NO rev limiter??

[Kooldino]

Ok, so on occasion lately I was running too rich and borderline stalling out. So I'd drop it in neutral and floor it just to help burn the extra fuel. It would studder for a few seconds and not make it past 4K, and then all of a sudden, rev high and stop studdering, at which point I'd let off the gas and let it idle at stoich.

However, a few times when it finally broke free of it's 4K RPM studder, it would INSTANTLY rev to ~8K. That can't be good. I'm guessing that the MPI has something to do with it...any input?

 

[Bigg Tim]

Do we have one stock?? I can't see how the MPI would affect it if there is one already. Lets have some FACTS on the limiter if we have one.

 

[acidbug]

MPI tuner don't raise rev limiter. It could..but nick has opted not to do it!

Could your stock injectors be stuck open?

Chas

 

[changedman]

i know the mp3 has a rev limiter. I've hit it many times.

 

[SpicyMchaggis]

Good question dana, mine does the same thing..It revs wayyyyy too high..

 

[mp5jeff]

the rev limiter is at 7200 i thought...

 

[p5sundevil]

yah the MPI wont raise that in its current state, i assume in the NA version of it it will since that is almost necessary, which also means it can be done....maybe a glitch in it?

 

[MPNick]

Ok, so on occasion lately I was running too rich and borderline stalling out. So I'd drop it in neutral and floor it just to help burn the extra fuel. It would studder for a few seconds and not make it past 4K, and then all of a sudden, rev high and stop studdering, at which point I'd let off the gas and let it idle at stoich.

However, a few times when it finally broke free of it's 4K RPM studder, it would INSTANTLY rev to ~8K. That can't be good. I'm guessing that the MPI has something to do with it...any input?

Yes it does.

 

[acidbug]

Yes it does.

What kind of answer is that?

Does it indeed raise rev limiter? If so...to what??

Chas(scratch)

 

[smp3000]

woa I'm confused!

 

[Kooldino]

Do we have one stock??

Of course we have one stock. Every modern car I know of does from the factory.

I can't see how the MPI would affect it if there is one already.

Well, it intercepts the RPM signal. So that shows that it COULD right there.

Lets have some FACTS on the limiter if we have one.

Some facts? It cuts spark and or fuel at ~7200rpm. That's about all there is to it.

 

[Kooldino]

Could your stock injectors be stuck open?

Maybe, but I somehow doubt that's it. That's kind of hard to test though.

 

[Kooldino]

Good question dana, mine does the same thing..It revs wayyyyy too high..

Do you have an MPI?

 

[Kooldino]

What kind of answer is that?

Does it indeed raise rev limiter? If so...to what??

Chas(scratch)

Yeah, what Chas said.

 

[PaulMP3]

Mine still had fuel cut around 7k... i hit it a few time in 1st with heavy wheel spin.

 

[BradC]

MPI tuner don't raise rev limiter. It could..but nick has opted not to do it!

Could your stock injectors be stuck open?

Chas

But wouldn't stuck wide open squirters make it fall on its face. Without the air to support the crazy rich mix it would just bog to hell/stall, right? Vaccuum leak somewhere??

 

[acidbug]

But wouldn't stuck wide open squirters make it fall on its face. Without the air to support the crazy rich mix it would just bog to hell/stall, right? Vaccuum leak somewhere??

Which is exactly what he is saying..the car is idling bad..and falling on its face until he get's his rmps up & above 4k..

Chas

 

[Installshield 2]

I haven't looked into this in a very long time...But it is indeed lower than 7200 rpm from what I remember...its a problem with the accuracy of the stock tach...I remember some MP3's and P5's bouncing off one at 6900rpm on a dyno, and claimed their tach was saying over 7200rpm...

In either case, I thought we had a fuel and ignition cut limiter...that could vary with load slightly...meaning it was not the exact same rpm cut in every gear...I know I have hit mine in third a lot lower than my tach reading of 7200rpm...but in first I can wind well into that before bouncing off anything...

So with that said, there is something confusing...the MPi tuner is controlling fuel and spark correct? When the triggering system sees to high engine speeds, it immediately pulls spark, and then fuel (so you don't ignite a lean mixture)...If the MPi is taking over this triggering system affectively, it may scew that system...but then you would be able to set a specific limit, at least I would hope so...Is there anywhere with the software to do that?...If you can't, I would hope it would keep your stock limiter in place...

 

[Installshield 2]

Now what is going on with your secondary injectors? forgive me for still knowing little about this system...but I assume for idle and low-load those are supposed to do nothing...and not spray any fuel...

and once load and engine speed, as well as boost, increases...the secondary injectors begin to help keep the mixture in the proper A/F range...Could your secondary injectors be clicking on at idle and low load...then you blip the throttle for a bit to clean that crap off, and the system wakes up and turns them off?

Also I saw you are running a WB02, are you able to set target a/f's at all engine loads? are your settings staying accurate within the software, even though it is obviously overly rich at idle?

Sorry for all the questions, just trying to get an idea of what is going on...

EDIT: Its unlikely that your injectors are sticking open by the way...possibly the secondary ones, but sticking primary injectors will almost immediately puddle the intake ports and stall the engine...if it is just idling badly, and being very lathargic at low rpm, but comes alive above 4k...its most likely very closely related to those secondary injectors...

 

[Kooldino]

I am running a WBO2. I tune so I'm in the mid 11's A:F ratio wise.

My additional injectors comes on when I hit boost.

The problem where I go stupid rich is ONLY off of boost, and I can't figure out why. Part of the problem in figuring it out is that I can't reproduce it. It's totally random. It happened yesterday for a minute in stop and go traffic. Today I drove for 2.5 hours, mostly highway, and didn't have an issue. Saturday morning I drove highway for 1.5 hours and it happened once, and was horrible. I almost stopped moving on the highway.

It's not due to a bad O2 sensor, as I replaced it to try to diagnose.

But regardless, I'm still overrevving. Does anyone know HOW to set a rev limiter in the MPI tuner software?? Nick told me awhile ago that it would not interfere with my stock rev limiter while it obviously is...