7.3 FORD DSL, HOW CHECK GLOW PLUGS??

[NIK OWEN]

93, I.D.I., NO TURBO...HAVE BOOK, NO HELP TO ANALYZE G. PLUGS...CAN I DO IT, W/ A METER? OR HOW? DETAILED IS GOOD, SHADETREE MECH, AGE 78THANK U. BE BLESSED, GRATEFUL, PREPARED, NIK

 

[G.Fields]

If you have a volt meter you can check the resistance. If my memory is correct it should be under 1 ohm. I think the new ones I got tested at .3 ohm. If you dont have a meter take a test light. One end in the + side of the battery and the other end to the top of the glow plug. If good it should light up. Both of these tests should be done with the harness off the plugs. If you have a bad one you may as well do replace them all. And pray that the tip hasnt swelled/burst on you. Not fun. Im sure others will chime in but thats my experience as the not so proud owner of a 1992 idi truck.

 

[wore out]

(quoted from post at 11:44:48 04/23/21) 93, I.D.I., NO TURBO...HAVE BOOK, NO HELP TO ANALYZE G. PLUGS...CAN I DO IT, W/ A METER? OR HOW? DETAILED IS GOOD, SHADETREE MECH, AGE 78THANK U. BE BLESSED, GRATEFUL, PREPARED, NIK

Disconnect all the G.P.'s and connect an ammeter capable of reading 20 Amps to the (+) battery post and momentarily touch the other lead to the terminal on each G.P..

If a given G.P. is OK it will draw in the 12 to 20 Amps range, all should test about the same.

If "open", (of course) there will be no current draw.

TYPICALLY they will test pretty close to each other (if made by the same manufacturer), most either work properly or not at all.

Alternately, if no ammeter is available simply connect a wire to the battery (+) and brush the end past the terminal on each G.P. and note that there's a similar small spark at all the ones that are good/drawing current.

No matter how you test them do not apply power for more than a few seconds, once the overheat they can blow open making removal difficult, or even break off and fall in the cylinder.

 

[wore out]

Also, if replacing, use Motorcraft or Bosch G.P.'s, there are a few other good ones, as well, on the other hand, some sold by a couple of the big names in SPARKPLUGS don't last.

 

[Fritz Maurer]

Disconnect all glow plugs. Probe each one with a 12volt test light. Replace the ones that dont light. Another common failing point on this system is the solenoid on the glow plug controller. A bad connection either of the large posts is indicated by discolored nuts, melted hot wire , or, in extreme cases, the housing of the solenoid burned up. The solenoid is available separately, the solid state unit is not. Depending on which controller you have, it will be either a 7 second or 13 second glow time at 60* F. Back to the glow plugs; after checking each glow plug, probe each glow plug connector on the harness. You will need to disconnect and ground the glow plug harness at the downstream end of the resistor. Any connector that fails to light must be repaired or replace the harness. Now move your test light clip to ground and check for power at the glow plug controller. The wires on the large post closest to the passenger side should be hot at all times, and there are fusible links near passenger side battery. If all this stuff checks out and you still dont have sufficient glow time , the GPC must be replaced.

 

[Fritz Maurer]

0*F not 60

 

[NIK OWEN]

FRITZ, APOLOGIZE, SHOULDA SAID, HAD SOLENOID REPL W/NEW, FORD...WUZ BAD...TO ALL, EXACTLY INFO I NEEDED, TO ATTACK...U R ALL BLESSINGS...MY LAST 93 WENT TO 349, 000...

 

[showcrop]

(quoted from post at 14:52:10 04/23/21) FRITZ, APOLOGIZE, SHOULDA SAID, HAD SOLENOID REPL W/NEW, FORD...WUZ BAD...TO ALL, EXACTLY INFO I NEEDED, TO ATTACK...U R ALL BLESSINGS...MY LAST 93 WENT TO 349, 000...

OHHHHH NOOOOO, NIK you just went and jinxed yourself.

 

[Fritz Maurer]

Good , one source of trouble eliminated!

 

[4play]

To clarify Fritz's post , a test light works good for open circuit glow plugs. The test light needs to be clipped to the battery positive and tip on the unplugged GP tip. Check the GP controller after verifying the GP's.

New glow plug resistance ( measured cold ) should be around .5 ohms, or 0.2-1 ohms. Resistance increases in hot engines so check them cold. Resistance check is a little more accurate than using a test light, at least it can find a marginal resistance GP, like 3 ohms or more.

 

[caterpillar guy]

I always just pulled them and hooked to a charger with my fingers on or watched for them to start to turn a slight red. Worked for me. If no color they were junk.