'84 1.8 petrol Laguna ignition Problem

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Sat 4 Sep 2004 15:27
'84 1.8 petrol Laguna ignition Problem - graemeb
Had the laguna for 2 years. Started backfiring sometimes when ever i had been driving for a while at speed, then perhaps left it ticking over or got stuck in traffic. It would then cut out. Got mechanic to have a look, he found a connector under the air filter was not properly connected. That fixed the problem for a month, then I started up one day, ran on idle for 3 minutes then cut out.

Again mechanic tested continuty between ECU, coil, sensors etc. Replaced coil/amplifier pack, still no spark. Removed and tested the ECU, ECU was fine. He then gave up in frustration and I am now onto 2nd Auto Electrician. He had performed the same set of tests and is convinced its the coil/amplifier pack again.

Having already had someone replace it I am confused. Anyone with experience of this please reply and pass on any information.
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Sat 4 Sep 2004 23:53
'84 1.8 petrol Laguna ignition Problem - Railroad.
Is this the earlier type with a Renix unit and dry coil, or later one with two twin coils?

If there is no spark then problem is most likely the flywheel sensor or the ignition coil, both are very easy to test. Unplug the flywheel sensor and check resistance at the two pins. You should read anywhere between 150 and 1500 ohms. The resistance is vitally important, if it's open or short circuit the sensor must be replaced. Then crank the engine and check for an AC voltage output of around 0.5 ACV or more. If all this is OK the sensor is fine.

The coil does seperate from the Renix unit, it's fixed by two torx screws. Rig up a conventional coil to the terminals of the Renix unit to test.

I have never known a Renix unit to fail, but I suppose there's always a first time.
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Tue 7 Sep 2004 00:11
'84 1.8 petrol Laguna ignition Problem - graemeb
Railroad,

Not sure, I know the coil has an 'amplifier' module attached, which according to the electrician is working (tested it with some Lucas unit with a flashing led?) He has tried to bypass the other bits and just get the coil to give him some life, but nothing, not even a tingle as he puts it. I know the coil is proving to be difficult to find, so it might be the older one.

The crank sensor is brand new, and the electronic module has been removed and sent for testing. The other mechanic went through similar diagnostics, and replaced the coil and amplifier pack. The only think the new electrician said was that he might have ordered the wrong coil? I will pass on your thoughts to him and many thanks for the reply.
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