+1 on that bring it back to stock > Most likely the switch was a attempt to avert a problem.
sitting that Long I would pull the plastic fuel tank and pressure wash it all out . The fuel
" Ethanol " has turned to goo / crud . Hot water and TSP works good along with several washes until finally it begins to come clear . Get the Pump working with fresh Gas and pump the fuel rail out of all the old crud . You can hook it to a clear Bottle if you want to see it . Save a bunch of time and next run a compression Test Next
( good screw in gauge ) and see if they are Evan enough to run smooth + or - 15 %
Test for basic good spark from the coil and plug wires . Look for bad or disconnected Vacuum lines . If they are sad looking replace them all .
Water Pump's get stuck Easy on these cars and brake things so if upon start up you hear front motor noise from that area "timing belt / cam gear / water pump / stop the motor and pull covers and investigate the front of motor .
You have a Interference motor so if something brakes hummm

Nice looking car, good luck with your new endeavor.

Brian.

to install/ remove the starter i would suggest to get a allen wrench and cut off about 2 inches of the long end,
this is used to turn the allen bolts in the starter with a box wrench.

for the fuel pump make sure you have 3 new sealing washers,
and a new hard line.
NOTE the hard line will be needed if the old line was over tightened thus crushing it.

always use new sealing washers ,
so its a good idea to get multiples of 3 to always have a spare set.
I like to remove the check valve from the pump and add some PTFE sealant to the threads with a new sealing ring then make this tight,
use a dab of anti seize on the capnut threads along with 2 fesh sealing rings

Another thing to be aware of if your experience is mainly on English cars,
English cars, wiring, -all brown wires are POWER
Porsche, all brown wires are EARTH
_that's a great looking car, they look superb in white.

Newbe with 928 S
 

Well Thanks so much for all the info and kind words, I finally got all the parts together ,Starter,fuel filter Fuel pump. starter was a snap moved on to dropping the fuel filter out it had so real dark Gack inside then I removed the fuel pump Even worse. I removed the fuel gauge and Wholy poop Batman nothing left of it it came out in pieces. also the flapper in the filler neck was rusted shut and when I put a funnel in it broke off.. fished it out with a magnet. My clothes smelled like dead gas (wife would not let me in the house . had to strip to my skivies in the garage) ordered a new fuel gauge and new hoses, plan on dropping the tank on Mon. I have to figure a way to flush the inj rail and the injectors, before I try to start it. . Having fun. with my new German car..

Gas Tank Removal -
 

Hey Jagawar, You'll find that the removal of the 928 gas tank is fairly straight forward and will appear to be an odd shaped, fat bottom horse shoe looking thing once it's out. As you begin the removal process be aware of a short length of hose about as big a round as your thumb that jumpers or balances the sloshing fuel between each side of the horse shoe (main tank and filler/gas cap opening. The problem is this hose runs through a sheet metal panel/grommet and because it is a little hard to get at - should be cut to simplify the removal process. It is actually not difficult to replace during tank reinstallation with a new hose and a couple of clamps.

Usually the original hose has long since rotted off at one end or the other and for a new 928 owner can be a surprising source of a substantial leak if the tank has ever been completely full of gas. Don't ask - :)

Good Luck, Michael

Newbe with a 928S
 

Well I tried to start it with an aux gas can . Starter works like it should. However my New Aftermarket fuel pump is Not working.. I jumped to straight off the batt and still nothing not even a burp bump or smoke just nothing.. presently soaking the old pup in Lac thinner trying to get the crud out,, maybe it will still work

try running the pump backwards by reversing polarity .

NOTE use MMO instead of flammable liquids,
as you could spark a fire with a stuck pump sparking at the studs

newbe with 928 probs
 

Well here is an update we ran a pressurized fuel line direct to the fuel rail ,. Engine wants to start but won't . Cked spark at the dist. No spark , Engine now turns over like normal. What do I ck next I am now realley lost with computerized systems/.

928 no start
 

I suspect a bad CPS can anyone tell me where it is and how to test? How can I test the dist to see if it is getting power from the mod. ?

Nice buy! I'd love to see a side-view. :)

have you done the CE panel refresh? did you replace the 3 running relays? and the fuel pump fuse?

928 prob
 

no not yet I put in a new fuel pump and jumped it direct with 12 volts still would not work presently sending it back and purchaced another one. also took a long shot and bought a CPS I figure i would need it someday. What is the CE panel? and where is it?

I would suggest that you get a WSM the one on CD is good .

CE = central electrics panel, located on the passenger forward foot well
WSM = work shop manuals

Thanks I will

Afraid I don't have anything technical to add.

Nice looking car, though - definitely worth the effort to get running again! I've owned several XJSs and an assortment of German vehicles, but no 928 yet.

Cheers from a fellow Jag lover and aspiring 928 owner!

Porsche 928s No start Poss bad CPS
 

Well I received the part today, Now I need where exactly to put it Where is this Bugger located? I think someone said it is under the air breather ? Is that correct. Any special tech, to remove it? Regards Mark

wpojbo928fs861779

Ability to curse in German might help, remove the correct one, iirc there are two of them with one only used for diagnostics? I might be thinking of a different model though. Look around the top of the bell housing directly above the flywheel.

newbe 928s
 

I found it I almost removed the wrong one though it was the diagnose one finaly got the little bugger in and finished the fuel system , I found some other probs blown fuel pump fuse missing relay also jumped out. Got her running runs rough so I am changing spark plugs tomorrow and putting in a little fuel inj cleaner, ordered some touch up paint I will have her spiffy in no time