Ok. So trying to troubleshoot everything systematically. I first tried reading the voltage at each glowplug by the method. Black probe to ground (by fuel filter), Red probe to the glowplug itself with the key in position II. ie the glow cycle should be operating. No sign of a glowplug light in the dash but my readings, starting from front of the engine towards the back assuming the front is #1.
11,43V 11,36V, 11,37V and 11,36V.

Each time I held the probes in position till the relay clicked off and the voltage on the meter went to 0V.

I wanted to re-check these results before moving on to testing Ohms etc but before I could do that the damn black cable on the meter good hooked on something and pulled out of the probe.

I printed out another coupon, started the car - started immediately but real rough so increased Idle knob to max for about 30 sec's. Went to HF and got another free tester. Second round of testing Voltage at the glow plugs themselves with the new tester.

11,73V 11,6V 11,6V and 11,5V.

Again meter went to 0V at each plug when the relay klicked off.

Wifes' just come back with the dinner so I gotta go. I'll try to do the Ohm testing later this evening if I can get to it. But from these figures it seems that I'm getting good voltage at the plugs am I not?

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

Ok, so I did some ohm testing here. Never done this sort of stuff before so I hope I've read the posts here correctly.

First I tested the internal resistance of the multimeter across the two probes by touching their ends. It was 1,2 Ohms. I read that you need to do this and subtract it from the actual readings to get the correct result. Is this correct?

I used the same methodology as for testing the voltages. Using the ground by the fuel filter and the red probe on the tip of each glow plug. Readings from front to rear as follows. First reading is direct from the meter, second in parentheses is with the 1,2 ohms subtracted.

1,5 (0,3) 1,3 (0,1) 1,3 (0,1) 1,6 (0,3)

I then pulled the smaller plug, the pigtail that goes back to the ignition and measured the resistance inside the four plugs therein. They have numbers on them. Not sure what they mean but #50 measured 1,7. #31 1,3. #15 12,4 and #L6 18,2.

Finally I pulled the large plug, that goes to the glow plugs themselves and found the following resistance. #1 = 67. #2 = 1,7. #3 = 1,8 and #4 = 1,7. I tried several times again on #1 but still got a reading that fluctuated between 65 and 69.

So. I don't really know how all this ties together. Seems to me that the plugs should be glowing but the rough start and lack of dash light would indicate otherwise. Might it be best to start by replacing the relay?

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

The 67 ohm reading on #1 is not right. Snug up the 8 mm nut (do not over tighten) and measure again. Could also be corrosion on the wire crimp or solder joint on the large connector which can be inspected by removing the plastic cover.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

To which 8mm nut are you referring?

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S