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Hi guys we have a evo 4 at work that has a weird issue that i just cant seem to find. the car has a link g4 plugin ecu. its a built motor etc gt45 turbo. loaded up base map and just checking basics ie injectors and coils boost solenoid valve etc all working ok. car starts and runs ok good idle. run it on the dyno to set up the fueling all fine. until it hits 4000rpm. and then the car just splutters like its hitting a limit of some sort. if i attempt a power run it starts fine then as soon as it hits 4000 the power just drops off does the splutter business and then builds up again. its not missfiring at all. i have logged it and uploaded the file. if you look you can see 100% throttle and 4000 you see the map goes up and down and this is the point its doing it. have also tried at lower throttle but as soon as it hits the 4000rpm it does it.. i have checked map limit. all correction tables etc. it sounds like antilag/launch is the best way i can describe it. it isnt mapped yet as want to find out what this is before anything else. as cant even get a run out of it with it doing this. i have also uploaded the map incase i am missing something. i am using a plex knock monitor and am not getting any knock either. have also disconected the boost solenoid and run direct from the turbo to the external waste gate to eleminate this and it still does the exact same thing. also has brand new plugs in gapped correctly. has an uprated fuel pump and injectors. the customer doesnt want massive power out of this so its not like we are ringing its neck. if you have a look at the log we are only get at around 0.7 bar of boost. any ideas guys ? as i said scratching my head.
Well you check most of the turbo and fuel injection system, just remember the engine is a mechanical system .
Only for give you an example , in an opportunity I build a new engine and at 4500 rpm it starts to rattle like an ignition cut and didnt want
to pass those rpm under no reason, I check and change all ignition components , wiring, check fuel system , etc, etc.
Finally the reason was mismatched valve springs , the valve springs were shorter for the lenght of the valve stem and did not have the sufficent installed
and open pressure so they could not control the valves from 4500 rpm ..... Happily no fisical damage occurred .
I do not say that you have the same issue but try to check all the engine package , springs pressure, lifters , compression and leakage test, etc
Got a pulse damper or plenty of soft line in the fuel system?
Completely standard fuel system. Except for the pump and injectors
I'm not too familiar with the Evo platform but looking at the ignition dwell your map has 4ms, I'd try closer to 2.5 or 3. I've had it before with a Toyota where the dwell was too much for the coils and they'd fire early to protect themselves
Ok. So had some time on this evo today. And done a few changes. Changed the dwell of the coils to 2.5ms. Set the gearchange duty cycle table to 0. Checked the fuel pressure and fitted new plugs gapped to 0.5mm. All ok and running well.... however. Now if we try and adjust the boost up the car has the same problem that it had before of that bogging down and cutting. We cannot get it to run anymore than 1.1 bar or boost. It made good power at this. However cannot work out why we cannot run anymore boost. Fuel and ignition are good. Why can we not run anymore boost ? I have attached a photo of the run we managed to achieve. Any ideas as to what’s causing the issue guys ?