Sexy928Porsche

Hello,

I recently purchased my 1st 928 just a little over a month ago. I'm a novice when it comes to this car, so I need a lil help. Please.

For the past 2 days, I was driving her at normal speeds (55-60mph) in my area and all of a sudden, when I'm going up hill, she decelerates and will not accelerate pass 20mph. *Note(Cruise Control was not on). Once I get to level ground, she'll accelerate fine.

Yesterday I went out for about 10 minutes and she would not accelerate up hill at all! I managed to get her back home and I got out of the car and heard this Buzzing from the fuel tank area. Also, when I got back in the car, there was grayish-blue smoke coming out of the automatic shifter and the car had a very bad idle (it was trembling very badly), so I turned her off and haven't started her since. Any ideas and suggestions would be greatly appreciated!!!!!

Oh, prior to this issue, when I start her up (anytime, warm or cold start), at idle, she sounds as if she wants to stall, then gets louder and then stall sound again and loud again....any idea? She never stalls though.

Here's my info: 1987 Porsche 928 S4
Mileage: 71K
Automatic Transmission

Thanks!!!!

-Jennie

david928

Jennie,

Welcome to the 928 world!! I have the same year car as you.

The cheapest thing to do is replace the fuel filter. It could be clogged and the engine is starving for gas when under load.

I also have seen a small amount of smoke come through the shift plate after parking. That might be oil leaking from the cam covers onto the exhaust. Which may be unrelated to the acceleration issue.

There are many more knowledgeable people on this forum who will undoubtedly give their opinions.

Good Luck!
David

Sexy928Porsche

David,

Thank you for your suggestion!! I will do that!!! I thought it could have been a clogged fuel filter, but I wasn't too sure, so I thought I'd get a few suggestions from here. Thank you!

Oh, I was curious, maybe you might know since you have the same model year as I do, do I have one or 2 fuel pumps? Reason I'm questioning is because when I went to Autozone to get a quote on some prices, the guy at the parts desk asked me if I need the "in-line" pump our the outer pump? Any clue?

Thank you again.

-Jennie

Rich9928p

Hello Jennie,

Welcome to 928 owenrship. You do have a problem, the 928 has plenty of power to climb hills.

Do you get a service history for this car when you purchased it? If not, you should get this problem fixed and also replace the cam belt and water pump. A cam belt problem can cause bent valves and the repair cost can be over $5000!

Unles you have some mechanical experience, have a good set of metric tools, and have access to the factory workshop manuals I would suggest that you find a mechanic that knows the Porsche 928 - not just someone with Porsche experience - one that knows the 928. You will save time and expense because many Porsche shops don't know 928s and will spend time learning that you may end up paying for.

Now, back to your problems. Easy and inexpensive items should be checked out first.

When was the last tune up? No records??? Replace the air filter and spark plugs. If these items are old and not good shape, the engine will have trouble making power.

You may have a fuel restriction or failing fuel pump. The 928 has a fuel filter in the rear that isn't too difficult to replace - and also an in-tank fuel strainer. If you have no service history it makes sense to drain the fuel tank and replace both of these items (there also is a gasket for the in-tank strainer). After replacing these items I recommend a fuel pump test that checks three items

- pressure
- fuel flow (in 30 seconds)
- holding pressure after 30 minutes.

If these items are all ok, you go to the next level.

Corroded connections and grounds can cause problems. The connectors for the LH, EZK, spark final stage, and other items such as coil and spark plug ends should be all inspected and cleaned as necessary. There also is a big ground strap between the engine and chassis that should be cleaned and inspected at both ends.

Vacuum leaks can cause a loss of power (but rarely result in an over rich air-fuel mixture). Check for cracked hoses or plastic connectors.

Relays often can cause problems, normally you'd have a no start situation but it is possible that a bad relay can present a large voltage drop. An easy test is to toot the horn to make sure it works, if it does try this. One at a time remove the EZK, LH and Fuel pump relays and put in the horn relay. If your problem goes away replace that relay.

A leaking fuel pressure regulator or pressure dampener can cause an over-rich condition. These should be inspected.

What next? Check the Temp II sensor, if the fuel and spark controllers don't get an accurate reading of engine temperature you can have an over-rich fuel condition.

The next step is to check the mass airflow sensor - an easy test is to warm up the engine slightly, stop the engine, remove the connector and restart. This forces the LH into a limp-home mode where only two pre-set injection pulse widths are provided - but it is enough for the engine to run. If the engine runs better than odd are good that your MAF is bad.

A failing LH fuel injection controller can cause loss of power and an over-rich situation. The easiest test is to plug in a known good LH to your LH connector and see if the problem goes away.

If you need details about these tests, send me a PM and I can provide the information.

Good luck to get your 928 back to running 100%

dr bob

It sounds like one of the coils is 'dropping out'. The loss in power, the rumbling that's the pre-curser to a cat fire, all says one of the ignitions is shutting down. I use the word "pre-curser" because there will indeed be a lot of cursing if there's a cat fire.

As Rich suggests, start off with the basic tune-up and maintenance stuff. Check that the ignition wires are OK and that you have spark to both distributors after you replace the caps and rotors. Your car is 20 years old, and deserved new wires at 10 years. If yours are original (and many still are...) then it's past time for new ones.

Oh--

Congrats on your new car!

tv

Rich and Bob gave you great advice. Replace all those electrical things and you should be good to go. One other item is the flex plate issue. I hope it was checked before purchase and has nothing to do with your stalling out. Once sorted out, you should have many thousands of smiles per mile.

blown 87

You might want to check for clogged cats also.

Tommy928

Jennie,

Both of the coils went out on my 87' at the same time with similar symptom as your's. 928 International told me that there were bad batches of coils that year. By the way, my 944's also went out at similar age, same coil as the 928. The smoke you saw could be the cats getting too hot and starting to ignite the under coating. If you smelled gas then it is almost certain that the coils are bad. I read on this site that the ignition modules (in front of the raditator) could also cause the same sympton. In fact I changed my ignition modules first on my car before I realized that the coils were bad. What ever you do, do not drive your car until this is figured out as this is a safety issue. Good luck.