240 - Won't idle on cold start - LPG - carburetor.

Post by **billofdurham** » 05 Mar 2010, 15:40

That is the 1983 Volvo petrol pump. It would appear that whoever switched engines retained the mechanical pump. It would also explain why you can't hear the pump when you switch on.

Bill.

Harvey Birdman · Post by **Harvey Birdman** » 05 Mar 2010, 20:54

Hi Bill

I've had 6 Volvo 240's starting with a 76DL and this is the first time I've had one without an electric fuel pump but it's also the first one I've had that's not fuel injected. So what drives this mechanical pump?

I have to figure out why I'm not getting the blue spark at the output of the coil. Do these breakerless distributors have a condenser and if so where would it be located. I'll check all the earthing today as I live near the ocean and rust and corrosion is a major problem.

Thanks
Greg

Harvey Birdman · Post by **Harvey Birdman** » 06 Mar 2010, 07:09

Still can't get it started. Took some voltage measurements today. Maybe some one can shed some light on this.

Coil Voltage - Ignition On

Coil Terminal +15 = 7.2 Volts referenced to ground.

Coil Terminal -1 = 1.3 Volts referenced to ground.

Measured across Terminal 15 and 1 = 5.9 Volts.

Coil Voltage - Cranking Engine

Coil Terminal +15 = 10 Volts referenced to ground.

Coil Terminal -1 = 2.8 - 3.5 Volts referenced to ground.

Ballast Resistor = 1.45 ohms

Voltage across Ballast Resistor - Ignition On = 4.15 Volts.

Ballast Resistor - Brown wire to Ground = 7.2 Volts

Ballast Resistor - Blue wire to Ground = 1.3 Volts

Impulse Generator Resistance = 1100 ohms ( within spec )

I tried another coil with basically the same outcome so I don't think it's the coil.

It has the older Ignition Control Unit - Bosch 0227100018. These are supposedly very reliable. Does anyone have a circuit for it or can explain how to test it. The Haynes manual I have doesn't cover this particular unit. It 's the one with 2 wire conector to the Impulse generator.

When I measure the voltage across the primary coil on my '88 Volvo 240, with the ignition on and I get 12 Volt.

Any ideas what's happening here.

Post by **billofdurham** » 06 Mar 2010, 12:34

So what drives this mechanical pump?

A cam on the camshaft. A mechanical pump is no good for fuel injection as the pressure isn't high enough. However, the basic design is ingenious and they rarely went wrong.

This attachment gives a description of the breakerless system. There is no condensor.

240 breakerless ignition system.pdf: (549.69 KiB) Downloaded 328 times

Bill.

Harvey Birdman · Post by **Harvey Birdman** » 11 Mar 2010, 22:37

Hi Bill

Thanks for the reply and the test procedure.

I went thru the test procedure.

I get an orange spark but it will only jump 1/2 inch (12mm) not 3/4" (19mm).

Now the document specifies a 0.9 - 1.1 ohm resistor for the breakerless system but the car has been running without fault for 2 years with this 1.45 ohm resistor. Do you know the wattage of this resistor.

I get to point 5 and it passes all the checks so it says replace ignition control unit. See further down.

I've checked all the earth connections and the all seem solid.

Cleaned all connectors.

Purchased a 2nd hand Ignition Control Unit and substituted for the original and basically got the same results. So I either have 2 faulty ICU's or the problem is elsewhere.

Please see attached ignition diagram... I've added in the voltages I measured with the ignition on.

http://www.glowfoto.com/static_image/11 ... 5/glowfoto

I noticed that after a few minutes the coil gets warm and the ballast resistor gets very hot. By my calculation there is about 2.7 amps running thru it.

I've been told these Bosch Ignition Control Units are very reliable. I've attached some pics of the inside of the 2 units. There is a slight difference between them... 2 components less on the later revision. Diode D11 and Resistor R21, lower right hand corner.

http://www.glowfoto.com/static_image/11 ... 4/glowfoto

http://www.glowfoto.com/static_image/11 ... 6/glowfoto

I've done basic checks on the components in both units, everything appears to be OK but without a schematic it's a bit hard.

Would anyone on the forum have access to a schematic or service data for this ignition unit. Bosch: 0 227 100 018

If I had a circuit with some nominated test points and voltages I could at least verify the unit is working.

To rule out the ignition switch, is there a way of hot wiring it to just test the basic components?

I've got a feeling this is something simple but at the moment I just can't see it.

Looking forward to your reply.

Thanks again

Post by **billofdurham** » 12 Mar 2010, 12:06

Much as I dislike pointing members towards other sites I found this one whilst researching your problem. Scroll down to the second post which specifically mentions the ignition control unit.

is there a way of hot wiring it

Your friendly, local car thief will do it FOC, but only if you let him break in.

Remove the plug from the ignition switch and do a direct power connect to terminal 50 which, depending on the wiring diagram used, should be a blue or a pink wire.

Bill.

Harvey Birdman · Post by **Harvey Birdman** » 12 Mar 2010, 12:37

Hi Bill

Excellent detective work. I'll heat up the soldering iron tomorrow, remove the the power transistor and have a good look at the the back of the circuit board for dry joints.

After doing that I'll refit the unit and check voltages again. If nothing has changed I'll follow your instructions and hot wire it.

If all else fails I'll contact my local car thief and see if he can get it started.

Thanks again.

240 - Won't idle on cold start - LPG - carburetor.

Re: 240 - Won't idle on cold start - LPG - carburetor.