2ndof2

Apparently my old mechanic, who did a PPI on the car I just bought for the PO who only had it 2 or 3 weeks before I bought it, did not do a full diagnostic. He said the car is in great shape and isn't burning any oil. My bad for not specifically asking if he checked the computer. I took the car in for an oil change to my NEW mechanic today who has the software to do the diagnostic test and showed me the CEL (or at least a SAI fault) was reset 8 times!!!!!!!!! It also showed one bank of cylinders currently were showing a SAI fault. The CEL wasn't on. The car had been smog tested only 2 weeks before I bought it and it passed though I never saw the actual test results. The PO only had the car 2-3 weeks before he sold it to me. I'd be surprised if my old mechanic had set me up. I don't think there would have been anything for him to gain...maybe some money but I don't get the sense he'd stoop that low and risk his reputation, especially after having known him for years. I never had any past situations where I thought I was being ripped off or any hint of fraud. All that said, is there some reason the CEL light isn't going on? The light is functioning correctly according to my mechanic. The car was 3+ quarts down after being driven at least 4,000 miles and probably at least another 1,500+ by the short lived PO. I plan to ask my old mechanic if he changed the oil for the last owner who I suspect didn't do anything besides a few other things like removing a fixed wing and performance mufflers that he said were resonating and bothering him. I hope he didn't change the oil while he had it since being that many quarts down over such a short span of miles would be an alarming rate of oil loss. There may be a valve job in my future if the oil loss is that severe, but I'm keeping my fingers crossed!

2ndof2

Woops, "....that I just bought FROM the PO"

kkim

If you are asking why your CEL light is not on even with a history of codes, I can tell you it takes some time before the CEL light will come back on once it has been "cleared".

Sounds like it might have been cleared sometime just prior to you purchasing the car if it's been on 8 times.

Did you talk to your old mechanic about this?

Good luck!!

2ndof2

I haven't spoken to him yet but I plan to tomorrow. It should be real interesting. My bet is he's just going to tell me he doesn't have the diagnostic computer software and say he had no idea about any problems, which may be the truth, but he should have disclosed this. I didn't pay for the PPI so he had no obligation to. His words were you don't even need to pay to get the car checked because I just did it. Since his is the only shop in the area I know (did biz with them for 4+ years) I wouldn't have taken the car anywhere else. I had seen them do PPI's and work on many other 993's in the past for other customers. His staff has mechanics experienced with 993's, but without the correct software how could they possibly know the whole story? I don't want to give away what shop this is without proof of negligence (actually I'm beginning to think the negligence was my own for not specifically asking...although he and I DID have a detailed discussion about the SAI issues of the '96 and older 993's previously when I was looking for one) but I will say one of the technicians fromerly worked for California Cars in Calabassis and I am pretty sure he knows what the deal is regarding SAI faults. I'm not sure I have any recourse in the matter even though no bill of sale stating the car was sold "as is" was ever signed by me.

David in LA

Hmmm...if there were a way for the CEL not to get tripped even though the car is throwing off an SAI code I think there would be a lot of people interested in this "fix".

Hope you are able to resolve this

JasonAndreas

The design/plans for a simple circuit that tricks the computer into ignoring the SAI and not throwing a code was posted here ages ago. The reason you don't find that many mechanics installing the circuit is the $10-30k USD (per install) fine they'd receive from the EPA if anyone ever found out they were disabling emissions equipment or selling a kit to do so. Similar to what happened with West Coast Customs (MTV) and the fines they received for disabling/removing front airbags so they could install LCD screens in steering wheels.
I'm curious to know the reason the PO gave for selling the car after only 2-3 weeks?

mborkow

"but without the correct software how could they possibly know the whole story?"

i believe any generic reader would have indicated that the SAI fault had occured (my $150 reader will).

2ndof2

Jason,
The PO has another 911 which in his words he said "he just couldn't part with." I've owned this 993 for about 2 months now and other than a master brake cylinder that is losing pressure, a check door strap repair, and replacement of the reverse light switch on the tranny, the car has been great. I would expect any shop doing PPI's on these cars should at least have an OBDII reader that could at tell them if there were any historical fault codes on the vehicle; there is such a thing is there not? I plan to call the shop later this morning to find out why they either didn't check the computer or why the poor results of this test were not disclosed to me. I'm disappointed in the shop but also at myself for letting my guard down and relying on the opinion of a professional I trusted. I mean I didn't have to go through a list with him, item by item did I? ....how were the tires, how were the brake pads, how did the door locks work, how was.....etc etc....Seems like his job was to tell me like it was right? Granted I didn't pay for that recent PPI but I was planning on doing one with that same mechanic....it had only been 2-3 weeks so he said I don't need to bother with it and began to tell me about the car and how good it was. Again, I trusted this guy and got burned.

FisterD

If you have the SAI error code, your CEL should be on. Try looking at your CEL light when you turn your key on, it should come on momentarily, if not, either the bulb is bad , or someone disconnected it.

2ndof2

FisterD,
Check engine light DOES come on when I turn on the ignition then goes out just like you describe. The mechanic who did the PPI said he does have a reader and did check the computer on my car. He says no history of CEL's or SAI came up. Some of you have said if there is a current SAI fault, the CEL should be on. No idea what's up with that - I really don't want to see the CEL light stay on anyway. Its easy enough to periodically plug it into my tech's computer and run a diagnostic every once in a while, but I'm beggining to wonder whose computer equipment isn't working right, or who isn't using their computer correctly. Injection code 1-3 is what my new mechanic found when he ran the diagnostic yesterday is all I know. Why 8 incidences of the SAI fault being cleared showing now but did not show up for the guy who did the PPI is very strange. I have never had a CEL light cleared since I've owned the car. Bottom line is I'll just keep an eye on my oil consumption, which, by the way appears to be consistant with the factory's estimates (if memory serves: about 1 qt every 1000 miles). Thanks for reading guys....I just really like to know whats going on and was surprised by all of this. I'm just gonna drive and enjoy my car.....not going to stay up nights worrying about it until I have to. Have a great weekend everyone!

aam993

I think quote above contradicts with quote from this article:
"With most OBD2 problems, the check engine light doesn't come on right away. The system usually waits until the problem has occurred on two separate drive cycles before it turns on the warning light. This is to reduce the number of false warnings that might otherwise occur if the light turned on every time it saw something amiss. So if the light is on, it means the problem has occurred before and has occurred again. It's not just a temporary glitch but something that needs to be diagnosed and corrected."

Also, according to this : "If the condition that caused the MIL to come on goes away, and the OBDII system doesn't detect a reoccurrence, the system will turn off the MIL."

The code for the problem will be stored in the computer memory, however.

FisterD

I am saying, if your car has the dreaded Carbon Buildup problem, and your OBDII is registering P0410/HP1411 SAI Malfunction, your CEL light will come on, and STAY on. It WILL NOT clear itself, no way-no how. I know because I had this problem when I bought my car, and there are other people on this board who have also had this problem.

aam993

Well, I'm not sure if it's so black and white. If the problem with SAI just started(passages partially clogged), then it might not be consistent enough for CEL/MIL to come on up, or stay forever.
My car also had a SAI error code stored in computer, which was read during PPI - CEL/MIL was off, however.

FisterD

Yeah, you may be correct on this. If you are in the very early stages, you can reset the error, and it may not come back for quite a while. If you are logging this error,though, I would tend to believe it is only going to get worse over time. I am also unsure how many times this error must be detected before it fires off the CEL. I would check my car with my OBDII scanner, and as long as there where "No Errors" on my scanner, everything was fine. As soon as the error appeared "P0410" the CEL would come on. This made me believe that as soon as this error is registered, the CEL illuminates. Maybe it has to read the error a certain number of times before this happens, I don't know. In my case, it seemed that as soon as this error appeared, "CEL" lit up. It was a real PITA until I had the clean-out done.
Over 4K miles without the little red devil rearing it's ugly head.

2ndof2

Darin,
When you say you "had the clean-out done" what do you mean by this exactly? Did you have your motor all apart or did you do some procedure to clean it? I've followed the CEL SAI posts on the board for quite some time leading up to my purchase of the car.
Alex,
Thanks for the informative articles.