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Hesitation/Missing
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11553
Location: PacNW

PostPosted: Sun Mar 21, 2021 1:36 am    Post subject: Reply with quote

MikeDanger wrote:
Can a Headgasket be "just barely bad" to cause this?


Totally, classic HG symptoms (runs fine cold, then misses when warm).
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2223
Location: MI

PostPosted: Sun Mar 21, 2021 4:22 am    Post subject: Reply with quote

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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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Sun Mar 21, 2021 5:34 am    Post subject: Reply with quote

Fasteddie313 wrote:
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?


cap and rotor are new, Don't notice any bubbles, and the system seems to hold pressure, I did just swap to a 944 tank (used).

Wouldn't a blown Hg show a "washed" Spark plug?
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Rasta Monsta  



Joined: 12 Jul 2006
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Location: PacNW

PostPosted: Sun Mar 21, 2021 5:42 am    Post subject: Reply with quote

Depends on the location of the damage. There are oil passages in the HG as well.
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MikeDanger  



Joined: 21 Nov 2002
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Location: Denver

PostPosted: Sun Mar 21, 2021 6:15 am    Post subject: Reply with quote

really don't want to hear this
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MikeDanger  



Joined: 21 Nov 2002
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Location: Denver

PostPosted: Sun Mar 21, 2021 6:30 am    Post subject: Reply with quote

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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Mike9311  



Joined: 14 Dec 2004
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Location: Chicago-ish

PostPosted: Sun Mar 21, 2021 6:42 am    Post subject: Reply with quote

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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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Sun Mar 21, 2021 9:36 am    Post subject: Reply with quote

Mike9311 wrote:
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


Well I cleaned/torched the plugs before I put them back, didn't keep them in order.
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MikeDanger  



Joined: 21 Nov 2002
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Location: Denver

PostPosted: Sun Mar 21, 2021 11:58 am    Post subject: Reply with quote

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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Fasteddie313  



Joined: 29 Sep 2013
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Location: MI

PostPosted: Sun Mar 21, 2021 10:30 pm    Post subject: Reply with quote

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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Mike9311  



Joined: 14 Dec 2004
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Location: Chicago-ish

PostPosted: Sun Mar 21, 2021 11:19 pm    Post subject: Reply with quote

"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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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Mar 23, 2021 7:16 am    Post subject: Reply with quote

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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MikeDanger  



Joined: 21 Nov 2002
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Location: Denver

PostPosted: Tue Mar 23, 2021 10:18 am    Post subject: Reply with quote

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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