bmodelsrus Posted August 20, 2008 Share Posted August 20, 2008 we have a 743 nhb with a single disc pump its skipping like crazy and loads of fuel in oil, its not fuel dribble, there is way to much fuel in oil to be that, pulled #1,2 , injector copper sleeve might be cracked, i would like to pull them out but i dont want to destroy them . have motors manuals coming out my ears and none of them have 'how to' also have tons of cummings manuals also no" how to". single dics pump also has oil preasure feed to it wondering if seals might be bad , engine is running on 3 maybe 4 cylinders, 1,5,6 not working going to try to mve injectors to other cylinder to see if the skip will follow ,but its not easy as rocker boxes have to come off with each move, the external fuel lines are in good shape as are the tubes from the outside of the head to the injector dont really want to pull pan off and preasurize fuel system but i am almost sure i am going to have to Quote Link to comment https://www.bigmacktrucks.com/topic/4120-743-cummings/ Share on other sites More sharing options...
Bollweevil Posted August 20, 2008 Share Posted August 20, 2008 You may have two issues caused by the same faulty part. I don't know about a single disc pump, I have never seen one much less had one apart. But I know from experience that a Cummins AFC or PT type pump is capable of delivering 5 gallons of diesel into the oil sump in 5 miles. If you can make the engine run, you can find which cylinder is not fireing with an infrared heat gun. If it is a timed injection like a Mack, crack one line at a time. Kind of like pulling one spark plug wire at a time. You may not be getting fuel to the top on all of the cylinders. Try to post a picture of the pump. Personally, I would not start swapping parts around. Find the offending cylinders first then find out why. Quote Link to comment https://www.bigmacktrucks.com/topic/4120-743-cummings/#findComment-21445 Share on other sites More sharing options...
theakerstwo Posted August 20, 2008 Share Posted August 20, 2008 And another thing a injector tube or sleeve will not let fuel to get into the oil or into the Cylinder. But a leaking injector inlet tube copper washer will let fuel into the oil and if bad enough could make it miss. That is common on a 743 engine.I am sure the fuel pump could do that also. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/4120-743-cummings/#findComment-21446 Share on other sites More sharing options...
red smith Posted April 25, 2009 Share Posted April 25, 2009 Distributor disc most likely scored. If you want them refinished please contact me. RED Quote Link to comment https://www.bigmacktrucks.com/topic/4120-743-cummings/#findComment-34360 Share on other sites More sharing options...
heavyhauler Posted April 26, 2009 Share Posted April 26, 2009 Turns out that this 200 HP Cummins engine has 3 head gaskets and the one for cylinders 5 and 6 was blown and had been like that for some time. Replacing that head gasket solved most of the problems.Best regards,John Quote Link to comment https://www.bigmacktrucks.com/topic/4120-743-cummings/#findComment-34370 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.