Intro and Dilemma!

[Sargepug]

Hello all, I'm new here, but a long time member of Rennlist since '09.

First 911 was a new '09 997.2 C2S, then I bought the '84 and sold on the '09. I've owned the '84 for about 5 years and bought it w/ 67k on the clock. I now have 81k on her.
You can see in my signature, which mods have been done to the car.
My dilemma is troubleshooting a stalling issue. A full service was performed at 80k, which was the 15k incremental valve adjustment, dist cap, rotor, plugs and fuel filter. Coincidentally when my clutch went soon after(another story), when I would start the car, the idle would "hunt" badly at startup until it finally settled down. I obviously couldn't drive it w/ the blown clutch, so I had it towed to the shop in that hunting idle condition. Mechanic did a "smoke test" on engine and saw that it was leaking from the intake manifold, so those gaskets were changed. Engine was obviously out anyway for the clutch, so was good to catch that then. That manifold job eliminated the "hunt", but then a new problem emerged not to long after. One time I started the car up and it immediately stalled, it took 3 attempts to start and maintain an idle not to stall. Then soon after, it would intermittently stall when I would come to a stop. It would start back up right away and then I would go. Brought her back in and mechanic tested throttle position switch and replaced the throttle micro switch. He removed the throttle body and freed up the ICV. He then cleaned the ICV, drilled out plug and set CO% on air meter. My mechanic is highly reputable in the NYC metro area and services all of Seinfeld's Porsches. Almost every time I'm there, "Jerry" has one of his cars in. He even had an '88 959 w/ 6k on the clock in the other day.
Now she is just about 100%. Starts w/ no issue and can go on a drive never stalling or maybe it will do it once. It's the once that is throwing me! I've driven about 50 miles since repairs. Do I maybe need to drive it more, for the computer to adjust / calibrate or something of that nature, to the new switch and settings?
What else do you guys think can be the cause of this?

[KNS]

I don't believe there is any period of time for the older cars to "adjust" their ECU, they're not that sophisticated (I could be wrong). What RPM does the engine idle at? It should idle at around 800 RPM.

[ClickClickBoom]

ICV, sometimes they can be cleaned, mine only worked OK after cleaning, symptoms you described. Bought a new one, all problems are a distant memory. After getting new ICV have the CO rechecked. Driving helps the seals stay compliant. My car wakes up and only gets truly happy after getting fully warm.

[wrxnofx]

There are a finite number of items that impact the closed loop for the DME:
O2 sensor - you can test the O2 sensor or disconnect it to see if that impacts the stalling behavior.
Speed and Reference sensors - if the signal is lost to the DME from either of these, I think the car will stall
Cylinder head temperature sensor
The ICV can also affect idle. Cleaning mine didn't really help. I bought a used one and that cleared up my idle hunting
The DME can obviously impact stalling behavior if it has cracked solder joints.
The DME relay - contains a relay that engages the fuel pump. Perhaps if there is a cracked solder joint the fuel pump would cut out, causing the car to stall.

[DRACO A5OG]

Have him ohm out the Speed/Ref Sensors, CHTS sensor and the ICV. Make sure they are all within tolerances. Then verify yourself.

When he adjusted the AFM, why? was it rich or lean? After the 50 minute drive what is the RPM's at a stop sign or right before shut down?

Quick self test, while idling, remove oil cap after the 50 min run. Does idle change?

No there is no break in period.

Last thing, place your DME into another 3.2 to see if it will stall out.

While you are there, have him ohm out the coil. Several of us have been experiencing bad coils, even when they ohm out properly but mostly NO Start issues

[DRACO A5OG]

Oh yeah, Welcome Aboard! Pics please

[Sargepug]

Originally Posted by KNS

I don't believe there is any period of time for the older cars to "adjust" their ECU, they're not that sophisticated (I could be wrong). What RPM does the engine idle at? It should idle at around 800 RPM.

She idles at 800, drove her another 30 miles yesterday and no stall at all. Sometimes she got close at 600/700 rpms, but held on each time.

[Sargepug]

Originally Posted by ClickClickBoom

ICV, sometimes they can be cleaned, mine only worked OK after cleaning, symptoms you described. Bought a new one, all problems are a distant memory. After getting new ICV have the CO rechecked. Driving helps the seals stay compliant. My car wakes up and only gets truly happy after getting fully warm.

Maybe I will go that route, is the removal / install a quick one or will take some time?

[Sargepug]

Originally Posted by wrxnofx

There are a finite number of items that impact the closed loop for the DME:
O2 sensor - you can test the O2 sensor or disconnect it to see if that impacts the stalling behavior.
Speed and Reference sensors - if the signal is lost to the DME from either of these, I think the car will stall
Cylinder head temperature sensor
The ICV can also affect idle. Cleaning mine didn't really help. I bought a used one and that cleared up my idle hunting
The DME can obviously impact stalling behavior if it has cracked solder joints.
The DME relay - contains a relay that engages the fuel pump. Perhaps if there is a cracked solder joint the fuel pump would cut out, causing the car to stall.

Already went the O2 route, didn't help.
DME wise, I also heard a wire needing soldering can cause this issue. Is that an easy thing to check?
DME relay was replaced about 2 yrs ago, when I had an issue that she wasn't starting. Cleared it right up

[mreid]

Sounds to me like an Italian tune up is in order.

How often do you get it out and really open it up, flex its leg, give it a good run, run it through its paces, blow out the carbon...you get the idea?

[Sargepug]

Originally Posted by DRACO A5OG

Have him ohm out the Speed/Ref Sensors, CHTS sensor and the ICV. Make sure they are all within tolerances. Then verify yourself.

When he adjusted the AFM, why? was it rich or lean? After the 50 minute drive what is the RPM's at a stop sign or right before shut down?

Quick self test, while idling, remove oil cap after the 50 min run. Does idle change?

No there is no break in period.

Last thing, place your DME into another 3.2 to see if it will stall out.

While you are there, have him ohm out the coil. Several of us have been experiencing bad coils, even when they ohm out properly but mostly NO Start issues

If you mean test all the sensors, he did that already and replaced what showed a fault.
not sure why he adjusted AFM
RPM at stop sign is usually normal at 800, not sure before shut down, because it doesn't hover at a lower rpm then stall. It's a complete rpm drop to zero.
idle always dropped when I removed the cap, I understand that to be normal??
I'll ask about the coul

[Sargepug]

Originally Posted by mreid

Sounds to me like an Italian tune up is in order.

How often do you get it out and really open it up, flex its leg, give it a good run, run it through its paces, blow out the carbon...you get the idea?

hahaha, never heard of an Italian tune up! Maybe a German one is in order here?
I don't get that chance very often, but taking her on a 150 mile trek this Thanksgiving weekend.

[Sargepug]

Thanks all for the help above and any further feedback!
Yesterday I took her on a run of about 30 miles, in which she had a least a dozen chances to stall. Only a few times rpms dipped close to 600, but never stalled once! Time before that, she only stalled once in same type of run / distance. Maybe if she's no longer stalling, I should leave good enough alone??

Also, here's a pic!

[mreid]

She's a beauty! Good luck and have fun.

[NYNick]

Sarge,

Bring it back to Gaspar and tell him it's still messing up,(if it still is).
If he can't fix, nobody can.

Maybe we've met there one day?

Nick

[DRACO A5OG]

Originally Posted by Sargepug

If you mean test all the sensors, he did that already and replaced what showed a fault.
not sure why he adjusted AFM
RPM at stop sign is usually normal at 800, not sure before shut down, because it doesn't hover at a lower rpm then stall. It's a complete rpm drop to zero.
idle always dropped when I removed the cap, I understand that to be normal??
I'll ask about the coul

Yes, I meant test all. He appears to be a Porsche wrench, good .

RPM, good. Okay so no laboring before shut down, then it is ignition/electrical related.

Yes, cap off idle drop is normal, good.

If he has another 3.2, ask him to swap your DME into that car to look for symptoms.

edit: re-read OP's other post, 600 RPMs is way too low. +1 check DME in another known good 3.2.

[Sargepug]

Originally Posted by NYNick

Sarge,

Bring it back to Gaspar and tell him it's still messing up,(if it still is).
If he can't fix, nobody can.

Maybe we've met there one day?

Nick

Good pull on the shop, which was given away w/ the Seinfeld comment, to us in"the know". haha
Gaspar is the one that is on it! He's a great guy and obviously the top dog there. Since all the fixings, I've driven her about 50 miles and she only stalled out twice. Once was driving in the first 10 miles of bringing here home, and another was immediately after getting her home and blipping the throttle multiple times in driveway, to further test the situation. Since then, she hasn't stalled out at all, in 40+ miles of driving on back roads w/ multiple stops. Got close a few times, but held on and all rest of times was perfect. I think I am going to rack up some more miles on her and if all remains stable, let it be. I'm going to give her a good run on Wednesday and bring her out to Hamptons for the holiday, which is where I usually keep the car. It's perfect out there.
Maybe we've met, you recognize my car? Where is a pic of yours?

[Sargepug]

Originally Posted by DRACO A5OG

Yes, I meant test all. He appears to be a Porsche wrench, good .

RPM, good. Okay so no laboring before shut down, then it is ignition/electrical related.

Yes, cap off idle drop is normal, good.

If he has another 3.2, ask him to swap your DME into that car to look for symptoms.

edit: re-read OP's other post, 600 RPMs is way too low. +1 check DME in another known good 3.2.

I'll look into the DME, if she starts stalling again. As I posted above, all seems stable at this point. fingers crossed!

The 600 rpms only occurred a couple times in 50 miles of driving and then she immediately corrected to 800.
Given the latest info of "non stalling" I posted, I think I should just leave it alone and see how it goes / rather than tinker with it more. I'm getting tired of running to shop and spending $$. What's your opinion on that?

[NYNick]

Your car does look familiar, but there are a lot of black on black Targas out there. Mine's a silver SC with green wheels. Check my profile and garage for pics!

Have great weekend out on eastern LI!

Nick

[Sargepug]

Originally Posted by NYNick

Your car does look familiar, but there are a lot of black on black Targas out there. Mine's a silver SC with green wheels. Check my profile and garage for pics!

Have great weekend out on eastern LI!

Nick

Wow, that's a beauty and does look familiar! We should hook up for a run sometime..