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Electrical 1989 mustang no injector pulse

  • Thread starter Thread starter FoxbodyGage
  • Start date Start date Nov 20, 2021
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FoxbodyGage

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Nov 20, 2021
#1
  • Nov 20, 2021
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Getting sick and tired of this car I can't for the life of me figure out why I'm not getting injector pulse. I replaced the pip sensor and the computer but still nothing. I also tested the injectors with a noid light and nothing no pulse. They all have 12v to them as well. If someone can tell me what to look for or try I would really appreciate it
 

OldManRiver

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Feb 14, 2015
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Central Wisconsin
Nov 20, 2021
#2
  • Nov 20, 2021
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Does the injector harness ground wire have a solid connection?
The ground lug is usually attached to one of the upper bell housing bolts.
 
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FoxbodyGage

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#3
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OldManRiver said:
Does the injector harness ground wire have a solid connection?
The ground lug is usually attached to one of the upper bell housing bolts.
Click to expand...
I had it grounded on the firewall but then I moved it to the front of the aluminum head ??
 

General karthief

wonder how much it would cost to ship you a pair
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Codes?
 
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FoxbodyGage

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General karthief said:
Codes?
Click to expand...
Will it read any codes if the car hasn't fired up? I just swapped my 5.0 from my 95 into the foxbody and did heads and cam. Also changed from a c4 trans to a t5.
 

General karthief

wonder how much it would cost to ship you a pair
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Well, no use it checking for codes if the engine has not run.
 

Mustang5L5

That is…until I whipped out my Bissell
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  • Nov 21, 2021
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FoxbodyGage said:
Will it read any codes if the car hasn't fired up? I just swapped my 5.0 from my 95 into the foxbody and did heads and cam. Also changed from a c4 trans to a t5.
Click to expand...

Couldn’t hurt.

Too high of a TPS voltage at idle will disable injector pulse as “flood clear” mode. This would show as a code despite the engine not able to run.

I would check them
 
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manicmechanic007

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Codes will (should) be stored every time the start is energized and the engine fails to run
Look into the PATS with a NGS to check theft status
 

manicmechanic007

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The pip signal goes right thru the TFI module You should swap that too or make a test TFI to use
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
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Massachusetts
Nov 21, 2021
#10
  • Nov 21, 2021
  • #10
manicmechanic007 said:
Look into the PATS with a NGS to check theft status
Click to expand...

No PATS in 1989. 1994 was the first year in a Mustang for that.
 
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FoxbodyGage

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General karthief said:
Codes?
Click to expand...
I did also swap the dizzy with a new tfi module. I hear the fuel pump and the eec relay clicking so I assume those are good. My fuel pump does stay running constantly in the run position. Could that indicate a fried eec ?
 

Mustang5L5

That is…until I whipped out my Bissell
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Feb 18, 2001
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Nov 21, 2021
#12
  • Nov 21, 2021
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Yes, that is a good indicator of an ECU issue. You’ll want to open the case up and look for leaking capacitors and/or a burned pin 46 trace.

Test for continuity between pin 40/60 and 46. You should have it
 

manicmechanic007

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Mustang5L5 said:
No PATS in 1989. 1994 was the first year in a Mustang for that.
Click to expand...
No gem module to run it PATS either but swapped to a 95 harness and processor right?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,248
17,929
224
Massachusetts
Nov 21, 2021
#14
  • Nov 21, 2021
  • #14
manicmechanic007 said:
No gem module to run it PATS either but swapped to a 95 harness and processor right?
Click to expand...

I’m assuming he just moved the 302 over to the Foxbody and is running 100% the fox wiring and ECU.
 
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manicmechanic007

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Processor running the fuel pump constantly?
Big problem
Wrong processor?
 
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FoxbodyGage

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#16
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yes just pulled motor out and did some work, %100 fox harness
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,248
17,929
224
Massachusetts
Nov 22, 2021
#17
  • Nov 22, 2021
  • #17
Verify your TPS voltage at idle is around 0.5-1.25 volts. Like said, a high TPS voltage will signal the ECU to not fire the injectors as it will think it's in "flood clear" mode.

If you were to pull the codes, this would be a code 63 if this was the case
 
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paul87gt

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#18
  • Dec 12, 2021
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Speed density check m.a.p. sensor..
 

General karthief

wonder how much it would cost to ship you a pair
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paul87gt said:
Speed density check m.a.p. sensor..
Click to expand...
It's an 89, mass air car
 
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FoxbodyGage

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Dec 12, 2021
#20
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Its an 89 mass air car
I haven't messed with the car in some time but I did pull out the eec and its a cw3 computer for an auto transmission and found the circuit board burnt. Would this be the reason why its not wanting to pulse
 

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