78 Euro CIS ?

rick2 · 02-08-2007, 10:29 AM

My know enough to get himself in trouble uncle has a 78 euro 911 3.0L all stock and bought it with the engine in boxes. I rebuilt the engine for him and he installed it in the car. He went to start it and finds a bunch of fuel coming out of the exhaust. He unpluged the fuel pump and now it wants to start for 10 seconds but dies quickly due to no fuel. I was told locally by two wrenches their thoughts were the check valve in the fuel distributor. I am an early guy speciallizing in webers and MFI so I don't know what to tell him. Thanks in advance.
Rick

Vin-barrett · Vin-barrett's Garage

Would the round flapper in the fuel metering "see saw" be stuck in the up position? Maybe not centered in the bore, touching the side?

rick2 · 02-08-2007, 11:13 AM

I told him to burp the system again and see if it is sticking. He says the CIS sat for a good year and a half.

RarlyL8 · RarlyL8's Garage

CIS is notorious for not liking down time.
To do it right you need to pull and clean everything from the fuel tank to the injectors. The system has very small tolerances and any amount or dirt or rust will cause a problem.
It is possible to hydrolock these engines; you may want to pull the injectors and jump the fuel pump to see what they are doing. Don't forget to change the oil when you're finished cleaning everything and it's running well.

rick2 · 02-08-2007, 05:56 PM

Thanks for everyones help! He has pulled the injectors and they seem to be spaying fine. The tank was dipped prior. Doesn't mean the lines aren't rusting but he said the fuel looked clear in a jar. I think the flapper is not closing all the way. Does anyone know how many mm of space for idle? I've warned him of the hydralocking and hope he stops prior but there sounds like a ton of fuel coming out of the exhaust. Oil change a very good idea as well.

Porsche_911s · Porsche_911s's Garage

Rick,

Did you guys have the gas tanked sealed? I had mine dipped by a radiator shop and it built up rust and is why I had FD problems. I figured out the tank was rusting by putting a glass filter (AutoZone) after the fuel pump. The inline fuel filter was just a temp setup to watch gas flow for about 10 minutes back into the tank. (cirulation). I was amazed at the amount of rust that was flowing in the system.

I took my tank up Hemphill and had it "Renu'ed". I'd have your uncle try this or something similar. Bypass the 911 fuel filter and just rig a hose to an inline filter. Run it back to where you fuel the car and into the tank. Let it circulate and see what type of trash (if any) is floating in the tank or lines.

rick2 · 02-11-2007, 01:40 PM

Good idea. We'll try it.

turbobrat930 · 02-12-2007, 05:19 AM

If I was a bettin man.....I would be almost certain that it is the metering piston in the middle of the fuel distributor. When the flapper valve moves up or down, this is the piston that it is actuating. CIS does not like allot of down time, and if you either have trash, water, or a combo of the above, the piston will sometimes stick open. That creates a continuous fuel flow to your injectors, and since the injectors are CIS injectors, and not electric, they will open up any time they see more than a set pressure.
IIRC, when the air plate ( not the correct term) opens from a flow of air, it pushes on the bottom of the pistin in the fuel distributor, causing it to move up in it's bore. HOWEVER, the piston is not attached to the air plate, so when the air plate moves back down due to a lack of air flow, idle or shut off, the piston moves back on it's own. ( fuel pressure usually helps this out). If the piston is stuck, it will stay in the open position, causing the above mentioned problem.
Take the fuel distributor off of the CIS box. ( where the air plate is), and flip it upside down, you will then see the piston. DO NOT break apart the distributor for any reason, as they do not make gaskets for these any more. Lightly clean the piston with brake clean, and a rag, or something else. And see if it works. You can take the piston out, as there is a retaining clip under the piston...
You can also source rebuilt ones for about $500.00 if you need to get a new one... or there are some good used ones for sale for about $400.00 good luck...hope this helps... Brad

rick2 · 02-12-2007, 05:53 AM

Thanks Brad, I told him to try it.
Rick