LexKY928

Hi all! It is nice to finally have another 928, I sold my last one about 9 years ago, I sure wish that sites like this existed back then as most of my repairs were trial, error, and luck. But on to the question, my 85 928s that I just bought last week has shown a persistent problem(besides a handful of the usual gremlins) In the morning, when I start the car she idles a little rough, but runs like a scalded dog when I take off. After she warms up to operating temps, she stutters and bogs real bad every time I take off from a stop, she will not smooth out and pull strong until the revs get over about 3500 or so, unlike when she is cold and pulls strong from idle all the way up. Any ideas? I have already ordered plugs, wires, caps, rotor buttons and coils just for piece of mind. Is it likely that once these parts are installed(sometime next week) that my hot performance issue will go away, or should I be looking at something else?

On another note, I have to say that this has to be the premier forum for 928 knowledge. I have been reading non-stop for several weeks now. I have previously owned a 78 5 speed, and an 83 S euro Automatic, and finally found a decent example to purchase to satisfy my 928 passion(1985 S auto, Grand Prix White, White leather interior, White carpet 125,000 miles for $3000). The exterior and carpets look like new, but the sun has faded the leather on the doors and seats, but that will be taken care of once the mechanics are in shape.

I am looking forward to being a faithful helper when I can be, and of course a faithful reader always. Thanks in advance for any suggestions.

Ron Tussey

Lexington, KY

jpitman2

Ron,
Sounds like the temp sensor has gone open circuit, or not reducing resistance as it warms - easy cold starts, but rich once warmed. Signs of excess fuel when hot? black smoke? IIRC, the sensor should go from 3k ohms cold to around 250ohms hot - locate the connector, pull off the sensor, bridge with something between 200-250ohms, see if that helps. If it does, put a dvm on the sensor and check its readings. COuld also be the connector or the cabling, or the brain.....or something else entirely.
good luck, welcome back.
jp 83 Euro S

GoRideSno

Welcome! $3k is a steal for that car. Can you post a pic of the whole car?

Andy K

PorKen

I'll wager it's the MAF.

Jessa

wow, triple white. Its like a 928 angel. Beautiful.

Sias

I had similar problems recently. after I tested and replaced just about all of the aforementioned items, I found out that the MAF went bad. I suggest start checking all the items one by one, the MAF would be the most expensive part so you want to make sure it is not something else before you replace that.
Sias
85S (US 32v)

DG84S

Ron,
Great find! She's a beauty. When you get around to the leather, check out the folks at http://www.leatherique.com/

LexKY928

Thanks for all that have posted so far. One question about the temp sender, is there more than one temp sender, as the guage works fine. I seem to remember I had an older mercedes that had one for the guage, and one for the fuel injection computer.Hmmm....... I have my fingers crossed that it is not the MAF, however I guess I'll cross that bridge when I get there.

Does anyone know how rare the triple white option is(was)? I like the way it looks, but I can not imagine too many people ordering white carpet...I'm sending off for the Kardex just to make sure it is all original.

I'll update as soon as I t-shoot a little more tonight.

Thanks,

Ron

LexKY928

OK, I have replaced plugs, wires, coils, caps, rotor buttons, and misc. vacuum lines I am still having a performance issue. There is no smoke at start up, but on a cold start the engine stumbles a little and I think I have heard it "backfire" a few times. A warm start is no problem but there is a lack of performance that should be there. Is there a simple way to test the MAF? The old plugs looked fine, like the mixture is/was okay. I am at a loss of where to check next. TIA

Ron

Red UFO

You should bump this thread with more PICs!!!

Back seats, pod, carpet, etc... Excellent price on your shark..

John Speake

Hi Ron,
Welcome to the list. If you still have problems after changing the ignition leads etc., and have checked out temp sensor 2 hot and cold, also check there aren't any air leaks into the inlet system.

Also worth checking out the O2 loop sensor. The system works open loop before the engine gets to normal operating temp., and then works on the loop thereafter

If after all that you think it might be the MAF, you can borrow one from my US agent, who has one in stock, on a sale or return basis. If it turns out not to be the MAF, return it to the agent, and you will just pay my expenses, $33.

If you keep it, it's $350 exchange

Regards,