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-   -   engine will only idle (http://forums.pelicanparts.com/porsche-911-technical-forum/354874-engine-will-only-idle.html)

jtparr 06-30-2007 01:57 PM

engine will only idle
 
hi from a wet and windy UK

the restoration of my 75 model year Euro spec 2.7 Carrera was all going to plan until we fired up the engine after having had it laid up for over 2 years

Its been backdated to an RS Touring look body, in gleaming shiny black,

the restoration is on the DDK site if you'd like to have a look

http://www.ddk-online.com/phpBB2/viewtopic.php?t=12123


in simple terms it will only idle and no more, and its a hell of a mystery

over the last 2 weeks I have generally checked

fuel pressure
connections of all fuel lines
fuel filter
timing
MFI pump rack movement
MFI pump timing
delivery of petrol through the injector pipes


and now have absolutely no idea what to do next...all very depressing

there's a long post on the DDK site

http://www.ddk-online.com/phpBB2/viewtopic.php?t=15535&postdays=0&postorder=asc&sta rt=0


just wondered if this struck a chord with any of you folks, it must be something either fundamental or just plain simple, which I cannot see



help please


thanks a lot
Jonathan

unclebilly 07-01-2007 05:45 AM

Is your throttle linkage connected?

Purkinjefibre 07-01-2007 06:19 AM

2.7 trouble
 
J, read through your DDK story. You say before the resto that it was running OK- a bit vague, was it really running well or not? Anyway it sounds like fuel pressure to me also. There is only one thing that sounds troubling, POR15 treatment of CIS petrol (gas) tanks can cause narrowing and or blockage of the fuel pickup lines that leave the gas tank. I don't know if anyone has reported similar difficulties with MFI tanks. Simple test would be to feed fuel to your MFI fuel pump from an unrestricted source, e.g. a fresh fuel line running to a fuel can (fire extinguishers handy, as always).

Good luck

jtparr 07-01-2007 11:25 AM

hi Purkinjefibre

I'd go with whtat you say except that I have managed to easily get the 1 litre of fuel delivery in 30 seconds in a test run

also as of today took one of the injectors off (as it enters the engine block end) and put the end into a small jar

filled about 1cc in 10-15 seconds and came out in a fine mist, so I think petrol delivery is OK


I did renovate the tank but flushed it out with about half a litre before I connected up the outlets, so I'm fairly sure its clean......

thanks for the reply

jonathan

DanielDudley 07-01-2007 03:02 PM

Mouse nest in exhaust ?

bigchillcar 07-01-2007 06:32 PM

timing? everything on the list is fuel-related. what about ignition concerns? granted my early car background only goes back to 1974 and cis..

JP911 07-02-2007 04:23 PM

I'm with Ryan. Start going through the ignition, starting with a timing check. It sounds like you're not getting any advance.

bigchillcar 07-02-2007 05:51 PM

Quote:

It sounds like you're not getting any advance.
yep.

jtparr 07-03-2007 01:17 AM

thanks

have done a simple timing check, but will do it again this weekend a bit more carefully

jonathan

bigchillcar 07-03-2007 06:08 AM

check both static and dynamic timing.

svandamme 07-03-2007 02:11 PM

plugged vacuum ports on the throttle bodies or vacuum lines perhaps?

94teener 07-03-2007 02:26 PM

I had a similar problem with my '77 911S - not exactly the same symptoms but it could well be the cause of your problem - check the vacuum hose leading from the brake servo to the engine. The hose is well hidden from view. My car ran like ****e for about 6 months and I went absolutely mad checking everything to no avail. I finally took it to my mech. and he diagnosed it quickly as that hose had split - $5 hose and now runs perfect.

Good luck!


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