Smoke test, possible vacuum leak from throttle body? - TCCoA Forums
 
LinkBack Thread Tools
post #1 of 6 (permalink) Old 10-26-2018, 11:53 PM Thread Starter
V22
2nd Gear Poster
 
V22's Avatar
 
Join Date: Jan 2015
Location: Maryland
Age: 23
Posts: 77
Smoke test, possible vacuum leak from throttle body?

Hey guys,

I've been fighting a rough idle for quite some time now. I figured it might have a vacuum leak (I'm hearing a very loud hissing near the throttle body area), so I thought I might as well use my handy dandy ebay smoke tester I used for my sisters 08 mustang lean codes (worked great). I replaced all the vacuum lines quite some time ago, and visual inspection did not reveal anything substantial.

Anyways, I saw a few puffs of smoke coming from the side of the throttle body where is the spring and linkage is, and huge streams of smoke coming from this hole under the throttle body, near the throttle position sensor. If you look at the front of the throttle body, standing from the passenger side, it's under the right side. I see there is a hex bolt and o ring under it, and it's pretty loose when I touch it (I can feel it rocking back and forth). What exactly is this screw? Does it have anything to do with the tps? I can't find anything about it in the service manual. I don't see how smoke coming out from it would be normal. Can I just snug it up? Or will it disturb a preset adjustment?

Any guidance would be most appreciated!
Attached Images
File Type: jpg 104_0191.JPG (790.4 KB, 9 views)

1996 Mercury Cougar XR7 4.6L , Vermillion
If you see a shiny red car swerving around potholes and parking 10000 miles from all the other plebeians in parking lots, then it's probably me.
V22 is offline  
Sponsored Links
Advertisement
 
post #2 of 6 (permalink) Old 10-27-2018, 12:16 AM
No, Mr. Lemmywinks, No!!!

Moderator
 
Grog6's Avatar
 
Join Date: Jun 2005
Location: Harriman, TN
Age: 56
Posts: 9,869
Garage
Is that Blue tape holding the intake on? and is that a snake under it...

Red '96 Cougar XR-7 240k mi. '02 4R70W, PST DS : '03 PI engine, 04 maf, 24lb injectors, 2.5" exhaust, '02 4r70w + Jmod, DirtyD0g TC + cooler + 3/8" lines, 255 walbro fp. Alpine system.
Black '96 Cougar XR-7 (Lazarus) 210k mi PI Intake, '02 4R70W, Jmod, PST DS, GrogTune, Konis, Mark LCA+Poly, racecougar Custom Engine Chain, and JL and racecougar Bracing.
Black '97 Tbird Limited Edition, '02 4R70W, 255 walbro, PST DS, PBR Brakes&SS lines, Toicko Blues & Springs, GrogTune.


"War Is Peace. Freedom Is Slavery. Ignorance Is Strength." - George Orwell.
Truth Isn't Truth. - Rudy Giuliani, 2018 Award winner, “Most Outrageous Diversion” by MSNBC for this quote
Grog6 is offline  
post #3 of 6 (permalink) Old 10-27-2018, 10:14 AM
PostWhore
 
T6Rocket's Avatar
 
Join Date: Nov 2004
Location: Raleigh, NC
Posts: 1,715
Might be worth picking up another used throttle body. Someone on here might have one, or check on Car-Part.com--Used Auto Parts Market

A vacuum leak should just produce a high idle. A rough idle in my experience points to possibly an EGR valve stuck open.

Al

97 T-Bird LX 4.6 - 80k miles
94 Supra TT Auto - street/strip car
04 CVPI- Brenda's car - 76k miles
Previous Fords:
95 T-Bird LX 4.6 - fully optioned, owned 15 years, 220k miles
96 Cougar XR-7 4.6- Brenda's car, owned 11 years, 187k miles
88 T-Bird 3.8 - first T-Bird, owned 5 years, 206k miles
T6Rocket is offline  
Sponsored Links
Advertisement
 
post #4 of 6 (permalink) Old 10-27-2018, 10:48 AM Thread Starter
V22
2nd Gear Poster
 
V22's Avatar
 
Join Date: Jan 2015
Location: Maryland
Age: 23
Posts: 77
Very funny...that's shop towel stuffed into the throttle to keep crap out, and that snake.... well it happens.

Anyone happen to have the powertrain/emissions manual? The shop manual references this bolt, but directs you to the powertrain manual. It wasn't in the zip file that was posted a while ago.

The EGR is fairly new, and was not stuck open when I tested it. Spark is good at all 8 plugs, plugs and wires are newish (replaced recently). Smoke test did not reveal any other vacuum leaks. The thing is, if the EGR was stuck open it would act as a vacuum leak, so a large vacuum leak at the throttle body would have a similar effect.

1996 Mercury Cougar XR7 4.6L , Vermillion
If you see a shiny red car swerving around potholes and parking 10000 miles from all the other plebeians in parking lots, then it's probably me.
V22 is offline  
post #5 of 6 (permalink) Old 10-27-2018, 05:09 PM
No, Mr. Lemmywinks, No!!!

Moderator
 
Grog6's Avatar
 
Join Date: Jun 2005
Location: Harriman, TN
Age: 56
Posts: 9,869
Garage
The bearings that support the shaft for the butterfly have a a silicone seal; the ones in the imrcs in the dohc b heads I have were wasted, and that could be it.

You can get new bearings from VXD, if I remember correctly.

Note: I am snake friendly.

Red '96 Cougar XR-7 240k mi. '02 4R70W, PST DS : '03 PI engine, 04 maf, 24lb injectors, 2.5" exhaust, '02 4r70w + Jmod, DirtyD0g TC + cooler + 3/8" lines, 255 walbro fp. Alpine system.
Black '96 Cougar XR-7 (Lazarus) 210k mi PI Intake, '02 4R70W, Jmod, PST DS, GrogTune, Konis, Mark LCA+Poly, racecougar Custom Engine Chain, and JL and racecougar Bracing.
Black '97 Tbird Limited Edition, '02 4R70W, 255 walbro, PST DS, PBR Brakes&SS lines, Toicko Blues & Springs, GrogTune.


"War Is Peace. Freedom Is Slavery. Ignorance Is Strength." - George Orwell.
Truth Isn't Truth. - Rudy Giuliani, 2018 Award winner, “Most Outrageous Diversion” by MSNBC for this quote
Grog6 is offline  
post #6 of 6 (permalink) Old 12-30-2018, 09:48 PM Thread Starter
V22
2nd Gear Poster
 
V22's Avatar
 
Join Date: Jan 2015
Location: Maryland
Age: 23
Posts: 77
Sorry for the late update, I have a habit of not concluding my posts. Too busy with school.

Anyways I marked it with some paint in case turning it screwed up some delicate setting, and tightened it. No difference in the engine running, I'm still trying to diagnose my rough idle. Might just make a new thread.

1996 Mercury Cougar XR7 4.6L , Vermillion
If you see a shiny red car swerving around potholes and parking 10000 miles from all the other plebeians in parking lots, then it's probably me.
V22 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the TCCoA Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome