Chris(MA)

Incidentally I just heard back from a job app I applied for, so texted an offer on a car I already went to see/drive. I'll see what the guy comes back with

5CHN3LL

Makes sense. There are some reagents you can get to determine what kind of biological remains are oozing out if you're worried that it might be something worse than mice. Like ferrets. Those little bastards are BRUTAL on cylinder walls.

DreamCarrera

No, unfortunately it doesn't seem to have an end in sight.

Many of the 996ers on here remind me of Chicken Little with some of the vendors playing the role of the sly fox who takes advantage of them...the other thing that sometimes comes to my mind is the old cliche; "a fool and his money..."

hitthecones

Exactly my point! There are certainly a few vendors capitalizing on fear. I refuse to fall in line with the thinking that Porsche grossly mis-engineered this product and that the aftermarket has it all figured out.

I love the aftermarket, however, the validation requirements do not even come remotely close to what the OEM demands. There is no comparison.

docmirror

IMNSHO, Porsche did grossly mis-engineer the M96 engine. In fact, the courts have said so with the(lousy) partial make-good lawsuit. Further, engines which score bores so easily and have a grenade in the IMSB are two examples of poor engineering, or very poor mfg.

I've seen the run-out results on some of the IMS parts in another thread. They are - horrible. I have no idea if the engineering spec was so loose, or if the mfg was so sloppy but these are bad numbers. Shameful that the M96 engine was not taken out of the market, and better designed by 2001 at least.

There's a budding relationship between scored bores coming along and high fuel consumption. I'm speculating that maybe a injector/MAF/FI problem could lead to one or more cyl getting the oil washed out. Thinking that if one starts experiencing poor fuel econ that it's not being a lead-foot, but possibly the stoichiometric ratio may play a part in this.

DreamCarrera

Really? You think "the courts have" spoken on this topic? You are not too knowledgeable of the law I see...

docmirror

It is what it is(or was what it was). I don't need a law degree to know that Porsche agreed to some kind of remediation for owners with prematurely failed engines.

BTW, I'm 4.5 for 5 in my civil court appearances(one no decision), and the prosecutors are 0 for 3 in criminal court, so - seems I'm not doing too bad.

BlackSlacks

that.....is awesome

pdxmotorhead

If anything is going to really cause bore scoring its most likely leaky old tired injectors..
Rings like Oil on them not gasoline.
Standard injector life is around 80K average last I checked, They get progressively less
accurate after that, and that assume you didn't get a load of dodgy fuel at some point.

Good Luck

NuttyProfessor

So basically what you're saying is Lokasil, piston pin offset, forged pistons, deteriorating skirt coating, piston slap, and cold climate impact are not contributing factors to cylinder bore scoring in these engines? It can all be contributed to faulty fuel injectors?

pdxmotorhead

I believe a lot of way too much over-thinking goes in to certain problems.
And on a 20 year old car with relatively low miles, bad injectors are a higher percentage
cause of failure than potential mis-engineering considering how many cars make high miles,, its not all luck..

All of the factors listed can be contributors to the issue, but testing your injectors is a fairly economical
preventative maintenance item. Personally I've seen enough injector initiated piston fails that Its my
first check.. Before going all in on the rotating assembly..

I used to have access to a shop with a cleaning station, I went and grabbed a bunch at a
u-pullit yard to see what the spray patterns looked like.. More than half the sets I tested had
at least 1 bad injector in the bunch.. I went after 7 year old cars for the test units..

AnthonyGS

I’m always amazed how lay people think. A fuel injector will see millions of cycles in 7 years of driving and fuel isn’t the clean fluid it is thought to be. To think there is no wear in the injector resulting in leakage after shutoff with heat cycling and 50psi pressure differentials is insanely optimistic at best. I’m just a stupid $350/hr consulting engineer though.... I’ve never thought about problems like this.

The main reason people have ridiculous expectations surrounding these engines is the word “Porsche.” The expectations imposed on these cars by their ill-informed owners and prospective buyers IS THE SOURCE of paranoia. Sorry, I’ve met these evil vendors. They aren’t making exorbitant profits or spreading panic. They are actually working to solve problems to maximize the enjoyment of cars they love. The M96/7 and Porsche’s are not big profit sources for small businesses. They are labor’s of love. If you are looking for profiteering unethical businesses look to payday loan places and hedgefund managers, etc.

NuttyProfessor

In that case, wouldn't it be easier to just say, "screw it!" and replace the injectors after a reasonable service life? How would a 996 owner test an injector that doesn't have an Durametric? Can they be removed like on normal cars?

pdxmotorhead

You could say yes,, and be right.. Takes a couple hours to swap the injectors,, new ones every 80K ish,, not going to hurt a thing.
You might even notice a pickup in mileage with nice tight new injectors as well.

One issue is injectors have different failure modes, electrical/mechanical/clogging
The durametric + good troubleshooting skills will usually find a electrically failed one quickly.
Clogged injectors, will run you lean and you "should" get a check engine light if bad enough
durametric/pwis/scanner while running should show a lean condition..
A leaking injector (Mechanical fail+clogging) Is often less obvious, because the 3
cylinders share 1 O2 sensor, and its less of a problem at open throttle, the damage
occurs at mostly lower RPM (In my experience) when the injector drools raw fuel in to the engine,
washing down the cylinder walls. Worse yet on the Porsche engine,, the injector can drain after shutdown
straight in to the cylinder and then it soaks in fuel till the next startup or worse the fuel dries up leaving
varnish on the cylinder wall.

I see this a LOT at the track because a lot of race cars end up with used/old injectors because
for the most part racers are cheap bastards when buying certain kinds of parts,, its weird,
I've had a guy insist on a 2500 dollar titanium bolt kit, then bitch about the cost of rebuilding
his fuel pump (175 bucks)... Also installed a $35K engine,, and the owner would not buy
a new set of injectors for < 800 dollars.

As mentioned back a ways, I also send the injectors to get flow tested even if brand new,
DOA injectors are a thing.. Unfortunately..

Oh and if I've got the timeline right doesn't the water-cooled intro from Porsche coincide
with Bosche moving most all of their injector manufacturing to China?? (Coincidence? Hmmm.)

A misbehaving injector can also cause one exhaust tube to run significantly different
temperature, so a IR heat gun can give you a direction to look..

Cheers,, good discussion I hope!

JTT

pdx, where would one send an injector for flow testing? Your idea sounds very reasonable, if they are accessible and inexpensive enough. This is all new to me, so trying to learn what I can about these injectors. Thanks