So... An N14 again

My intimate familiarity with N14's payed off today... '99 Freighliner died on the freeway at Sunset. He coasted to Iowa street and came to a stop here. Nothing like working right in the middle of the road!

While Insite locked itself up and froze the computer I checked all the usual suspects. ECM fuses at the battery, cranking voltage (11.5 okay there), fuel in the tank, coolant etc... Once it decided it wanted to talk I found DTC 0254 ECM turns off fuel valve supply voltages. Interesting.

According to the troubleshooting an ECM draw of over 2 amps or measured voltage below 6 volts at pin 16 (Fuel shut off solenoid) will set the code. Found the ECM ground fuse blown. Replaced but the code stayed active and Insite will not allow you to clear engine shut down codes. The ECM has to detect that the problem is fixed but since it has shut off feed to the solenoid how do I tell it to reset? Hmm, jumper wire from the starter to the solenoid post for just a second and the code resets and goes inactive. Truck starts right up.

Why would the ECM draw over 2 amps I wonder? I bet if the solenoid was failing... Passed the ohms test but man it's hot if you put your hand on it. Checked it again 0.0 ohms. Yeah, that's not right. Went back to the shop and got a new solenoid. Checked the old again before taking it off and it's at 1.8 ohms (Spec is 6-12 if I remember correctly). Change it out and check it again just because and it's over 13 ohms. Truck starts up, no faults, no leaks, ice is on it's way to Concrete again. Solenoid was heating up and the current draw went up with it. ECM says woah wait a minute and shut's off power to the solenoid.

Fascinating thing is this truck had a new ECM and harness put in a year ago. I wonder if they were having trouble?

Last week of school

Just finished up a few things at school this week. Ended up off work after having the pin removed from my finger. Starting to heal up and gain some motion again. 5 degrees of movement in that joint. Therapist figures about a month before I have close to full range of motion in that hand again. What an interesting learning experience this has been... I think I'll avoid breaking any more bones in the future.

On to International's training now!

Week: 30
Total: 480

SPQ2014

Did a relative compression test on the International

Found the code on the 6.7 with IDS... That was a learning curve. Ford needs to update their software to the 21st century. Got a bit frustrated with it for a while.

Used the Modis on the Dodge to cycle the wipers and horn.

Fuel rated synflex hose because OE parts are what we do.

Learned a bit about Isuzu sensor wiring... Still haven't figured out why they need 4 ECT sensors to run a '94 model year engine. Wire harness chaffed on a clamp and the truck wouldn't idle right and gauges started doing odd things.

Week: 50
Total: 450

SPQ2014

Had a little re-wiring project on Saturday... 8 hours to re-wire the rear of the trailer and fix a broken wire in the front wall of the trailer. New everything from the cord back. Used Tectran shielded wire for everything and marine grade sealed splices. Sorry for the poor quality pictures.

I've been learning how the parts department works lately. Stocking shelves, labeling parts, did MSDS sheets for a few days. I filled in for the service writer on Friday also. That was interesting... I've decided that I'm not the best at understanding accents.

More ThermoKing APU work...

They're using an Ingersoll branded Yanmar engine which has a tendency to smoke when not serviced regularly as I found out when I ran one with the shop doors closed.

Went and helped my dad out for a bit and fought with the GPS. The line would drift a few inches in the time it took to get out and check the gearbox temps on the rototiller. Decided that the treeline was messing with the GPS signal.

Doing a fan test on a MaxxForce. Pulse width control is great when it works! I've learned that dust does not agree with these Horton fan clutches.

Week: 50
Total: 400

SPQ2014

We finished the measurements on the CAT 3176 this week. Learned about cylinder pack replacement rather than having a tech install the piston/rod in the liner. Truth be told I like the idea.

The motor's manual does not give a lot of specs as we found out.

Checking wrist pin and rocker for wear.

Removing valves to check the face and seat for wear.

Torquing the head bolts and setting valves.

I've had a few engines apart before but never one good enough to put back together so setting the valves etc... was new to me. Everything before I've pulled a piston and decided the engine was scrap metal. It's always been a visible failure without needing to go as far as checking clearances.

This is a coolant temperature circuit.

Week: 60
Total: 350

Engines 2014

Having a steel pin put in my hand has slowed me a down a bit... I was helping Joe with the CAT but have had to leave early for doctors appointments unfortunately. I did the research assignment on the Maxxforce.

The cold start system used on Maxxforce engines is inactive above 50 degrees. This isn't in the manual but from personal experience with these engine if the ECM commands cold start assist the engine will not start until it has completed its cycle (cranks but doesn't fire). I wonder if there is a start inhibit until it cycles off? They use a grid heater with a low pressure fuel injector. This is installed in the intake and when active fuel mist is drawn across the grid heater element. It cycles on and off for a time after the engine starts.

I've tested thermistors in an A/C system using the palm of my hand and watching the readout with International BodyBuilder software

A thermistor sensor changes electrical resistance with
changes in temperature. As temperature changes
at the thermistor, voltage at the ECM will change
accordingly. Thermistors work with the control module
to produce a voltage signal directly proportional to
temperature values.
A thermistor sensor has two electrical connectors,
signal return and ground. The output of a thermistor
sensor is a non-linear analog signal.

I've tested magnetic pickups when troubleshooting an engine speed sensor on a Detroit 60 when the tach was inop. Found a clear pulse but the 0.2v reference dropped off when the gauge was plugged in. Found some damaged wiring.

A magnetic pickup sensor contains a permanent
magnet core that is surrounded by a coil of wire.
The sensor generates a voltage signal through the
collapse of a magnetic field created by a moving metal
trigger. The movement of the trigger then creates
Alternate Current (AC) voltage in the sensor coil.

I've tested a potentiometer when working on a Freightliner with surging problems. Ended up replacing the throttle pedal assembly.

A potentiometer is a variable voltage divider that
senses the position of a mechanical component.
A reference voltage is applied to one end of the
potentiometer. Mechanical rotary or linear motion
moves the wiper along the resistance material,
changing voltage at each point along the resistive
material. Voltage is proportional to the amount of
mechanical movement.
The engine has two potentiometers, both contained in
the Accelerator Pedal Position (APP) Sensor.

Week: 40
Total: 290

SPQ2014

Somehow I'm the APU guy now... ThermoKing has some interesting service procedures. Refrigerant capacity of 1.2-2 lbs (Nice of them to give a definitive answer). Once you've added enough refrigerant to run the system you work it to it's max and add an ounce at a time while watching the sight glass. When it's clear at 150 psi you're good.

Had some trouble with a Ford Hydro-Max brake system. Pedal pulsed intermittently with the park brake released. I found a Bosch service guide (Bendix valve... Figure that one out) for it after searching through way too many websites.  The park brake valve was leaking internally and relaying it into the foot pedal.

Did some work with CAT's Electronic Technician. No cruise control and I found the brake switch for the computer had a 10v drop across it when closed.

Week: 50
Total: 250