1995 850 non turbo ignition control signal issue?

Discussion in 'Volvo 850' started by themonkeypeas, Mar 20, 2012.

  1. themonkeypeas


    Mar 20, 2012
    Likes Received:
    Hi all,

    Im hoping that there's someone on here who has more know how than me and can solve an issue I'm having with ignition on my 2.0 1995 850 Estate (a.k.a "The Beige Flash")!

    I initially started having intermittant starting issues where the engine would turn ove fine but would not fire and needed trying a few times now and then. This eventually got worse and now the car will not fire at all. First test was to check fuel supply and pressure and all seems ok and then I removed the HT lead to the distributor and found that there is no spark. I sourced and have changed both the ignition coil and camshaft position sensor but to no avail.

    As this then seemed something more serious, I managed to get hold of the Volvo System Component Test sheets and have worked through what I could but obviously I don't have a break-out box to try the more advanced stuff. The results of my tests are as follows:

    Coil wire removed from distributor cap: No spark (although gives one spark when stopping turning engine over)
    Ignition coil terminal 15 (red wire) to ground (key position 2): 12 volts (ok)
    Ignition coil terminal 1 (blue wire) to ground (starter turning): 6.8 volts (should be 0.7 to 1.3 volts)
    Coil power stage connector terminal 1 (resistance to ground): 0 ohms (ok)
    Coil power stage connector terminal 3 (key position 2): 12 volts (ok)
    Coil power stage connector terminal 4 (starter turning): 0.3 volts (should be 0.7 to 1.3 volts)

    Engine speed sensor (just test of sensor resistance): 265 ohms (ok)

    Camshaft position sensor terminal 1 (resistance to ground): 0 ohms (ok)
    Camshaft position sensor terminal 2 (starter turning): 0 - 5 volts (ok)
    Camshaft position sensor terminal 3 (key position 2): 9.6 volts (ok)

    I have also tested the MAF sensor (not the problem but when you're testing everything!) which checked out ok and have made a box for accessing the fault codes which turns up 1-1-1 (no faults).

    Judging by the above results, it would seem that the issue is with the ignition control signal which is not at the correct voltage. Without a break-out box, I am unsure of where to go from here although I have found a used ECU at a reasonable price which I might buy.

    Can anyony help me wiith the following points:

    1. Has anyone experienced this problem and know the solution? (obviously!)

    2. Which ECU does what on the car, there are 2 on mine, a 2.1 and a 2.2?

    3. If replacing the ECU, which numbers are important? Is it just the Bosch number (0 280 000 955 (956)) or are the other 4 on top of the unit of relevance?

    4. If I do replace the ECU, will it need reprogramming to match the security codes of the car?

    Many thanks for any help anyone can give me.
    themonkeypeas, Mar 20, 2012
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