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Buffalorider · Joined: 12 Dec 2014 Posts: 13 Location: Montrose, Colorado

Had the car running fine (well pretty good anyways) in warmer weather. Did a full tune up & new vacuum lines. Car would always start but idle would remain suspiciously low until it warmed up and then would stay around 1K rpm's. Now that it is zero outside and the car is not in a heated garage, it wants to act like it will start, but is refusing. Tried some starting fluid but no use. Cold start is spraying fuel. Any ideas I should check? could it be distribution fuel center is gummed up and sticking? Thanks folks!

Scott in cold-ass Colorado
1977 924

scriblz7 · Joined: 07 Dec 2008 Posts: 112 Location: kirkland WA.

could be your warm up regulator is stuck in warm mode so it doesnt give you more fuel when cold, also could be the auxiliary air valve

procedure for checking fuel system operation: http://924board.org/viewtopic.php?t=35734
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Riley
79 924 n/a with gt body
15 VW GTI

Fifty50Plus · Posted: Thu Jan 01, 2015 6:21 am Post subject:

I had a VW Scirocco with the same CIS system that wouldn't start in really cold weather (also tried starting fluid). If I changed the plugs it would then start up. Only happened on Really cold days (~0 degrees). Rest of the time, it was fine.
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1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

Buffalorider · Joined: 12 Dec 2014 Posts: 13 Location: Montrose, Colorado

Update: Took my wife's heat gun and held it on the fuel distribution center for some time then got in and pushed pedal to the floor and it finally started up. Could that be any indication of gum & sticking things in there? Kinda hate to pull that thing apart. That warm up regulator looks like a chore as well. Thanks for the replies!!

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

run some lucas fuel adiditve and/or ATF fluid or any other lube/oil/cleaner you can add to fuel.
the distributor is not hard to pull apart and clean. one of mine was stuck; just a little wd40 on the piston and it was good to go.
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Buffalorider · Joined: 12 Dec 2014 Posts: 13 Location: Montrose, Colorado

In all my years of wrenching, I never knew that ATF fluid will do a fuel system some good! What is the dilution rate? When you took your distribution top off, do you need gaskets or O-rings etc? Is there anything to watch for as far as small parts falling out of sight never to be seen again?? Thanks for the tips. I may just dig into it.

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

about half a qt should do, but theres also otehr stuff like marvel mystery etc etc.

no not really many small parts ecept for the springs under the diaphram. just do it on a clean table or sink
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It was either this or a giant box of legos

musicalannette · Joined: 21 Feb 2012 Posts: 413 Location: UK

sure you battery is good?
just try connecting jump leads to see is it is ok.
i would say move to texas!!! but a non starting car is far from funny.
if you cold start injector is firing - then my next best guess would be plugs, check to see you have a nice spark. find an old plug and place it on top of the engine whislt you turn it over.

if you replace the plugs - get side gapped plugs if you can.

just be sure to check it all when it is cold - otherwise you wont find the fault!!

this sort of design is the best i have found.

http://www.ebay.co.uk/itm/4-X-NEW-BOSCH-SUPER-4-SPARK-PLUGS-HONDA-CIVIC-ACCORD-CR-V-HR-V-SET-/290813726472?fits=Car+Make%3ANissan|Model%3AMicra
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Buffalorider · Joined: 12 Dec 2014 Posts: 13 Location: Montrose, Colorado

no plugs are new, no problems there. Battery is new as well. I never said it wasn't turning over. Once I took a hand held heat gun to the top of the fuel distributor, it finally fired up. It started again today but remains a fairly low idle until it warms up, then the idle increases which tells me the warm up regulator may be to blame. Not sure how to test or clean that thing since it is in a lousy spot on the back of the intake. Or....maybe just start it every day if possible instead of letting it sit while it is this cold.

If Texas is the place to go, why do they all come here in the summer?? That state doesn't get too hot does it???

musicalannette · Joined: 21 Feb 2012 Posts: 413 Location: UK

Your comments made me laugh!! A few years ago i spent a summer on the continent of Europe, at 37/8deg C it was ridiculous! The humidity was just crazy!! To much for this island dweller!! Honestly, good luck if you live in-land!! Unless Its Finland I dont want to know!! Even rain only gave 30 mins of fresh air!!

Its hard to do fault finding when your not sure what or where someones been before!! Never tested 1 before, but i would look to see if your getting a resistance on the heating element, and check the current it draws when you connect 12 volts to it, something might go wrong when it all gets warm and moves.

It looks like it is an extra pressure regulator, upping the fuel pressure and thus giving a bit more fuel. So if you have a suitable pressure gauge you can connect in to the fuel and see the fuel pressure and watch for a change when you connect up the wire or when you do you heat gun trick you should see a change in pressure as the regulator operates.

No change in pressure or no resistance measurements and I am guessing its had it.

Hope this helps.
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

musicalannette · Joined: 21 Feb 2012 Posts: 413 Location: UK

Had a quick look online - seems some have a hot/cold pressure adjustment - not sure the 924 does!! i would not adjust it (if you can) until you know what to adjust it to!!
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

Ian89C4 · Joined: 01 Apr 2011 Posts: 561 Location: North Carolina

The pressure adjustment is via shims in the fuel pressure regulator ( you will see a bolt on the front of the Fuel Distributor, if you take that off you will see a little piston with a spring at the end, inside the bolt that holds that in you will see 1-3 shims of different thickness, adding or removing these is how you adjust the pressure)

DO NOT REMOVE THEM UNLESS YOU TEST THE PRESSURE PRIOR. You need to get a CIS pressure testor:

http://paceperformance.com/i-5926816-cta3420-fuel-injection-pressure-tester-bosch-k-jetronic-c-i-s.html

There are cheaper ones out there but it needs to be specifically for the K-Jetronic.

From there go through your cold, hot and system pressure checks and it will let you know exactly what is wrong.

The cold is most likely affecting everything and components that are on their last legs will be more strung out in the extremes. But unfortunately this system is very hard to diagnose without the proper tools.

Hope she gets to feeling better soon.

Cheer!

Ian
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Ian Edgerly
North Carolina

Current:
1981 924 SCCA/ChampCar Weissach Race Car ("Serenity")
1987 924S ChampCar Endurance Car ("Der Weg")
1980 924 Euro ("Wahala")

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

I don't get it how us cars run so poor.
I had 3 924s, all started perfectly below freezing.
You can check if the Sparks are flooded and if you have the right spark plugs...not any wil work that good below freezing temps.
You can also check if the auxiliary injector is working..perhaps it is not getting enough fuel but my money is on flooded.

I drive my cars mainly in the summer but I give them a start and warm-up once in a while even during winter.
I drive them rarely and when I do I drive them for days with little pause.
They always start and run no matter what conditions.
Here is one of them starting at -13.

http://youtu.be/2Pm51LQJyp0
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