Ausmoo2 Posted September 17, 2019 Report Share Posted September 17, 2019 I've been having some issues with the RPM limit on my 2004 sti running a g4 V7-9 ecu. The car will sometimes rev all the way out to the 7800 limit, but most of the time when it hits a wall anywhere between 5000 and 6500 rpm and the ecu is telling me that the RPM limit has been activated . When I check the logs the times when it hits this "RPM limit" the RPM is jumping up to 18000+ RPM. This won't happen at the same RPM every time or in the same gear. For example 2nd gear will have no issues and then 3rd gear it will hit this "limit" and other times it will do it in 2nd but not 3rd. I've tried replacing the Crank angle sensor as well as the Cam angle sensor, but neither have made a difference. Any help would be much appreciated. Thank you Quote Link to comment Share on other sites More sharing options...
Simon Posted September 17, 2019 Report Share Posted September 17, 2019 It is likely getting noise on the trigger signals so could be a coil breaking down causing noise and then the RPM error. I'm assuming this is an older install and it has developed over time. Ausmoo2 1 Quote Link to comment Share on other sites More sharing options...
Ausmoo2 Posted September 18, 2019 Author Report Share Posted September 18, 2019 Hi Simon, thanks for your reply. Yes, the ecu was installed about 4 years ago before I purchased the car. The problems only started occuring after I installed a new engine. Would you suggest replacing the coils? Thanks Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 18, 2019 Report Share Posted September 18, 2019 Another thing you can try is set the trig2 lockout to below the point where your trigger issue often occurs. The ecu will then ignore the cam sensor above this RPM, if the error is related to the cam sensor or cam timing etc that may help. Ausmoo2 1 Quote Link to comment Share on other sites More sharing options...
Ausmoo2 Posted September 19, 2019 Author Report Share Posted September 19, 2019 Quick update: Changing coil packs hasn't made any difference, but changing the rpm lockout seems to have fixed the issue. Should I leave the lockout at 4000rpm or continue trying to chase down any noise on the sensor? If so what would be the best way to find it? Thanks Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 19, 2019 Report Share Posted September 19, 2019 I dont think there is any harm in leaving the lockout at 4000. If you wanted to diagnose further, really the next step would be to get an oscilloscope capture of the crank and cam at idle and say 5000RPM, that would usually give you some good clues where the issue is coming from. It could be something as simple as the cam timing moves slightly out of the allowable range at high RPM for example - I have seen this before with engines that have been "decked" significantly or have mismatched heads/cases. Quote Link to comment Share on other sites More sharing options...
Frank B Posted July 28, 2022 Report Share Posted July 28, 2022 reviving this thread could i run without the cam sensor like put the lockout in 0 rpm if you could retard or advance the cam could help with that issue im having the same exact issue and my block is decked badly at it, compression on one side is 165 on the other side is 140 regards Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 29, 2022 Report Share Posted July 29, 2022 What ecu do you have? Quote Link to comment Share on other sites More sharing options...
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