Hard to start at 40 degrees

[Power Hungry]

So my family got back from a couple weeks trip (part of a 3 month larger itenrary) and found our truck had trouble starting after nights when the temp was about 35 to 40 degrees -- wait for the glow plugs, then crank crank crank for a bit on and off then the engine catches with a cloud of white smoke. Once started up, the truck runs fine but I am worried when we are in the 20 degree range up in the sequoias later in November, camping in found spots off the beaten path. We're running b20 for starters and would like to run b100 with confidence, but worry the viscosity is too thick to allow for the cold temps. One mechanic said just spray WD-40 into the air intake while cranking the engine -- is this safe? We just replaced the fuel filter and cracked fuel pump, hoses and air filter just before our trip.

Chris Hall -- 1997 7.3 PSD F-350 Crewcab Longbed 4x4 with a Ramsey 8000# winch

 

[Scarlet_Nape]

Chris,

I'm having the same problems, but I don't believe it has anything to do with your Bio. I would check the glow plugs and the relay. I have not tested mine, yet, but I'm pretty sure one of them is the culprit.

I "borrowed" this from another site:

To check the Glow Plug Relay (GPR)
· Be sure the engine is cold, so that the PCM will tell the GPR to turn on. If the engine is hot, you won’t have as much time to check.
· Locate the GPR – Its behind the fuel filter on top of the engine, a little bit toward the passenger side of the valley. There may be two relays there. If so, the rear one is the GPR. It will have two fairly large wires (yellow and brown) connected to one of the large posts.
· With your multitmeter set to DC volts, and 15 V range (if not autoranging), clip the positive (red) lead to the output terminal (with yellow and brown wires connected), and the negative (black) lead to a good ground point (like the battery ground terminal or someplace metal directly on the engine block.)
· Turn the key to ON (do not start)
· If your GPR is good, it should click, and you’ll see 11 volts or so on your meter, then, depending on temperature, it will click off up to 2 minutes later. You should do this a couple of times to make sure it consistently makes the connection.
· If you don’t get voltage with this test, confirm by retesting as follows.
· Remove the two small wires from the smaller two of the four GPR terminals.
· With jumper wires, apply voltage from the battery across the two small terminals. If your voltmeter now reads voltage on the output terminal, your GPR is OK, and your problem is in the PCM circuit that tells the GPR to activate.

To check Glow Plugs.
· Remove the electrical connector on the inboard side of valve cover at the gasket. Press down on the top of the connector latch and pry gently with a screwdriver. Photo of disconnecting one and another Photo of it loose.
· There will be 9 pins on the valve cover gasket where you removed the connector. The two pins furthest forward and the two pins furthest back are for your glow plugs.
· With your multimeter set to resistance (ohms) and low range (single digits) if not autoranging, clip the negative (black) lead to a good ground point.
· Probe each of the 4 outer pins individually with the positive (red) lead, noting the resistance. Good glow plugs will have a resistance between 0.6 and 2 ohms. If you get infinite resistance on any glow plug, that one is either bad or the connector under the valve cover has come loose.

 

[Tx_Atty]

Im sure there are those in the world that will argue but, I say NO do NOT spray anything into the intake. If you have access to electricity, plug in the block heater but do not try to use any form of starter fluid. B20 will not be gelling at 40. I wouldnt try b100 at 20* though.

 

[JOAT]

Im sure there are those in the world that will argue but, I say NO do NOT spray anything into the intake. If you have access to electricity, plug in the block heater but do not try to use any form of starter fluid. B20 will not be gelling at 40. I wouldnt try b100 at 20* though.

Ditto. You have a short stroke high RPM diesel engine. There is no throttle, so any fuel sprayed in the intake will cause the engine to rev as fast as it can till the fuel is depleted. If you really have to, then very small bursts of WD40 won't be too likely to cause damage, but better to fix the problem.

Sometimes the programming isn't real effective at certain temps. Mine is hard to start at 20 F, but fires right up at minus 10. Often when that is the case you can crank it with the throttle part way down and it will be more likely to fire.

Making sure all the glow plugs are working is important. With Bio your glow plugs have to be working or it is going to be hard to start.

In some cases, you can wire a potentiometer in series with the EOT sensor (Engine Oil Temp). Then you can increase the resistance which tricks the PCM into thinking it is colder than it really is. Usually makes starting easier.