I'm guessing this emissions warranty is only applicable if you're the first owner...? When I first brought this problem to the attention of a local dealer service department, they asked if I was the first owner. I could never figure out the reasoning behind this question; now I know why.

I think if you can show you had this problem before your emissions warranty expired, it should still be covered.

 

In California it is I believe 7 yrs/70K. I don't think it matters whether you are the first owner. Afterall, you are still responsible for the smog certification. In the case of my Merc the warranty had expired(too many miles) and I WANTED to pass the smog test. If it was under 70K I would've run it cold in hope of failing, and written a complaint to MBNA with a copy to the EPA and state agency.

 

The diagram that Tom posted is for a turbo. The n/a version is similar but differs in the routing of the pipes to the head.

Here is a pic of my '97 M64/21 euro anyone know if the circled area is the secondary air pump? Its the only thing I can't identify.

<img src="http://boards.rennlist.com/upload/993circle.jpg" alt=" - " />

Only the 964 turbos had secondary air injection, normally aspirated did not.

Here is a pic of that area on my 964

<img src="http://boards.rennlist.com/upload/engine_transmission_051_small.jpg" alt=" - " />

<img src="http://boards.rennlist.com/upload/engine_transmission_008_small.jpg" alt=" - " />

 

Does this cause an emissions problem? Anyone know?

If it does, then it seems to me that Porsche has to fix it. Has anyone failed a smog test and forced Porsche's hand?

I for one as a guy living in California plan to do so.

It may also be a good idea for people to get together, present their collective stuff, and ask Porsche for a permanent fix. It SEEMS like this will affect every 993 at some point. If not, why? Can we hear from the people with high milage 96-98 cars -- maybe an analysis of what fuel they're using or their driving patterns can help others avoid this debacle.

5500 bucks out of pocket for what clearly appears to be a design defect is a bitter pill to swallow.

 

I think I found the purpose of the red circled pieces in my previous post, tempostat(cruise control)?

 

'97 993 Cab - 68,000 miles - second owner - daily driver - ONLY Chevron gas and Techron treatment two tanks prior to each oil change. No light yet.

BTW - I think that I read on other threads about this topic that this issue does not apply to pre '96 (non-Varioram) cars.

 

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by fbfisher:
<strong>BTW - I think that I read on other threads about this topic that this issue does not apply to pre '96 (non-Varioram) cars.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">That jibes w/ my memory of a previous board discussion. Started to look for it but figured Dan in St. Louis would know exactly where to link and post it ASAP

 

Bill writes:

"...Only the 964 turbos had secondary air injection, normally aspirated did not..."

For what its worth Bill, when I got my 1995 993 back from the wire harness recall, my paperwork read:

"26651900 secondary air pump removed+reinstd"

When the dealer had the car apart for the recall, they called me and said that the electric airpump (the one that only runs the 1st few minutes on start up) was locked up and needed replacement. They said that Porsche would pay for the fix if I wanted it done, and of course I did.

I dunno if that is helpful or not. Just wanted you to know.

fbfisher,

You are correct about the non-varioram cars.

The fact that they dont seem to have the issue may stem from OBD-1 though. I think the varioram OBD-2 cars are more sensitive to the carbon. Either mechanically, or perhaps just warning light wise. To my understanding, both versions do have these small passageways. Maybe the OBD-2 cars are the only ones that have a computer warning system for it, or maybe the 1995 is construted differently enough that the carbon issue is moot.

 

MB, I don't understand the purpose of your post I was refering to 964s the turbo have secondary air injection the n/a do not. A previuos post had alluded to 964s having s/a/i, I was merely pointing out a minor error.

The current discussuion is about 993s, JC w/ a 95 euro and myself w/ a 97 euro can not find the pump on our engines. I know that all of the US cars have the pump.

My question is "What does it look like when installed on an engine?"

 

I just recieved a private reply from a person familiar w/ these engines. He says that the euro versions do not have s/a/i

 

According to the below diagram, it appears that the air is injected directly into the exhaust manifold. In the pictures above, the exhaust system isn't stock, looks like it has home made heat exchangers.

<img src="http://boards.rennlist.com/upload/air.jpg" alt=" - " />

 

My bet is that the DME knows the air injection is not working because of the information it gets on Air/Fuel ratio from the O2 sensors.

I know in one of my other vehicles that the engine computer can tell whether EGR is working properly based on O2 sensor information - it looks for differences between having EGR valve open and closed. If there is no diffence, it assumes the EGR valve is malfunctioning and sets the check engine light and appropriate code.

If this is the case, there is not going to be any sensor to bypass, you are left only with trying to knock that piece of code out in the DME firmware. Or getting those passages cleaned.

Chip

 

Gentlemen:

I thought I would step in here briefly and touch on this subject. I'd like to make a few points about this,.............

1) As some people already know, Porsche fitted an electric air pump to all OBD-I & OBD-II 993's that injects air into the exhaust ports to help the cats get up to temperature quicker. OBD-II cars monitor this function differently than their predecessors; the '95's are not as sensitive due to the different emissions standards between OBD-I and OBD-II. After 2-3 minutes, after a cold start, the pump switches off since the cats are doing their job by then.

2) Carbon buildup is due to the after effects of using unleaded gasolines. One really cannot avoid this problem aside from driving the car immediately after a cold start (gently), running the engine toward 6000 RPM from time to time, minimizing idling (as much as is possible) and using a good fuel additive such as LubroMoly or Techron. From what I've observed, cars that are driven in stop-and-go traffic (lots of idling) and are rarely taken close to redline, are the most prone to having this happen.

3) These small passages in the heads & cam towers are simply prone to clogging with that soft carbon and I do not think think that any fuel detergent or additive can clean them out. That will require mechanical means. Once they are clogged sufficiently to trigger the codes and turn on the CE light, you have a problem that will not go away. Proactivity is the key here toward any prevention, if thats possible.

4) This problem in no way affects how the car runs. The engine will run fine and there are really no adverse effects, aside from the emissions & smog compliance issues. In some states, all '96 and later (OBD-II) cars are tested by simply checking for any resident codes and in those cases, it will not be possible to clear the codes until the car is fixed.

I have no idea about Porsche's liability here on these particular smog isues, but since this problem is really not caused by any component failure, I do not know if they are on the hook on this. From what I've heard and read here on these Forums, they have helped some Porsche owners out on resolving this but they might not do this beyond 50K or 70K miles. This is a very different situation than some defective wiring harnesses.

This might not be what everyone wanted to hear and I wish I could offer an easy solution, but emissions related issues may not be cheap to fix. Certainly the root cause is the chemistry of the fuels we use and I cannot tell any differences in occurrances between MTBE-laden gasolines and ones with Ethanol.

 

Once again that diagram is for a turbo car, normally aspirated 993 are some what different. I could post the correct one but JD has asked that we not post copyrighted material. The n/a heads are drilled through the cam towers and heads on US cars only for s/a/i

Yes, those are most certainly homemade headers, a small outfit somewhere in Az. makes them, probably in their garage. Totally worthlesss pieces of junk.

Since I needn't worry about this topic I think that I will sign off, sorry to have tried to help any one.

 

Steve, thanks for taking the time (again!) to address an issue that concerns many of us. The generosity with which you give your time and expertise is VERY much appreciated.