240 What the Heck is Going on? 81 Volvo 242 WILL NOT SPARK HELPPPPPP PLEASE

Hello: Again I am not getting any voltage at the coil Pos. 15 post. with the key on. I only get voltage there if the engine is cranking or if the neg.1 side red/white wire from the ICU is connected to the coil. I realize that I'm far from the brightest bulb in the pack when it comes to fixing this spark problem. I tried running a wire from the coil pos. side to the fuse panel. with the key on tried every fuse there it only engaged the starter. Any ideas where the problem lies Thank You so much in advance.

Post a wiring diagran

Post up a wiring diagram.

I don't know if the coil has 12v key on. MSD ignition, for example, do NOT. I learned that the hard way.

Since this B21f MPG was only produced in 81 . Wiring diagrams for other years are somewhat different. The Volvo wiring diagrams site does not offer any for the 81 models. Volvo Tips site does have a few for 81 but I cant print or copy them thus far. Ill keep trying to copy them something . When I do I will post what I have. Thank You

I have the '81 electrical Greenbook. Not sure how to send 38mb to you but have the two ignition pages for the MPG saved as .pdf. PM me an off forum email and I will send them to you.

Trace the circuit!

Learn to diagnose a "rpm sensor".

Find out where the voltage goes missing

The B21F-MPG was actually produced for two years. 1981 and 1982.

In any case, it'd be much easier to just get a Bosch Breakerless system and swap over. I've done it on at least one B21F-MPG car. Very simple swap. Need ignition box with its harness, ballast resistor with mounting screws, and distributor with two-wire harness that goes to ignition box and a Bosch cap and rotor.

1) Rotate engine to TDC on #1
2) disconnect negative battery cable
3) remove Chrysler distributor and coil
4) remove Chrysler box and its harness (you can leave knock sensor in place - it just won't be used)
5) install distributor so rotor is pointing at the notch on the housing
6) run two-wire harness from distributor under front of engine
7) install coil, making sure white-red wire goes to terminal 1 and brown wire goes to terminal 15
8) mount ignition box to washer fluid reservoir bracket
9) connect white/red wire on ignition box harness to engine harness and plug two-wire harness into ignition box harness
10) run white/red and blue wires on other end of ignition box harness to the area behind the passenger side strut tower
11) install ballast resistor and wire it up how it was connected on the donor car (take a pic of the ballast resistor prior to removing, so you can see which wire goes where)
12) reconnect battery
13) start engine, then loosen bolt for distributor and set timing. 10 deg BTDC should be ok with the L cam in the engine. If you go to a B cam, set it to 8 deg BTDC and bump idle up to 900 rpm from 750 rpm.

Enjoy using a system that uses readlily available Bosch parts, instead of either full-on Mopar, or partial Mopar parts.

-J

Hello Thanks so much for the input. I would like to change the entire ignition system to one that is totally interchangeable.with the 81 242 with B21F-MPG meaning coil/ dist./ ICU / harness. Does anyone know which years and models with work? This car has has two additional electronic control units {one small black plastic} {one small silver metal brain type} behind the kick panel at passenger side. . If I cant find the information as to what voltages are supposed to be where and when, Can I still determine the solution? Thank you very much

If you are not showing any voltage (12V+) on the coil positive terminal (15) with the ignition switch on, this is most likely the root of your problem.

First, try jumpering 12V from the battery positive directly to coil positive terminal (15) and see if the engine will start.

Do you have 2 wires on the (+) side of the coil (terminal 15)?
Blue and Brown?

Multimeter and wiring diagram

One must train in the ways of electronic ignition circuits.

No power the the coil is a huge red flag. Btw, it would be present on either side with key on; the voltage passes thru the coil!

Looking at the diagram, 12v comes from fuse 11. Is fuse 11 blown? Then, it goes to the starter for whatever reason, and then back up to the coil. This fuse also powers up the ignition box. Check for power at pin.....goes back to WIRING DIAGRAM....pin 2. Blue wire. 12v here?

Starter lead bypasses the ballast resistor while cranking.

No one has junked a Volvo 240 in 6 years in Utah. It would make things very simple I just go get the parts off one. Calif. Ore. Wash.seems to still have them going to salvage. I will have to contact a parts puller on row 52 when I find out exactly what im looking for . Is it the Bosch breakerless system that was used from about 75 to 85?

Splicing in some new **** seems like more work and money. What if the new stuff doesn't go?!

roady61 said:

No one has junked a Volvo 240 in 6 years in Utah. It would make things very simple I just go get the parts off one. Calif. Ore. Wash.seems to still have them going to salvage. I will have to contact a parts puller on row 52 when I find out exactly what im looking for . Is it the Bosch breakerless system that was used from about 75 to 85?

Click to expand...

Or put a post in Wanted, I'm sure one of our members or dismantlers has a known good one they can slap in a box and sell to you.

Hello Can one of the moderators change my settings so I can insert a few pages of diagrams in my post. It says I am not allowed to to attach anything Thank you. Wanted to respond to your questions and wanted to include a few attachments.

Thank you ZVolV and Coalminer and all others for the input and suggestions.. Yes I have checked the fuses 11 is good I usually check them every ten minutes when I am working on the car.about a week ago I run a wire from fuse 11 to 15 on the coil. it only engaged the starter. Have also tried Pos. battery to 15 coil. nothing or it engaged starter cant remember Was going to buy a 12 inline diode to see what would happen, Haven't found one in town yet. Yes I have check the blue input wire at the plug on the ICU. Its the only live wire at the icu plug {unplugged} with the key on. But every wire has some voltage coming out of the ICU with the plug plugged into ICU I pierced the insulation to get the reading I posted them When I first started this thread. I tied three different ICU. all about the same readings. Red and white wire from icu unplugged from coil #1-- 12.86 Volts// red and white wire plugged into #1 at coil 6.5volts.// #15 Pos. side .07 volts with red and white plugged in to #1 Neg side . With red white unplugged from #1 --#15 pos is 0.00 Volts. I have looked and looked at wiring diagrams ect. I have just located the new additions supplement for 1981 242 B21f MPG . one page is so,me tests but shows the starter with two wires from one post. I have not seen this before and Ive looked at every diagram I can find. I have I think always only had one wire to # 15 coil. but Im will to try more to get spark!!! Thank you for your nice replies.

According to new additions supplement for 1981 242 B21f MPG with the ICU plug unplugged from Dist. should be a very simple test. put wire from B- hole to c-hole many times to get sparks . pin or hole A has 12.95 Volts// hole B has 12.46 volts// hole C has 10.32 volts. I have 3 of the ICUs for this car and not one will make spark at plug end doing this test.I know for fact they are not all no good. just cant get my finger on the problem. Thank you all

Hello ; Thanks so much for the input . Whats been said by Zvolvo and Coalminer. About 12+ Voltage at 15 pos. on dist. that Voltage should be there but do not say anything about # 1 Neg. being plugged in or not . This is what I Need to know with a 100% correct answer to find the problem. .I think I will need to find someone with the same or similar car that can check the voltage at the coil #15 with the # 1 side red/white unplugged.. I agree with Zvolv when he says" Splicing in some new **** seems like more work and money. What if the new stuff doesn't go?! " When I first posted this thread that day I bought new coil. not Bosch but was close to being within specs. After trying many tests it is not at the same specs as when I bought it. I have now 5 Bosch coils and new different Brand from Advance Auto Parts. All of them make tiny spark with a spark deal. neg. side of batt. to pos. side coil with a switch in between. and the Neg side of coil to the pos. side of the batt. Spark deal to the HT tower and other end to ground. I Think that's correct as I don't have the paper with me of the diagram. I should be able to replicate this simple set up using the wires on the car but no spark. its the wires at the starter hooked up wrong { Dave Barton site says the way I have them is correct. car cranks but still no spark even with coil isolated .unless the one wire at ignition switch are is in wrong position. I don't know if that's possible.should be able to set up the wires at starter to coil to get coil to spark. But what Ive tried so far only engages the starter!!! I will try to locate a 12 inline diode today and see it that makes a difference. Thank you

Well if there is only 12v with the coil negative hooked up, that means it's coming FROM the coil negative, which it shouldn't be.

Slow down, study wiring diagrams, and carefully trace the circuit.

Make sure your grounds are good. Voltage will go strange places when the ground is bad for a circuit.