No fuel injector Pulse

Tiny
R BILLMEYER
  • MEMBER
  • 1989 FORD E-SERIES VAN
  • 7.5L
  • V8
  • 70,000 MILES
I have good rail pressure measured with a pressure gauge at the test point on the rail. I have a new computer, TFI module and fuel pressure regulator. 12 volts on the injectors but no pulse when cranking, when I manually pulse the injectors with a clip lead the engine receives fuel and fires. I was wondering if the IDM lead has a open 22K resistor and most importantly where is the resistor located? Help please.
Tuesday, June 16th, 2020 AT 4:27 PM

7 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

I attached a diagram for you to view of the injectors.

Did you verify power at the red wires to the injectors? You need that power.

If you do, then look for power to the ECM at the terminals I circled. They need to have voltage with the key on. Then the ECM does the job once the engine cranks and an RPM signal is sent to the ECM. It will ground the wires from the injector and they will fire fuel into the intake.

https://www.2carpros.com/articles/how-fuel-injection-systems-work

Roy
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Wednesday, June 17th, 2020 AT 4:16 AM
Tiny
R BILLMEYER
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I am looking for the location of the 22K resistor between pin 4 of the computer and the control terminal of the coil.
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Thursday, June 18th, 2020 AT 3:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
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The resistor is around the coil area. I attached a diagram for you with the resistor and the part number.

That is not your issue. The ECM is responsible for controlling the injector pulsing.

Roy
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Friday, June 19th, 2020 AT 5:19 AM
Tiny
R BILLMEYER
  • MEMBER
  • 1 POST
I located the 22k resistor, for future reference it is contained in the wiring harness approximately 8 inches from the connection on the coil.
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Saturday, June 20th, 2020 AT 10:22 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good find. As I stated it was located by the coil.

Did it fix your issue?

Roy
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Sunday, June 21st, 2020 AT 4:03 AM
Tiny
R BILLMEYER
  • MEMBER
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Still trying to figure out why the computer is not allowing the injectors to pulse. I have resorted to ohm metering out the entire harness and have great continuity to all of the components. Also there are no leads with any shorts to ground.
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Tuesday, June 23rd, 2020 AT 1:53 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Just to jump in on this one. If you proved out wiring then I am thinking it is the control module. The TFI module that you replaced is for the ignition system and the EEC controls injector pulsing. Roy mentioned earlier that the ECM (EEC is the same thing) controls the injectors so we need to check the pin 58 at the EEC to see if we have voltage. I assume we don't. If not, and you have no codes, then I suspect the control module is the issue.
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Friday, June 26th, 2020 AT 6:01 PM

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