Tracking ignition voltage problem
 

Hi All,
The crux of my problem is that there is no measured voltage across the ignition coil (point #1 anf #15) and am trying to back track the lack of voltage. I have a Haynes workshop manual for my 1984 GL 240 Volvo, but the electrical diagram lacks in the way of practacality so I am looking for some advice on backtracking the voltages from the coil to,.., well the problem.

What lead me to measuring the voltage across the coil was the fuel pump! I pulled up at home after work on a Friday and a couple of hours later went to start the car. Well, no go. The (main) fuel pump was not priming and oddly enough before I had turned the key, the dashboard lights were dimmly lit (note there was no key in the ignition switch!). After a bit of lengthy trouble shooting (checking the fuel pump relay, fuses, spark) I came to measure 0 volts across the ignition coil (with the ignition on).

Other symptoms are all itermittmet such as the day lamps bein on continiously and the main fuel pump continiously operationg (or not at all) - both with the ignition swithch off.

I would appericate any advice on the goast in my volvo!

RE: Tracking ignition voltage problem
 

apolgies for the incorrect spelling in advance.

RE: Tracking ignition voltage problem
 

Check to see if the coil is bad. You just check two resistances. If your manual doesn't say how post back and i'll check mine and tell you what they are.

RE: Tracking ignition voltage problem
 

You did not say what car you have but on the 240 the wire to the coil comes from the back of the speedo, before there it comes from the electrical part of the ignition switch (this is a part that is known to go bad) I think you can get one at www.fpcgrotn.comIF this is your problem. That would be my first suspect......


by the way to remove unplug connectorthen remove the two screws. 10 min (hanging upside down) you will see what I mean.

RE: Tracking ignition voltage problem
 

Hi All,
I have replaced the coil and still no luck. However, in my initial post I reported that there was no voltage across the coil, well I confess to a small blunder. There is 12v between the 15 terminal and earth so there is power in the low tension ignition circuit.

I have since measured a few other components - the is approximately 1.1k resistance in the impulse sender coil (the induction coil in the distributor which sends a timing signal to the ecu), and the correct voltages going into the ecu.

When I crank over the engine, there is a oscillation in the input signal to the fuel relay (the red and white wire) but am unsure of the exact value.

Is there a way to determine if the ecu is functioning? I have rung around the state I'm in and the closest parts are 1500km away!

Cheers.

RE: Tracking ignition voltage problem
 

There is no way for you to test it yourself. You have to have an expensive piece of equipment that only a good volvo shop will have. My '82 had the same problem a few months ago and it was the impulse sender. But i would eliminate everything else as the source of the problem before you try to replace that because it was expensive and complicated. I took it to my volvo shop for only the second time because i couldn't figure the damn thing out myself and it cost me 320 american.

We just had our 82 244 DL (B21-F w/ CA Emiss) die on us here in Coos Bay, OR after a camping trip/business trip to teh area. We were ready to leave, and car would just not start at all. Replaced coil, as we didn't detect a spark coming off of it. That of course didn't work (but hey, no harm in replacing a 30 year old coil, right?), and so we had it towed; turns out the electronics in the Dist Cap (the impulse sender iirc) was the issue. On 3rd day now, waiting for part to get shipped down here, but sounds very similar to what you had.

This sounds like a bad ignition switch, which also feeds the voltage to the coil.

Got word today that that did NOT fix the issue; we rented a car to get us back to Beaverton, and told the mechanic to take his time figuring it out. Honest mechanic as well, as he's only charged us for one hour labor so far, and he said next hour is on him since he didn't solve the issue. So rare these days. . .

hayes' wiring diagrams kinda, well, suck.

try http://www.k-jet.org/files/greenbook...985_PRELIM.pdf which is an 1985, but should be pretty close to the 1984. (large file, slow site, best if you download and save it locally then view it).

hmmm. three possible ignition systems? SZ with Contact Breaker, Chrysler Computerized Ignition, and TZ-28H ignition. I'll assume the SZ was not used in US cars by 1984... hah.

so... Chrysler is wired like...
battery + -> red wire -> positive terminal on fender -> red wire -> ignition switch -> blue-yellow wire -> hot side of fuses 11,12,13 -> blue wire -> ignition coil -> blue wire -> pin 2 on the ignition control unit.

green wire from ignition control unit goes to other side of coil and provides the timing.
green, yellow, black wires from ICU go to distributor hall sensor.
brown wire from ICU goes to knock sensor.
orange wire from ICU goes to breaker unit and to LH ECU.

and, the TZ-28H is wired like...

battery + -> red wire -> positive terminal on fender -> red wire -> ignition switch -> blue-yellow wire -> hot side of fuses 11,12,13 -> blue wire -> ignition coil -> blue wire -> pin 4 on the ignition control unit.
white-red wire from ICU to coil provides timing.
black, blue-yellow, and yellow-red wires go to hall sensor in distributor.
black wire from ICU to ground, too.


oh, note, those fuses aren't in either circuit, the 'blue' wire (power to the ignition) is just is tied in at that fuse bus strip.