RPM cuts at 4000 on load

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guricha
 

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RPM cuts at 4000 on load

Post by guricha »

Hi guys,
I have strange issue with RPM or load cut after swapping the engine,
Car was 1999 year model HR34 with rb20de engine manual gearbox, have transplanted RB25DET series 2 from R33 successfully not changing wiring, car drives well but only problem is at load it cuts at 4000 rpm depends on gear, cut is like car hits rpm limit and drops power all the down
does anyone have some idea what could be reason ?

I try Maf, change TPS but nothing, all the sensors are connected except boost sensor . . . Did research on the net and seems like common problem after swapping the engine but nobody have actual answer what exactly could be fault
thanks for attention
bachig24u
 

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Re: RPM cuts at 4000 on load

Post by bachig24u »

Pretty sure it needs MAP sensor input;

ecu part number?
address file?
bin file?
speed sensor working?
guricha
 

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Re: RPM cuts at 4000 on load

Post by guricha »

bachig24u wrote:Pretty sure it needs MAP sensor input;

ecu part number?
address file?
bin file?
speed sensor working?
Speed Sensor is working i can see it with nistune
address file is ER34 RB25DET
bin files i have checked almost all

Ecu part number i will write down later, this problem was in stock ecu also, i made some search and this problem happens often even on stock cars, funny thing is that boost is around 5 psi
Actually i dont have much experience with ER34 ecu because i search for some help over here

Could it be problem of the timing ? maybe its out ? what you think ?
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Re: RPM cuts at 4000 on load

Post by Matt »

You will need the boost sensor connected for starters, otherwise it will cause problems

Produce a lot of as many sensor inputs as possible as well as TP, Inj time etc and post it here. I can simulate on bench. There must be one or more inputs its not happy with
guricha
 

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Re: RPM cuts at 4000 on load

Post by guricha »

Matt wrote:You will need the boost sensor connected for starters, otherwise it will cause problems

Produce a lot of as many sensor inputs as possible as well as TP, Inj time etc and post it here. I can simulate on bench. There must be one or more inputs its not happy with
Matt, i wrote you regarding this particular swap, i did't wanted change wiring from HR to R33, probably that is my mistake, now i don't even know where to install boost solenoid as the wiring does't have it cos the car was NA, I still hope that problem is coz of timing or some other mechanical issue... my good friend owns R34 GTT and hes car doesn't have boost solenoid as well i just remove it last time but car had no issue with loading
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Re: RPM cuts at 4000 on load

Post by guricha »

Here is some screenshot for DTC errors, also today i have checked voltage at fuel pump and it quite low 11.8 volt
Image
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Re: RPM cuts at 4000 on load

Post by Matt »

Those codes are normal for an engine in the car without TCS and ABS connected. You can hide the DTCs by masking them out using the 0.10.17 version uploaded last night
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Re: RPM cuts at 4000 on load

Post by guricha »

Matt wrote:Those codes are normal for an engine in the car without TCS and ABS connected. You can hide the DTCs by masking them out using the 0.10.17 version uploaded last night
Matt,
what about throttle motor sensor? TPS is connected and what is this fault ?
then i don't know what to do wit this issue ?
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Re: RPM cuts at 4000 on load

Post by Matt »

Throttle motor opens/closes as part of diagnostics. Used for the TCS to close the throttle. Wont cause the 4K cut issue as I dont see that on the bench and my R34 ECU revs right up

Need that log file as mentioned earlier
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Re: RPM cuts at 4000 on load

Post by guricha »

Matt wrote:Throttle motor opens/closes as part of diagnostics. Used for the TCS to close the throttle. Wont cause the 4K cut issue as I dont see that on the bench and my R34 ECU revs right up

Need that log file as mentioned earlier
Matt, i think i found the problem - What about constant? I have removed sparks today and seems they work lean, is there big difference between injectors from R33 and R34 ? or i just have problem with fuel system ?
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Re: RPM cuts at 4000 on load

Post by Matt »

ER34 380CC
ECR33 370CC

About the same
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Re: RPM cuts at 4000 on load

Post by guricha »

Problem with Fuels solved, I dont know why but i adjust constant to 650 from 560 and fuel got ok, now there is problem with timing and with knock
Nistune shows timing 5 when actual is set to 15
about knock : car goes to knock map as soon i will rev it in gears :(
Anyway I will play few day and then will change wiring to R33
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Re: RPM cuts at 4000 on load

Post by guricha »

I think i found the problem, it could be cas i have checked and cam position sensor From R33 rb25det engine has different plate for timing then later one, is there any chance to adapt the sensor to ER34 map?
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Re: RPM cuts at 4000 on load

Post by Matt »

Remember timing can change based on other timing adjustment tables (eg cold start timing etc)
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Re: RPM cuts at 4000 on load

Post by guricha »

Yesterday i start testing the TPS also
Image
i found through internet some way to testing the TPS
Fully open should be about 4.5 and closed 0.45 volt,
depend on Nistune its ok but when am measuring information by the volt tester its mirror measuring, on the opened is 0.45 and at closed its 4.5 volt
that should be like this ?
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