My truck wont fire first try & it only got down in the 40s then when it started next try a lot of extra smoke which looked like fuel came out the exh, r my glo plugs bad or relay ?
what does the relay have to do with not starting right away ? yes im a dummie... the volt meter does jump around a bit if that is anything pointing to that..:dunno:Set the meter on DC volts. Put the black probe on one of the negative battery posts. Put the red probe on one of the "big" terminals on the relay. Then put it on the other. One of them should read 12V (aprx) and the other should read zero.
Now turn the key to RUN and do the same exercise. Now, the terminal that showed 12V above should show something less, probably about 11V, and the other terminal should show _almost_ the same voltage. The _difference_ between the two (also known as voltage drop) should be no more than 0.3 volts.
now u tell me lol .. where is exactaly is the relay & or what does it look like ? Is it the starter relay ?the relay supplies power to the glowplugs, no power to the glowplugs= no heat in the cylinder to help start. which would cause hard starts and lots of smoke
The starting circuit and the glowplug circuit are two completely seperate things. If you find the glow plug relay maybe you can have someone else turn the key on and you can at least see if you can feel it click..then you can go to the voltmeter/test lamp methodnow u tell me lol .. where is exactaly is the relay & or what does it look like ? Is it the starter relay ?
The glow plugs stay on for 2 minutes or so after the WTS light goes off.I shouldnt have to plug it in till it gets below 30 anyhow It got down to 37 I went to my truck this morning & left the key on longer than the wait to start said so & it started right up, same thing after work the wait to start light goes off fast , but if I keep the key in that position longer it starts right up, does that mean anything ??? Thanks ..
and you "shouldnt need" to plug in your truck until the weather is 0 or below.. thats really whats its made for. people just plug them in for the convience and to make it easier on the truck.. AND - if your truck starts easier when you leave the key foward for a while - then i would say the relay is working.. maybe then its time to check the glow plugs themselves.. if not - maybe theres nothing wrong at all..ok I will do checks on relay or just get a new one not much money anyhow, & that will get one thing out of the way.. Thanks for input..
Indeed, and it's actually not that uncommon. This is where the critical "voltage drop" test comes in. Rather than just a crude test light or "is it hot" test, you need a voltmeter that measures tenths of a volt. Either a digital, or an analog with a fairly steady accurate needle. Turn the key to RUN and measure the voltage on the hot side, then on the switched side. As said above, voltage will be less than 12 because of the load, but the important thing is the _difference_. The switched side will be lower, but if the difference (aka voltage _drop_) is more than 0.3 volts, the relay is bad. Indeed, it closes, makes a clicking noise, but can't provide the power to fully light the glow plugs.although uncommon - a relay can still pass current and not trigger "on" which it what it does when you hear it click.
Still could be either one. It may be doing what you describe above, but providing insufficient power to the GPs. They'll still light, but they'll be like a "dim bulb". Imagine the heating elements of a toaster not getting enough juice. They'll glow, but not as hot. It'll take longer to toast your bagel. Same possibility here; weak relay, GPs running at less than full power, so it requires longer run time (pause with the key in RUN) to start. One of our GPRs did this; voltage drop was something like 0.8 volts, it still triggered, but "underpowered" the GPs.AND - if your truck starts easier when you leave the key foward for a while - then i would say the relay is working.. maybe then its time to check the glow plugs themselves..
Actually, it's a variable cycle, anywhere from about 10 seconds to just 2 or 3. It's based on the EOT (engine oil temp); the hotter the engine, the shorter the WTS time. Same idea with the glow plug run time, but the range is from two minutes down to about 30 seconds. There are graphs charting the WTS time and GP run time as a function of EOT posted as pictures on one of the PSD forums (possibly here on the org; I don't remember).your wait to start light - has 2 cycles, a long and a short.
Ya that means you need to cycle the gp's longer :laugh:I shouldnt have to plug it in till it gets below 30 anyhow It got down to 37 I went to my truck this morning & left the key on longer than the wait to start said so & it started right up, same thing after work the wait to start light goes off fast , but if I keep the key in that position longer it starts right up, does that mean anything ??? Thanks ..