1976 911 Targa losing power

[South65ss]

Hi to all! Iīm new here and new to the Porsche world. I just purchased my first one (somebody told me I canīt have just one!) and of course I have the first headache.
This car has 240k km and seems like the previous owners didnīt took much care of it. The old man that sold it to me didnīt rode it for at least 2 years. He just started it from time to time but almost no movement in 24 months. I changed oil and filter and took it home. The man told me it was working great at the time he parked it, but everybody says that when selling a car. The fact is, it started fine and rode decently for about 30 km but I started to note that when I tried to accelerate more than 1/3 of the pedal travel it hesitated and stumbled severely. No power beyond 1/3 of accelerator. I was close to home so I arrived miserably using just 4th and 5th gears (really lucky to live very close to the highway).
Next day I changed spark plugs, fuel and air filters and checked oil level. Inside fuel filter I found some rust so next step will be fuel tank cleaning. The car started fine and run great for about 30 or 40 km and then exactly the same problem. Stumbling and lacking power. Seems like the problem starts after 180 degrees but Iīm not sure hi temp is the problem since the meter ends at 300. Donīt know, first Porsche experience!
Now, the engine looks good. Thereīs not a lot of leaking or abnormal noises (I have a Karmann Ghia, I know air cooled engines are noisy), I looked for stripped bolts and all that stuff and I couldn'tīt find anything strange other than one of the oil tubes that run under the rockers has a long heavy dent that could be restricting oil flow, but other than that the engine runs fine before reach at least 180.
So, does it sounds like a typical Porsche problem?

Thanks in advance!

[boyt911sc]

South,

When you get a chance, could you post pictures of the engine. I am particularly interested to see the left side where the CDI, fuel filter, and fuel accumulator are located. Have you checked your fuel pressures (control, warm, residual, and system)? Thanks.

Tony

[universeman]

If it were mine, I'd take it out and thrash that engine a while, rev it hard and get it hot, before I started throwing parts at it. Sounds like a 911 that hasn't been used lately like it was designed.

[wgirardot]

Originally Posted by South65ss

Hi to all! Iīm new here and new to the Porsche world. I just purchased my first one (somebody told me I canīt have just one!) and of course I have the first headache.
This car has 240k km and seems like the previous owners didnīt took much care of it. The old man that sold it to me didnīt rode it for at least 2 years. He just started it from time to time but almost no movement in 24 months. I changed oil and filter and took it home. The man told me it was working great at the time he parked it, but everybody says that when selling a car. The fact is, it started fine and rode decently for about 30 km but I started to note that when I tried to accelerate more than 1/3 of the pedal travel it hesitated and stumbled severely. No power beyond 1/3 of accelerator. I was close to home so I arrived miserably using just 4th and 5th gears (really lucky to live very close to the highway).
Next day I changed spark plugs, fuel and air filters and checked oil level. Inside fuel filter I found some rust so next step will be fuel tank cleaning. The car started fine and run great for about 30 or 40 km and then exactly the same problem. Stumbling and lacking power. Seems like the problem starts after 180 degrees but Iīm not sure hi temp is the problem since the meter ends at 300. Donīt know, first Porsche experience!
Now, the engine looks good. Thereīs not a lot of leaking or abnormal noises (I have a Karmann Ghia, I know air cooled engines are noisy), I looked for stripped bolts and all that stuff and I couldn'tīt find anything strange other than one of the oil tubes that run under the rockers has a long heavy dent that could be restricting oil flow, but other than that the engine runs fine before reach at least 180.
So, does it sounds like a typical Porsche problem?

Thanks in advance!

make sure your fuel pump fuse is free of oxidation; takes a few seconds and may solve your problem

[South65ss]

Originally Posted by boyt911sc

South,

When you get a chance, could you post pictures of the engine. I am particularly interested to see the left side where the CDI, fuel filter, and fuel accumulator are located. Have you checked your fuel pressures (control, warm, residual, and system)? Thanks.

Tony

Well, I just found some kind of epoxy sealer under the fuel pressure accumulator! I guess I have to start from there.

Thanks for the hint and will post the result after swap accumulator and check pressures.

Thanks again guys!

[boyt911sc]

Originally Posted by South65ss

Well, I just found some kind of epoxy sealer under the fuel pressure accumulator! I guess I have to start from there.

Thanks for the hint and will post the result after swap accumulator and check pressures.

Thanks again guys!

South,

Since you are doing the troubleshooting and we rely only on your feedback, could you post a picture of the section I mentioned earlier? Thanks.

Tony

[South65ss]

Originally Posted by boyt911sc

South,

Since you are doing the troubleshooting and we rely only on your feedback, could you post a picture of the section I mentioned earlier? Thanks.

Tony

Ok, Iīm not with the car right now but I asked a friend to send me a couple of pictures. Heīs not a great photographer....

[93nav]

After the car starts to run poorly, how long do you need to wait before it will run good agian? Hours, a day, until the engine temp is lower? This info may help the diagnoses.

I am not even close to being a mechanic, but two thoughts occur to me. Is the fuel tank vent plugged? To test, when this problem occurs, take off of the fuel cap and see what, if anything that does. The other thought is that the coil may have issues when it gets hot. Not sure how to test that, a digital mulitmeter? (cold, and when hot). Again just some thoughts from a complete amateur. And a bump to the top.

[timmy2]

Change the fuel filter.

[South65ss]

As soon as it cools down a little it works fine again. Half an hour is enough.
Fuel filter is new and the vent of the tank is working properly.
One thing I forgot to post is that when it turns really undrivable it starts to idle at around 2000 rpm and that becomes the only usable range.
I ordered the fuel acumulator yesterday but I have to wait at least two weeks to receive it. This saturday I will check the fuses and fuel pressures.

Thanks.

[gomezoneill]

Remove the fuel tank sender and look inside the tank with a flashlight could have a rust issue. Only takes a couple of minutes to check.

[Flat6pac]

Another possibility is the points in the distributor are collapsing. Check against dwell meter.
Bruce

[South65ss]

Yes, there's a lot of rust coming from the tank but first thing I did was change the filter and the problem remained exactly he same. I will clean the tank but I don't think that's the main problem. I also have distributor cap and rotor on its way.

Thanks!

[South65ss]

Well, tank is clean and new pressure accumulator was installed. Now it started to fail even before reaching temperature! Will change the fuel pump, which looks like itīs the factory one and Iīm still to check fuel pressure.
Any other clue??

Thanks!

[zelrik911]

This could be easy to fix - happens on this era 911 very often.

Check your Fuel Pump Relay (Red - 1st one) in the trunk.
It can come loose, then fall out.
It also can fail. Buy a spare red one.

[Targalid]

As per post #12, check your ignition point gap: Your symptoms can be explained by improper point gap. It is easy to measure and takes less than 5 minutes. Don't buy parts without a good diagnosis. Measure the fuel pressure before you buy a fuel pump.

[RSTarga]

Check the filter at the bottom rear of the tank, sounds like the pump pulls debris into the mesh and reduces fuel flow.

[Charles Freeborn]

CIS equipped car that runs poorly when warm or hot sounds like the WUR is not operating correctly.
There are many threads about "waking up" a car that has sat for a long time. Use search for that.
My short list of things to do is: flush all fluids, change all filters (including the screen at the bottom of fuel tank) change all ignition parts (plugs, points, plug wires, distributor cap, rotor) , adjust valves, charge battery, then try to start it. If no-go or not good, check fuel pressures of CIS, and check all injectors and their seals for proper operation.
Before you drive it, flush & change brake fluid, inspect all brake lines and calipers. You will probably need to change flexible brake lines if they have not been done in the last 10 years. Tires too.

What ever you do DO NOT run it hard to "blow it out" until you have gone through all the above. If the cause of your problems is a clogged injector, running it hard (while in a over lean condition) risks serious damage.
-C

[Spumato]

Agreed, I would start with flushing and cleaning your fuel tank, replace your fuel pump, new accumulator, new fuel filter, replace all fuel lines in the engine bay from supply side to WUR, to fuel distributor, and return. Then I would order a rebuilt fuel distributor. You will need to obtain a electrical meter and measure the voltage of your WUR. If it's not working, she'll never run right. Also, sitting for 2 years is just death on these machines. They behave much better when driven weekly. And I would also replace your coil. And this is just to get it running right. Chances are you will continue to run into many more issues that will continue to creep during the short-term that all stem from the cancer of sitting. Running the engines do little justice other than move oil around. And considering that these units do not do most things right until warm, 210 degrees, just running the engine isn't enough!

[Spumato]

Sorry to offer disheartening news, but welcome to pcar ownership.

They are expensive vehicles but well worth the investment.
In addition, if your 76 still has heat exchangers and has never been rebuilt, you may want to look into a rebuild. Get rid of the heat exchangers asap, and find 74 or older style SSI's.

Good luck! Use this board. You will be thankful for it.