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Discussion Starter #1
Ok its driving me crazy....when my truck sits over night and i try to start it in the morning it cranks real good and almost wants to start after 25 sec of cranking..then i turn the key off cycle the wait to start light again and it cranks and fires right up and runs normal and drives fine the rest of the day with all the power it normally has. this just started happening in the last month. truck is on a fresh oil change, new fuel filter yesterday, air filter is clean..

i might add it does not matter what the tuner position is on it wont start...i always start in stock mode but i was trying all the positions and its same issue.

any ideas please help me out...its one of my work trucks and it cant afford to be down
 

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My guess glow plug relay and/or glow plugs... if you have a block heater plug it in overnight, if the truck start up then I'd replace the gpr and go from there.
 

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Cycling the WTS light does nothing. The glow plugs stay on for waaaaay longer than the WTS light. It's to warm up the fuel faster; it's all explained in the PSD supplement of your owner's manual.

Rather than throwing parts at it, TEST. The various forum sites have threads on testing the voltage and voltage drop of the relay, and the resistances of the glow plugs. It can all be diagnosed with a sub-$10 voltmeter.
 

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Discussion Starter #4
I understand the WTS i was only trying to explain everything going on...here is one other issue i now notice.....The volt gauge stays down and if i do not let the truck idle for like a minute sometimes the gauge will oscelate and the radio goes on and off, headlights flicker is that the glow plugs sucking juice. Its a brand new altenator and 2 new batteries in august.

i will test but could this be a problem
 

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The volt gauge will stay left-of-center (but it should be steady) for up to two minutes as the glow plugs run, then will swing right-of-center. If, after the two minutes, it swings right-of-center and doesn't fluctuate, and the radio and headlights behave normally AFTER the two-minute period, that indicates that the charging system is probably working fine (it should, with new alt/batts), and indeed, either the glow plugs or the relay are drawing too much power.

GP relay test - easy way to test from under the hood without messing with the key. Pull the #22 fuse, then turn the key to RUN. Then, under the hood, put a voltmeter with the black probe on a ground (battery neg), and the red probe on each of the big terminals, one at a time. One terminal should read about 12.5V and the other should be zero. Then push the #22 fuse back in (see? using the fuse, you don't have to hop back into the cab to turn the key). At that time, the terminal that was 12.5V should read around 11.5V, and the other should read just a little less. It should read no more than 0.3V lower than the first big terminal. If the difference (voltage drop) is more than 0.3V, the relay is bad. Another way to test the relay is to put the voltmeter with each probe on each of the two big terminals while the fuse is in. It should read no more than 0.3V (or -0.3, if you get the probes reversed).

GP test - disconnect one of the valve cover harness connectors. Set the meter for resistance (ohms) and put one probe in the first terminal on the valve cover gasket, closest to the front, and the other probe on a good ground. It should read right around 1.0 ohms (IIRC, the range is 0.6-2.0). If it's out of that range (esp lower), or shows infinite resistance (typically a "1" in the LEFT-most position on the display), that glow plug, or the wiring to it under the valve cover, is suspect. Do the same with the terminal on the other end of the connector. Then do the same for the other three connectors, to test all eight.
 

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Discussion Starter #6
thank you...too bad its raining today and i can not fit my truck in the garage. i will try soon
 
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