Monthly Archives: April 2015

New radio for the Ram

I bought and installed a Pioneer DEH-X6710BT head unit. Having Bluetooth to stream stuff from my phone again is nice. I had assumed that you couldn’t use Bluetooth in a greater than one-to-one configuration, but apparently that’s not the case. So I might be able to use my phone with both my OBD dongle and the head unit at the same time.

It’s also nice to be able to make hands-free phone calls again.

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Ram’s first workout

We got two full loads of compost on Saturday. I’d estimate 2100-2200 lbs per load. The truck had no problem. I do notice less acceleration and definitely increased braking distance, but still plenty of power. Boost was the same as unloaded, as were EGTs.

Ram hub / rotors / brake pads replaced

I got the Ram’s front end all put back together, after several evenings of work.

Replaced the driver’s side front hub with a Timken HA590032 from AutoZone.

Replaced both front rotors with Bosch QuietCasts from O’Reilly with a lifetime warranty.

Replaced the front brake pads with BrakeBest (the cheapo ones) from O’Reilly.

I also replaced the caliper slider bolts and boots and the anti-rattle clips, and greased everything. Also, I put anti-seize on the hub bolts and mounting surfaces, and on the back side of both rotors. Hopefully when I have to take this all apart again (to replace ball joints / track bar ends / u-joints) it’ll be easier to get apart.

I still have up/down play in both front wheels, even after replacing the hub. So I don’t think the hub was causing the wobbling issue at 65-70 mph (it’s still happening, but goes completely away around 72 mph). In fact, I think the old hub might still have some life in it, so I guess I’ll hold on to it.

K2500 SES and poor fuel economy

The K2500’s latest fuel economy: 8.7 mpg. I almost ran it out of fuel driving home on Monday. When I left work, the needle said I had a third of a tank. Then, by Rio Bravo, it was hovering in the red. After I climbed the first hill and went down the other side, the engine started sputtering. Fortunately, I got it to run again after the road leveled out, and I filled up at the first station in Isleta.

The SES light is still on, and when I pulled the codes, I got just one code, 42:

Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.

During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then “tells” the ignition module via the EST circuit.

An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.

The conditions for setting this code are:

  • System in BYPASS mode but the ignition module is still controlling timing
       - or -
  • Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.

Typical causes for this code include:

1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM

Now, I recently replaced the ignition module, so I don’t think that’s the problem. Most likely whatever is causing this issue is contributing to the poor fuel economy.

Also, apparently disconnecting the battery for ten minutes will clear stored codes. I should do that and see if it throws this code again.

Mercedes cruise control ideas

According to BenzWorld, the cruise control not working could be caused by a faulty ABS speed sensor (not a cheap replacement — about $110 per wheel). It could also be caused by tire tread wear being different enough among the wheels to throw off the computer’s calculations, disengaging the cruise control. Or it could be something else, which might be indicated by stored codes.

This page has instructions for using the supposedly built-in blinker box. I’m not sure if it’s present on our 300SD. If not, that same page has instructions for how to build a blinker box.