WTS too short when cold

[mitchedo]

I know the answer is here somewhere, but the search function on this forum just stinks on ice.

My truck runs great. Now that the weather has turned cold, when I go out to start it, the WTS light only comes on about 1-2 seconds and goes off. The ol' gal will almost start, but not quite. This happened the other day, but I got it started; then when it warmed up, the WTS light acted more normal. The WTS light is normally about 15 seconds or so when the engine is cold.

Tonight, I went to start it, and the WTS only came on for a couple of seconds. It would probably start with a few more seconds of cranking, but I don't wanna run down the battery. It normally starts with about a second or two of crank time -- a little longer when warm.

Engine is new; glows are new; GP relay is new; grounds were all cleaned while the engine was out.

I seem to recall something about a defective temperature sensor, but I don't remember. I'm too lazy to go out and hook up the laptop and see what the temp sensor says.

I only start the thing up about once every week or two.

 

[Dieseldad97]

Mine stay on for maybe 5 secs when the truck is cold. Not enough. I installed the glow plug overide a few weeks back and problem solved. Try doing the overide, you'll like it.

 

[Matt Bachand]

Perhaps the ECT is bad, thus the PCM can't properly identify proper temps. Try unplugging it, it should force max cold advance/glow cycle, making it think its -40 out.

 

[Dave Barbieri]

Temporary fix: disconnect the temp sensor wire from the sending unit on your thermostat crossover. This will give the computer a max resistance reading, which the computer interprets as REALLY COLD. Your WTS light should stay on for approx 8 - 10 seconds. Once started, reconnect the wire to the sending unit.

 

[Dave Barbieri]

Hey Matt -

I guess we were both typing/thinking at the same time!! ):h

 

[Mudbath]

:iagree: Here's a post from the stickies with a Ohms-Temp conversion chart.

Up here in Canada where it gets cold in the winter the Glowplug over ride mod is a must.



http://www.thetruckstop.us/forum/showthread.php?p=5572&highlight=coolant+temperature+sensor#post5572

 

[JiFaire]

Good work, guys!

 

[mitchedo]

Update -- a self-repairing problem

I can't get the glow cycle to be too short now. Go figure. When I got it started last time, and drove it to get the emissions test done, it ran fine once I cleared the codes.

I think it must be the ECT sensor. Perhaps running it is good for it; I understand they can get less sensitive over time sitting in the coolant. I should have changed it when I changed everything else, but I was running out of cash, and it looks pretty easy to change.

Maybe I'll put it on my list of things to do next spring. I still have the overheating problem and all I can figure is one of my thermostats could be bad. The water here boils at 190, so when I tried to test the brand-new-from-the-stealer thermostats, I couldn't get the water hot enough. Either that, or the water pump I got from Peninsular is the wrong one. Everything else is new, including the radiator and AC condenser.

 

[Missy Good Wench]

The glow controler is probably getting ready to head for greener pastures.

The CTS can influence the issue but normally the glow time ios very close even when hot.

Very cold temps will allow for a longer afterglow cycle and more of them.

if unplugging the CRS does not bring about a longer cycle time then its the controler..

Missy

 

[knkreb]

Short glow cycle could mean a shorted engine coolant temperature sensor wiring. Extremely long (and other issues like no overdrive) could lead to open sensor being seen by ECM. With all that engine work, something may have been displaced, rubbed, chaffed, messed up or intermittent connection....

If you power down the ECM and then repower it up... the first crank only gives you about 1 second of glow time.... or at least that is what I always experienced. Why does it do that? I don't know, but others have said the same... So if you pull battery power to the ECM for some reason, that will give you the same effect.

 

[knkreb]

The glow controler is probably getting ready to head for greener pastures.


Missy

When my glow plug relay took a dump, the WTS light stayed on regular time, but it did light the SES light afterward with a code for glows or relay (several years ago, gotta look back). It had feed back from the relay on an OBD-II system to code if the glow plug relay failed to send voltage to the glows themselves.....

 

[Missy Good Wench]

Failure to glow will set a code on the OBD2 system. A short glow cycle may not set a DTC

The short glow cycle after a "POWER DOWN" is due to the ECM having to regather data from all the sensors and set the system back into normal parameters.

OBD1 will do this as well.

Just hook the batteries up, CYCLE the glow plugs once, crank the engine a bit, shut the key off and wait a few moments and things will reset.
The next cycle will be right back to where it should be.

I have seen this on many rigs that I have had my fingers into.

All very normal.


MGW