did on the 92 marine versions w/ DDEC.



Goodluck

Dave

 

[MRushmeyer]

Hey Chris, heres some things to check. Recheck your fuel pressure to see if your getting around 20 to 24 psi at idle and 75-80 at full throttle no load. If not theres a restriction on the suction side probably, if so run a line from a jug of fuel to see if its better. DO NOT change your injector codes to all 75 that is a truck driver myth for horsepower. You can also check the injector heights and codes to make sure they are set right since cummins may not have had the correct height tools. Is your present boost 30 or was that before problem.

Mike

 

[TAbbott]

The 75 injector code for power works for some trucks and not for others. On my particular truck, it made an additional 7-8 psi of boost and 1/2 a gear difference in the hills, which is no myth. If you are going to try this, make sure you record the injector codes you have before you change them. If it doesn't work, you can then easily change them back w/o a problem. Changing the codes takes less than 5 minutes with the reader, start to finish.

 

[CSnyder]

Well it turns out to be mostly my dumb mistake and partially the mechanics for not double checking. My truck is a 2000 model and requires a DDec 4 ECM and I was trying DDec 3's. I sent a runner after a new ECM (the correct one) and had it programmed and guess what... . YEP the truck stands tall once again! I used to think it had LOTS of power... Now it feels wicked!



Thanks for all the help and thought fellows!

 

[CSnyder]

Im still curious about why it used to run great and then turned crap. I kinda wonder if these morons accidently swapped my DDec 4 for another guys DDec 3 when it was in for service? Or did someone purposely swap them out? I have a few different drivers for 7 trucks in my line so I dont always hear about issues until a few days later.