Evo9 random rpm limit

[borr]

Hi Guys

Evo8 usdm converted to Evo9

Strong internals, good fuel, big turbo

Trigger errors during rpm limit, on just warmup'ed engine everything fine

Later 8500 limit goes down to 7k, later 6500

Crank trigger wheel looks like new, we put new wire from crank sensor to ecu.

Try different ecu (also Link G4x) same

Mivec have "noise" 0-7 degree when target is 0, means always 0-7 cam degree on Idle and high RPM

Red Evo 9 6.5 rpm limit error latest.llgx red Evo Trigger Scope Latest - 2024-04-22 7_53_33 pm.llgx Red Evo 9 98Oct 620HP 5.pclx

[Adamw]

My suspicion is more around ignition noise than an issue with the trigger as it is just coming on to full load around that RPM.  Im assume if you lower boost it will rev cleanly to the RPM limit?

Wasted spark ignition generates a lot of noise so all noise reduction considerations need to be well covered for wasted spark ignition at high boost.  Does it have resistor spark plugs fitted?  Are the HT leads OEM or a good quality performance brand and in good/new condition?  What sparkplug gap is it running?

[borr]

Hi AdamW

Thanks for promptly reply

 

We have other Evo in our shop. Lets call it Wht Evo. Its equipped with PRP coils

Scope is very nice, and car runs good.

We put coil assy from that car to our car with rpm limit problems, and scope absolutely same (weird)

Originally we use Spoolinup evo coils on that car.

 

Pictures:  https://photos.app.goo.gl/bYFdZgd4ocBrPGx28

 

 

 

[Adamw]

The "noise" on the scope is normal, this is artificial noise caused by a combination of the 8bit resolution and aliasing due to the sample rate.  I see the same "noise" even with a clean computer generated signal on the bench sometimes.

The exhaust cam sensors are pretty prone to failing on modified evo's, so if you haven't tried that and still have the other car available you should try swapping that as a test.

But apart from that I would still be concentrating on ignition system noise.