Quote:
Originally Posted by KaiserChief
Long time reader, first time poster--but I know there are plenty of sagacious folks on this forum...
A cold snap just hit, and I forgot to plug in my block heater. Previously, my Benz didn't like to start when it was under about 40 degrees (had to hold the accelerator down after ignition to keep it running for 30 seconds) but now it's 15 out, and I can't get any ignition at all.
Battery is good, starter cranks fine (as far as I can tell). I plugged in my block heater about 6 hours ago, so that should've helped by now...?
I also tested the glow plugs and the relay--I'm getting 12v at the plugs, and the relay works fine. I even jerry-rigged a straight line from 12V+ to the glow plugs, bypassing the relay, and that didn't help either. The glow plug indicator light hasn't been working for a few days--I assumed it was a bad bulb, but maybe there's a systemic issue.
Finally, since I know fuel leaks can be an issue, I used the hand primer pump, and then loosened the bolt on injector 1 and cranked away--no luck. Frankly, I think less fuel was spurting after I tried this then when I used the same trick after replacing the fuel filter a few months ago.
I have not yet pulled the plugs...but again, it feels like 15F thanks to the wind, and the plugs check out electrically, so I'm hoping I don't have to.
Tips, pointers, complaints, or suggestions? Call our hotline at, er...here.
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I disagree with the ohm testing theory, as anything but a vague (possible) indicator.
A new glow plug at 70° F is 0.7 ohm.
A marginal or bad glow plug can have any reading.
I have boxes full of used glow plugs that read correctly, but either do not glow or have random dull glow.
NOTE: I have many new glow plugs damaged by owners over torquing the 8 MM electrode nut.
Here is a simple graphic showing why the TIP must glow as hot as possible, NOT the element body.
READ THIS BEFORE TESTING.
Never Touch Hot Diesel Glow Plugs!!!
The pencil type are easy to test:
#1. Just pull each one.
#2. Trap the hex wrench flats with the heat element pointed inside the vice jaws.
#3. Use a car battery or charger to apply power.
#4. Attach ground to the vice body.
#5. Hold the positive to the threaded glow plug power pole.
#6. Fifteen seconds is more than enough for maximum visual display.
#7. If it glows like this, it's good.
#8. Use pliers or channel locks to handle HOT glow plugs, and have a METAL tray or can to put them in for cooling.
NOTE: Never quench hot glow plugs in water, it can cause a steam explosion and/or damage the glow plug. Other liquids (soap, oils, etc) can flash fire.
#9. Half an hour of cooling time, and you should be totally safe to reinstall any good used glow plugs.
My personal rule of thumb:
If it has difficulty starting 32° F and lower:
* Check the valve adjustment, and reset as needed.
* Remove the glow plugs.
* Ream the holes.
* Install new glow plugs.
* Glow test the old units.
* Junk the bad glow plugs.
* Give away any usable glow plugs to economic hardship customers.
Don't always trust your glow plug indicator light!
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