Aircooled 911s
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By jacke2c
#2179
A place for aircooled 964 owners to share their expertise...
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By amdavid
#3646
Someday again. Had a 91 Amazon Green C2 for a few years.
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By Marine Blue
#8184
Hopefully see some more activity here....
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By Rocket Rob
#9984
Me too.
Rocket & Elf.jpg
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By JRMaroon
#11969
Not a 964 expert but will share the results of a lower valve cover replacement in the next few weeks.

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By sundog
#19245
I'm happy to answer any technical questions that come up. I've done a ton of rework on my 1991 Carrera 2, rebuilt engine, suspension, exhaust, many electrical things, and a ton of weird issues.
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By fpena944
#19254
Had a chance to buy a 1991 C2 for $17k back in 2008. Ended up with my 996 a year later but that 964 brought a smile to my face that no other vehicle has done since.
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By Rocket Rob
#22345
C4 vibration at 60mph - torque tube bearings?

I have vibration at 60mph. You can feel it at 40 and up to 90 but its worse at 60mph. I have tried two sets of wheels/tires without change. I have new axles and wheel bearings, shocks and shock mounts. New trans mount and the vibration remains. I have swapped my wheels/tires from my other car and the vibration remains and does not move to the other car. I'm running out of ideas on what else it could be.

Very frustrating. Wondering if the bearings in the torque tube are worn??? Has anyone had to change them? If so, what is involved in doing so?

Car is a 1990 964 C4 cab
Mileage = 262K

Thanks in advance
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By jacke2c
#147563
Although I sold my house with a shop and a two post lift two years ago, I figured it was time to continue with the upgrades on restoring my junk yard Porsche to its former glory. I had bought a used bumper cover from Autobahn1 about 4-5 years ago that had the Tech-Art fog lights and brake ducts. Apparently the original bumper had been damaged slightly and was filled with bondo, and then bumped again cracking it... It was that way when I bought it... apparently it had been driven fairly hard at one time. Its amazing how time consuming it is to do something as simple as a bumper cover when you don't have your lift and you have to crawl around on the floor to get to all the screws at a youthful 64 years old.

BEFORE:
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AFTER
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By jacke2c
#172014
You know, 32 year old cars get tired and just drip 9on your floors... so I did something about it....

I have always had to put down cardboard to catch the engine drips and the front radiator drips on my 1990 Carrera. So I looked into what others had done and decided to bite the bullet and replace all my leaky lines where the oil hoses had deteriorated over the last couple of decades. The 1st thing I needed was a good crimper. A Cohline crimper, if you can find one, is about $14-1600 dollars. I looked for months to find a used one on -bay, but have had no luck scoring a used one. I know elephant racing uses a Parker crimper... but they are for the low-volume average guy cost prohibitive. I found an Eastman Electro-Hydraulic crimper and was told it would work... it did, but leaked more on the floor than it put through the pressure lines and one of the cylinders leaked. I rebuilt it over a two month period and it works as new with new cylinders and a new reservoir.

The one thing about using this crimper is that it has specs for every hose and crimp diameter. You set the press to the desired diameter and press to that point and you get a perfect crimp.... well after 6-8 practice crimps to see what happened if you over or under crimped a fitting. If you go to measures over, you collapse the pipe internally. If you go two setting slack, you can still turn the pipe fitting in the hose.... (I practiced on some identical diameter copper tubing from a hardware / supply shop.)

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Now that I had the tool, I sourced original Cohline fittings from England and they were delivered in 3 days. Wonders never cease.

I stripped the old lines out, and replaced the lines one at a time using the crimper.

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There is a certain amount of butt pucker tension since one screw-up and all the effort would have been cost prohibitively expensive to fix.

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Lines installed at front radiator where they had been leaking. The old lines were so brittle that you could spin them in the fittings. It was no wonder that they leaked.

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Now for the hard part..... The oil tank, and oil console lines.... 8 fittings into one tank that fits inside the rear fender well in front of the right rear tire. but first clean the old tank....

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Then cross your eyes, and hold your tongue at a counterclockwise corkscrew coming out of the right side of your mouth to refit the tank... AS you fit one of the side hoses onto the tank....

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AND make connections to the thermostat housing which rests below the tank with 5 fittings and one rubber isolating spacer.

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And then you can tighten the oil console line that has about 1" of clearance for your 36mm oil line wrench to secure that fitting snuggly.

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By fpena944
#172082
@jacke2c - Love these home-grown solutions!

I know on my 996 I had a pesky leak for a while as well. My father crafted some home-built solution which wasn't the prettiest but since then not a single drop of oil has come out of the 180k mile engine.

Good to remember that the "right" way to fix something, which usually involves buying new parts at extraordinary prices, isn't the only way to get the job done!
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By LPMM
#193263
@sundog @Rocket Rob @jacke2c @SeanR @ROG100 and everyone else.

Question for the experts…

I have been chasing an issue for some time now. The 964 started dying randomly while driving and then not wanting to start again until the next day when the engine was cold. I did some reading and came to the conclusion that my crank sensor could be faulty. When I removed the original sensor, I noticed some grinding on it as the gap was not properly set and some rubbing occurred. So I purchased a new sensor and this is where things get interesting. The crank sensor for the 964 with the original square plug is NLA and it has been replaced with the updated 996 sensor with an oval plug. Instead of cutting the harness in the engine compartment to fit a matching oval plug, I purchased a 928/944 sensor (FAE 79208) which has the square plug and I cut it to make a pigtail to mate between the engine side original square plug and the new 964 (aka 996) sensor oval plug. I followed the instruction in the Porsche bulletin which show:

Terminal 3 = Sheath
Terminal 2 = Brown (or Black)
Terminal 1 = White

I set the gap, put my new sensor in, clipped the pigtail and the 964 cranks but the idle is very rough and then the car ends up dying. So:

Question #1: Would the car still crank and run (albeit not right) if my wires are crossed or would it not fire up in the first place?
Reason I ask is that when I researched 944/928 sensors, some pics show the White as Terminal 2 and Brown (or Black ) as Terminal 1.

Question #2: If correctly wired, any thoughts on what else could cause my issues?
I replaced the FPR a few years ago and the ISV last year.
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By sundog
#193356
I doubt it would run correctly with it wired incorrectly.

Do you have the diagnostic kit which reads the DME? I’ve had similar issues when the idle switch is sticking, and the engine head temp sensor is bad.
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By jacke2c
#193388
When I bought my car out of a salvage yard it kept giving me all kinds of troubles as each have described. What I have found is that there are about 12-15 ground points all around the car that become corroded over time. There are some behind the coils, the one next to the starter, the one behind the alternator, etc., etc., and several others that I can't remember (it's been 15 years or more). Bad grounds to me are the major culprit for the 964. everyone of my ground points had a white powder residue that I had to wire brush away, and then I coated all my ground points with dielectric grease when I remade the connections.

Also, the wiring harness that plugs into your mass air flow sensor is supposed to be folded and tie wrapped to keep it form becoming straight. I know this sounds strange, but I cut mine because i thought the wires would be in a bind, but I soon learned that they need to be folded as per Porsche Specs. rough idle was one of the symptoms. Again, that was 15 years ago...

Have you checked your secondary distributor belt? Have you tried disconnecting one ignition ignitor (the little module located bolted to the face of the coil bracket) (beware that they will be hot if the engine is or has been running) at a time to be sure its firing on each coil? Both are symptoms that are common in the 964-993 world.... That is why a lot of 964 owners convert to 993 coil systems to get rid of the weaker failure prone 964 coils.
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By LPMM
#193390
sundog wrote: Sun Jan 08, 2023 11:38 am I doubt it would run correctly with it wired incorrectly.
Do you have the diagnostic kit which reads the DME? I’ve had similar issues when the idle switch is sticking, and the engine head temp sensor is bad.
Background on issue…. The 964 would run fine and then after some time and without any warning, it would buckle, want to die, then back on after some delay between pressing the accelerator and rpm’s going back up, basically it would be quite the rodeo, and then die. When initially researching, it seemed to be due to a faulty crank sensor but now I am thinking something else (unless I crossed my wires) hence the poor running and dying upon startup. Perhaps AFM or head temp sensor as you mentioned?

I have a PDT999 but it showed 0 faults when I plugged it in, so :surrender:
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By LPMM
#193394
jacke2c wrote: Sun Jan 08, 2023 2:53 pm Also, the wiring harness that plugs into your mass air flow sensor is supposed to be folded and tie wrapped to keep it from becoming straight. I know this sounds strange, but I cut mine because i thought the wires would be in a bind, but I soon learned that they need to be folded as per Porsche Specs. rough idle was one of the symptoms. Again, that was 15 years ago...
I read about that last night and I pulled the TSB which appears to be for MY89 and MY90 and mine is a MY91, so I don’t think I would have an issue due to shielding/wiring. Worst case is that I pull the air box and AFM to give it a cleaning and check the wiring to make sure it is ok.

jacke2c wrote: Sun Jan 08, 2023 2:53 pm Have you checked your secondary distributor belt? Have you tried disconnecting one ignition ignitor (the little module located bolted to the face of the coil bracket) (beware that they will be hot if the engine is or has been running) at a time to be sure its firing on each coil? Both are symptoms that are common in the 964-993 world.... That is why a lot of 964 owners convert to 993 coil systems to get rid of the weaker failure prone 964 coils.
I removed the distributor caps and tried to turn the rotors by hand but could not, so I believe the belt is fine. I have not played with the ignition coils yet but will do so if I can keep the car running long enough, thanks for the suggestion.
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By sundog
#193450
LPMM wrote: Sun Jan 08, 2023 3:04 pm
sundog wrote: Sun Jan 08, 2023 11:38 am I doubt it would run correctly with it wired incorrectly.
Do you have the diagnostic kit which reads the DME? I’ve had similar issues when the idle switch is sticking, and the engine head temp sensor is bad.
Background on issue…. The 964 would run fine and then after some time and without any warning, it would buckle, want to die, then back on after some delay between pressing the accelerator and rpm’s going back up, basically it would be quite the rodeo, and then die. When initially researching, it seemed to be due to a faulty crank sensor but now I am thinking something else (unless I crossed my wires) hence the poor running and dying upon startup. Perhaps AFM or head temp sensor as you mentioned?

I have a PDT999 but it showed 0 faults when I plugged it in, so :surrender:
Ouch, if no other codes, then check the live values and compare with normal values for startup, in Adrian’s book.

I had issues with a bad battery that turned out to be similar to these. Also ground issue is possibility.
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By LPMM
#194093
Good news!
After you guys mentioned the grounding points and battery health, I checked both. The battery grounding point looked a bit suspicious so I used some coarse sandpaper to remove any residue and have shiny metal, and I also sanded the new negative cable end for good measure. Even though the battery seemed to be holding the charge, it had completely died on me (no measurable voltage) before all these issues started so I wonder if it was damaged internally. So, I decided to swap it with my old Jeep battery that has been sitting in my garage for 4 years and still showed 12.8V. The second I hooked it up, I heard the DME relay kick in and pressurize the fuel system (Solid State relay) and when I fired it up, the 964 purred like a kitten. I let it idle for 20mn last night and no hiccups so far, so I will go for a few short drives in the next few days hoping that my issues are now resolved. Not sure if it was the ground or the battery or both (I should have done one at a time), either way I will have the battery tested but I don’t really trust it and I will most likely replace it regardless of the results.
Thank you both for your time and insights.
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