Injectors have no power

Tiny
LILCHRIS_KING
  • MEMBER
  • 1997 VOLKSWAGEN JETTA
  • 100,000 MILES
Ok I changed the injengion, and it drove fine I parked it went inside for a couple hours and went to start it agian and it wouldnt start I have checked pump relays fuses regulator and changed the ecu still nothing it has power every where except to the injectors what can I do on dash when u turn it over it reads in o2
Saturday, May 4th, 2013 AT 5:47 AM

7 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
The injectors are powered by the fuse box with 12 volts key on, the pcm controls grounding.

First, put your old pcm back in as I doubt that was the failure.
Check all fuses with a test light and verify wiring to the injectors is not faulty.

Roy
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Tuesday, December 20th, 2016 AT 12:10 PM
Tiny
LILCHRIS_KING
  • MEMBER
  • 4 POSTS
Ok ive check that b4 I put a new ecu in the injectors dont have any power
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Tuesday, December 20th, 2016 AT 12:10 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
You checked it before? What were your results?

Roy
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Tuesday, December 20th, 2016 AT 12:10 PM
Tiny
LILCHRIS_KING
  • MEMBER
  • 4 POSTS
Ok I had a couple bad fuses I changed them and the wireing is good also I bought a new relay still no power on dash it reads in o2 whsn you crank it over I have no clue if that js important or not im up a creek without a paddle here
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Tuesday, December 20th, 2016 AT 12:10 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Did you verify power with a test light at the fuses and at the injectors?

Roy
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Tuesday, December 20th, 2016 AT 12:10 PM
Tiny
LILCHRIS_KING
  • MEMBER
  • 4 POSTS
Yes power at fuses but not to injectors
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Tuesday, December 20th, 2016 AT 12:10 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Fuse #18 is power FROM the fuel pump relay (feeds the fuel pump, O2 sensor heater).

The relay also supplies power to the injectors (non fused) when the relay is closed.

The relay is NOT always energized. When you turn the key ON, the relay closes for a couple of seconds and then opens again. Checking
for power at the Injectors or at fuse #18 AFTER the relay opens again, will show NO power.

You can bridge the relay slots in the fuse box to "bypass" the relay for testing purposes, to see if the injectors then get power.

Thomas
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Tuesday, December 20th, 2016 AT 12:10 PM

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