78 928 runs rough and stinky rich

[RadioDjKev]

I am getting very frustrated! Can anyone help!!!

My 928 still runs rough. I think it is something minor.

I installed a new Bosch Alternator today on my 1978 Porsche 928. Now I have a charging alt and 14.5 volts at the battery when running, 13 when not running, I also charged my batt fully. Now The alt light go's ON when the ignition is turned on, and it go's out when started.

However My volts gauge still stay's in the red??

And my engine still running rough and very stinky rich.

[Danglerb]

You fixed a thing that needed fixing, thats a good thing.

Gauges in my 84 weren't working, and I was kinda frustrated sitting in the car one day, so I released the pod height adjustment and wanged the pod up and a down a couple times. I do NOT recommend this, but it did get my tach working awhile, and got it working the next time it wasn't. I've decided I won't do it anymore though, if it stops working I dig in and fix the grounds etc.

First thing to check on a CIS car is the fuel pressure.

If you want to shotgun, next target is the WUR, warm up regulator, which basically controls the air fuel ratio and gets gummed up when you have old gas.

[928inAtlanta]

Got a very basic suggestion for you if you haven't already checked..... pull your spark plugs and inspect them (and replace them especially if they haven't been changed recently). A bad plug can give you the symptoms you describe.

[RadioDjKev]

Still runs rough.
I changed all 8 plugs today and bench checked all 8 plug wires
(wires are good).
Still runs rough Very rough, not even drivable.
All of the spark plugs taken out of the right bank (1-4) were black and damp. Other plugs looked normal but were old, 1 was broke.
Still runs rough. I am really getting de-motivated.

[Danglerb]

I think you need to check your fuel pressures to find the problem, but if you want, wait til Monday and call Jim Bailey at 928Intl or Wally Plumley at 928 Specialists and they can talk you through some things to try. The one bank wet most likely will mean something to the guys that know CIS (I haven't looked at one in 20+ years).

www.928intl.com
www.928gt.com

[rhjames]

do you still have a rich condition on one "side" of the engine after new plug installation and wire check???


If so:

I believe you have an issue with your CIS fuel distributer.

If you have an excessively rich condition on one side of the engine, as the fuel distribution lines are routed that way, it becomes an indicator of a fuel distributer that either needs a rebuild or replacement.

There is no cheap fix for this, but the distributer can be rebuilt. there was one on eBay recently, freshly rebuilt, that sold for around $600.

Injectors may be an issue, but you can confirm or dismiss this by swapping injectors from one side of the engine to the other. if the rich condition goes to the other side of the engine, you have bad injectors. (To do this test, also put in a fresh set of plugs to get an accurate reading of fueling conditions.) I doubt that this is your problem....but you can do this before changing out the fuel distributer....

I do not believe you have an ignition issue, due to the placement of the rich condition plugs (only one side of the engine).


hope this helps------

[RadioDjKev]

Thanks,
That sounds like a good one.
But why only the right bank? Could it be a fuel regulator for the right bank?

[Danglerb]

You could always measure the fuel pressure and see. A gauge is like $35 at Harbor Freight (official tool supplier to the Porsche community).

[rhjames]

if you look at he way the injector fuel lines are routed, one half of the them go to the right side, one half of them go to the left. if the engine is excessively running rich on only one side, the fuel distributor is not functioning properly. in other words, it is fueling one side and not the other. it can be rebuilt, or you should find another one that is in good condition. I doubt you have problem with injectors at this point, considering the location of the cylinders you are having issues with.

There are no regulators for each engine bank.

[Danglerb]

Check this WUR info, but the author is of the opinion, buy a new WUR and drop the gas tank and clean before replacing.

http://www.landsharkoz.com/tt/ttwur.htm

[RadioDjKev]

My timing belt was on wrong, the right bank cam shaft was off 180 degress. The guy I bought the car from put the belt on and did not finish the job as he got busy with other projects. I bought it like that not running. He told me it was set right but it was not.

Anyways I decided to remove the cam covers and check all the alignment marks and there it was.

The car runs great and I drove it around today.

Thanks for everyones help on this.

Kevin

[Danglerb]

Congratulations!

Wow, thats a new one for a problem to me, but I can understand how the PO might have done it, just not why they would have left it, or not noticed it.

180 off would still show normal compression wouldn't it?

Maybe even run if the ignition timing was shifted to match (like swapping plug wires with the other bank). I have to wonder how far down the list would it be before normal trouble shooting found the problem?

[RadioDjKev]

no, I meant 90 degress off.

Well I finally got it all worked out with an oil pump, timing belt, and tune-up.
Also cleaned out oil pan. The car runs great!

Thanks