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Fasteddie313 · Joined: 29 Sep 2013 Posts: 2223 Location: MI

I never experienced poor running with my barely bad HG.. Just some bubbles in my coolant after it warmed up..

You check your distributor cap and rotor situation?
Any bubbles in your coolant?
Coolant system hold pressure?
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80 Turbo - Slightly Modified

MikeDanger · Joined: 21 Nov 2002 Posts: 636 Location: Denver

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11553 Location: PacNW

Depends on the location of the damage. There are oil passages in the HG as well.
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Toofah King Bad

WeiBe (1987 924S) - 931 S3
Red (1987 924S) - Pro44/Spec944
Shaggy (1980 931) - SOLD (unlucky, but tried hard )

MikeDanger · Joined: 21 Nov 2002 Posts: 636 Location: Denver

really don't want to hear this

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It was either this or a giant box of legos

MikeDanger · Joined: 21 Nov 2002 Posts: 636 Location: Denver

Ok well, Im going to check the Injectors first, but following that, whats the steps you'd take to test for HG?
Should I run the car up to temp then check compression? or just do it cold?
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It was either this or a giant box of legos

Mike9311 · Joined: 14 Dec 2004 Posts: 1102 Location: Chicago-ish

I don't trust spark plugs so at a minimum switch them around to see if the dropped cylinder, or "wetted" plug, follows the plug or stays with the cylinder

I think you where at #3
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

MikeDanger · Joined: 21 Nov 2002 Posts: 636 Location: Denver

MikeDanger · Joined: 21 Nov 2002 Posts: 636 Location: Denver

well heres what I found testing the Injectors:
1st vid Cold control
https://www.youtube.com/watch?v=LqTzUf6Nzuo

second test I left the key on for a bit to try and heat up the WUR

https://www.youtube.com/watch?v=W8YdqU22ZV0

Last video I raised the Control Pressure to simulate "warm control"
https://www.youtube.com/watch?v=hw-eLQq_qA8

This clip show what happens when i turn on the fuel pump
https://youtu.be/s5hR8ihKVGc
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It was either this or a giant box of legos

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2223 Location: MI

1. Control pressure has absolutely nothing to do with injector flow for any given plate position..
Control pressure adjusts plate position for any given airflow through/passed the metering plate.. It only adjust how easy or hard it is to move the plate, adjusting plate position vs airflow..

Drop your control pressure way down, feel the plate stiffness..
Raise the control pressure way up, feel the plate stiffness..
You will see..

2. Your injectors for one have terrible spray patterns and are also horribly uneven..
The one to the right seems the best.. Try that one on the right on all of the lines, and if it is always still the first one to pop off your fuel distributor is probably ok..

Replace those injectors.. Holy smokes they are bad..
No wonder it’s missing..

Maybe dump a bottle of tecron on a 1/4 tank of fuel and run those injectors into bottles for an hour, dump it back into your gas tank if it looks clean..
Let it sit overnight and do it again the next day..

My guess is though, those injectors are toast..
Maybe try blowing them out with air, even hold the pintails out with your fingernail and blow through them backwards..

You can try saving them, but they look pretty darn bad..

Nice videos.. Worth a million words..
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80 Turbo - Slightly Modified

Mike9311 · Joined: 14 Dec 2004 Posts: 1102 Location: Chicago-ish

"safe" out of Sweden called it

Nice

At least its not a head gasket! Injector issue is nice news

And...a big And...any build from now on is getting an injector check
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

MikeDanger · Joined: 21 Nov 2002 Posts: 636 Location: Denver

Well I found 2 decent spraying injectors. replaced 3 and 4.
I First sprayed Seafoam DeepCreep penetrating lube through them with the straw. then tried them, took a second for them to "pop" then they sprayed a good pattern.

I reinstalled and used sealant on the spacer threads let it cure overnight.
Im about to go try and start here shortly.
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It was either this or a giant box of legos

MikeDanger · Joined: 21 Nov 2002 Posts: 636 Location: Denver

Well, Im keeping my fingers crossed; I started it and ran it for 5-6 min, and didnt hear a miss, and the AFR were steady.

Not sure that explains the sudden lack of power on take off I got on the last test drive, but I guess we'll see.
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It was either this or a giant box of legos