Rev limiter not working.

Hi guys,

i want to know what can cause the rev limiter not to work ? i dont feel the cutting sound it is just making a sound like burrrrrrrrrrrr..

1- faulty speed sensor ?

2- bad spark plugs ?

3- it works in conjunction with map limit ?

need your advice

Try dropping your rev limit down to a really low level such as 2500rpm and see if it works, you may be getting an ignition breakdown before you reach your limit

Hi Chris,

I tried dropping revs to 6000 but still no limiter.

ill try to lower it more and see if the limiter works.

Ignition is distributor type.

Should i try changing other trigger filtering ? any other thing to look at so that i can narrow down the problem ?

Can you please have a look at the pcl and check if you find anything which is causing this ... This is unfinished map still in the process of refining.

https://www.hpacademy.com/forum/general-tuning-discussion/show/234

Last post by K TUNER can be my problem.

update -

Connected the stock ecu and the car is hitting limiter .

Can this be trigger related issue ? engine is 3sgte 3rd gen.

By "not working" you mean your engine can rev past the set rpm ? Or does it struggle bellow it ?

There is a firmware issue on LINK ECU, which turns Fuel cut off, if Injector Duty Cycle goes above 100%. Lower your boost or fit bigger injectors or change to ign cut if possible.

Check the LINK ECU forum for more infos.

Are you serious? How can an ECU manufacturer have a known serious issue like this and not have it fixed immediately?

Well, you have a more serious issue with your built if you exceed 100% duty cycle in the first place...

agree with you 100% - but an ecu should never stop an RPM limit from working.

Hi all,

Not hitting the limiter means nothing cuts of neither fuel nor ignition and i experience a sound burrrrr , when a car struggles to rev.

Yes i know the injectors are hitting 100% duty cycles as i just switched from 1450s .

Ill be getting new High Z injectors.

In Evo stock ecu you can get to max 120% dutycycle and still get to hit the rev limiter.

I got to read that thread on Link forum where this Fuel cut issue was identified.

Although i am getting peak 55% duty cycle when hit the limit while being stationary but still no limiter.

I feel thats a serious issue , since i first noticed this i tried looking for mechanical issues and spent alot of time in that.

Moreover , in boost spike condition this will be catastrophic.

Ill try to use ignition cut instead of fuel cut and see if it works out.

You still did not answer whether or not the rpm exceeds the limit and you are referring to the "brrrrr"... which leads me to believe you do actually have a working soft cut in place.

As far as the 120% duty circle statement on OEM ECU is concerned, this is simply impossible and that value may represent something else but not injector duty cycle.

UPDATE -

So i tried IGN CUT instead of FUEL CUT - as rev limit = Still didnt get the ding ding

Set rev limit to 5000 and tried but no result. same brrrrrr brrrrr type cutting.

Advanced mode off - Hard cut activated = no limiter.

hard changed to IGN cut = no limiter .

Max Injector duty cycle at 5000 rpm i saw was 60 % .

Can this be wiring related issue ? but then again as soon as i connect stock ECU i get those limiters.

I am running out of possibilities !!!

Dynodom - 120 % dutycycle has a whole background . It is written in a thread on evolutionm.net. may be in the minimum IPW thread or

injector linearization table thread .

Is it still able to rev past 5000 when you dropped it?

no it didnt rev past 5000 but made that same noise.

So the rev limit is working, it's just not making the noise you're expecting?

I'm not at a computer so can't see your map just now, are you using the adaptive cut?

Your log shows the Limiter working? As Simon from LINK has explained. You should be looking at you time plot to see whats really happening instead of basing off a sound.

Chris - Yes using adaptive cut. 200 rpm before actual hard cut.

Ducie - Yes exactly - its working but the cutting sound is not like a stock rev limiter.

Its what you call bouncing off the rev limiter. Is this usual or unusual ?

It's usual for the Link ECU, it cuts cylinders in a random pattern to try and keep away from any one cylinder getting cut to often, it does re-introduce quickly but is still under control. If it does get out of control it is tuneable.