mcandmar

Hello everyone,

We recently bought a 1994 993C2, car had a few issues with hesitation and inconsistent performance. After we dismantled the intake manifold we found leaks around a few of the intake runner seals, cleaned the ISV and fitted a new O2 sensor and POS units which transformed the car. No more hesitations or miss fires. We do still have a flat spot just before 4000rpms, it feels like the ECU is holding back, then it recovers and the power comes back. Engine runs nice and smooth at low revs, very progressive throttle, and equally over 4000rpms on the power band it builds power in a nice linear fashion.

Question is the bit in the middle, is this normal for a non varioram car to have a flat spot in the mid range, or is there still something not quite right we haven't found yet?

Unfortunately i have never driven another 993 so i have nothing to compair its performance against.

Thanks,

Mark.

Stealth 993

Yup, they are known for the flat spot, get it chipped & it will almost go away.

shamrock

Hi there Mark,
Good to see another 993 driver logging in from Dublin!
Are you doing the work on the car yourself?

TheOtherEric

Look at a dyno plot and you'll see that the flat spot, or dip, is normal in the (roughly) 3000-3500 rpm range.

AOW162435

Mark,
I typically check my voice mail when the car hits the flat spot.


Andreas

rconnon

mcandmar

Thanks guys, good to know its a feature and nothing to worry about.

@Shamrock, my dad and i always work on our cars ourselves, though with this car we did leave it into a Porsche specialist to inspect before we bought it. It was more for piece of mind having somebody who knows the cars take a look at it. We have never owned a Porsche before so were learning as we go.

We are also going to join the Porsche owners club here so maybe we will bump into each other at the next meet

Cheers,

Mark.

shamrock

I'll look forward to that Mark , sounds like you're well versed on the oily bits too .. top man , wish I had your knowledge .. See you out there.

Eta .. Will you post some details of your car when you get a chance? .. Did you buy the Porsche Club presidents old car??

mcandmar

I think it is, name rings a bell. I found a pic of the car on the club website...

Mark.

shamrock

Yep I'm fairly sure that's his car .. Congrats , it was looked after very very well .. By a Porsche shop he knew very well .. His brother's!!

Eta , I believe there's a 993 registry about to be started in the Porsche Club of Ireland .. Hope you log on after you join up!

mcandmar

Hello again,

Just thought i'd post an update to this thread. After much poking about we discovered one of the ignition coils was dead and had shorted out an ignition module too. Basically the car was only running on 6 spark plugs since we bought it. Everything is sorted now and its purring like a kitten

Cheers,

Mark.