TTRon

I have '96 993 Twin Turbo for five months now, and the car is nothing short of fantastic!

Recently I've noticed that when accelerating through third (5-6000 rpm) and fourth (4500-6000) the engine seems to run a little rough....not smooth like you'd expect.

I'm using 91 octane (live in CA).
The car has 16K miles and had the 15K miles service at 12K (2K before I bought the car).

I had a '91 911 (964) Turbo and had to blow out the wastegate above 5500 rpm. Didn't note anything in the owners manual for the 993TT on the wastegate.

I'm running a Turbo S computer box and Ibox springs on the car.

Appreciate any guidance.

Thanks, Ron

Ran

TTRon, welcome to the forum.

I can't say what the problem is exactly but if I was running with the Turbo S ECU, I would also get the Turbo S auxiliary oil kit or equivalent at a minimum (it might not solve the rough engine problem but it sure was how the turbo S ECU was supposed to run in the turbo S - with additional oil cooler for additional heat - may well be overkill but thats why our Porsches last so best to keep it that way. There is also a factory powerkit option on the turbo which ups the power to about 450 hp I think. In that case too other upgrades need to go with it (oil cooler, turbo, etc.).

My point is that an upgraded chip COMBINED with lower quality fuel is best avoided IMHO. Your turbo S ecu is only good for a few more horses and may well be fine but does not hurt to play safe in the oil cooling area. And as for fuel, bigger the upgrade greater the need for better fuel - the turbo S upgrade is small of course but... I think some California people reported using a blend of unleaded 100 oct. and 91 oct. There was also some talk about using items like techron or lubry moly to clean out the gunk but I dont know if that causes what you describe. Steve or others who post on these topics might weigh in with ideas on the exact cause of your rough engine.

AND CONGRATS on your new acquisition. All the very best.

TTRon

Thanks!!

Will the aux oil kit alleviate the 7:30 to 8:30 oil temp movement (back and forth regardless of easy or hard driving)?

Ran

I doubt it (since what you are seeing is normal IMO). I think what you see is the fan kicking in taking it back down to 7:30 position from the 8:30 position. I think the fan kicks in around the 8:30 position.

The oil kit will only be good to keep the car cool in more adverse (than 8:30) circumstances. -- to the best of my knowledge of course. In your shoes, personally, I would get the oil kit because of the upgraded ECU.

EDIT: In fact, please check if your previous owner already installed the oil kit by any chance.

SundayDriver

Ron,

I strongly suggest two things:
1) Get the S (or cargraphic) oil cooler if the previous owner did not do this. When you drive hard (DE?) this summer, you will need it. Many of the S ECU's were sold in a kit that included the oil cooler.

2) You probably need to mix fuel with that ECU. I am pretty sure you will need to this summer, when it warms up. (Higher ambient temps require higher octane.) I run a mix of about 1/3 100 octane with 91. At the track, I run 100 octane.

Also a warning about the Eibach springs. If these are the Pro Kit (?) springs, they are much too soft for your car. Mine came that way from previous owner. The car is nice and cushy on the highway, but the handling leaves much to be desired. Too much roll and the car tends to rock around opposite corners with those springs and the TT shocks. I would switch to PSS-9 coil over setup, or go to the ROW M030 springs that match your shocks.

TTRon

UPDATE:
The spark plugs where loose, so they replaced along with distributor cap. This seemed to clear up the acceleration problem.

However, I think I feel a slight hesitation crusing at 50-60 mph. Any ideas? Dirty fuel injectors? Fuel filter? I would think if it was either of these I'd have a more severe acceleration / crusing problem, for this problem is very slight. The car didn't have the problem when I bought it 3,000 miles ago. Car has 17K miles.

Dumb question, does the car have any engine diagnostic ports the dealer can plug into to verify / fix what I'm feeling?

Last comment, I cannot get unlead gas over 91 octane here in Calif...at least not yet, still working it.... Can get 110 octane, but it leaded gas.

SundayDriver

I would do a Techron add and see if that helps. If you really want the car checked out, get it to Mike Schatz at Rusnak - Westlake. It is a long haul for you, but would be worth it to have him check it out. (I'd even meet you for coffee if you take it in to him.)

As far as 100 octane, I buy from 76, but according to their website, there is no station that carries it anywhere near SLO. I'm lucky with one within 10 miles of my house - I run over there and get ~15 gal in jugs and use one for each fill of 91. Try checking with a local speed shop and see if any local stations carry 100 unleaded. There are ususally small stations that carry it, but they are hard to find.

TTRon

Do speed shops or auto parts stores carry techron? I'll get it in a heart beat!

Also, what 76 site are you using for locating 100 octane? I'll check out the small stations here and Santa Maria.

I like your Rusnak idea. San Luis doesn't have the Bosch / Porsche equipment to do any diagnostics, nevermind a Porsche dealer. I'm 90 miles from Cutters, have you heard anything about their staff? Regardless, I have no problem going to Rusnak to get this resolved!

Thanks Mark!

Ron

LR993TT

You can get Techron at any Chevron gas station.

Les

SundayDriver

You can get Techron at Chevron, as Les said and also at any auto parts store. I would go the extra distance to see Mike - He REALLY knows turbos and all their quirks. If you make an appointment, make sure you specify that Mike is to work on the car (nothing against the others, but he is the best there). When you take the car, get introduced to him and chat directly about your issues and questions. You do not have to be insulated by the service writer with Rusnak and Mike.

<a href="http://www.76.com" target="_blank">76</a> has a station locator, but I didn't see anything close to you.

Anir

Ron,

Techron is a fine product, but you might also consider adding one can of Lubro Moly Jectron (fuel injector cleaner) and one can of Lubro Moly Ventil Sauber (valve cleaner) to your gas tank. Then, follow Steve Weiner's recommendation of driving 100 x 100 (i.e. 100 mph for 100 miles) . After that, change your oil.

I perform this regimen prior to changing the oil every 6K, and it keeps my car smiling like in the Techron commercials!

TTRon

Thanks for the replys!!!

I've purchased both techron and injector cleaner, just need to follow the directions and empty my tank before using it.

I may also have 100 octane gas in site. Should know in the next couple of days.

I'll head to Rusnak if all three of these don't do the trick.

I got to believe it is a dirty fuel injector since if seems to happen between 2500 - 3500 rpm running at a constant speed / rpm. Don't feel any problems under heavy acceleration.

Will do another post with the outcome.

PramTT

Station locator in 76.com:

The station locator (76.com) is not always reliable. For example, the closest 100 octane stocking 76 station to my house is only 3 blocks away and yet the station locator is not showing it but rather pointing to other stations 10-15 miles away.

I hate using the their (76) 91 octane though since it is using the same nozzle for 89 and 87. I usually buy 100octane in 76 but the 91 from Chevron. Yes it is cumbersome but . . . .

ronnie993tt

Hey folks. Just purchased a '96 993tt with 8,443 miles on it last week and thought I'd better strart using Techron. Anyone know where you can get this stuff in Canada? It may be called something else here. Thanks....