Hi all, I have a few questons to ask in regards to the ignition system in my 1980 242DL (B21E, K-Jet injection)...

Yesterday, the car was running just fine while on the way to it's annual motor vehicle inspection (passed just fine). On the way home, it just died. I got the car home thanks to a push from one of the friendly local town cops. After a lot of time studying wiring diagrams and probing with a volt/ohm meter, I think my ignition module is dead. No spark at all while cranking the car. None of my local auto parts stores can test it for me, though. After checking on the price of a new one, I got really scared!

Can anybody tell me if there is a way for me to test this thing here at home using a volt/ohmmeter? It's a Bosch unit, pn 0 227 100 018. A trip to the local junkyard today yeilded no ignition modules anything like what I was looking for, though I did pick up a spare ignition coil...

If indeed my ignition module is dead, has anybody ever tried wiring in a 4 pin GM HEI ignition module in it's place? I noticed the plug that goes to my Bosch unit only uses 5 wires... I know it's a fairly common practice to use these HEI modules to replace the transistor unit in old Datsun 260Z and 280Z's (I have a 280Z with HEI, but only because of the hi-performance 383 small block Chevy engine under the hood!), has anybody done this with an older Volvo? The HEI module, though it has only 4 pins, has 5 "terminals" in that the back of the case is the ground. 2 wires come from the pickup in the distributor, and the other two are for swithched +12V in and coil hot wire. Can this be used to get my old reliable 242 going again at a much more reasonable price than a replacement for the Bosch 0 227 100 018 unit??

If the HEI isn't feasible, I also have at my disposal an MSD6A unit. Has anybody ever installed one of these into a 1980 model? Does it replace the existing Bosch unit, or does it work in conjunction with it?

I'd like to get the 242 going again as soon as possible, because the 280Z with the SBC motor burns premium fuel at a somewhat disturbing rate to be using it as my daily driver right now... Sorry to ramble on like this, but any answers to any of the above questions will be greatly appreciated!

Thanks,

billy242
1980 242DL/GT hybrid

Those modules hardly ever die; not so the coil in the distrbutor.
There should be ~1000 ohms between the green and black (7 and 31d) wires going from the module to the distributor.
There's a diagram of the early module at
http://www.stanford.edu/~mcduck/bosch.pdf
That's probably the one your car came with. The 005 and 018 are interchangeable.

Thanks mcduck, I will check out the pickup in the distributor tomorrow with my ohmmeter to see if I have the 1000~ ohm between the 31d and the 7 terminal wires. The sooner I can get the car running, the better!

billy242

Do you have any kind of 240 manual (even a Haynes?) McDucks circuit schematic is excellent, but most manuals have a circuit pictorial showing terminals and connectors where corrosion can cause a failure.

Like those 2 wires from the distributor to module 7 and 31d. If you follow them down from the module, you'll come to a 2-wire plug that may be your problem. Just reconnecting it 2 or 3 times can wipe corrosion from the connection. Same for the plug at the distributor, and at the ballast resistor over near the right hood hinge. I think the grounding terminal on the module 31 wire is accessible nearby too.

Also the Primary terminals 1 and 15 at the coil.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Hi Lucid,

Yes, I do have a Haynes manual for the car. I will check out those connectors that you mentioned while I'm out checking the resistance of the pickup coil in the distributor today. Thanks for your suggestions!

billy242

Hi Billy,

Last year about this time I got an '80 244 that hadn't run in 10 years, and had been outside for a good part of that time. I had no spark (after replacing the snapped timing belt) and going thru all those connections fixed it.

My Haynes shows the ignition layout at the top of page 5-7. Notice that the power from the Ign. Switch goes to the "hot" side of fuses 12 & 11, just as a connection -- it doesn't come thru any fuses.

Good luck with yours.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Thanks Bruce. My 242 also lives outside (no garage), the only difference here is that mine has been driven daily since I got it three years ago, and the previous owner drove it daily also. I can see how long term sitting could have this effect... it just seems curious that a corrosion problem would pop up while I am driving it down the road.

I'm just on my way outside to go do some more troubleshooting as per your previous post, and also that of McDuck. I will post if I get it running, or if I find other related problems. Thanks again,

billy242
Billy McCaskill
Baker, LA

Thanks very much to lucid and mcduck! The car is running again!

I went back out this morning and unplugged/reconnected the wires several times at the coil and at any other connectors associated with the ignition system to make sure the connections were sound. Then with my ohmmeter, I did a lot of probing in various places. I found a resistance of 0.9 ohms between the wires for pins 7 and 31d in the wiring harness instead of the ~1000 ohms I was looking for. So I unplugged the connector at the distributor, and measured the pickup coil directly and found 1116 ohms, just like mcduck told me to look for. So it wasn't the pickup coil...

Then I tested both the green (7) and orange (31d) wires individually for continuity, and both had exactly the same resistance of 0.9 ohms again. Now with the wires still disconnected from the distributor, I tested across terminals 7 and 31d in the connector again, and still had 0.9 ohms. Hmm. The wires must be touching together somewhere... So I climb under the car and follow the wires, and found where they had been pinched together between the alternator and the alternator mounting bracket. Seems when I changed the alternator back in February, I didn't see those wires, and apparently they got pinched way back then. It just took 7 months of vibration and compression to wear through the insulation to short the 2 wires together.

I loosened the bolts holding the alternator, and removed about 1.5" of the wires where they were crushed, crimp-spliced them back together and taped up the connections. I retightened the alternator, reconnected everything, and the car started up on the 1st attempt! So it wasn't the ignition module either... Boy am I relieved! Cost to fix, about 10 cents for the two crimp connectors that I used. Much better than the $199 that a local retail auto parts place quoted for a new ignition module...

Thanks again mcduck and lucid... I wouldn't have know what to look for if it wasn't for you guys... and even if I had replaced the ignition module, it still wouldn't have worked anyway since the signal from the pickup coil wasn't even reaching the module. Brickboard rules!

billy242
happy camper, and once again happy Volvo driver!