Started a thread here Wont start last week when the radio in my Mk2f 1994 Genesis Coupe blew a fuse and left the car not starting. It turns over but wont fire.

Have had a chance to do some investigating today and have replaced fuse 11 which got the radio going again but she still wont start. There is a live feed to the coil through the black wire and the brown earth works, can't find a trace of anything on the third wire from the ecu, but that may be because i am only using a test lamp and it doesnt carry enough power to light it up. A timing light on the HT leads shows no trace of any power. Suspecting the coil had failed we moved it to the bloke across the roads breadvan and it ran fine, so not the coil. there is fuel going in, you can see and smell it if you take the air cleaner off.

Any ideas anyone? Going to the scrap yard tomorrow to see if I can get a distributor and ECU.

Ok, if the is fuel going in you can discount the distributor as being at fault, if the hall effect switch in the dizzy was duff there won't be any fuel going into the engine.

It's not totally unheard of for an ignition driver circuit to fail inside an ecu, it does happen.. But. Before you go shelling out for a new ecu do a few basic checks like all your relays, battery connections, earths etc

Thanks for that Skodaboy

Went round loads of relays yesterday. Two by the fuse box, 3 and the flasher unit up behind the passenger footwell dash panel, all seem to be working OK. Are there any more relays????

Going to see if the guy over the road will let me 'borrow' his ecu, if that cures it I will get a replacement.

Had half an hour free this evening so I had a play with the multimeter on the connector on the distributor that connects the ECU to the Hall sensor Two of the wires have 11.5 volts on them, the other one is an earth. Is that right? Couldn't test it cranking as I couldnt hold the meter on and reach the key.

YeH that's right, one of them pulses to earth when the engine is turning. This feeds directly into the ecu and it uses it to figure out how fast the engine is turning, without this signal there will be no fuel and no sparks.

edit: a multi meter won't be much use to test this signal, normally they cannot react fast enough to the fluctuating logic level, you will need a logic probe or a test lamp to see it working properly.

as a matter of interest does you car have the combined type ignition amp/coil or is it the one with the separate tic ignition amplifier module? These often go wrong too!

Edited 24 July, 201214 yr by SkodaBoy

Cracked it today! Two problems, neither seem related to the radio fuse blowing, but voltage spike could impact both. Dodgy connection on the 3 way plug on the dizzy and the 20 amp fuse in the fuel pump circuit tested OK, allowed voltage through and then broke down a few seconds later, so some fuel coming through, then no fuel, then some fuel. Fixed dizzy connection and replaced fuse, tickety boo.

Enjoying being a Polo driver again, got to fit the lowered suspension now, but in hospital next week so will have to wait a while.