[Dj_Frost]

Hey everyone. I was on the streets 20 mins ago... and well, coming home I decided to punch it a bit and something really strange happened...

I hit it in 2nd gear and the rpms started climbing, when they reached around 5500-6000 they jumped to like 9000 in half a second and then bounced back to like 6000 and bounced up again, really weird.. it wasnt a smooth gain goin up and down, rather more like the needle was messed up and started moving around the place. What could this be? Thanx

 

[valheru]

the tach is fed off of the ecu.
a new ecu costs about 1200
i hear there are cheaper ways, though
have fun
mine's doing this too, but it's a link ecu and they're finding me a new chip as we speak

Matt

 

[Dj_Frost]

whaaaaaaaaaaaaattt... you gotta be kiddin meeee!!!!

So the Ecu is messed up?

 

[valheru]

don't take my word for it - go get it tested. do a search on this board (i did when mine started doing dumb things). and i think you can get them rebuilt for a "Reasonable price" or it's time for a "forced upgrade"
Matt

 

[Dj_Frost]

anyone else have any ideas on what it could be?

 

[Dj_Frost]

in case its really a new ecu i need... do i have to get the oem one or can i get another one (upgraded or something) and put it on my stock vr4?

 

[EVILTWIN]

how old is your clutch?

 

[Ruiner]

If you are still on the stock clutch @ 62,000 miles...then I am going to guess that it could be your clutch slipping.

ECU? Doubtful. 9 times out of 10 if your rpms jump when your engine is under load it is clutch related... Try this: Go out and put it in 4th gear at 60-70mph and go WOT. See if it starts to slip there as wel (rpms will go up but your speed really won't increase).

EVILTWIN beat me on this one. That was my guess as well.

 

[Dj_Frost]

But it didnt just jump up... it was like... umm *tilt* lol.. it went up and down and bounced around....

My clutch is like 5000 miles old, an ACT, not stock, look at my sig

 

[awild]

I would put more money than I have towards a bet that it is the clutch.

 

[Dj_Frost]

Really? Damn....

but from what i've heard ACT isnt a POS product.... i heard it was really good.
And I havent treated it badly either...

Couldn't it be something else?

I remember once when the rpms did jump, but ONLY upwards... from 4000 to 6000 and that had to do with the clutch cause it was the stock one and was quite wasted already. And well.. it was, had to change it in the next couple of weeks cause it suddenly died and had to call a tow truck. heh.

 

[Ruiner]

Maybe you can answer me this:

When the RPMS jump or does whatever, are you basically trying to accelerate? Is your car under load?

Maybe the clutch was just defective. Maybe it was installed wrong. Maybe it wasn't broken in properly. However, the assumption that it is the ECU would be one of the VERY last things that I would look at...

Could be a signal wire getting messed up, perhaps. Could be a few things...

 

[flyers1470]

Was it just the tach needle bouncing around or could you hear the engine reving with it too? Did the needle really go to 9000 or are you just exagerating a little? The engine itself can't rev past 7200 RPM's on stock ECU so that means if the needle went to 9000 then could be the ecu (but like Ruiner said that's doubtful). If the engine was reving along with the tach, then it's gotta be the clutch.

 

[Dj_Frost]

No, I didnt hear the engine rev up... it was just the needle.
At the time this happened, i was accelerating. I had the pedal to the floor.

YEP.. it went all the way to 8500-9000 and bounced off. It was just so fast I didnt see which number it exactly went to.

On the stock ECU the car wont rev past 7200rpm? i've done 7500 before if I remember correctly. I'd have to check that.

Also remember my 3000gt vr4 isnt a US spec one... its a really weird/unique one. For info see post (http://www.3si.org/portal/forums/showthread.php?s=&threadid=103576)

 

[awild]

yes was it just the needle jumping or your engine too?

 

[Dj_Frost]

I did not hear the engine jump. Just the needle.



uh oh

 

[awild]

Well just the needle means that it isnt the clutch. Did you recently change gauges or ever take that needle off?

 

[Dj_Frost]

Nop, Stock gauges..

 

[valheru]

awild
since i came up with the ecu and you bet more than you have that it is the clutch and not the ecu, i'll take monthly installments of $2000 until you're paid up

Matt

 

[awild]

How do you know I have more than $2000?