Cold start issue. Could use a little advice.

[onebadiditurbo]

OK its finally getting cold enough in Texas to have problems. When I first try to start truck the wait to start light just flashes for a second then goes off. I usually just wait for the afterglow cycling to stop and haven't had an issue until now. I checked all the glow plugs with a test light and all were good except one. I checked all the leads back to the test terminal on the glow plug relay and there were good so I don't have a wiring problem. So I'm thinking all that's left is the GPR itself or the temp switch for the system. Any ideas.

 

[TWeatherford]

One bad glow plug could easily be your problem. The gpr reads resistance, and one bad can cause high enough resistance that it thinks that the plugs are hot when they're not. I'd pull the bad one, if it's not a beru then replace the set. If it is then replace just that one.

 

[Knuckledragger]

X2 on that. I went from easy to start to crank-for-a-minute just because one GP was bad. The early GPRs last a long time, but are simple enough to fool.