Sooty #7

[Ccmano]

Dom,

Didn't you have an issue when the porting was done with a pinhole leak in the injector housing? I wonder if this might be the same issue.
H

[XfireZ51]

Originally Posted by Ccmano

Dom,

Didn't you have an issue when the porting was done with a pinhole leak in the injector housing? I wonder if this might be the same issue.
H

When I first ported the injector housing, I went thru the bolt boss at the very front of the IH. Vacuum leak into #2 primary runner. Welded that.
There have been other cases of oil seepage through a very porous casting of the cylinder head runner.
#7 is close to the PCV. Wonder if its related to crankcase venting and possible lack of restriction between IH and cylinder head.
Question for Mr. Haibeck.

[XfireZ51]

Interesting post I ran across while doing research on another topic. This appears to describe what I observed after doing the compression check.Same bank as well.

http://www.zr1.net/forum/showpost.ph...53&postcount=1

[jss06c6]

Watching closely to learn!

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[ssrszz4]

I know that '90's didn't have exhaust valve seals and was designed that way on purpose.



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[jss06c6]

Dominic,

Any updates?? Very interested to learn what is causing the fouling of #7 plug.. sure hope it's something "reasonably" easy to fix..

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[XfireZ51]

Originally Posted by jss06c6

Dominic,

Any updates?? Very interested to learn what is causing the fouling of #7 plug.. sure hope it's something "reasonably" easy to fix..

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Right now there isn't a further update. At this point, we'll begin looking at it after the 4th holiday or sometime after that. Given the results of the compression test and checking of injector and plug wire resistance, there's nothing obvious. It could easily be a leaky injector. But right now that's speculation. It could be something more involved. I'll have Dr. Polatsidistein have a look and I will update.

[jss06c6]

Thanks. Watching with interest..

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[Paul Workman]

A fuel injector leaking would show up if you pressurized the fuel rail and observed the time it takes to bleed off pressure.

As I recall, it took over 15 minutes to bleed off the first pound of pressure when I did mine the last time, once I found the leak (a bad check-valve in a fuel pump).

One other thought: isn't the vacuum line for the pressure regulator just about directly over the #7 plenum runner? You know where I'm going...!

Just some things to ponder before pulling the motor...

[XfireZ51]

Originally Posted by Paul Workman

A fuel injector leaking would show up if you pressurized the fuel rail and observed the time it takes to bleed off pressure.

As I recall, it took over 15 minutes to bleed off the first pound of pressure when I did mine the last time, once I found the leak (a bad check-valve in a fuel pump).

One other thought: isn't the vacuum line for the pressure regulator just about directly over the #7 plenum runner? You know where I'm going...!

Just some things to ponder before pulling the motor...

Well yes the PR vacuum line is by #7 but plenum volume is supplying vacuum so its hard for me to gather how it discriminates on #7.