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Registered User
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New fuel head - setup help
Installed a used AI fuel head today and it won't hold fuel pressure when pumps are turned off?
I setup the WUR not noticing this, once I had it setup I tried to start the car and it won't turn over. Went to the back of the car and a fuel puddle is coming from the exhaust. Hydro lock! I pulled the plugs to let it dry out and back out the idle enrichment screw thinking it is holding the fuel open. But no luck? Can't hold the fuel pressure after the pumps tuen off. Is it a bad fuel head?? Please help |
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Registered
Join Date: Jul 2006
Location: S. Florida
Posts: 7,249
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What is a AI fuel head?
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Registered User
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Sorry, IA fuel distributor
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Registered
Join Date: Jul 2006
Location: S. Florida
Posts: 7,249
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Oh ok.. Thats a CIS Flowtech modified fuel head that they sold and put their own name on it. Hard to say what's going on with your system from the description if it's a used fuel head. Could be the fuel pressure regulator in it has problems.
A CIS fuel pressure gauge is needed to really diagnose things without replacing or rebuilding parts till it runs right. Hopefully a connecting rod wasn't hurt when it hydrolocked on the starter motor. |
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Crotchety Old Bastard
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iA had CIS-FT modify fuel heads for them that were turned up to max which is way too much fuel for most applications. After they went under I worked with Larry to gather as many as I could find and turn them back down to the proper level for the engines.
What you are describing is a major malfunction. Could be a stuck regulator as Jim stated or one of the valves. You would be best served to send it back to Larry for repair and recalibration so when it is fixed it will work properly with your engine.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds '78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8 |
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Registered User
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Thanks guys. I will put my original FD back in.
I think I have had enough of cis now. Thinking of selling my car to more onto a new project. |
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Quote:
I thought about selling my 930 to because I had a hard time getting all those stuf fixed. To be honest, it took me almost six year to get the car running like it supposed to do. Now she runs strong with everything working and still happy to have her. We all are so lucky that we have this forum where a lot of good people are willing to help the newbies, like I was ![]() |
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Registered
Join Date: Apr 2013
Posts: 19
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o-ring
i had the same issue with my 91 turbo. bended a rod this way. i disassembled the fuelhead to find out why i lost that much money and found that one o-ring failed. there is the plunger that moves up and down. its case has little rings arround every slit. one of these was gone. so the fuel was pressed through the weakest injector and filled one cylinder with fuel. not enough for water lock in my case so it turned and then hit the rod. in your case it seems there is more than one ring gone.
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Registered
Join Date: Jul 2006
Location: S. Florida
Posts: 7,249
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I know the oval shaped o-rings around the fuel head control plunger chamber you're talking about and wow that sucks... This is the first time I've heard of a connecting rod getting bent because an o-ring in the fuel head took a s... and flooded a cylinder hydro locking it while cranking the motor over on the starter motor..
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Registered User
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I think I might be lucky in that when I went to start the car it didnt even attempt to turn over. The starter just clicked. Once i pulled the plugs and waited a day, I turned the car over with no fuel, ignition and plugs still out to clean out the remaining fuel. It turned over immediately and sounds completely normal.
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