cruz177 Posted March 31, 2022 Report Share Posted March 31, 2022 Hello everyone, I am writing to you because I am going crazy to solve a fault in this car A year or so ago we installed a g4x ecu with various modifications which has been working very well. The car has run 2 rallies without any problem and is also used on the road. About 4 months ago it started failing overnight and there is no way to detect the failure, it seems like a random cylinder fails. Things we have tried: -another ecu link g4x -other injectors -another resistor box -other coils (r8 cop) -spark plugs changed -check wiring and new gnd -checked fuel pump and pre-pump -tested pressure regulator -the engine was rebuilt completely thinking that a valve was left open or that there was a failure in a ring since sometimes the dipstick had been pulled out of the oil (although it worked well) and we thought it convenient to do it to rule out an air intake and that with something else After 300,000 km of the stock engine, it had to be tuned The failure only occurs from 50-60 degrees when the engine starts to be hot, when cold it never fails. No trigger failures are seen and the signal is always good with no error counts and on the oscilloscope everything looks ok We do not know what else to look at or what it could be since we are running out of where to look, I am attaching a log (being larger than 4mb I had to upload it to another platform) if someone can help me with this problem. If the activation test is done, all the injectors work as well as the coils. Thanks https://mega.nz/file/ygI0kZbb#iSGNpUhGM5PZgKNSGx8BVY4rNp01x99WttoHu79keEA Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 31, 2022 Report Share Posted March 31, 2022 Was the problem occurring in this log? did it cut out at the end? Its running extremely rich, lambda drops below 0.6 is some places and is 0.65 at WOT, sure its not fouling plugs? Quote Link to comment Share on other sites More sharing options...
cruz177 Posted March 31, 2022 Author Report Share Posted March 31, 2022 4 minutes ago, Adamw said: Was the problem occurring in this log? did it cut out at the end? Its running extremely rich, lambda drops below 0.6 is some places and is 0.65 at WOT, sure its not fouling plugs? In the registry the problem is present all the time but it is greatly accentuated when you exceed 15-20% the tps and the rpm begin to rise The mixture is not the best since the last thing I do is change the m3 e30 evo2 injectors for the original ones to rule out any open injector and simply change the master fuel to be able to test, having the same fault. It is as if the ignition of more than one cylinder was cut randomly It's very strange Quote Link to comment Share on other sites More sharing options...
cruz177 Posted April 5, 2022 Author Report Share Posted April 5, 2022 more checks today - the fault is that cylinder nº4 does not explode reviewed: - trigger signal OK without faults -compression test OK - coil replaced by another, same fault - coil when the engine is running, it is changed for another with a spark plug and makes the spark jump - revised itb's, especially cylinder nº4 where the servo intake has been well sealed - Completely revised 12v power supply, resistor box (5.3OHM wired without connecting injectors for each one). - Continuity from the link ecu to the correct injector, all the wiring was working for months without flry cable problems Does anyone have an idea what could be going on? Quote Link to comment Share on other sites More sharing options...
cruz177 Posted April 10, 2022 Author Report Share Posted April 10, 2022 finally every problem has its solution the problem was the spark plugs They were changed before the engine was built but not after. By continuing to think, the conclusion has been reached that when the piston rings dilated, they let oil pass into the chamber without burning, which made it ''pearl'' as they say here in my country in the spark plug, affecting the jump of the electric arc since the unburned oil settled on the electrode randomly. the synchronization fault that even caused cylinders to fire out of time was due to the fact that the m3 e30 needed a spark plug extension. In the case of insulating this extension with silicone, as one might think is the best option, it causes an electric arc to break towards the ground of the coil, meaning that if for any reason the spark plug is left with oil deposits, an electric arc jumps from the spark plug housing to the coil housing and induces a false current jump, of very little amperage but enough to make a cylinder explode. This is solved by not protecting the spark plug extension. thanks to everyone! Quote Link to comment Share on other sites More sharing options...
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