Injector pulse Pin 17

[flyingbrick242]

Symptom: Back feed through injector circuit causing green INJ/IDC and Red "sys on" led to stay illuminated all the time after starting engine. Shutting off while pump and system still spraying and both leds still illuminated. It will stop when disconnecting pulse signal.

Background: Sequential injection, pin 17 tapped into pulse signal of # 5 injector.

Engine: 2004 Volvo B5254T with ME7 Bosch fuel injection.

Any help would be appreciated.
Thank You.

[Richard L]

In future, please post aquamist relatived problems to the aquamist section., I don't always visit every forums on thsi site.

I need to know a few things first:

1. Which aquamist system do you have.
2. What version of the DDS3 junction board.
3.Serial number of the flow sensor.
4. Do you have a wiring diagram of the ECU pin you can post here?

I think there is a wiring problem. But I need the above anwsers to be certain.

[flyingbrick242]

My appologies to submitting in wrong section.

1-HFS-5
2-DDS-3 V10
3-Flow sensor serial# 3884
4-Sorry but No ECU wiring but can tell you its a typical ground pulse signal.

Let me know what other information you need .
Thank You

[Richard L]

OK, I have just had a chat with Jeff Howerton.

Your system is now basicalluy working as it shoudl apart from the injector pulse pick.

Lets work on this now:

1. Please disconenct the wirung that oyu splice into fuel injector's pulse leg.
2. Start the car
3. Does the resd and green led trigger?
4. With the engine still running.
5. Manually stabbing the injector pulse "pick up" wire to ground (from pin17 pg fthe juction box)
5. Tell me if this triggers the red and green led.

We stop at this stage and wait for your results.

[flyingbrick242]

Pulse lead disconnected engine running NO green led or red led.
While engine is running take pin 17 to ground green led is on including red led and pump stats to operate.

[Richard L]

This sounded like the pin 17 is picking up the wrong injector pulse signal. The system appeared to be working as it should.

OK, lets go a bit further....

1. Where are you picking up the "injector pulse" signal? Is it from the actural injector or ECU?
2. What type of fuel injector is it? 16 ohm, 10 ohm of 2.5 ohm?
3. Does the injector use a "resistror pack"?
4. Did you splice the wire from the ECU or at the fuel injector harness.
5. Important: Where are you picking up the 12V supply to the DSS3 junction board (pin24).

[flyingbrick242]

The injector- I made up connectors to splice in between

12 ohm injector

No resister pack

Right at the injector harness

Directly into the fuse box which is only powered when in pos II and cranking.

[Richard L]

Everything looks perfect.

1. Can you measure the voltage of the 12V wire from the fuse box at idle. (DDS3 pin24)
2. Can youi measure the volatge at pin 17 when the engine is at idle. (DDS3-pin17) with the green wire spliced into the inj(-).

All relative to a known good ground.

[flyingbrick242]

Pin 24 at idle 14.2v

Pin 17

Injector pulse disconnected 13.3v
Injector pulse connected 11.2v

[Richard L]

Originally Posted by flyingbrick242

Pin 24 at idle 14.2v

Pin 17

Injector pulse disconnected 13.3v
Injector pulse connected 11.2v

I think we might have discovered the problem. The differecne of voltage between pin 24 and pin 17 is outside our designed limits. There seem to be a dropof 0.9V between the two points. The design limit is 0.45V.

The best way to over comthis is by taking the 12V from the fuel injection +ve. (powering the DDs3's pin24). This way you willnot get the false trigger.

If you have time to look into this closely, check at each point of the electrical function between the Battery+ to the Injectot (+):

Battery -> FI relay -> Fuse -> fuel injector + , somewhere along this line, there is a high resistance junction. Or possibly the wire gauge is too thin. Another possibility is the fuel pump is load up the same supply anf drop it from 14.2V down to 13.3.

Alternatively, I can modify the v10 to suit your car. Either way, Try the first suggestion.