Author Topic: Cat 3126E check engine, won't start  (Read 154 times)

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Offline dieselnewbie

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Cat 3126E check engine, won't start
« on: May 20, 2018, 12:51:15 PM »
We recently purchased a 2002 Newmar Dutch Star with a Cat 3126E on a Freightliner chassis, our first class A.  This unit has been competently and impecably cared for AND improved!  It also comes with the invaluable resource of the availability and knowledge base of the previous owner as the account following will show.
Returning home after the 1st outing we stopped to fuel and afterwards noted that the gauge only showed 3/4 full.  I checked with the previous owner to see if I had short filled or if that reading should be expected.  During the 2nd outing when we fueled I put extra work into making sure we were full and the gauge showed full when we pulled away from the pump.  Within 10 miles the gauge was fluctuating between 3/4 and 7/8.  Within 20 miles I experienced total throttle loss.  I got pulled off the road, parked and contemplated, then called the previous owner who advised that the throttle was electronic and to turn the ignition off, wait briefly for computer re-set and re-start.  This solved the problem.
40 miles later the check engine light came on.  We had been fighting a 40 mph headwind in 95 F and I had watched the temps come up on both engine and transmission but both had stayed under 200.  I drove another mile and then pulled over and parked as we were heading into 100 miles of remote NE Arizona.  I reviewed all pressures and temps as we idled smoothly for a few minutes.  I decided that the nature of the problem might be the same as the electronic throttle and to shut down and attempt to re-start.  There was no re-start.
Having recently fueled I drained some fuel from the water separator.  There seemed to be no water but I felt like it smelled more like paint thinner than good fuel.  The unit has a manual primer and I began operating it without success.  A passerby stopped who obviously had much more diesel experience than I do and attempted to help for 1/2 hr.  One thing we accomplished together was verification that we had throttle operation.  When towed late that night I elected to be dropped at Freightliner where, the next day codes were pulled showing that the HEUI (Hydraulic Electronic Unit Injector) oil pressure was only making 240 PSI cranking which is insufficient.  At this point we needed to rent a car and get my wife back to her dying mother's bedside and leave the unit at Freightliner, 200 miles from home. 
This provided time for me to connect with the previous owner, who in turn contacted Brett Wolfe, who in turn contact David Atherton on my behalf. 
Let the following be a tribute to Dave who rescued this newbie. 
After I emailed Dave with a description of the events I had a return email and phone call within hours.  His diagnosis: 1 of 2 parts need to be replaced.
I called Freightliner the first business day that they were open and told them not to work on my unit & that I would return in 4 days. (after my mother-in-law's burial)  Followed that week from Dave photos and descriptions of the 2 parts plus their locations and even wrench sizes that would be needed by this newbie.   I picked up the parts from 2 Cat dealers and returned to the rig.  Step 1.  Disconnect the Injection Actuation Pressure Sensor.  This is the first sensor from the front of the engine located on top at the edge of the valve cover right by the HEUI pump.  This has a 10" pigtail to the connector into the wiring harness.  Attempt to start.  If the engine starts that confirms the sensor is bad.  It did not re-start so sensor not replaced.  Step 2.  I replaced the Injection Actuation Pressure Regulator (solenoid) at the base of the HEUI pump.  I'll be forever grateful to Dave's coaching that a 1 1/8" wrench was needed for this so that I included it in the toolbox before leaving home.  After replacement the engine started immediately.  All that remained, and certainly the most difficult, was cleaning and re-installing the driveshaft that had been removed for towing.  Time for this 66 yr. old to get back on the weight bench at  the YMCA!!  The fuel gauge appeared to provide a stable, accurate reading during the 200 mile trip home.
Dave Atherton's extensive knowledge, willingness to share it and spend time coaching this diesel newbie saved me thousands of dollars and gave me a good start on getting acquainted with my first power plant.  There is a huge debt of gratitude.
Thanks also to previous owner Wally McCorkle who spends much time coaching me and Brett Wolfe for his time.
Better days ahead!