Yet another update

max29a · 01-25-2005, 09:13 AM

Hello all,

As you may be tired of hearing about now, my car dies while I am driving, under accel or just idling, about once a day.

For Xmas my aunt got me shop time at her "high end" german mechanic in LA. They are not a porsche shop but they are german, and seem to do mostly Mercedes. I did see a TVR there, and when I came to pick my car up I saw a 928, but I think I should not have brought it there.

They had my car for 3 weeks and they smogged it and ended up changing the ignition coil and said they thought they had fixed it. They did not, it still dies.
They also said that it sounds like a rod is knocking and that the engine will die someday sooner rather then later, and seperately they said I should only put 92 octane gas into it. I said the manual said to put 87 and they said nowadays 87 is not what 87 used to be in 1980s.

I am wondering if any of this makes sense? I asked the PO about the rod knock and he said "That's the woodrif pin behind the cap and rotor." and not a rod knocking. He also said there were only 5k miles on the coil and they should not have changed it.

And I believe that I have read here that 92 octane gas really isnt neccessary unless you are getting knocking or pinging (which I am not).

What do you all think?

Zero10 · 01-25-2005, 10:24 AM

92 octane gas will be of no benefit in a N/A car, unless you have a very high compression ratio, or very advanced ignition timing. That's a load of crap.

As for the knocking, without hearing it in person, I would say the best thing to do would be to get a stethescope, and check out where it's coming from for yourself.

How is your oil pressure at a warm idle?

scottmandue · 01-25-2005, 11:13 AM

There are a couple of good 944 guys here at this board in your area, if you try starting a thread "looking for good mechanic in S. Barbara area" you might get some good advice... or maybe some free help.

TCMdocs944 · 01-26-2005, 07:30 AM

The PO didn't really know jack.

Woodruff pin shouldn't cause any noise......(*shaking head in silence*)

The mechanic is wrong about the gas.

The mechanic may be right about the bearing. (or not) You do have 255k on the clock. If you do decide to go all out, I would pull the whole engine and do the full rebuild to include seals, belts, gaskets, and bearings. Not really cheap but the engine could go another 255.

mattdavis11 · 01-26-2005, 09:19 AM

The knock may be the #2 rod bearing. The dying issue could be a faulty dme relay, which is common.

max29a · 01-26-2005, 09:42 AM

Thanks for all the suggestions as usual.

So far:
new ignition coil
3 new dme relays
new cap and rotor
new fuel filter
new throttle position sensor

I would like to start checking for vaccuum problems. How would I go about doing this?

SoCal Driver · SoCal Driver's Garage

Check the wires to the speed and reference sensors. Adjust the sensors.

nynor · 01-26-2005, 10:01 AM

the sticker on my car says to use 93 octane gas...

TCMdocs944 · 01-26-2005, 10:12 AM

The sticker is using the RON (euro) = 87 american

nynor · 01-26-2005, 10:39 AM

i see.... i'll take another look at it. i'll probably stick with the high octane anyway.

mattdavis11 · 01-26-2005, 11:11 AM

my 83 says 91 ron. equates to 87 octane if you look at the pump sticker.

pokey · 05:37 PM

The owners manual has a good diatribe on octane. It says to use 87 and why. You will actually get worse mileage and less power running high test gas, as it burns more slowly, and your dme sets the timing for 87, so you don't get a full burn during the power stroke, and you're running with retarded ignition. It will also raise the emmssions your car produces.