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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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 Posted: Tue Oct 11, 2011 7:56 pm Post subject: fuel lines |
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| i bought a 79 auto 924 a few weeks ago ,but it runs very rough and wont rev out or idle,i was comparing the fuel lines positioning to my other 924,and they seem to be placed differently,would this make a difference to the order of fueling in relation to firing . |
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stevekat
Joined: 19 Jan 2008
Posts: 719
Location: Los Angeles, CA
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| Posted: Wed Oct 12, 2011 3:44 am Post subject: |
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The CIS fuel injection in not sequential.
_________________
"Never get out of the boat. Absolutely goddamn right. Unless you are goin' all the way."
Gone to new home: '81 924T, US version, CGT Intercooler, UTCIS-PT, Euro DITC, Greddy Trust MBC, Forged Fuchs Flat Dish 6's, Factory Recaro's. |
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porscheboy79
Joined: 25 Oct 2010
Posts: 65
Location: Sydney , Australia
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| Posted: Wed Oct 12, 2011 5:27 am Post subject: |
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Hi spannernut.
Is the flap under the fuel dissy smooth going up and down?
You could do a test on the injectors by doing the time vs flow test.
Also how is the dissy for the spark plugs? points ok? timing right? because they would do what you have discribed.
Shane
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79 924. 100kph + wall at Mt Panorama = Gone.
77 924 SPIRIT project for racing. |
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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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| Posted: Wed Oct 12, 2011 6:12 am Post subject: |
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| porscheboy79 wrote: | Hi spannernut.
Is the flap under the fuel dissy smooth going up and down?
You could do a test on the injectors by doing the time vs flow test.
Also how is the dissy for the spark plugs? points ok? timing right? because they would do what you have discribed.
Shane |
to tell you the truth porscheboy79 ,the first thing i checked was the timing,thats spot on, incidently its electronic ignition, at some stage the fuel lines were changed using braided hoses,resulting in the injectors being very flexible.
as for the fuel distributer ,it seems ok as does the airflow meter [flap ]
strangely enough its got a weird head on it,that has reset plugs in ,so i'm assuming the heads been changed.
i have a spare set of fuel lines that i will fit on and see if that makes any difference,failing that i have another 924 ready to be stripped ,with a very good motor in it,but i had planned to use that in another 924 i have.
but thanks all the same for the advice |
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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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| Posted: Wed Oct 12, 2011 6:13 am Post subject: |
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| stevekat wrote: | | The CIS fuel injection in not sequential. |
Thanks very much for that stevekat ,thats good to know. |
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Ozzie
Joined: 12 Mar 2005
Posts: 4448
Location: Townsville, Qld. Australia
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| Posted: Wed Oct 12, 2011 7:44 am Post subject: |
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Double check the timing.
The flywheel and cam pulleys can both be fitted wrong.
Firing order, plug leads and vacuum leaks can play havoc
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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| Posted: Tue Oct 18, 2011 4:24 am Post subject: |
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| Ozzie wrote: | Double check the timing.
The flywheel and cam pulleys can both be fitted wrong.
Firing order, plug leads and vacuum leaks can play havoc |
i checked the timing with the piston,on top dead centre,and the cam belt was sitting at 9pm instead of 12 dead,so i reset the belt to the mark and the timing marks ,piston all match up ,i also set the HT leads the same way.
so next thing is do a compression test,i reckon the valves are damaged or possibly the injector o rings may be shot.
had another go at it yesterday ,it fired straight away but wouldn,t start.
so i will have a good look at it this sunday.
i'm curious as to what head is on it with the reset plugs in,any ideas ??? |
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Gene
Joined: 07 Oct 2011
Posts: 39
Location: Ft. Collins, Colorado
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| Posted: Wed Oct 19, 2011 2:00 am Post subject: 924 won't rev |
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| I also have a '79 that won't rev up. I put a fuel pressure gage on it and get correct system pressure of 72 lbs but the control pressure is the same as system pressure,control pressure should be no higher than 57 lbs. Maybe you have the same problem as I have, have you checked the fuel pressure ? |
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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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| Posted: Wed Oct 19, 2011 6:53 pm Post subject: Re: 924 won't rev |
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| Gene wrote: | | I also have a '79 that won't rev up. I put a fuel pressure gage on it and get correct system pressure of 72 lbs but the control pressure is the same as system pressure,control pressure should be no higher than 57 lbs. Maybe you have the same problem as I have, have you checked the fuel pressure ? |
yes the fuel pressure seems to be ok but without the proper gear i have no way of checking to be sure. |
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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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| Posted: Sun Nov 13, 2011 6:46 pm Post subject: Re: 924 won't rev |
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| Gene wrote: | | I also have a '79 that won't rev up. I put a fuel pressure gage on it and get correct system pressure of 72 lbs but the control pressure is the same as system pressure,control pressure should be no higher than 57 lbs. Maybe you have the same problem as I have, have you checked the fuel pressure ? |
Good advice Gene,as it is now running very well.i changed, the distributer, coil , cold start, transister unit, after being told by the previous owner that he power washed the engine before selling it to me,and couldn't get it to run after.
anyway after all the replacement parts were fitted it still wouldn't run right so i went to the fuel pressure regulator and turned it down ,and hey presto it fired up straight away,so i now have it running very well,starts very easy.
so thanks to all who took the time to give me some good advice. |
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Gene
Joined: 07 Oct 2011
Posts: 39
Location: Ft. Collins, Colorado
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| Posted: Mon Nov 14, 2011 5:04 am Post subject: '79 924 fuel pressures issues |
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| So are you telling me that you adjusted the system pressure regulator piston on the fuel distributor with shims ? or did you adjust the control pressure regulator ? Mine stil won't run, ran for a few start up after I replaced the control pressure reg. (wur) with a rebuilt unit but now doing the same thing again so am figting with the company for a replacement wur. |
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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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| Posted: Mon Nov 14, 2011 5:30 am Post subject: Re: '79 924 fuel pressures issues |
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| Gene wrote: | | So are you telling me that you adjusted the system pressure regulator piston on the fuel distributor with shims ? or did you adjust the control pressure regulator ? Mine stil won't run, ran for a few start up after I replaced the control pressure reg. (wur) with a rebuilt unit but now doing the same thing again so am figting with the company for a replacement wur. |
i adjusted the control pressure regulator,there was way too much fuel getting to the cylinders.
This is the way i did it, i removed one of the fuel pipes from the fuel distributer,i then switched the ignition on to see how much fuel was being pumped out,i then turned the control plunger anti clockwise ,to slow the flow down to a tricle.i then reconnected the fuel pipe and started the car,which started very easy.i then set about adjusting the control plunger to get the engine running smoother,its nearly perfect now.starts very easy.
might be worth trying on yours ??? |
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Gene
Joined: 07 Oct 2011
Posts: 39
Location: Ft. Collins, Colorado
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| Posted: Mon Nov 14, 2011 5:50 am Post subject: |
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| You must have a completely different control pressure reguator than I have or on either of my vw convertables. they are all the same non adjustable. Only pressure I can adjust is on the fuel dist. which controls the system pressure and thats controlled by shims. Where do you find the adjustable ones ? |
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Ozzie
Joined: 12 Mar 2005
Posts: 4448
Location: Townsville, Qld. Australia
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| Posted: Mon Nov 14, 2011 6:32 am Post subject: |
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Valves are non interference on the NA so wont bust up if the valve timing is bad.
test your leads as well. should all be under 5k ohms.
What you seem to be adjusting is the air/fuel mix.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
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spannernut
Joined: 09 Jan 2010
Posts: 74
Location: ireland
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| Posted: Mon Nov 14, 2011 6:42 am Post subject: |
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[quote="Gene"]You must have a completely different control pressure reguator than I have or on either of my vw convertables. they are all the same non adjustable. Only pressure I can adjust is on the fuel dist. which controls the system pressure and thats controlled by shims. Where do you find the adjustable ones ?[
this might help
http://www.southportfuelinjection.com/images/pic_fueldist.2.jpg
in the pic ,if you look between the air sensor plate and the fuel distributer body you will see a tube protruding next to the breather pipe you will need a 3m allen key to adjust it ,as it's a tight space you might get away with using a thin flat screwdriver.
hope yours is the same |
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