• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

blows blue smoke after startup

  • Thread starter Thread starter 87 GT
  • Start date Start date Aug 31, 2005
8

87 GT

New Member
May 6, 2005
19
0
1
Iowa
Aug 31, 2005
#1
  • Aug 31, 2005
  • #1
Hey guys. Please help me with a problem on my son's 89 LX 5.0. He recently bought this car, and is in the process of fixing all the drag mods done by the previous owner. The problem is that the car starts and runs fine, but blows a ton of blue smoke upon acceleration. Doesn't do it at startup. Just while driving after a minute or so of warmup. The car has no EGR valve (removed and blocked). The PCV system appears to be hooked up. The engine appears stock, with no aftermarket parts. What could be causing the blue smoke? (other than a shot bottom end.) Give us some troubleshooting ideas. Could it be a non-functioning PCV system?
 
B

bentley429

Banned
Nov 25, 2004
528
3
0
Connecticut
Aug 31, 2005
#2
  • Aug 31, 2005
  • #2
87 GT said:
Hey guys. Please help me with a problem on my son's 89 LX 5.0. He recently bought this car, and is in the process of fixing all the drag mods done by the previous owner. The problem is that the car starts and runs fine, but blows a ton of blue smoke upon acceleration. Doesn't do it at startup. Just while driving after a minute or so of warmup. The car has no EGR valve (removed and blocked). The PCV system appears to be hooked up. The engine appears stock, with no aftermarket parts. What could be causing the blue smoke? (other than a shot bottom end.) Give us some troubleshooting ideas. Could it be a non-functioning PCV system?
Click to expand...

My 89 does the same thing, 1st, 2nd, and 3rd gear blow out very little blue smoke when Iam on it pretty good. I plan on replacing my rings at some point. I dont really know anything about pcv valves though so Iam sure someone could answer that for you.
 
P

page90lx

New Member
Jun 27, 2005
15
0
0
dover tn
Aug 31, 2005
#3
  • Aug 31, 2005
  • #3
If it does it just on startup its probably your heads otherwise rings
 
B

bentley429

Banned
Nov 25, 2004
528
3
0
Connecticut
Aug 31, 2005
#4
  • Aug 31, 2005
  • #4
page90lx said:
If it does it just on startup its probably your heads otherwise rings
Click to expand...
A smile huh? when I noticed mine I was more like....
 
8

87 GT

New Member
May 6, 2005
19
0
1
Iowa
Aug 31, 2005
#5
  • Aug 31, 2005
  • #5
Thanks for the replys.

No, it doesn't do it on startup. Not valve seals.

It smokes like a bandit while driving and accelerating only.

Oh, and the plugs look pretty good. No oil residue. Thay all look about the same, dry and tannish/gray. So I don't think it's rings.

Again, can a bad PCV cause intense smoking on acceleration?
 

powertrax91

Founding Member
Mar 13, 2002
598
0
17
New York
Aug 31, 2005
#6
  • Aug 31, 2005
  • #6
87 GT said:
Thanks for the replys.

No, it doesn't do it on startup. Not valve seals.

It smokes like a bandit while driving and accelerating only.

Oh, and the plugs look pretty good. No oil residue. Thay all look about the same, dry and tannish/gray. So I don't think it's rings.

Again, can a bad PCV cause intense smoking on acceleration?
Click to expand...

It could be a number of things... how many miles on the motor?
 
8

87 GT

New Member
May 6, 2005
19
0
1
Iowa
Aug 31, 2005
#7
  • Aug 31, 2005
  • #7
105,000
 
8

87 GT

New Member
May 6, 2005
19
0
1
Iowa
Sep 1, 2005
#8
  • Sep 1, 2005
  • #8
btt
 

DTT92LX

New Member
Oct 28, 2003
185
1
0
Downingtown, PA
Sep 1, 2005
#9
  • Sep 1, 2005
  • #9
87 GT said:
Thanks for the replys.

No, it doesn't do it on startup. Not valve seals.

It smokes like a bandit while driving and accelerating only.

Oh, and the plugs look pretty good. No oil residue. Thay all look about the same, dry and tannish/gray. So I don't think it's rings.

Again, can a bad PCV cause intense smoking on acceleration?
Click to expand...


PCV is cheap and easy to replace. Might as well just try it to at least rule it out... Get it from the dealer I heard the diy stores valve don't fit quite right. And get the screen too while you're at it.
 

srothfuss

Last night I stabbed the same guy 7 times in a row
Oct 17, 2004
1,796
3
0
Woodward Ave.
Sep 1, 2005
#10
  • Sep 1, 2005
  • #10
Smoke while you are driving is usally of an idication of oil slipping past the rings and into the combution chambers.

These cars (until 93) came from the factory with forged internals which require more clearance between the piston and side wall. Overtime (espeically with hard driving) the rings wear out. This is probably what is causing the smoke.

There aren't too many temporary things you can do, except for run a thick oil to minimize the blowby.

Does it smoke when your just going down the road or when your shifting at 5,000+ RPM?
 

vikingpower

New Member
Dec 6, 2004
656
0
0
CWU Ellensburg, WA
Sep 1, 2005
#11
  • Sep 1, 2005
  • #11
its the pistons/rings, I just did my head swap and mine were worn out big gap between piston and cylinder (89K miles). But thats ok, I need a new project anyways!
 

powertrax91

Founding Member
Mar 13, 2002
598
0
17
New York
Sep 1, 2005
#12
  • Sep 1, 2005
  • #12
87 GT said:
105,000
Click to expand...

seems you're gonna need a rebuild... 105,000 miles, a 1/4 mile at a time, could be tough on an engine
 
You must log in or register to reply here.

Similar threads

K
Engine 2000 Mustang GT - Fuel issue post-blown spark plug repair
  • kenster1092
  • Feb 26, 2026
  • SN95 4.6L Mustang Tech
Replies
4
Views
328
SN95 4.6L Mustang Tech Mar 10, 2026
kenster1092
K
M
Engine Unexplainable Exhaust Pop and Gurgle
  • Mrnissen122
  • Feb 14, 2026
  • Fox 5.0 Mustang Tech
Replies
12
Views
527
Fox 5.0 Mustang Tech Feb 18, 2026
Noobz347
8
Engine Rough idle and aggressive sputtering when accelerating
  • 88vertible
  • Aug 13, 2025
  • Fox 5.0 Mustang Tech
Replies
4
Views
1K
Fox 5.0 Mustang Tech Dec 13, 2025
Jarhead67
J
W
Blue smoke..
  • Wicked_Rpm
  • Aug 11, 2024
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
479
1996 - 2004 SN95 Mustang -General/Talk- Aug 14, 2024
weendoggy
Engine 1990 LX 5.0L EFI Mustang Fuel Management Problems - HELP!
  • 5.0LXStanger
  • May 25, 2025
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
45
Views
2K
Fox 5.0 Mustang Tech Jul 11, 2025
5.0LXStanger
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?