355 5.2, no injector signals on bank 1

@Qavion , what would cause a no injector signals on all 4 injectors at bank 1? Can I get your latest 5.2 USA ECU schematics?

 

Fig11_1998_F355_5.2_Engine_Control_System

All 8 injectors have a common power source. There should be 12 volts on one pin of each injector if the ECU has provided a control signal to relay M in the footwell. If one bank is failing, then it must be an ECU control problem (or a faulty wiring splice 30009 or 30013). If relay M failed, you would have no injectors, no fuel pump, no... lots of things.

Here's another diagram showing the other side of plug 41090 (aka 41051)

Fig11a_1997_5.2_Injection_System_Ignitionv2

I suppose it could be a bank shutdown signal (high CAT temp, etc), false or otherwise? Or does bank shutdown only cut off ignition? I keep forgetting.

 

There is an additional clue: I get 6V at the drive pins (coming from the ECU) for all four injectors. Something is up in the wiring or the ECU.

 

CAT temp shuts down injectors.

 

Interesting. Then it's a wiring problem. Have you checked the volts at the other injectors? If low also, but somehow still operating, check that pin 4 on plug 41051/41090 hasn't been pushed back. The 9 pin plug is right next to the ECU.

 

If all injectors are low, you could also try disconnecting the fuel tank vent solenoid valve and the exhaust bypass solenoid valve to see if the volts go up.

 

Doesn't make sense. There would have to be some current through a resistance to drop the voltage. If all is disconnected there would be no current draw.

 

OK, It looks like power is routed to each bank on different splices. 0V on the pins where 12V is supposed to be for one bank and OK for the other bank. Something is broken in the wiring harness. I don't know if I can get to it with the engine in the car. Damn,.

 

Why ??

 

Ah, looks I missed the "drive" in Mitchell's comment. Ignore my last messages, unless you mean "drive" = "power"

 

Drive means the ECU signal that drive the injectors. I cannot get continuity from bank one 12V pins to the other bank 12V pins on the injectors. So, I think the splice is broken inside the harness.

 

Ouch. Seems so. Unfortunately, we don't know where the splices are. I'm starting to regret giving my old engine harness away. If you look at photos of harnesses online, you can probably get an idea of where the harness splits into two.

 

I thought if you had a power supply problem to all injectors, these devices could have a too low resistance (partial short), dragging down the power circuit. But since the volts are ok on your other bank, these devices will be ok.

 

I peeled back the cloth tape 12 inches from the ECU connnector and cannot find that splice. I am going to try and run a wire from the Pin 4 of the power connector to the injectors to see if it solves my problem before I do a more permanent fix. How much current is an injector consuming?

 

Sorry, deleted my last post. I misread your post again I basically said what you already said.

 

Ian, it's funny we are having an online conversation almost in real time from two continents.

 

The wire gauges are shown in the diagram i.e. 0.5mm^2 (20 gauge). This is up to the splice. If you can pull back one of the injector boots and attach the additional power wire (from pin 4) to the green/black wire, you should be ok (as each injector wire is capable of taking the current of all four injectors).

 

Looking at online pics of the harness, it looks like the splice (30013) could be anywhere from the section you unravelled to the fork in the harness, so probably on top of the fuel tank.

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Splice 30009 could be close to 30013... or not. Could be a lot harder to find.

Anyway, good luck with the temporary rewiring. Might look messy, but it may allow you to drive your car.

As they say in the electrical trade, if you can't figure out where the problem is, go to the last modification which was made (on the car).

 

Is that large "P" clip attached to the top of the tank?

I see there is some insulation damage in the splice area in the photo above. I wonder what the odds are of your harness being the same.

 

No, worse. It is attached to the timing belt cover on bank 1.

The splice is after the P bracket and the forks which leaves it some where under the power steering reservoir. Anyway, the temporary bypass wire is the ticket. The engine fired up on all 8 cylinders. And at that time, I shut the car down for the day. I have enough fun for one effing day.

 

For tomorrow...

Ah, you mean 30009? Or does the wiring double back from splice 30013 to the main fork? I've seen that a few times.

 

Nice trace guys