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

Help diagnose this problem..compression #'s

  • Thread starter Thread starter Idwitheld-1`
  • Start date Start date Sep 18, 2004
I

Idwitheld-1`

New Member
Nov 30, 2003
335
0
0
Portland Oregon
Sep 18, 2004
#1
  • Sep 18, 2004
  • #1
4 cylinder, odometer indicates 118,000 miles.

engine was hot for compression test, throttle wired WOT, all plugs out.
115, 120, 140, 120 PSI

Are these any good?

Engine has no guts under acceleration. I mean NO guts. In park, the motor revs quickly but under load....it takes a long ime to get upto 30-40 mph. I'm talking WOT and it barely responds.

I noticed when I pulled the PCV valve (engine running) there was enough pressure to blow my hair back. I assume this is blow by?

What do you guys think? Is the motor in need of a rebuild?
 
T

TheUser

Active Member
Jul 25, 2003
1,859
1
36
Springfield, MO
Sep 19, 2004
#2
  • Sep 19, 2004
  • #2
the biggest thing when checking compression is that the numbers are within 10-15%. Yours are a little more than that, so I don't know. It may not have as much power as a new one, but I wouldn't say it's done...I've had a 4 cyclinder and it was gutless no matter how you put it.

You might check your fuel pressure and see how much fuel pressure you have. When was the last time you did a tuneup(plugs, wires, cap/rotor, fuel filter, pcv valve)?

I checked compression in my GT and most of mine were 120-140, but one was 90. I can burn 'em off through 3rd gear...

I'd say your problem is in other areas besides compression, but that's just my opinion. Also, maybe your clutches in your torque convertor are slipping?
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Sep 19, 2004
#3
  • Sep 19, 2004
  • #3
i would answer, but im still waiting for pics of the lowered ride.











just kidding.
ill send you a PM. take care.
 
You must log in or register to reply here.

Similar threads

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
A
94' Cobra Dies with AC is on
  • Acj2001_Fordman
  • Jul 2, 2019
  • 1994 - 1995 Specific Tech
  • 2 3
Replies
41
Views
7K
1994 - 1995 Specific Tech Aug 24, 2019
Acj2001_Fordman
A
R
Engine 1992 Mustang Hesitation/Cutting-Out
  • RTW0223
  • May 2, 2018
  • Fox 5.0 Mustang Tech
  • 2
Replies
21
Views
14K
Fox 5.0 Mustang Tech May 26, 2025
Noobz347
3
Compression #'s
  • 363GT
  • May 1, 2016
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
0
Views
577
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 1, 2016
363GT
3
Need Help, Car Wont Start, I've Gone Through Both Checklists
  • 93silverlx50
  • Jul 22, 2017
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
54
Views
12K
Fox 5.0 Mustang Tech Apr 30, 2019
General karthief
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?