Normal
Seems to me that you replaced the fans when you swapped in the replacement radiator?? Manually spin them to see if the bearings are shot - pretty common for cheap economically priced electric fans. Simple resistance reading or current draw while powered could quickly confirm (or eliminate) the fans as the issue. If the voltage drop is exactly coincident with the fans coming on, it seems pretty likely that is the issue although I suppose there could be a problem with the fan relay itself.In any case, I still think that the poor running is likely to be a function of low voltage rather than low voltage AND poor running both being the result of something else. While 12 V is sufficient to run the ECU, spark and injectors, there is nothing to confirm that there is this much voltage where it needs to be.Did you check the hose coming from the MAP sensor?
Seems to me that you replaced the fans when you swapped in the replacement radiator?? Manually spin them to see if the bearings are shot - pretty common for cheap economically priced electric fans. Simple resistance reading or current draw while powered could quickly confirm (or eliminate) the fans as the issue. If the voltage drop is exactly coincident with the fans coming on, it seems pretty likely that is the issue although I suppose there could be a problem with the fan relay itself.
In any case, I still think that the poor running is likely to be a function of low voltage rather than low voltage AND poor running both being the result of something else. While 12 V is sufficient to run the ECU, spark and injectors, there is nothing to confirm that there is this much voltage where it needs to be.
Did you check the hose coming from the MAP sensor?
