Re: spark retard unit help
The car is Opel Calibra and the engine is 20NE
Engines E16NZ / C16NZ / C16LZ / 16SV / E18NV /
20Ne / C20NE / 20SEH have octane jack/switch (91/95 - 95/98), with which you can adjust engine to used gasoline. Its resistor which tells ECU what fuel is used, then ECU adjust angle of ignition. Also you should use ignition cables with resistive core.
Try resistor with 470Ω. Resistor with value 220Ω is for 95 octane, and 0Ω is for 91 octane. 91/95 is for US market, 95/98 is for EU market. Three positions 91-95-98, and for 91 you should remove resistor because its 0Ω. Lets say 95 is normal position, and with 470R you will push 3 degree to retard.
Now if you dont have resistor (0Ω for 91 octane), car must be very lazy.
Additional read this material :
RON Plug
A RON plug stands for "Research Octane Number" or also known as Octane Rating Plugs. These were introduced in 1987 on engines with fixed ignition distributors. That means you can no longer adjust the timing with a strobe gun as the ECU now automatically works out the advance or retard on the timing (usually with the help of a Knock Sensor). The RON plug value retards the timing a fixed amount.
Their main function is to prevent detonation (otherwise known as 'pinking') when using unleaded fuel. The plug is wired into the ECU (Engine Control Unit) wire loom so that it can be fitted into one of two positions. You simply unplug the RON plug and turn it over to be another value.
Inside the plug are two different fixed value resistors. The ECU provides a 5v reference source to the RON plug connector (see figure 4). When this signal is connected to earth, via the RON plug fitted which has a resistor inside, a voltage level lower than the 5v source will be returned to the ECU. The ECU may modify both the basic timing and fuel injection maps. Hence this RON code plug will advance up the ignition at different rates. The amount of advance under load is approx. 5deg less when coded for unleaded (95) than for premium (98) leaded fuel.
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Best regards,
Peter
:wink: