Compression query
Discussion
I have now removed the ECU from the car and carried out some very basic circuit tests.
I identified the two pulse wires which run from the coil connector to the ECU (BK/GN and BK/OG ) which earth out the primary coil when required .
Having disconnected the 60 pin connector block from the ECU , I connected the two pin sockets for the two coil wires with a paper clip so I could conduct the test from the engine bay .
I disconnected the wiring block at the coil and put 12V from the (disconnected) battery on one wire and ran my circuit tester between the other wire and earth.
The test lamp lit , proving a complete circuit through the two wires.
I also tried slightly pulling and wiggling the wires where they enter the connector block but the tester lamp shone without any flickering , so my guess is that they are sound .
My next step now , I guess , is to get the ECU tested ,
Incidentally , I read that a fault code which puts an engine into ‘limp mode’ needs to be deleted from the ECU memory before the engine will return to normal , EVEN if the problem which caused the fault has been rectified ! I wondered if this could apply to my problem ?
Thanks in anticipation guys !
I identified the two pulse wires which run from the coil connector to the ECU (BK/GN and BK/OG ) which earth out the primary coil when required .
Having disconnected the 60 pin connector block from the ECU , I connected the two pin sockets for the two coil wires with a paper clip so I could conduct the test from the engine bay .
I disconnected the wiring block at the coil and put 12V from the (disconnected) battery on one wire and ran my circuit tester between the other wire and earth.
The test lamp lit , proving a complete circuit through the two wires.
I also tried slightly pulling and wiggling the wires where they enter the connector block but the tester lamp shone without any flickering , so my guess is that they are sound .
My next step now , I guess , is to get the ECU tested ,
Incidentally , I read that a fault code which puts an engine into ‘limp mode’ needs to be deleted from the ECU memory before the engine will return to normal , EVEN if the problem which caused the fault has been rectified ! I wondered if this could apply to my problem ?
Thanks in anticipation guys !
Well , with my ignition set up , inside the coil block is a primary coil and two secondary coils.
The primary coil has a conductor at each end which is connected to the ECU.
Depending on which conductor the ECU earths out , the HT is induced in the coil on that particular side. Each secondary coil is responsible for two spark plugs , 1 and 4 , and 2 and 3 .Each pair of plugs fire simultaneously . One cylinder will be at TDC on compression and the other , on exhaust, (wasted spark principal)
Having tested the ignition system from the plugs right back to the ECU several times , and finding that the two plugs affected are controlled by the same coil , I believe that the ECU is failing to earth down the LT on one side of the coil.
The primary coil has a conductor at each end which is connected to the ECU.
Depending on which conductor the ECU earths out , the HT is induced in the coil on that particular side. Each secondary coil is responsible for two spark plugs , 1 and 4 , and 2 and 3 .Each pair of plugs fire simultaneously . One cylinder will be at TDC on compression and the other , on exhaust, (wasted spark principal)
Having tested the ignition system from the plugs right back to the ECU several times , and finding that the two plugs affected are controlled by the same coil , I believe that the ECU is failing to earth down the LT on one side of the coil.
Well my friends !
All is resolved and I'm back on the road !
Firstly , I want to thank you all for offering your kind advice !
Never had a response like it !!
The culprit ? It was the ECU which , apparently , is a common problem giving rise to a misfire on 1 and 4 or 2 and 3 !
Managed to get the original unit tested and repaired !
Safe motoring !
All is resolved and I'm back on the road !
Firstly , I want to thank you all for offering your kind advice !
Never had a response like it !!
The culprit ? It was the ECU which , apparently , is a common problem giving rise to a misfire on 1 and 4 or 2 and 3 !
Managed to get the original unit tested and repaired !
Safe motoring !
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