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Discussion Starter #1
I’ve been slowly fixing thing on my 96ss on the weekend, it’s a one owner in pretty good shape. I’ve been getting a mass air flow code and a high idle at times. It’s a new mass air flow and new plug so that’s not the problem I don’t thank. My buddy said he could here a vacuum leak so I’m going to start looking into that this weekend. My question is I noticed what looks like a long vacuum line dragging under the car between the front and back door on the passenger side, I don’t know what it is or where it goes.
Is there a vacuum line that runs from the fuel tank maybe?
 

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It could be the vapor return line. It can cause strange issues when not connected.
 

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there is a fuel tank vapor line .. no vacuum goes to the fuel tank....the vapor line runs to the charcoal canister hidden behind the front bumper pass side...

I have had vacuum lines crack... also the 90 deg rubber hoses as these I replaced with 3/8inch nylon so no more leaks..

#1 is the PCV and the hoses to the PCV.. use fuel hose to replace ..
#2 is the canister venting line pass side of engine.. when you check those hoses use gloves as these will get on your hands and very hard to clean as the fuel eats at these hoses.. my hoses collapsed so I had pressure in the fuel tank...

#3 your intake hoses after the maf may surely have leaks ..
 

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Discussion Starter #5
I spread the hole engine with ether today and not a single thing. Maybe I don’t have a vacuum leak
 

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I spread the hole engine with ether today and not a single thing. Maybe I don’t have a vacuum leak
high idle over 600 rpms in drive means most times vacuum leak.
what are the codes your getting ?

I would use propane to check for leaks.. but the hoses surely are a problem.

check all hoses first.. hook up a scan tool and monitor the RPMS.. should be extremely flat .. a scan tool that can indicate a charting display works best.
 

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Discussion Starter #7 (Edited)
mass airflow code and a Evap code. I lost the print out or I would tell you the code numbers. I got side tracked working on the ac system and gave up on the vacuum lines today.
I put my Refrigeration gauges on the car today to see what my pressure was because the ac system has never worked since I’ve had the car. Both Schrader valves were bad, they stuck open after I took the gages off so the car emptied itself out in my drive way.
I put new Schrader valve in and got a good vacuum to hold but right before I was ready to put refrigerant in I decided to try to spin that compressor by hand,
the clutch on the compressor Would not turn a full revolution.
I also could not get the compressor to engage even after a jumped the relay.

I unplug the compressor and put a jumper in the relay,check the wires at the compressor with my tester.
I’m getting power to the compressor wires with the relay jumped but the compressor is still not engaging.
at least I’m not hearing a click from the solenoid. I thank the ac compressor is bad
 

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My question is I noticed what looks like a long vacuum line dragging under the car between the front and back door on the passenger side, I don’t know what it is or where it goes.
Is there a vacuum line that runs from the fuel tank maybe?
Not sure if this was offered yet but I bet that hose is the transmission vent hose. It comes off the Trans case, runs down to the transmission crossmember and then run along the pass side of the crossmember over to the frame and just lays in the frame. IIRC - there are 1 or 2 plastic clips that secure the hose to the crossmember.

On the issue for the engine, if you have no history on the car....replace them ALL. There are numerous threads on this subject which should tell you where most are and the ones that fail most often....gas tank vent hose comes to mind here. Also be sure to look at the evap canister hoses as these can be a mess too. Be mindful that you will NOT be able to go to the gm parts counter and order all you will need. Those days are long gone. Some formed hoses may still be available but in a lot of cases you will need to get creative and make up your own replacements.
 

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Discussion Starter #9
That makes sense because I did just have the transmission rebuild.
And as far as the vacuum lines I saw a guy using spark plug wires.. lol I’m a union pipefitter I work in a power plant with a huge free stock store room so I’m hoping to lunch box every thing I need
 

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Damn Josh, you just made us all accessories to your deed. :grin2:
When I worked in a tire plant, there was a free stock there too. My tool box was well stocked to keep from making a run from one end of the plant to the other just to get a steam line, nipple or whatever.

Mark: Snowman-33
 

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Discussion Starter #12 (Edited)
I don’t have a scan tool but abt an hour ago I whent all over the intake, injectors and vacuum lines on top of the car with map gas and I found nothing.
That’s starting fluid and gas with no change I have to be missing something
 

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I don’t have a scan tool but abt an hour ago I whent all over the intake, injectors and vacuum lines on top of the car with map gas and I found nothing.
That’s starting fluid and gas with no change I have to be missing something
Quite possible a vacuum leak is not where you used the fluid/gas...While not always the reason, vacuum leak is strong reason for high STFT which is why I suggested a scan tool if available

FSM, Scan tool, FP gauge, IR temp gun are very good tools to have on these computer cars....paying for people to use them gets expensive.
 
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