shortround

Went out to start the truck this morning. Temp in the upper 30's. Wait to start light cycled. Turned the engine over and it started rough with blue smoke. Seems normal for a diesel. I noticed that the grid heater did not cycle at all when the engine was idling.
Any clue? Don't have my books with me, si I'm asking.
TIA.

Bruce

wgingg

i never noticed the heater cycle before. or is that why my lights dim on and off and made me want to check my batteries [lightbulb]

jfpointer

If it was cold, yeah, that's the grid heater cycling when the lights go dim.

jfpointer

I don't have my book at work, but as far as I can remember mine has always cycled at that temp and a cold start. Do you have the overhead outside temp display? Did it have a temp reading out of whack? I think the controller uses that sensor to determine what to do WRT the grid heater.

shortround

Overhead temp indicator read close enough to other thermometers.
(Light bulb going on overhead) The temperature sensor is mounted around the grill/bumper area. The grill/bumper area was replaced after the wreck. One of the battery temperature sensors was not plugged back in. Wonder if?????????????????? However, not all the trucks have the overhead display or do they?
Will have to break the books out when I get home.

thingsaregettingcuriouserandcuriouserShortround out

rossn2

Shortround....You gotta stop hitting those pesky deer with the front of your truck

jfpointer

It wouldn't be the first time a body shop forgot to plug in a connector. The wife's Jeep overheated in a drive-through after having front-end damage repaired because the body shop forgot to connect the switch for the cooling fan when they put it back together. I don't think all trucks have overheads, so I might be remembering incorrectly and there may be a different temp sensor unplugged that the controller uses for the grid heater.

phox_mulder

Correct, not all have the temp display.

All, however, do have the battery temp sensors, and I believe that is where the computer gets it's info from.


phox

OlBlue

From the Service Manual 2001 BR/BE

Section 14 page 102.

The ECM is responsible for operating the grid heaters. One of the control input is the Intake Air Temperature (IAT) Sensor.

The Battery temp sensor is used to determine the alternator field strength to set the alternator output. This is done by the PCM.

jfpointer

So Bruce, did you find something disconnected that was causing the problem?

shortround

Haven't had a chance to do much looking. Hopefully today I'll be able to get the meter out and check the relays and heater. I just plug the block heater in and it cranks smooth as silk.
Me thinks I have too many irons in the fire right now.

bouncingaroundlikeabbinaboxcarShortround out

shortround

Temp in the upper 40 range. At key ON, wait to start light comes on for 20 or so seconds. Grid relays did not activate. Checked trigger voltage to the relays and it read 8 vdc until the wait to start light went out and then it read 0 vdc. Jumper from battery will activate the relays and grid heaters.
Sure looks like the ECM is going south. With that in mind, could it be that the ECM possibly caused the injector pump electronics to take a dump back in August?
Headed out to the dealer and have them check it out, since it's still under warranty.
PS.... Do not back out of the drive with the block heater still plugged in. No damage to truck, but the extension cord died in the process.

goinginearly'causetheweatherisbeautifuloutsideShor tround out