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fiestacosworth

evo 4 issue cant figure out

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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

evo base map.pclr

Log 2018-12-20 11;38;58 am.llg

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I dont see any obvious signs of trigger error, but the first thing I would try (assuming it is still an evo4 engine) is change the trigger mode to Evo1-6, rather than the evo7-9 mode you are presently on.

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the pump was failing to provide enough fuel as to why i have not tested it yet. when boost started to climb it was like fuel cut / boost cut.

on removal it looked like the original. replaced it with an uprated version and the problem went away. the car started fine and ran ok off boost just would accept higher rpm/boost

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Ok so fuel starvation. I will hook up a fuel pressure gauge and check it. Customer told me it has a walbro unrated pump in there. But needs checking. I also read somewhere last night that the evos have a restrictor on the return line in the tank and it messes up the fuel pressure. So will have to check that also. 

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Ahh ok! So it’s applying 100% wastegate duty cycle all the time. Regardless of wastgate table! This could well be the issue! Why the hell would it be set to that as standard. We don’t have the gears wired in. So I can set this to 0 and just use the wastgate table. 

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-100 wastegate trim wont cause it to break up like that, will just operate at wastegate pressure instead of higher boost.  When you're tuning boost control you should be going through all the tables, I can imagine the -100 trim in there is more of a safety net so those that are blindly going about tuning don't grenade an engine

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Nothing obvious in the log to me, it would be nice to see a log with AFR and fuel pressure.  From the ECU statistics page it looks like this ECU has been in use for quite some time, so I'd be leaning towards more of a mechanical type issue, going back and checking the basics.

I had a similar issue with a turbocharged 1zz many years ago, where it would hit what seemed to be a premature revlimit around the 4000rpm mark.  For that one it was a trigger issue and I had to use the 1NZ trigger setting for it to work correctly

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The guy bought the car with the ecu fitted. And a blown engine. He supplied a new engine turbo etc and we installed in. It is annoying that lambda isn’t on there or fuel pressure. However when on the dyno we are running a wideband so can see what it’s doing and it’s ok. I do agree I need to perform a fuel pressure test to be sure it’s ok. 

When it happens the lambda reading goes rich - lean - rich - lean and then carry’s on smooth. 

Also we have 0 trigger errors so I ruled that out. 

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tried checking on your Plugs buddy? 


mine last time, evrytime the boost climbs up, or hard step on the accel, would trigger the problem. 
some sort , a Boost cut? or fuel cut sounds alike.

my pump also change to unrated walbro pump. , i change the settings to Open loop on the fuelpumpcontrol.

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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 ? 

E575C009-49F1-4BDF-B01F-C797B3BBA933.png

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Map limit is set to 320kpa. Map sensor is built in on board 4 bar that comes on the link xtream ecu. Not tried a manual controller no as we have control. Just can’t go over 1.1 bar of boost or it’s like there is a cut. But there are no limits set that low. 

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On your statistics

 

max rpm is 11446 rpm

Do you have a trigger issue ?

 

also max map pressure is 280kpa so it has seen 1.8 bar of posistive pressure

 

max Air temp input is 100’C that will pull boost 

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The ecu has been fitted to the car for a wile and had another engine previous. This statistics are old. It hasn’t made that rpm or air temp or map with us running it. 

No trigger errors at all. 

Very confusing. 

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