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 1987 S4 Engine Has a Bad Cold 
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Granny Driver

Joined: Wed Sep 28, 2011 7:22 pm
Posts: 19
Location: North Alabama
Post 1987 S4 Engine Has a Bad Cold
Just bought it and had it towed home yesterday. (you can see pics in the pictures forum). Originally I figured the cats were shot, so I put a vacuum gauge on it this morning and at idle it reads low, but steady. Vacuum gauge says late ignition timing. I then revved it up to 2500 rpm. Gauge indicated good steady vacuum in the green region. Maybe my cats aren't fried after all...

When I cut the car off, there was a smell, like maybe unburned gas - not sure, but it didn't smell like a good running engine should.

I then proceeded to do a compression test. Pulled all eight plugs, but haven't performed the test yet. Will do this tomorrow.

Anyway, on the driver's side I noticed that 3 or the 4 plugs were literally coated in oil when I removed them. I don't believe its from the combustion chamber, but more from the o-ring leaking into the spark plug hole. If this oil got in the combustion chamber when I removed the plugs (and I'm sure some of it did) it may affect the compression readings.

Will report back on what the compression tester reveals...

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1987 928 S4 - 5 Speed


Sat Oct 01, 2011 7:12 pm
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Post Re: 1987 S4 Engine Has a Bad Cold
Interesting. Looks like you got a good handle on testing things through. Keep us posted.

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1981 Porsche 928 "Euro" 4.5 Litre Auto Gunsmoke Metallic Flat - Black Interrior
1983 Porsche 928S "US" 4.7 Litre Auto Light Bronze (Copper) Metallic - Brown Interior


Sat Oct 01, 2011 10:20 pm
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Granny Driver

Joined: Wed Sep 28, 2011 7:22 pm
Posts: 19
Location: North Alabama
Post Re: 1987 S4 Engine Has a Bad Cold
Ok. Results of compression test:

Driver side, front to rear:

170 190 190 180

Passenger side, front to rear:

180 155 170 160

I figured the Driver's side would be a little high because of the oil leaking into the cylinder when I pulled out the spark plugs, but I believe the compression looks good. On the passenger side 155 & 160 seem a little low to me - but I don't have the specs for compression. Anybody know what they are?

Also, where is a good book source of 928 engine rebuilding, specifications, maintenance, etc? I got three manuals with the car, one for ABS, one for general light maintenance, and one for information only. I was hoping I had better documentation than this - so now I need to find some real documentation. Any good places to look/buy?

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1987 928 S4 - 5 Speed


Sun Oct 02, 2011 7:59 am
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Post Re: 1987 S4 Engine Has a Bad Cold
Roger at 928srus.com sells a DVD of the WSM (Workshop Manuals). Give him a try. Before thinking of rebuilding. Your numbers look fine. Not a lot of us here on this forum are S4 experts but lot's of talk about checking Crank End Play, Temp II Sensor that is moot on the earlier models. Your going to have to do a full Intake Refresh first of all and a Timing Belt/Water Pump if you have no history on your car. Especially since you have a 32v.

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1981 Porsche 928 "Euro" 4.5 Litre Auto Gunsmoke Metallic Flat - Black Interrior
1983 Porsche 928S "US" 4.7 Litre Auto Light Bronze (Copper) Metallic - Brown Interior


Sun Oct 02, 2011 10:41 am
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Granny Driver

Joined: Wed Sep 28, 2011 7:22 pm
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Location: North Alabama
Post Re: 1987 S4 Engine Has a Bad Cold
Thanks for the link and the information. I'll email Roger here shortly as I cannot find the WSM on their website. BTW, what is up with the intake refresh? Can you give me any information as to why it is needed and what it involves.

Agree on the timing belt. Its on the list..

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1987 928 S4 - 5 Speed


Sun Oct 02, 2011 12:36 pm
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Speed Limit Obeyer
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Joined: Thu Mar 17, 2011 7:37 pm
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Post Re: 1987 S4 Engine Has a Bad Cold
id definitely get new fuel lines while your at it from roger if you dont have replacement listed in the history under 10 years.

here is the cd/dvd mpdano is talking about, also known as the jim moorhouse cd and contains not only the workshop manuals in digital form, but lots of other helpful information as well from what i hear.

This also may help: http://dwaynesgarage.norcal928.org

Dwayne who is a very well known pictorial guy has done many complex-operation-demystified write-ups for the later models, here is his intake refresh:

http://dwaynesgarage.norcal928.org/1987 ... efresh.htm

Best of luck!
Jonathan.

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Porsche 928S - 84 (Quartz Grey Metallic)
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Euro Intake manifold/Cams/Injectors, Headers
Left to do/fix: Sunroof,electric locks,some interior, paint body,replace hood lining, bad gas milage
A little of a fixer upper, but a labor of love!


Wed Oct 05, 2011 2:34 pm
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Granny Driver

Joined: Wed Sep 28, 2011 7:22 pm
Posts: 19
Location: North Alabama
Post Re: 1987 S4 Engine Has a Bad Cold
Boy - that pictorial from Dwayne is fantastic! Thanks for the links!

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1987 928 S4 - 5 Speed


Thu Oct 06, 2011 8:07 am
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Granny Driver

Joined: Wed Sep 28, 2011 7:22 pm
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Location: North Alabama
Post Re: 1987 S4 Engine Has a Bad Cold
Update..

This past weekend I checked all 8 plug wires with an ohmmeter and found them all within spec. Replaced with new spark plugs, I then put a timing light on each of the 8 spark plug wires. Found 4 to be working and 4 not working. Thought it was the distributor cap, but it checked good - then I saw that the ignition coil on the driver's side had puked its guts out!

No one in town had one, so I had to order one - should be here this afternoon!

Oh, BTW - I know have the Jim Moorehouse CDs!

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1987 928 S4 - 5 Speed


Mon Oct 10, 2011 9:41 am
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Post Re: 1987 S4 Engine Has a Bad Cold
post up the pics of the bad coil.

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1981 Porsche 928 "Euro" 4.5 Litre Auto Gunsmoke Metallic Flat - Black Interrior
1983 Porsche 928S "US" 4.7 Litre Auto Light Bronze (Copper) Metallic - Brown Interior


Mon Oct 10, 2011 9:44 am
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Granny Driver

Joined: Wed Sep 28, 2011 7:22 pm
Posts: 19
Location: North Alabama
Post Re: 1987 S4 Engine Has a Bad Cold
You can see here where it puked on the engine bay...

Image

Picture of the coil removed...

Image

Picture of the coil itself after removing the protective cap...

Image

Gonna pick up the new Bosch coil this afternoon after work and do the install - provided it doesn't rain. I think we're suppossed to get rain this afternoon..

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1987 928 S4 - 5 Speed


Mon Oct 10, 2011 11:18 am
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