SR20DET doesn't rev over 4000 rpm

[Thilo]

Hi,

I have a problem with engine rev. At 4000 rpm it feels like a hard fuel cut, but I hav no rev limiter set for this point.
I'm not running lean, I have no overboost, dwell time is correct...
For checking that, I attached a log file and my projekt.

My set up:
-SR20DET
-Engine bored 2045cc
-755 Jecs Injektors
-NGK BKR7EIX
-Bosch 2x2 wasted spark coil pack

Hope somebody knows a solution

[Kisielisodd]

Your log file shows issue with synchronization around 4000rpm. it can be caused by several factors. If You have strobe lamp, change in secondary trigger, nissan sync window width from 4 to 8. It will change ignition timing, so You need to correct first trigger tooth to set timing properly.

Other settings are correct ( I started sr20det yesterday with identical settings and it revs up to 7500 without any timing errors)

Also common factors are wiring mistakes and damage CAS plug and worn-out CAS itself.

[clem]

Just to tell everyone: My setup, SR20det with Bosch 2x2 double fire coil, needed a shielding for CAS and some part of CAS Wiring. I had similar problems which were solved by proper shielding.

kind regards

[Thilo]

Hi,
thanks for the fast answer, I was so much thinking about problems with programming, I forgot to check timing with a strobe My sensors are all shielded correctly and I don't think, that there is any problem with the wiring, cables and wiring sensors is allmost my job I will try that first with the strobe and adjusting the cas, thanks again. Great community

[Thilo]

Hi,

so I tried adjusting my trigger parameter to sync window with 8 (old: 4) and changed first trigger to 37 (old: 8), timing is correct and the engine runs like before. But the problem with cam sync trigger tooth falling down under 50 (under 4000rpm is allways 120) still exists.

My next idea would be trying to wrap everything in aluminum foil for shielding everything a bit more. So I want to wrap around the ignition wires, coil, CAS and the cables from the CAS.

I added a drawing how I wired up my CAS, just for checking I've done that right.

greetings
Thilo

[Thilo]

Hi,
so I tried shielding all up, but nothing has become better. Problem still exists.
So the next thing I want to try is changing the CAS. But I'm a bit wondering, cause my engine ran very good with the original ECU... So I would say, it's not logic, that this is because of my CAS gone bad or the plug. Any other ideas?

But for my understanding, what's the CAS doing exactly? It has an inner circuit wich makes two signals from the two circles, the one with 4 different spaced holes is for primary trigger and called sync window (4,8,12,16 spaced), and the 360 1° slids are for secondary trigger. So there are 360 slids, why I have to set the trigger settings to 60-2? Does the circuit in the CAS forming a Signal, which appears like a 60-2 one? what does the signal from the secondary trigger look like?

Greeting
Thilo

[jt-performance]

Jakub isn't it a version from a batch that I had. A trigger filter issue

[clem]

Hi thilo, just to let you know, I have used a shielded cable for the cas signal, shield grounded at ecu. Ignition cables shielded, grounded at the valve cover (valve cover grounded to the head), AND had to make a sheet metal cover for the CAS and a section of the wiring to the CAS due to problems with higher revs.
Where is your coil located, may your sensor ground from a different sensor is an antenna close to the coil?

BTW: your CAS wiring is not correct on the picture, but i assume it is correctly made... it should be like this:

CAS wiring.PNG (8.08KiB)Viewed 4312 times

I looked through your project again, and what I would recommend you to do is, set fuelling mode to advanced lambda, so that you can see the engine's real VE and autotune will work

kind regards Clem

[Thilo]

Jakub isn't it a version from a batch that I had. A trigger filter issue

What do you mean by filter issue? Have you set a filter for the Nissan CAS?

@Clem:
So I did, I used shielded wires for the CAS and every other sensor. But not for ignition outputs. My coil is in front of the VTC Cover, so I think it is far away enough from the CAS. Either I think it has to do with inductive disturbation. I will try to relocate some wires and change a few things. And if it is really caused by the induction, I think lowering the dwell times should show at least a minor improvement, so I'll try that first.

Oh yes, I did a mistake with the drawing of my CAS, but it is done correct
The setting for fueling mode will be changed soon Thanks

[jt-performance]

We are Ecumaster Holland. The first test unit we received was in dec 2014. We tried this on a rb25 and had triggering isues. 4000rpm was the max. Feeled like a rpm limiter.
I talked to jacob and he send me some new capacitors. Tthe emu I received had some new trigger filterering build in. We changed them and I could rev above 4000rpm
Maybe this is the same issue.

We did this in a few days and re rest of the emu's received the new capacitors.

Please contact ecumaster and talk to them about it.

We developt a nissan plug and play module after testing.
It can be used on all nissan 76pin wiring looms.
Rb25, rb26, sr20, vg30

[Karel]

I am distributor for Czech,

in oposite to you ..... i made some SR20DET engines, and no one did make some problem. Timimng works perfect, no missfire, no errors on sync, no "drift" in timing.

[Kisielisodd]

I was testing p&p connector for SR20DET last week, and also have no issue with RPM readings. Stock CAS doesn't require shielded wires (Of course it can not hurt).

[Thilo]

Hi,
so you say, it's more a bad ground, bad plug or the CAS is broken?
Here I have a picture of whats happening at about 4k rpm with the trigger signal.

[ATS_Scott]

Check grounds between EMU and engine.

[Karel]

I always do :

Ground from engine to chasis
Ground from gearbox to chasis
Ground Ecu wiring to chasis in cabin
Ground Ecu wiring to chasis in enginebay

Yes, you can still see some noise on sensitive sensors, like magnetic pickup, even if you use shielded cables. But still the most (not all) problems of any cars electric will be result of bad grounding.

[Thilo]

So I've got a message from Kisielisodd, saying there was a problem with too strong hardware filtering in older ECUs and he will send me a picture of a capacitor in the ECU I habe to remove.

I just rechecked my hole wiring and I don't habe ground problems.

Hopefully it is the capacitor, that isn't needed. Will keep you up to date.

Thanks to all

[Thilo]

Update:

So the hardware filter consists of a resistor and a capacitor. Older ECUs have a 1 MOhm, newer a 1.6MOhm resistor. I didn't had a SMD resistor so I took two normal (1.5MOhm and 100kOhm) in series. I attached two pictures of this.

ECU still works but the problem hasn't gone

[Thilo]

Hi,
so: the problem is solved!

Kisielisodd has send me another solution and this time it worked He said, I had to remove two capacitors (C58 and C63) which are for filtering the trigger input. I attached an image where those capacitors are marked.

Car now runs like a fucking rocket

Thanks for the support, great board (Y)

[jt-performance]

Good to here it is fixed. The same fix as we did.