Coil testing specs. (stalling at low load) ?
 

My usually-reliable 1992 B200F has been dying at junctions, etc., whenever I've been out recently (not often!), and I (on Sunday) and AA man (today) found no spark from distributor ... but occasionally it will run - e.g. after rotating fuses or cleaning plugs or interior of dizzy cap. Fuel is getting through. So maybe the coil is u/s, but I'd like to test it before buying another. Car and I brought back this evening on a rescue truck; will only go out again when I'm sure of reliability!

My Haynes manual - no. 270 - covers only up to 1988 [my later book has gone missing] and details testing of all older systems, with widely varying primary & secondary resistances for the coil - but not LH 2.4. Can somebody quote me the values for checking the coil on my vehicle? (And /or suggest any other potential cause of this trouble.)

I haven't thought of the Crank Position Sensor being faulty, as I replaced it about 25,000 miles ago - but will do so in the morning. Maybe the electronic ignition module .. (but how to know if it's not working /giving output?) [.. for the same reason].

Thanks all.

Have you read this?:

https://www.volvoclub.org.uk/faq/Ele...nitionAmplifer

Thanks for the link, Clifford - with the test for the coil and useful anecdotal stuff.

From the AA man I could see that I have no spark from the coil lead to the distributor. I've replaced the coil with a new one [not full price but I was assured it is good], and the Ignition Amplifier with a s/h one supposedly "in full working condition". Is there a test for the Amplifier (beyond 'it works and the car goes now')? I'd like to know if mine was faulty, and also the replacement with which I still have no spark and no go. Also how to fix it if it is dud. (Don't want to have to find another, "guaranteed" & expensive, one.) Have also swapped the coil lead with one of the plug leads but still nothing, even with a well-charged battery. The c.p.s. cable is solid, not frayed and worn-out like it was before I replaced it the last time I had a no-start.

Any suggestions welcome! - as I've been car-less a month now and really need to sort it out.

Have you tried connecting fuses 4 and 6 together, eg with a short wire with a crocodile clip on each end? This will bypass the fuel pump relay and run the pumps continuously.
It's a good quick test for a failing relay, which is a common fault, and will get you home if the relay fails.

Otherwise, you seem to have covered my Big Four of usual faults.


I'm not sure how to test a coil other than by substitution. I know they can gradually break down with age, and the usual symptoms are missfiring and then stalling and non-start after the coil has got very hot, recovering when it has cooled down.

There's a thin braided earth wire attached to the camshaft cover, which is said to be important for the low-current electronics (ie not starter motor) which can crumble and break.

Rotor arm - cheap modern ones are always said to be poor quality and break down.

Distributor cap? Unplug each lead and check for corrosion, and look for tracking inside.

Thanks for the fuses 4 + 6 tip, I'll try it when it's reliably dry.

I could also have said that after the last time it ran (a couple of minutes) soon after getting back here I checked the fault codes, and got 1-1-1 on both sockets (main & ignition ECU's).

I'm wondering if maybe my lambda sensor has failed (it wasn't a top-price replacement, about two years ago) - as thay don't seem to last very long, even though it didn't show up as a fail by the diagnostic.

Also - after reading the anecdotes again - will check out the AMM, hoses, and security of all cable connections.

My cam cover's earth lead is O.K.

I will think of checking other stuff, and anything else that occurs ... when it stops raining!

Cheers.