I have read lots of interesting and valuable posts with winter/colds start issues. Thanks in advance for all those who have posted info and for those that may try to help me.

My 01 7.3 Excursion (replaced my 00 that ate a guardrail in the spring of '10) worked great until last winter. I have the Edge CTS and the truck threw a code for a bad glow plug (no starting issues or white smoke). A mechanic friend and I changed all the glow plugs (on the right) and the wire harness since we were there. Ran great for a few weeks then the Glow Plug Control Module started acting up (throwing a code) and the truck intermittently would not start.

If I shook the GPCM then some of the times I could get it not to throw the code. I couldn't get it to fail to start but my wife repeatedly got stuck with a truck that would turn over (a handful of times before slowing) but not start. The CTS would show 12.4v pre-crank and 9v to sometimes 7v during the crank. Initially the batteries tested good when fully charged (after dealing with this for a while they were not so were both replaced). When the alternator was running it said 14.1v but it would get quite warm so it was replaced. I have a 0.4Amp to 0.2Amp draw on the batteries when the truck is sitting with the lights off.

I noted that the truck was not sensing the back window was closed and the running lights would stay on too long. Lubricated things and resolved this. The truck continued to have intermittent non start that sometimes would happen after multiple days of sitting and other times the truck had been driven the day previous. It did not seem to be directly related to the temps (Colorado) nor did pluging in the truck.

I replaced the GPCM and stopped getting the codes but did not change the intermittent non start. None of the changes stopped the intermittent but as the temps warmed up we didn't have the problem in the summer. As the cold temps began again the problem returned as did a fuel leak from the drain valve gasket. I replaced the gasket and that stopped.

I replaced the starter to see if that was the issue but it didn't help. If I pull the PCM relay (302) then the draw falls to 0.02Amp.

Any thoughts or suggestions would be much appreciated.

Lane

 

I'm wondering if their is a bad sensor which is turning of the glow plugs too early and its not warming up the cylinders enough to burn the fuel. If I remember correctly there are three sensors that calculate the air temps and stuff to tell the glow plugs how long to stay on for. You could get a digital power tester that plugs into the cigarette lighter and see if your getting a voltage drop indicating the plugs are turning on.

I know this is a silly thought but is your wife waiting for the glow plug light to go off before she cranks the motor ?

 

Voltage drops from 12.4ish to 11ish when the key is turned and the glow plug light is on (edit: initially for up to 10 seconds). The voltage stays that way for a couple of minutes (edit: before returning to 12ish).

My wife has been waiting an appropriate amount of time before starting. Oddly this truck does not have a light that says "wait to start" but rather a resistor looking symbol that we interpret to be the wait light.

 

The resistor looking symbol is the same as I have. A "couple of minutes" is way too long for that light to stay on, mine stays on for 10 seconds tops when its -20C. If it is really staying on for 120 seconds then I don't think they are working or one of the 2 sensors is bad.

EOT (Engine Oil Temp) and BARO (Barometric pressure sensor) = Glow plug on time.

Edit: The PCM will only allow the light to stay on for 10 seconds and the plugs for 120 seconds max.