Gents,

Took my 996TT for government required e-test.

Directed both the tech and the manager twice that the vehicle is AWD and to perform two speed idele test with exhaust sniffer..

I return from lunch and see my car on the 2 wheel drive dyno in 3rd gear at ~30 mph. Only rear wheels are spinning. I'm not happy with - lost my temper.

Damage to front diff / viscous coupler / awd system? I'm told that they turned PSM off.

Thx!

 

Quite possibly. This link is from an old thread. Why not show it to the test station and ask them if they now understand why you lost your temper.

http://blog.titanmotorsports.com/?p=293

 

Anyone else? I'm sure most members have had their car smog tested...

Keep in mind this is a 3rd gear at 3000 rpm test, not WOT.

Perhaps I should refer to the owner's manual.

Thx!

 

Here in california they do not set the cars on a dyno-only rev the car in neutral. They do have spot check points sometimes where they have a 2wd dyno, but AWD cars are waived for obvious reasons. I would get the car checked and if any damage - hand them the bill. PSM means nothing - at least 5% of the power was going to that differential which was fixed in place.

 

sounds like you'll be getting a new front diff from them. it doesnt matter if they turned PSM off or left it on. wow this is unacceptable.

 

WOW...subscribed, I love how government mandates that we do this or that, but they CAN NOT GET A COMPETENT PERSON TO DO THE Fing WORK!!! Especially since you told them 2 times that it is an AWD car, you CAN NOT USE IT ON A 2wd DYNO!!!

op - make SURE you bring it to Porsche and have them check EVERYTHING that is associated with testing the front diff, then send that shop the bill!

 

I'd document the FACTS:

1. The station has ONLY a 2WD dyno.
2. They completed a dyno test on the car.

What you told them is moot, they'll just say otherwise.

It is their obligation to determine the configuation of the car. They have access to the VIN, they can put it in the system and get a go/no-go for a 2WD dyno. If they don't have such as system, I'd argue that they're negligent.

Stupidity equals negligence and negligence is compensable if you have damages. Since it didn't explode on the dyno proving damages is the difficult part. It would be interesting to hear what a Porsche mechanic thinks about this. Excessive wear? Early failure?

 

I live in Denver and here they use 4 wheel dynos for the smog test on all the 4wd or awd cars. I have a Audi quattro and a Lexus SUV and both of those were run on the dyno with a sniffer in the pipe. When I brought my 996tt to them to do emmisions they told me that in Denver they no longer put these cars on a dyno because they have fried several front differentials and had to pay to get them replaced. They now do just a stationary idle test which was just a sniff test of the tailpipe while that car sat there at idle. There are only a handful of awd sports cars including the 996/997 awd cars that are exclude from the dyno test...

My bet is that these guys owe you a new Porsche differential......Good luck...

 

The challenge is this... There is nothing to inspect as everything is internal. My mechanic suggested swapping the fluid out to check for metal bits. I'm documenting the case now and serving them tomorrow.

 

See if the dealer will go after the testing center. They're qualified to say that there is probable damage, and they may have been through this before. Perhaps they can invoice the center for an inspection and then for whatever is damaged inside there.

You may be able to cut yourself out of the billing process if you're not the middle man.

 

Test only shops in Cali seem to get it with AWD cars, but to be safe I remind them and have it put its AWD on the sales reciept before the test and watch them test it. So for no problems. Tested at 10% of maximum in all catagories. Very nice Vietnamese couple own the shop and there are always a few exotics there waiting to get tested so they must get it. The wife is really funny. She hands you your smog certificate likes it's your college degree.

 

All underbody shrouding was removed. Everything was visually inspected. All fluids swapped. Fluid completely clean (like new). No damage. It's all I could do!

 

glad there was no damage...there is one more thing you can do...next time take it somewhere else

 

This is a slam dunk for a litigation lawyer if you have proof they actually did run it (like a test result sheet with the information, photos, other). The lawyer will take it happily, win the case or get a nice settlement for the damage done to the car even if it doesn't break today it's likely to break soon, possible leaving you stranded in a dangerous situation.

Lawyer up and see this one go your way.

 

This wouldn't have damaged the front diff or crownwheel and pinion as not enough torque will have been transmitted in the above test.checking the diff fluid will tell you nothing.

What it will have done is given the viscous coupling a very hard time.The viscous coupling is located in the rear part of the front diff housing.It is a sealed unit and has its own special fluid inside.Its job is to transmit drive to the front diff,it does this via plates that are surrounded by the special fluid. If the front wheels are prevented from spinning as in your case the fluid will heat up very rapidly as the energy fed in is turned to heat,if this happens for too long the fluid and plates will be damaged resulting in the coupling not being able to transmit the correct amount of power to the front.

If this has happened you probably wouldn't notice if you don't drive the car that hard ,but the symptoms would be the car wheelspins more in the wet and feels like it wants to go sideway more easily. This is because you will have lost some of the drive to the front, you might even be completely rear wheel drive.

Porsche have a test they can do to make sure the coupling is working as it should,they put the car on rollers and drive the rear wheels at a slow speed of 3 or 5 mph (slow enough to make sure the coupling doesn't get too hot)and then measure the force at the front wheels. They compare the results to a graph to make sure it is correct.

This is the only way to be certain no damage has been done

Hope this is not too confusing