Allright guys... Chalk this one up as a new one for me.. Last night I was driving around and I noticed my redline seemed it crept up awful fast...I did a full throttle run from 2nd gear, and my car is hitting the rev limiter at about 64-6500 rpms!!!WTF!!! I have a stock ls computer with a stock ls/turbo setup..I am using a fmu setup right now, and the car had been running great...My w/b stays in the 11.8-12.2 area, and my plugs look fine....But make no mistake this is NOT detonation or a misfire....The car pulls perfectly strong and solid up to 6500 rpms and then hits the rev limiter...You can definitley tell the car is being cut short 500 rpms...I figured the easiest thing to do would be to switch my ecu with a friends, so I will probably try that first....Oh and there are no cels, or stored codes in the computer...Any help on this would be greatly appriciated!!!!

 

are you sure your tach is not off? Plus I thought stock ls redline was 6800 not 7k

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by underpressure02 &raquo;</TD></TR><TR><TD CLASS="quote">are you sure your tach is not off? Plus I thought stock ls redline was 6800 not 7k</TD></TR></TABLE>

Well if the tach is off, than it just started to be off in the last day or so...I guess it could be, but it really feels like the power is falling off very early as well...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by underpressure02 &raquo;</TD></TR><TR><TD CLASS="quote">are you sure your tach is not off? Plus I thought stock ls redline was 6800 not 7k</TD></TR></TABLE>

redline according to the gauge says 6800, but the actual rev limiter isn't until about 7200.

 

datalog a run and see where it cuts out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">datalog a run and see where it cuts out. </TD></TR></TABLE>

Hes only running the FMU now.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kabaroo &raquo;</TD></TR><TR><TD CLASS="quote">Hes only running the FMU now.</TD></TR></TABLE>
well he shouldn't be

 

ditch the fmu and get a real fmu . Back to a ls swap huh?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">
well he shouldn't be </TD></TR></TABLE>

My tuning sessions get a little gangsta, ask anyone who knows me...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by roydogg &raquo;</TD></TR><TR><TD CLASS="quote">ditch the fmu and get a real fmu . Back to a ls swap huh?</TD></TR></TABLE>

Whats real fuel management?? I thought there were only afcs, and fmus???

I took the car out again today and the first few times of wot it was fine, and rpms were back up to normal...After about 15 minutes or so of driving and boosting, it started happening again, this time around 66-6700...I think whats going on is that my injectors are locking up...Anyone have any expierence with injectors doing this and what it feels like??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by underpressure02 &raquo;</TD></TR><TR><TD CLASS="quote">are you sure your tach is not off? Plus I thought stock ls redline was 6800 not 7k</TD></TR></TABLE>

Verified tach with another one today, and its dead on...So its not that.

 

I am willing to bet its an ignition problem. When my friend was running a hacked and messed up distributor he would have ignition problems after driving it for a little while. Also what is your plug gap?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">I am willing to bet its an ignition problem. When my friend was running a hacked and messed up distributor he would have ignition problems after driving it for a little while. Also what is your plug gap? </TD></TR></TABLE>

I am running an msd btm, but all the wiring is clean and correct...Plug gap is at .30 (gapped with a feeler gauge).. Also I am running 10-11 psi of boost w/ stock injectors, inline pump, and 255 hi press. intank...As mention a/f is in the 12.0 area..

 

my turbo type r did that to me..would run great ,even in boost,right up to about 6 grand then started breaking up..i thought it was the rev.limiter..after a day of wtf i found that the coil way going bad...it looked fine.but i put in a new one and the problem was gone..good as new..well just my 2 cent.
could also be your ignitor...

 

was the car at normal operation temp. if not thats usualy why. the ecu will retard the timming, dump more gas and even lower the rev limiter. might also want to put in some bigger injectors.. 10 psi with dsm 450 cc injectors have a high percent duty cycle. heh the stock ones are WAY maxed out.. they were prolly maxed out around 6 psi.

 

My car was at normal operating temp when this is happening.... But the longer I drive it, the worse it got...

 

Tried re-gapping plugs, switching the coil and ignitor with no luck at all... Also, I ruled out the injectors locking up because I free reved the car in neutral building no boost, and it still cut out at 6500....This is very strange, and has me baffeled right now...The strangest thing is the longer the car runs, the more the rev limit drops...After the car fully warms up it revs to 7200 like it should, and the longer the car runs, the shorter the rev limit gets...Can someone please elaborate a little here...

 

I've never heard of anything like this before frank. Hope you get it figured out. If you need anything just LMK, I'll do my best to help.

Phil

 

try swapping on a distibuter from another car.

 

same problem happened about 2 months ago to my teg. The longer I drove the car the more it won't sputter like as if I'd hit boost cut and this would happen at part throttle or wot. thought it was a ignition problem so I just changed the rotor & cap but it'll still sputter so I changed the battery and it all of a sudden stopped ( ?). **** was getting really annoying driving in the city and everytime you get on the gas it would feel like you've hit a brick wall at every stop sign taking off .[QUOTE=99lspwr]

Whats real fuel management?? I thought there were only afcs, and fmus???QUOTE]

You gansta with your ghetto setups . **** as long as you make powa right dogg .

 

Sounds like ignition gremlins are attacking you or your alternator is not putting out enough voltage at that RPM, Which will make your car stumble because you cant produce the voltage to build up the primary in the ignition, which the ecu will see this and send the car into an early rev limit.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaguyef &raquo;</TD></TR><TR><TD CLASS="quote"> I've never heard of anything like this before frank. Hope you get it figured out. If you need anything just LMK, I'll do my best to help.

Phil</TD></TR></TABLE>

Thanks man, I appriciate all your guys help and suggestions...I will most definately keep you guys posted when I get this fixed...I am hopefully going to be swapping ecus and distributors with a friends tomorrow to see if this helps....At this point I am now leading to believe its a distibutor problem, but who knows....Man, its funny all my local friends thought I was crazy until I showed them the problem, and how it got worse the longer the car ran....This is a freaky one....Got me real pissed off at this point.....I will keep u guys updated tomorrow..

 

By process of elimination, it looks like as of right now it may be leading to a faulty msd boost timing master...My buddys took a **** this weekend too!! See what happens when I try to do old school management!!

 

stop being cheap and get a real fmu .

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by roydogg &raquo;</TD></TR><TR><TD CLASS="quote">stop being cheap and get a real fmu .</TD></TR></TABLE>

Oh, you must mean the adjustable vortech fmu...huh??