sirbower

Hello, I own a 1983 Porsche 928S 4.7 Liter 5 speed manual transmission.

The engine seized and I changed the old CIS engine with a used 1983 4.7, Liter Jetronic Fuel Injection engine. The replacement engine came with the Fuel Injection Control unit and the Fuel Injection Wire Harness.

I installed the engine and the harness/control unit and now have a technical problem: The engine starts but stops within a few seconds. I troubleshooted the fuel pump, it works... My problem is the injectors are not dispensing fuel to keep it running. I pulled the 35 pin connector and determined I do not have power at the two AFC 12 VDC pins. The 35 pin connector grounds are working. There are also 2 other wire lines from the fuel injection harness, I am unsure where they go or what they do...

Any insight?

CW4 Johnny Bower
AH64D Longbow Pilot - Backyard Mechanic

DANdeMAN

Fuel injection relay?..... XVI

James Bailey

It sounds like your car was a Euro spec CIS which means the fuse relay board is much different odds are you are starting on the cold start injector only and once it shuts down you are done. There are many differences between th CIS S 4.7 and the USA Jetronic...not to mention about a 70 HP deficit ! The CIS is basically mechanical but the Jetronic needs more information from the engine to run properly.

sirbower

The fuel injection relay slot was empty. I used the intensive washer relay in its place.

sirbower

I believe the car was modified from a L Jetronic to a CIS, but I do have the Blue 8 pin connector attacked in the next to last spot on the right side.

Note: I have a wire bundle with a Black 8 Pin Connector that was laying behind everything, but I do not have an open Black slot???

James Bailey

How about posting a vin # or if it has ZZZ in the sequence ?

sirbower

VIN# WP0JB0925DS860456

James Bailey

OK was a USA car that was "retrofitted" with a CIS engine wonder if it was a Euro S or just a 78-79 USA ?? get the engine number off the block so we can see what it was and if it is an S the heads and cams and intake are valuable ! I would give you $500 for them Also not sure what you mean by this..."The fuel injection relay slot was empty. I used the intensive washer relay in its place. " they are different relays different functions you need the 928 615 119 00 injection brain relay for it to work as designed....

sirbower

I will purchase a AFC Relay, I did read on rennlist the IW relay would work...

The engine stamp number is M28/19 81D 0482

danglerb

Thats USA 83/84, but what about the old motor?

With a motor swap car, chances are great that the previous owner made other creative changes, so I would not assume anything about the electrical system. If you plug in something wrong, or short some wires you will release the magic smoke that makes the car run, and repairs will become less fun.

sirbower

Victory................

The car now starts, remains running and runs smoothly.

I bridged the 30 slot and both 87 slots on the AFC Relay, I have ordered the missing AFC Relay.

Thanks to all that provided guidance.

My military leave ends in in 6 days and it is time to go back to the box.

I am very happy to know I will drive the 928 before I leave.

End of thread...............

CW4 Johnny Bower
AH64D Longbow Pilot - Successful Backyard Mechanic ...............

James Bailey

M28/19 is a USA 4.7 ....