Neptune RTP as engine management, rev limit @ 7600 (fuel cut) Forged H22

On the wastegate spring (11psi) it will hit rev limiter (first/second gear when full boost hits and gets instant wheel spin) and it will recover as it should (one bounce, maybe two off the limiter)

If I turn on the controller (PWM set @ 16psi) and the same thing happens (obviously more violent and happens very fast) it will backfire as if I'm on lanuch control/anti-lag and I will lose ALL throttle response for 2-5 seconds. Boost gauge registers throttle movement (WOT will go to zero but not into boost) and the engine will decel as if I was coasting in gear. It's like it completely cuts off fuel AFTER the rev limiter deactivates.

Now before you say "stop bouncing off the limiter!" I realize that, but this shouldn't happen either way.

 

Do a datalog of your tps and map.

Sounds like an electrical problem

 

Do you have a soft limit set up as well? Sometimes if you're inbetween the soft and hard cut this can happen.

Also sometimes there's a setting in the limit (depending on ems) that sets a recovery rev limit or time after you hit the hard limiter. This basically allows the motor to recover after it hits the limit so you don't bounce off of it and potentially damage something.

It's like if you hit spark cut or fuel cut it basically says after the cut is hit wait till this rpm/tike point to resume fueling/spark.

I haven't really played around with Neptune much so I'm not familiar with the different settings.

 

No datalog yet, but here are my limiter settings. Haven't messed with them at all

Vtec is at 5000

Low cam restart 6500
Low cam limit 6600
High cam restart 7500
High cam limit 7650

Cut Fuel (not ignition)

 

I think I had a sort of similar issue with s300, but it was caused by the power reductuon being set to none vs full. At none, it would smack the limiter at full power, cut back completely, then hammer back into it. I set it to cut full power at the limiter and now its like a machine gun since it bounces quick now.

I would try bumping the 'resume' limiter higher. That might be part of the limiter power cut. It smacks the limiter and doesnt recover till it hits the resume point

 

sounds more like boost cut. neptune will shut down the engine if you hit boost cut (or some other protection limit). why are you hitting your rev limiter anyway? you should be shifting before you hit the limiter so you're not losing acceleration.

 

I've hit boost cut when I melted a wastegate line, it isn't the same. I really need to get a datalog/video of it happening. It's getting dyno tuned in two weeks though, so hopefully he can address that.

My tach has been freaking out lately, goes wild above 6k (datalogs read RPM fine, just the tach signal is bad) and I have nothing besides my CEL shift light to go by after that. 16psi in 2nd gear isn't exactly easy to keep from spinning lol

 

It does sound like boost cut. A datalog will tell you.

 

WTF bro. You've been on the forums for 5 years. If your foot is more than halfway to the floor and you haven't tuned the car, we're not ready to have a conversation.
Come back in two weeks.

 

AFR's have been dialed in on the street. Just because it hasn't seen a dyno doesn't mean I'm rolling around untuned, this ain't my first rodeo lol. Ignition is untouched, except for 1.5 deg. retard per psi. Trying to work out all the bugs before I drive 6 hours to my tuner. The less dyno time I have to pay for, the better

Anyways...haven't driven the car since I last posted, will try to get a datalog

 

Your tuner will probably respect that too. Personally I'd give you a discount for making my job less of a pain in the ***.

 

So I figured it out. Combination of two things:

I pulled THE BIGGEST Honda noob move ever...I'll give you a second to guess...the one thing everyone has at least once forgot to do on an engine replacement... Tighten the damn thermostat housing ground!

Unfortunately, I discovered this too late, and it smoked my ECU. New ECU is in and running better than ever. Normal rev limiter, no cutting out of any sort. Car runs 100 times better than before with ZERO map changes, only fixing that ground.

Second, I do believe it was barely grazing boost cut. Built boost fast enough to where my electronic gauge didnt register it, but the map sensor did. It was set @ 16psi when I thought it was at 18. Datalog showed hitting 16psi when the gauge only registered 15

Figured I'd update this for anyone interested. I appreciate the help guys!

 

thanks for the update! it's so easy to forget that ground, I've dones it a couple times myself. not exactly the best design for a grounding terminal though IMO

 

Interesting . I just had exactly the same thing happen to me at an IFO event . I hit the limiter hard in 1st and 2nd gear and then it just died . I pulled the log and everything was normal except the injectors were shut down and the rev limiter was activated . It however was just dying and not bouncing off the rev limiter . Grounds are good as is wiring . I think it could be distributor related or something in the settings with the s300 .

 

That's exactly what mine did too. It would hit once, then die. Zero injector activity. Check your boost cut and rev limit settings. Use fuel cut, not ignition cut.

 

Hondata only has the option for fuel cut, or fuel+ignition cut.

The reason is doing an ignition cut but not fuel cut runs the risk of washing out cylinders, and burning up components when the ignition cuts back in (making a big bang)

 

Sorry, I meant it the other way around! edited