Intermittent cold starting problems

uncaged · **Posted:** Mon Dec 07, 2020 6:05 pm

Sometimes it starts easy, sometimes not. I noticed this when the weather started dipping below the 40F mark or so that sometimes it starts right up with the surge and a little clatter, and sometimes it seems as though the glow plug cycle never happened at all. I always wait until the end of the chimes before starting.

When on a "don't feel like starting" day, if I hold the starter on, it'll eventually start and smell like a ton of raw fuel. If I hold the starter for the normal amount of time, turn it off, and cycle the glow plugs again, it'll start normally.

Last night, it was plugged in, was 18F this morning, the snow was melted on the hood above the motor, and it didn't want to start. Leaving work, not plugged in 27F out, and it started right up.

Any thoughts? Nothing about this is coming to me, other than maybe throw a glow plug module at it?

WWDiesel · **Posted:** Mon Dec 07, 2020 7:00 pm

On cold mornings, I always cycle the key twice until the chime stops and most of the dash lights go out. It always starts right up and I have the 7v metal glow plugs. But I don't live in real cold climate conditions, it rarely get below freezing here.
If I was having problems, I would install the 5v Bosch GP's.
You can test using a test light or volt meter to see if the GP relay circuit is functioning properly.
Simply attach the test light or volt meter to one of the GP leads when temperature is low, turn on the key and observe the test light or the volt meter to see if the GP relay is working properly. (will require two people)
Please note, this will not tell you the condition of the GPs. You can measure each GP individually with an ohm meter to check the integrity of each GP electrically, the ohm meter reading for each one measured individually should be very close to each other. A flyer or one very different from the others is telling you it has a problem.

uncaged · **Posted:** Tue Dec 08, 2020 11:46 am

Thanks for the ideas. 22F this morning, not plugged in, first key cycle it started right up. It has been running the 5V Bosch plugs for a couple of winters now. Typically it will start fine on the first cycle down to the mid teens. It'll light in about 2 revs with a "ba ba BA BA" surge the RPMs to about 1200, and settle right down to about 800 immediately. Typically. Colder than that and I double cycle the key.

It's the *intermittent* not wanting to cooperate recently that has me stumped. Maybe I can cob a test light to one of the GP leads and monitor that for a few days and see what happens.

uncaged · **Posted:** Thu Dec 31, 2020 1:01 pm

The glow plug module was original to the vehicle (part number 56044671AA), so I replaced it with the updated part (56044671AC) and after the next start I had a CEL and a code! Old one never threw a code. Pull DRBIII out, and it says glow plug #4 or harness. Ordered all 4 steely Bosch 5V and the harness (15 years and ~160K old) from idparts and we are back in business.

Intermittent cold starting problems

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