Hello so I checked the + and grd on all injector harnesses and got 8v. When keeping the + lead attached to the harness and the grd lead switched to engine block I get 12v. Backprobed ground on harness with test light hooked up to b+ no light, no pulsing when cranking. What could cause this?

 

The relay 2/32 provides power to the #B3 fuse that sends 12 volts on the green wire to all injectors 8/6-10, and sends power to the 7/17 AMM and 2/23 the fuel pump relay. The ECM grounds the injectors to fire them. Unplug all the injectors and the AMM. Turn key on and check for 12v on the green wire at any/all injectors if you think that's where your problem is. Use a $10 noid light to check injector pulse.

 

I already replaced relay 2/32 . I did test the green wire. With the positive lead on the green wire and the negative lead on the engine it's 12v. With the negative lead on the harness it's 8v,

 

And does a test light hooked to b+ touching the ground terminal on the harness not simulate a noid light ? I was under the impression I could use a test light instead of a noid light this way.

 

In my 38 years with a Volvo shop I've only successfully tested injector pulse with a noid light. (or a stethoscope)

Do you have spark at a spark plug?

Any codes? (in all control units, not just ECU)

 

I didn't check for spark when I seen the injectors whernt pulsing I assumed that was it. I will grab a noid light and try the test but I was under the impression it was just two leads that plugged into an injector not sure why the test light wouldn't work. Any idea why the circuit on the harness shows 8v but when changing the ground to the engine it shows 12v? I have a Ford explorer and performed same tests and test light flashed on and off and the circuit on the fuel injector shows 12v so I'm just wondering if I have found my problem or if I need to look elsewhere and this is normal

 

Who knows. You're not using a noid light, and the concept of "ground wire" is unclear.

The wire that turns the injectors on is only grounded for a few milliseconds every so often when the car is running. But it's not clear what this wire is. The fact that you don't have 12 volts across it suggests to me that you could be looking at the "other" wire connected to a single injector. One wire has power on it, and the other wire is pulsed. It's maybe not clear to refer to that wire as a "ground" wire.

It takes a little time to get a light bulb hot enough to glow, so my inclination is that we haven't really discovered anything so far, except that you do have injector power.

 

I am referring to the harness that plugs into the injector and has two wires running to it. A pulsing ground signal and constant 12v. When probing with multi meter it shows 8v with key turned on engine off. When I remove the black lead from the "other" wire on the harness and touch it to the engine block it changes from 8v to 12v. The bulb does not take time to warm up I have a noid light I can use as well just didn't. I have performed this test on many other vehicles and when testing the two contacts at the harness read 12v not 8v. And also when clamping the test light cable to b+ and probing the "other" wire on the injector harness it flashes on and off while cranking simulating injector pulse. Since it already has power everytime the computer sends that pulsing ground signal the bulb should light up. on every other vehicle I have done the test on ford's and gm vehicles this is what happens. so why not with Volvo? I will go test vehicle spark, use a noid light, and get all the DTC codes when Im with the car Monday.
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