Sudden RPM falling problem

Omibi · Post by **Omibi** » Fri May 20, 2016 2:26 pm

Hello,
talking about a emu mounted on a S50B30 BMw M3 engine and I´m having sudden rpm falls and don't know exactly why. I attach you a log file to see if you cam help me. I'm have this problem with and without load when I reach about 1300-1400 rpm. In the log you will see this problem at the begining of the log and at the end. At the beggining is idling and at the end the car is with load on a dyno and I go little by little taking off load to increase the rpms, suddenly about 1330 rpm I got the rpm fall. First stand alone ecu and the car should racing next weekend

Thanks!

It looks that I reacehd my quota, I can not attach the file

, If anyone wants to have a look to the log I will send it via mail.

RHD · Post by **RHD** » Sat May 21, 2016 6:10 am

check your fuel cut RPM and the TPS threshold (raise the rpm and lower the threshold)

Omibi · Post by **Omibi** » Mon May 23, 2016 11:10 am

It seems that is a cam sync probem, working on it.... Noisy signal, is making me carzy. About the fuel cut, how can I disable deceleration fuel cut?

forti · Post by **forti** » Tue May 24, 2016 9:09 pm

Have you found any solution? i have similar problem, but my engine is m42, and i reach only 2500 rpm.

Omibi · Post by **Omibi** » Wed May 25, 2016 8:06 am

Not yet, four days working on this and no solution. I have cram, cam1 and cam2 wires shielded and since yesterday, coil wires shielded and routed away from the other wires but no difference, I keep loosing cam1 syncronization. I will try with a difference cam sensor today but I think everything will remain the same, I don't see sensor mistakes with the electronic scope. About the signal noise, the only noise I see is the noise produced by the voltage peaks of the coils that is present in all signal including the power supply but only cam1 signal seems to be affected. This noise was also on the OEM ecu and OEM harness, but worked ok. We have a race next sunday but seems that we are going to miss it. If I find a solution I will inform to you.

MrBmw · Post by **MrBmw** » Wed May 25, 2016 10:52 pm

Omibi wrote:Not yet, four days working on this and no solution. I have cram, cam1 and cam2 wires shielded and since yesterday, coil wires shielded and routed away from the other wires but no difference, I keep loosing cam1 syncronization. I will try with a difference cam sensor today but I think everything will remain the same, I don't see sensor mistakes with the electronic scope. About the signal noise, the only noise I see is the noise produced by the voltage peaks of the coils that is present in all signal including the power supply but only cam1 signal seems to be affected. This noise was also on the OEM ecu and OEM harness, but worked ok. We have a race next sunday but seems that we are going to miss it. If I find a solution I will inform to you.

Take a look here:
viewtopic.php?f=19&t=485&p=3289&hilit=S50b32#p3289

forti wrote:Have you found any solution? i have similar problem, but my engine is m42, and i reich only 2500 rpm.

Have tried to disable camsync above 600rpm?

forti · Post by **forti** » Thu May 26, 2016 10:24 am

MrBmw wrote:
forti wrote:Have you found any solution? i have similar problem, but my engine is m42, and i reach only 2500 rpm.
Have tried to disable camsync above 600rpm?

I will try tomorrow, thanks.

forti · Post by **forti** » Fri May 27, 2016 11:37 am

This was it. Thanks a lot. I will try in future change cam vr.

Omibi · Post by **Omibi** » Sat May 28, 2016 10:23 am

It is also working for me,teeth count remains constant in 115, it is suposed that should be 116 but the engined looks to work ok. How is know syncronicing the engine? I'm going to check spark timing. Thanks!

forti · Post by **forti** » Sat May 28, 2016 6:42 pm

Omibi wrote:It is also working for me,teeth count remains constant in 115, it is suposed that should be 116 but the engined looks to work ok. How is know syncronicing the engine? I'm going to check spark timing. Thanks!

My engine has constant 116, but i think as you. Engine works well but louder i think injectors work in groups.

Omibi · Post by **Omibi** » Mon May 30, 2016 7:59 am

I checked and the engine keeps working secuencialy. Spark advantage is ok, I checked with 0, 6 and 12 grades of advantage (0, 1 and 2 teeth of advantage).
I think I know what is the problem. Is not a noisy signal, is not a grounding problem... There are 6 allen bolts (At least in the S50B30 engine) that fixes the sproket to the camsaft, what is happening is that over 1000 rpm more or less these bolts are readed by the sensor and when these happens the engine looses the sincronization. These should have happened to everybody that tried to set a secuencial ignition-inyection mode with these kind of engines. I asked to the technical support if we can have any problem disabling cam sincronization so low, let's see what they say.

Omibi · Post by **Omibi** » Mon May 30, 2016 4:09 pm

Seems that if you are not using VVTI control there is no problem with this setting. I'm going to use intake vanos control so this is not a solution for me. I will change the bolts and put stainless or titanium bolts, that should solve the problem...

Omibi · Post by **Omibi** » Mon May 30, 2016 8:13 pm

I changed the bolts and seems to be solve. I will have to see what happens at higher RPM, but up to 3000 rpm with no problem.

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