williamreinecke

Hello folks, I have a "situation" I would like the group's help with. I accidentally hit the rev limiter in 2nd gear today. Now the car feels a bit sluggish, and the power cuts out at 4,000 rpms. I checked the distributor belt and it seems fine. As I recall, the rev limiter is basically a fuel shut off. Could there be something wrong with the fuel system? Would a quick battery disconnect cure the problem? Thanks!

Gary R.

How did you HIT the limiter, downshifting into 2nd by mistake going 90MPH or just winding 2nd gear out? BIG difference...

williamreinecke

I hit it on the upshift, not a missed shift. Thank goodness!

Heirsh

Unfortunately I have to admit I hit my rev limiter occasionally.

I'll go hang my head in shame now.

I havent had any problems that I know of arise from it.

dfinnegan

I've been above 6800 rpm, but I don't know what my rev limit is! I have an after market chip and I believe it has lifted the limit. On one occasion I went past while accelerating. I thought I was in third, but I was in second and I went above 6800rpm. 7000, possibly a touch more. I've had not problems that I'm aware of.

springer3

You are correct that the rev limiter only shuts off the fuel. It sounds like you sent the DME into limp home mode. If that is the case, a battery disconnect should re-set it as long as the fault is not real. It may be time to get "hammered" to see what the DME thinks the problem is. The only other choice is mechanical damage or jumped time due to the overspeed. If the rev limiter kicked in where it should, I don't think there is any chance the engine is damaged. I have hit the rev limiter on occasion and not been fearful or suffered any problems. I think the stock setting is pretty conservative, but if you had a component ready to die, the overspeed might just have been what sent it over the edge. Good luck and keep us posted.

LouZ

I have a Tip, and when DE'ing, it generally bounces off of the rev limiter before it shifts. There is no correlation that hitting the rev limiter will cause a problem (it's there specifically for avoiding a problem).

Generally too high of a rev (+++7000), something in the valve train goes amiss, rocker, spring, etc. This shouldn't be the case in your situation.

Did you immediately have a loss of power at 4000? Was the problem after a stop / restart? Any noise or smoke eminating from the engine?

You state that you checked the dizzy belt. How? Are you sure that the secondary is firing?

skruggs964

Ouch! I feel guilty if I take it over 4000 rpm.....which doesn't happen very often...

Tom W

Simply hitting the rev limiter prior to an up-shift is no big deal and will not hurt the car.

You know it was the rev limiter (the gas cut out and the car sort of sputtered) as opposed to something going wrong while the revs were climbing?

X2Board

Sell me your car so I can drive it the way it was meant to be driven

X2

Rick964

You don't the know the fun your missing then. These cars really come alive over 4000 revs.

911addict

Do all 964's have such rev limiters (ie. that cut the fuel resulting in loss of power)?

If it doesn't work (like on my 965) then is it disconnected?

springer3

Don't feel guilty. First of all it is fun. Second, it is good for the engine. Always wait to be fully warmed up, but you should take the engine to full power every drive. If you have not been doing so, carefully increase the RPM and power over many drives until you routinely take the engine to high power and RPM settings. Here is why:

1) You need maximum RPM to condition the upper cylinder walls where the rings stop between each up and down stroke. I have seen two examples of engines with broken top rings caused by impact with the upper cylinder deposits. Regular runs to the upper range keeps the cylinders free of deposits.

2) Your resonance flap is dead weight if you don't use it (opens around 5500 RPM IIRC).

3) You need to make power to get the engine hot enough to drive off condensed blow-by acids. Failure to boil off the acids can lead to stuck rings and other corrosion-related problems.

4) You need high power settings to blow out the combustion chamber deposits and keep the injectors clean.

5) Regular high speed operation of the cooling fan will help prevent dirt build-up on the cooling fins.

There really is no down side unless, of course, you are observed by the highway patrol. The Alabama troopers got me Friday on my return from some business in their fine state.

DrJupeman

If it encourages you any, Porsche specifically recommends in the manual a run to redline at WOT in first gear every time the owner drives a C2 Turbo!

jimq

I have tried to do it in my TIP but it always shifts up on its own a couple hundered short. I tried it in manual mode and still havent been able to do it. Maybe I need it on the track so it "learns" not to shift in grandmaw mode