chrisper993

I've also done the above procedure as a maintenance item on my 96C2. I didn't use the compressor as long but I also plan to do this procedure every 15-20K.

I cut open with a grinder the old check valve and found an air nozzle at NAPA that had a wide enough tip to seal against the opening of the cut open valve. I was able to drive the techron through the ports. At startup lots of smoke as mentioned. It took a few miles to burn all of it out.

My car has 39k it will be interesting if I can fend off the CEL over the long hall. I rack miles very quickly so we shall see.

kkim

Wow, if the SAI passages can be cleaned w/o heat exchanger removal, what about adding a T fitting right above the SAI valve with a hose running out towards the front of the engine so you could just pour cleaner down into the SAI system w/o disassembling anything?

Simple, clean and easy.

MadMarkie

It's not that hard to drop the headers/heat exchangers.... if you soak the nuts with a little penetrating oil for an hour or two first, they really shouldn't strip the studs. DC the terminal ends from the CAT (three bolts each), DC the heater air hose clamps, and the headers drop right out. It's nice to verify flow from each port (see Kelly's recent post, my car has the same problem), and the use of more aggressive cleaners might not be very kind to the CAT (I will be shopping for J&B "with Carbon Blaster" on the way home tonight).

On the other hand, I can't think of any way the Techron would hurt the CAT, and the smoke screen must have been spectacular! Post a picture if you do it again........

kkim

Dropping the HE costs over $100 in gaskets, unless you plan not to replace them. I had no problems with the HE nuts. Mine were tight and rusted, but fortunately nothing that a 24", 1/2" breaker bar and a six sided socket couldn't undo.

There has been great concern that not removing the HE would let the flushed particles contaminate the cat, but here is proof that it isn't so.... in this case, at least.

Laura

$100 Mickey Mouse Fix? or ?...

In our humble opinion, and some experience, the method of repair descibed above by Tim is not adviseable. Running high concentrations of harsh chemicals, with bits of caron residue, through the catalytic converters and past the oxygen sensors is pretty risky. The damage to the cats may not be imediatey known but may start a matrix meltdown. The sensors may be coated and shorten their life expectancy. By not removing the heat exchangers, one has no way of knowing how many ports are clear nor access to the ports that haven't cleared.

KKim in Hawaii closely followed a procedure similiar to the one we use and his results were very positive with no risk to his cats and (4) sensors ($2500 in parts).

As an individual owner the risk vs $ may not be an issue, but as a Porsche shop trying to provide quality work, we feel it is not the way to take care of the problem.

Mark - 27 yrs owning this business, day in and day out working on Porsches.

soltino

Thanks Mark.


tino

Chris Brown

What is the expected lifespan of the (4!) O2 sensors in the US 993 Exhaust system?

Chris

'96 w/ engine out and clear SAI ports but occasional CEL SAI fault

epj993

I think it's a great idea for a periodic maintenance approach, but would have to agree with Laura, er Mark. My guess is that not all ports were cleared or were not very clogged to begin with - it's impossible to know.

As much as I hated spending a week, $200 in parts & just sheer frustration, I know all 6 of my ports are clear without the possible damage to cats or sensors. Now that it's done, I planning to replace the check valve at 10k intervals.

Coleman

I have the special fabbed wrench which fits the valve.. Offer still stands if people need to borrow it.. PM me and I'll have it sent to you.. it's been to about 10 people so far..

Coleman.

Laura

Chris,
Rarely have we seen fault codes that are directly related to a faulty oxygen sensor. We have probably only replaced a handful and some of these being damaged externally by collision, wiring... Most of the 993's on the road I would bet have their original sensors in good working order. (and if you are told all 4 are bad, they cannot find the problem and have decided to start there - the chances of all 4 going bad at one time, slim to none)

Now if you have a 996 or 986, these sensors routinely have problems.

Chris Brown

Thanks Laura, I am not eager to replace the O2 sensors at all, even less so after pricing them! I'm going to focus my attentions on the rest of the emission system used for SAI.

Cheers,

Chris

Edward

This is in no way inteded as disrespect to Tim as I always applaud and admire creative solutions, especially the home-grown variety.

The procedure sounds good, and very effective, up until the point you pour 2 bottles of raw Techron into the engine. I don't know enough about the chemistry of Techron, but I absolutely would not feel comfortable about pouring a 40 oz. of fluid into the ports, especially when that fluid was designed to be combusted in dilution, then just start the car and have said fluid (at that quantity!) potentially washing out the bores?!! Not for me, thank you. These are just my suspicions, mind you, and it is entirely possible I am entirely off base ...wouldn't be the first time. But I would be wary of taking that risk unless I knew, absolutely from an expert, that it was kosher to do so. With components and labor as pricey they are, I'd err on the side of caution, personally. But then again, I have OBDI and a single O2 sensor

Oh, and BTW, I didn't much care for the "in-your-face" tone of the original post toward Mark and Laura. Yes, it is "personal" to me as I respect them and the dedication, honesty, and cameraderie they offer to the Porsche community. If one disagrees, one can do so without spite. Moreover, the post would have been equally effective w/o the sarcasm. Not to mention such a tone berates fellow Rennlisters, not something I wish on anybody here. ...soapbox off


Edward

Tim Sullivan

Edward: My apologies to you if you took offense to my post but in my experience laughing at customers is not good for business--even if you think they are pretty darn stupid customers. Moreover, I simply suggested what at the time, I thought was an effective $100 solution to the $1,000 solution Mark and Laura offer.

Now for an update. About 3 weeks ago I took my C4S for a run down to the Chrystal Cove car show and the CEL came on. Got it back home and ran the codes (and very importantly was able to reset the CEL light successfully) with my Actron ORB II Autoscanner CP9135 (brand new for $100 on Ebay) and sure enough PO410 read out (secondary air injector). Please note that it was not PO1151/P1119 or other codes indicating a problem with the Cat 02 sensors. I'd say I drove for about another 250 miles over the next couple of weeks with limited weekend runs. As of last Saturday I had 68,242 miles on my car when I took it for a ride and once again I got a CEL light with the PO410 read out. That means I went just about 4,000 miles since the original flush job and the first, new CEL about 3 weeks ago.

Though I am mighty tempted to do what another collegue suggested here on another post and simply ignore the problem by taping over the dash CEL like he has done for the past 2 years--after all the this problem has nothing to do with the engine's performance, my engine's never run stronger-- and much to do with a silly emission control device that injects air into the intake port for a few seconds at start up, I probably won't. Even though, realistically, I could pass California DMV emissions test in a heart beat by resetting the CEL just before I drove in for the emissions test with my trusty Actron.

Was I ultimately successful with my cheap fix? Obviously not as I could only get just over 4k miles before the CEL came back on. Did I damage my Cats by using the Techron? It appears that I didn't as I've gone over 4k miles with no problems. Granted, we'll have to see over the longer term but I kind of doubt I'll see any problems as I think I would have by now. Time will tell.

Next steps: I'm going to yank those pesky Heat Exchangers off (allready bought the 8mm HE nut removal tool at Pelican for $30 and off course a nice pint size propane torch at Home Depot to get those HE nuts nice and hot before I hopefully, don't break off my head studs) and do what everyone else is doing and try to clean out those dinky little ports with some stiff guage wire and lots of good 'ole Techron under some hefty air pressure.

Am I going to take it back to Hergesheimer's in Lake Forest for the work? Not in this life time--you laugh at me once-- I'll walk away, you laugh at me again and I'll punch you out MF. Oh, sorry Ed-- I know your real sensitive about talk like that. I can see it now: "The audacity of someone to critize poor customer service at one of our esteemed (and very expensive) Porsche repair shops in the OC! We have to put a stop to this Tim Sullivan guy! I say ban him from the forum before he insults anyone else with the truth.... Heck he probably even gets his hands dirty too, in the OC no less! It's going to put our expensive repair shops out of business!!"

chris walrod

While I am not certain why you have an axe to grind with Hergesheimers, I do, however find it surprising you feel you received 'poor customer service' from the good people like Mark and Laura.

I have to agree with others that doing this flush without removing the heat exchangers leeds one only to assume all ports are flowing. This in addition to potential O2 sensor and possibly worse, cat damage. Then again, I am not sure actually how much occlusion requires an SAI code to be logged.

Reality is shops much like Hergesheimers offer much less expensive alternatives to what any dealer would do, a complete top-end overhaul. I honestly dont think any dealer would be so kind to offer anything less expensive.

Dan V

Thanks alot for the update Tim, and sorry to hear your flush didn't have the long term benefit, but at least it seems no harm was done. Please let us know how it goes with dropping the HEs -- at least you won't have any trouble getting your SAI check valve out.