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Vacuum smoke test / 3800SC by TXGOOD
Started on: 07-17-2015 05:47 AM
Replies: 4 (117 views)
Last post by: TXGOOD on 07-17-2015 10:39 AM
TXGOOD
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Report this Post07-17-2015 05:47 AM Click Here to See the Profile for TXGOODClick Here to visit TXGOOD's HomePageSend a Private Message to TXGOODEdit/Delete MessageReply w/QuoteDirect Link to This Post
I wanted to run this by people and maybe get some ideas.
My car has been showing some pegged positive short term fuel trims at idle and back to normal at close to 2500 RPM.
So, suspected vacuum leak.
I took it into a shop and they did a smoke test and it showed smoke getting into the crankcase.
Maybe LIM gasket but new aluminum ones were used before swap.
I have bought new ones to replace again but I`m hesitant to think the new ones could be leaking.
What else might cause a vacuum leak besides leaking gaskets?
I don`t even want to think of the possibilty of something being cracked but I guess it`s not out of the question.
Thanks
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84fiero123
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Report this Post07-17-2015 10:12 AM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
Any cracked vacuum line could cause a vacuum leak and some can be a real biatch to find sometimes. I use starting fluid when the engine first starts before it get to hot and spray around all the hoses and when the RPMs rise you found your problem.

Steve

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and one big pain in the ass when it doesn't



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phonedawgz
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Report this Post07-17-2015 10:26 AM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
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darbysan
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Report this Post07-17-2015 10:29 AM Click Here to See the Profile for darbysanClick Here to Email darbysanSend a Private Message to darbysanEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not sure if this applies, as I'm not an expert on the 3800SC (yet ) Something to consider might be the PCV system. On a Non-SC car, that might be a symptom of the PCV valve sticking open. Like I said, just don't know how it works for the SC version, but maybe others can chime in and educate us (me)!

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'87 GT in process, including GA / Seville brakes, Poly Suspension, '95 3800 Series 1 SC ( 225 hp ) T460e.

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TXGOOD
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Report this Post07-17-2015 10:39 AM Click Here to See the Profile for TXGOODClick Here to visit TXGOOD's HomePageSend a Private Message to TXGOODEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well, it has been determined that the leak is more than likely in the valley because they put smoke into the supercharger and it came out the oil filler and dipstick hole.
As far as I know the PVC valve is blocked off, at least it has a plate over it, or is that normal.
At least up on top of the supercharger.

[This message has been edited by TXGOOD (edited 07-17-2015).]

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