More questions from a new guy

[bbulkley]

I'm still learning the details of my '73S Targa, and I've noticed a couple things lately. Both concern the engine, which like the rest of the car has 42,000 miles on it and is all original (other than replacement filters, distributor, etc.).

1. I know these cars leak oil, but are they supposed to burn oil as well? To keep the oil topped up (like it recommends in the manual), I add about one quart per tank of gas (about 200 miles). I don't see a lot of leaking oil - just small stains on the driveway. It doesn't smoke or smell when it's running either. Is that a normal amount to lose?

2. When the car is warm and I let off the throttle, it often backfires slightly. I'm not sure if you'd really call it a backfire - it's a deep, round popping kind of noise (if that makes sense). It only seems to happen if the temperature is above 200 and the engine is at fairly low rpm and throttle. Is that normal?

[Flat Six, inc.]

The oil consumption sounds excessive. You should check the compression and leak down.......look at the plugs.

It's possible the car needs a good tune up but you may find the fuel injection needs rebuilding.

Exhaust leaks can cause backfire on decel too.

I hope this helps....

[Intheshop]

I think I would call both of those as "common" but not normal. The oil consumption is way high -- normal is more like a quart per 1,000 miles. As for backfires, those unfortunately can happen often -- but can usually be fixed with repairs. Causes for the backfire can be running too rich, poor timing, worn out muffler, etc. But even a perfectly running 911 may backfire just a bit -- coasting downhill when unburned fuel hits the hot muffler, etc. Sounds like a visit to a Porsche shop is in order to confirm that the engine/MFI is in good order. Good luck -- when I first bought my '71 Targa it took me almost 2 years to get it running well -- its paid me back with 16 years of fun -- so do not dispair.
SCOTT

[Jeff Higgins]

Boy, that is a lot of oil. Going through that much it should either be smoking like an old locomotive or leaving big puddles under itself. Are you checking the level in the same manner every time? Car warmed up (temp at at least 180 so the thermostat is open) idling on level ground?

MFI will backfire on decell at low RPM if the fuel shutoff system is faulty. There is a switch on the left end of the rack, mounted close to the #1 cylinder's stack, that is depressed by a phillips head screw on the rack when the throttle is closed. Make sure the screw actually trips the switch and it has both wires connected. This switch sends current through an RPM sensor to the shut-off solenoid mounted on the back of the MFI pump. Make sure the single wire is connected to it as well. Those are the two simplest things to check.

If all is well there, check continuity through the switch on the rack. If it's good, then check to see if the solenoid fires when current is applied to it. If it does, you might have a bad RPM sensor. It's under the plastic cover on the left of the engine bay. CMA describes how to test it.

The backfire really won't hurt anything. You'll see cars without the shut-off solenoid, usually race cars, but some guys even get rid of them on street cars. It makes for an impressive low "pop" and flash out of the pipe, anyway... Mine does it all the time because my RPM sensor just crapped out. Keeps the tailgaiters at bay for now. Someday I'll replace it, when it gets annoying enough.

[TRE Cup]

ok- basics first. Are you checking your oil with the car fully warmed up , engine idling , on a level surface? If not, you will not get an accurate reading. Being a dry sump system, the engine thermostat does not open and allow circulation to the tank (where you check level) till 180+ degrees have been achieved.
The difference between the upper and lower dimples on the dipstick is 2.5 quarts. We like to run the level smack in the middle. Why? because under hard use you can get some oil backing up into the breather/ air filter out of the system.
Third. While the car is idling and warmed up, does it puff out air from the oil filler neck? rev it up to 2500 quickly and let off. does any white smoke come out the tail pipe? try this again by driving up a hill with a long straight. On the way down, leave the car in a lower gear with you foot off the gas , rpm about 4k. See what sort of smoke comes out the tail pipe. this is an indication of worn rings

Check your consumption again using the above

[bbulkley]

I do check the oil with the engine warm and idling on a level surface.

I just noticed the other day that it does smoke, but not all the time. I see smoke out the back when I'm pulling away from a stop. Other than that I don't notice any.

I was keeping the oil level at the top mark. The manual said something about keeping the oil up if you drive in hot weather (I live in LA). Maybe it's just overfilled?

Speaking of mechanics, who should I see in the area? I live near Santa Monica and work in the valley. Are there good mechanics nearby? None of the independent Porsche shops I've talked to have a lot of experience with early cars.

[Paul Schooley]

Ya might wanna pull the air cleaner and see if things are all choked up in there with oil. Running too much oil will get up there quickly.

[porschefan]

new guy too.

I have some questions

1) I have painted head light rings, Can I just buy the chrome rings to put on my car? if so where can I buy? how much?

2)What happened to redline in santa monica,ca ?

[69Sman]

Speaking of mechanics, who should I see in the area? I live near Santa Monica and work in the valley. Are there good mechanics nearby? None of the independent Porsche shops I've talked to have a lot of experience with early cars.

Hey, I live in Brentwood and work in the Valley. In the Valley, I HIGHLY recommend TLG (Tony Gerasce) 818-982-7610. There is nobody in SM any longer, now that Redline is closed. You COULD try Specialists Inc on Lincoln, but ONLY IF Fred is still there.

If you feel like making the trek to Torrance, there's Callas Rennsport, also excellent. 310-370-7038. There are others, and I'm sure you'll get some other opinions, but these 2, you cannot go wrong.

[69Sman]

2)What happened to redline in santa monica,ca ?

Mark lost his lease and had to close shop. He called me about 2 weeks ago, and said he was hoping to re-open soon, however, in the Long Beach area.