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

Engine need help car has a hiccup

  • Thread starter Thread starter 89llx
  • Start date Start date Sep 17, 2018
8

89llx

5 Year Member
Aug 31, 2009
302
5
29
Sep 17, 2018
#1
  • Sep 17, 2018
  • #1
I have and 89 lx and I can be driving along and the car will hiccup its like you turned it off and back on with super quick speed it DOES NOT blow a fuse and it keeps running I switched out the whole distributer but that did not help


can anyone please help

thanks 5speed
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Sep 17, 2018
#2
  • Sep 17, 2018
  • #2
89llx said:
I have and 89 lx and I can be driving along and the car will hiccup its like you turned it off and back on with super quick speed it DOES NOT blow a fuse and it keeps running I switched out the whole distributer but that did not help


can anyone please help

thanks 5speed
Click to expand...


Dump codes sticky

Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/
 
8

89llx

5 Year Member
Aug 31, 2009
302
5
29
Sep 17, 2018
#3
  • Sep 17, 2018
  • #3
does it make a diff if my computer has a chip for the sc
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Sep 18, 2018
#4
  • Sep 18, 2018
  • #4
89llx said:
does it make a diff if my computer has a chip for the sc
Click to expand...
An add-on chip doesn't affect anything when dumping codes.
 
8

89llx

5 Year Member
Aug 31, 2009
302
5
29
Sep 22, 2018
#5
  • Sep 22, 2018
  • #5
I was just afraid it might clean out my chip also thanks
 
8

89llx

5 Year Member
Aug 31, 2009
302
5
29
Sep 22, 2018
#6
  • Sep 22, 2018
  • #6
thanks a ton jrichker I just got back from a test drive and it seems fine

it was flashing twice then one so 21 I think but no more hiccups
 
8

89llx

5 Year Member
Aug 31, 2009
302
5
29
Sep 23, 2018
#7
  • Sep 23, 2018
  • #7
I have not been on here for a long time

I don't see the other guy that would reply often like you he had a light, I think we was called the wizard maybe
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Sep 23, 2018
#8
  • Sep 23, 2018
  • #8
Code 21 or 116 – ECT sensor out of range. Broken or damaged wiring, bad ECT sensor.

[color= blue]Revised 6-Apr-2017 to add diagrams and resistance check for ECT wiring.[/color]

Note that that if the outside air temp is below 50 degrees F that the test for the ECT can be in error. Warm the engine up until you get good hot air from the heater and then dump the codes again.

The computer Engine Coolant Temperature sensor has absolutely nothing to do with the temperature gauge. They are different animals. The ECT sensor is normally located it the passenger side front of the engine in the water feed tubes for the heater. It has two wires that connect by a weathertight plastic connector.

The water temperature sender for the temp gauge is located in the driver's side lower intake manifold. It has a single wire that connects by a push on connector on the temp sender.


If you have replaced the ECT sensor and are still having ECT like problem symptoms, check the ECT wiring .

Computer wiring harness connector, wire side


Computer wiring harness connector, computer side



See the graphic for the 10 pin connector circuit layout.


Check the resistance of the green wire on the ECT connector to the green wire on pin 7 of the computer connector. You should see less that 1 Ω (ohm)

The ACT & ECT have the same thermistor, so the table values are the same

ACT & ECT test data:

Use Pin 46 on the computer for ground for both ECT & ACT to get most accurate readings.

Pin 7 on the computer - ECT signal in. At 176 degrees F it should be .80 volts

Pin 25 on the computer - ACT signal in. At 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.


Voltages may be measured across the ECT/ACT by probing the connector from the rear. A pair of safety pins may be helpful in doing this. Use care in doing it so that you don't damage the wiring or connector.

Here's the table :

50 degrees F = 3.52 v
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
212 degrees F = .47 v
230 degrees F = .36 v
248 degrees F = .28 v

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.

50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
212 degrees F = 2.07 K ohms
230 degrees F = 1.55 K ohms
248 degrees F = 1.18 k ohms

Diagram courtesy of Tmoss & Stang&2birds



Wiring_Diagram.gif[/

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
(website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg
 
You must log in or register to reply here.

Similar threads

F
Electrical Foxbody wiring harness 2.3 to v8 swap
  • Foxbodyjake
  • Mar 23, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
24
Views
653
Fox 5.0 Mustang Tech Apr 13, 2026
Foxbodyjake
F
9
Fox Hazards not working but blinkers do
  • 93fox_c
  • Dec 2, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
1
Views
184
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Dec 2, 2025
AeroCoupe
L
2000 Mustang PATS - Broken Key and Wire - HELP!
  • Laree Taylor
  • May 7, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
10
Views
148
1996 - 2004 SN95 Mustang -General/Talk- May 12, 2026
manicmechanic007
Tuners come on inside
  • squeak93
  • Feb 13, 2026
  • SVT Tech Forum
Replies
1
Views
237
SVT Tech Forum Feb 20, 2026
squeak93
M
Need help!
  • Masonevans726
  • Dec 17, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
227
1996 - 2004 SN95 Mustang -General/Talk- Dec 17, 2025
Masonevans726
M
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?