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

Issues After Rebuild

  • Thread starter Thread starter Hunter Hill
  • Start date Start date Dec 26, 2016
  • Tags Tags
    #rebuildissues #sn95 #motorrebuild

Hunter Hill

New Member
Jul 27, 2015
6
0
1
Kemah, TX
Dec 26, 2016
#1
  • Dec 26, 2016
  • #1
Hey hows it going guys,

I just did a full rebuild on my 1994 Mustang 5.0 about 6 months ago, it is the first time i have rebuilt a motor, and am having some issues after the rebuild. Here is what the rebuild consisted of so you can get an idea of what was done to the car, and then ill go on to explain the issues that i am having:

Upgrades:

1. New upgraded cylinder heads
2. New 24LBS Injectors
3. Bored out .030 over with new pistons, bearings, etc.
4. Upgraded E303 Camshaft
5. Full offroad pypes exhaust headers all the way back
6. New fuel tank with upgraded fuel pump
7. Upgraded roller rockers
8. Upgraded lower and upper intake
9. New Piston Rods

Original Parts (That Have Not Been Replaced):

1. Crank Shaft
2. Block
3. Distributor
4. Intake
5. Electrical Components/Wiring
6. Computer
7. Lifters

Deleted Parts:

1. AC Compressor
2. Smog Pump
3. EGR

The car will start after the rebuild, but has no power and hesitates and occasionally dies. The vehicle has only died a few times and it was only when the vehicle was moving, it will run for hours just sitting in my drive way with no issues. I have been told that one of the reasons the vehicle acts this way is because it needs a chip and or because there is a vacuum leak. I have attempted to search for a leak by using carb cleaner and spraying it on vacuum lines to see if there is an idol change... but have found no leaks. I have been told that it could be a fuel issue, however i have replaced the fuel tank and the fuel pump and have cleaned the fuel rail - the issue still remains. I have noticed that the car will not start at times, unless you push the gas pedal and turn the car over it will eventually start. The starting issue will only occur if you turn it over and then stop before it gets a chance to start. I have noticed that the cars temp will start to rise at get close to over heating until the fan kicks on and brings it down to normal temp... not sure if that is because it needs a new fan or not... i have been told by a shop that that could be occurring from a timing issue which us causing the engine to overheat. Car runs very rich but im not sure if that is because of the EGR delete or not. If you have any ideas to what could be causing my issues please feel free to give me some input, it would be greatly appreciated. Again i am a rookie at all this, this is my first rebuild.

Thank you,

Hunter
 
Last edited: Dec 26, 2016

mikestang63

SN Certified Technician
Aug 27, 2012
11,606
8,859
214
In the garage
Dec 26, 2016
#2
  • Dec 26, 2016
  • #2
Your problems are
1 bunch of poorly matched parts
2. 24# injectors with stock MAF and EEC
3. E cam
4. deleted EGR


You dont mention brand and type of intake, heads, throttle body, rockers, fuel pump, rings, pistons, head gaskets head bots- you did use new ones right- so ut us a guessing game.. Did you burp all the air out, pressurize the oil system, measure for proper pushrod length. use a new balancer.. Vacuum leaks may not be in a place you can see- make a smoke machine. I would start by running the codes, going back over every bolt, wire and hose and checking they are connected and torqued to spec
 
Reactions: A5literMan

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
27,846
10,522
203
polk county florida
Dec 26, 2016
#3
  • Dec 26, 2016
  • #3
Can you run the codes on a 94 stang?
Of course you can.
If you are confused, like me, there is a sticky thing for that
 

Hunter Hill

New Member
Jul 27, 2015
6
0
1
Kemah, TX
Dec 26, 2016
#4
  • Dec 26, 2016
  • #4
mikestang63 said:
Your problems are
1 bunch of poorly matched parts
2. 24# injectors with stock MAF and EEC
3. E cam
4. deleted EGR


You dont mention brand and type of intake, heads, throttle body, rockers, fuel pump, rings, pistons, head gaskets head bots- you did use new ones right- so ut us a guessing game.. Did you burp all the air out, pressurize the oil system, measure for proper pushrod length. use a new balancer.. Vacuum leaks may not be in a place you can see- make a smoke machine. I would start by running the codes, going back over every bolt, wire and hose and checking they are connected and torqued to spec
Click to expand...


I had a shop button it up. I brought it to them after I put the motor in and had them get it running.
 

Hunter Hill

New Member
Jul 27, 2015
6
0
1
Kemah, TX
Dec 26, 2016
#5
  • Dec 26, 2016
  • #5
karthief said:
Can you run the codes on a 94 stang?
Of course you can.
If you are confused, like me, there is a sticky thing for that
Click to expand...

It's throwing a code for the EGR, SMOG PUMP, and I believe for a cylinder #1 misfire.
 

A5literMan

At least it is lumpy...
5 Year Member
Jul 30, 2011
4,674
2,343
194
Illinois
Dec 26, 2016
#6
  • Dec 26, 2016
  • #6
Plug wires crossed? Clogged injector?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,179
17,881
224
Massachusetts
Dec 26, 2016
#7
  • Dec 26, 2016
  • #7
24# injectors with stock MAF certainly isn't helping much. You either need an aftermarket MAF calibrated for 24s, or a chip to tune for them.

What heads did you install?
 

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
6,945
5,816
213
Dec 26, 2016
#8
  • Dec 26, 2016
  • #8
if in doubt....put the stock injectors back in and see how it runs. Your car is running too rich and the timing may be off, too.

The brand of the heads and the intake are important because of fitment issues with gaskets. It's not uncommon to get what they call an internal vacuum leak. That's when the intake gasket slips and allows air to be pulled in from the lifter valley under the intake.
 
You must log in or register to reply here.

Similar threads

D
Fox won't crank over and fuel pump won't kick on.
  • djj62478
  • Jun 7, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
16
Views
223
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 11, 2026
General karthief
A
1987 5.0 speed density Foxbody crank no start
  • Alan2204
  • May 23, 2026
  • Fox 5.0 Mustang Tech
Replies
10
Views
152
Fox 5.0 Mustang Tech May 30, 2026
Mcmahst
H
Fuel starvation issues, 91 EFI to carb swap. Car dying after 1-3 gallons used. EFI tank, electric fuel pump, bypass regulator. Dual fed carb
  • hassler
  • Oct 11, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
8
Views
701
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 12, 2025
nickyb
L
1997 V6 Starting issue
  • leanzik04
  • Mar 20, 2026
  • SN95 V6 Mustang Tech
Replies
3
Views
205
SN95 V6 Mustang Tech Mar 20, 2026
Noobz347
K
86 GT Water Pump
  • Kade5114
  • May 11, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
3
Views
76
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 11, 2026
nickyb
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
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?