Dan951Man

Correct me if I am mistaken, but the 997 SAI gets its 12v from the starter lug sandwiched with the starter-alternator harness (where they were notorious for melting).
If you had to do any monkey business to that harness (as mentioned the 997 does not have a jumper lug) perhaps that needs double checking. But the good news is you don’t need a fused feed to the pump. That’s whey the 997’s have a fused ground instead.
So your SAI relay “power input de-pinned and a new ground lead added instead” method of changing the control could work great! I would confirm the 996 harness has no pin matching the 997 harnesses SAI switched ground pin. Then add a new 1 wire harness around the engine bay to the 996 SAI connector 12v feed (now modified ground). I would put a fuse in this harness, in the engine bay. This way the rest of your control circuit downstream is protected.

finally, it’s not THAT hard to get in there. Remove the airbox and the alternator. That will give you enough room to get a flashlight and mirror in there to verify the 997 stuff is intact. Removing the throttlebody and distribution pipe give you more room.

colmfmurphy

@Dan951Man Yes, thinking about it overnight, I think that's how I'm going to move forward.

As far as access to the pump, yes it probably wouldn't hurt but after wrenching on this for the last few months, I'm more a fan of smart work rather than hard work...

Oh and the 997 DOES have a jumper "lug"; it's under the car along the passenger side of the transmission ahead of the wheels... At least, that's where it was on this '07 donor...

colmfmurphy

Just have some time to dive into this and I have to say, Fabulous info in there for the 997.Found my SAI connection, am working on a plan of action for Saturday...

Would you happen to have similar for the 996?
In all of the various manuals/info I've collected for the 996, there's nothing as comprehensive as that 997 set.

No worries if not, and thanks for all of the help so far.

Ahsai

The amount of info is crazy. Sometimes it pays off to hangout in the 997 forum I wish I had such comprehensive info for the 996.

colmfmurphy

@Ahsai ok, need to pick your brains on this again please...still can't get the SAI fault cleared...

Using the 996 SAI connector I wired on a relay that switches on a 40A fused ground onto the 12v+ from pin 20 on the engine block connector. All perfect in theory...

I can fire the 997 SAI by grounding it and it is working fine.

Problem is my 996 is not turning on the 996 SAI connector and I cannot figure out why. I have a meter plugged into it and nothing at all...

Is there some other trigger or valve that tells it to turn on the 996 SAI when the engine is cold?

Worst case, I'm going to wire in a switch instead of the relay...

Ahsai

If memory serves, the DME supplies ground to the 996 SAI relay coil to activate it. The DME does that at cold start and whenever the SAI test is needed by the DME (usually when the engine is still not fully warmed up and you idle the engine after a short drive).

Not sure why you want to wire a switch instead. You want to control the SAI pump manually? But why?

colmfmurphy

2nd answer first... It won't throw a CEL and I can get smogged... that's my biggest priority right now...

I'm understanding the first part of your answer but what tells the DME that it's a cold engine? I'm plowing through everything I have but the programming side of it is a black box.
The 996 when it was original never had any SAI issues so I know it has to be connected to something I've done with the engine swap or something has changed because of the engine swap.

I wonder if the DME is reading the thermostat on the block and determines that the block is below a certain temp and so it will turn on the SAI...

I don't have a duramatic(?) so i can't do a whole lot in that regard. I'm using an iCarsoft to see what's happening. Doesn't give me enough info tho.

Got any recommendations for a good indy P shop in the SF Bay Area?

Ahsai

Yes the DME reads the coolant temp sensor so it knows when is a cold start. I don't think you can fool the DME easily because other than cold start, as I mentioned there are other conditions the DME will activate the SAI test and you won't be able to know when. The DME reads the O2 sensor to confirm the extra fresh air introduced by the SAI pump.

I think the right fix is to find out why the 996 SAI relay is not activated during cold start and go from there.

colmfmurphy

yes, worked on that today; no idea so far tho.

Agreed on the random times it's supposed to go off. It ran great over a 75 mile run of mixed driving but as soon as I pulled back on the road after gassing up, it threw up a CEL...

Do you have the 996 engine block pin outs? It's the one thing I don't have and can't find.

I think there must be something on the engine connectors that's changed. I'm planning to print out the 997 wiring diagrams and see if I can figure out the differences.

Thanks again for the help, it's good sometimes to be able to talk something through...

Ahsai

The 996 engine harness pinout of the x59 connectors is in the 996 wiring diagrams. You got that from the 997 link I sent above, right?

If memory serves, the 996 SAI pump wiring does not go through the x59 at all. The 996 SAI pump socket connects to the SAI relay at the rear relay panel directly.

colmfmurphy

yes on your memory. The key now tho is to see what triggers the DME to turn on that SAI relay

There wasn't any 996 info on that torrent link, all 997 stuff, a great collection.

Ahsai

I guess you missed EuroRAE's reply to you. He added a 996 folder for you! Post #34 here.

https://rennlist.com/forums/997-foru...l#post15738108

colmfmurphy

woohoo!!

Homework!!

I was in page 2000 of 8161 of a service manual... this might be easier... :-)