WICruiser

It sounds like you have a short to ground in your injector harness that is basically eliminating fuel control - full flow from the injectors (your very rich condition. The injector harness is snaked through the intake area and could easily have been pinched when you switched out injectors (latest black smoke - rich problem). I assume because all of your injectors are away being tested you have the fuel rails off. You should be able to move the injector harness out from intake area and inspect for potential pinch points and also confirm a grounded condition. If the ground condition remains with the harness away from the intake, then keep following the harness back through the engine campartment to the interior until you determine where the short is located. There is a good chance that the short was developed through the intake project by either cracking of old insulation on the wires or a wire getting pinched.

Tampa 928s

Pulled Lh Ez and Fp relays one side is still showing 1.3 ohms to ground. I moved the harness all over the place no change is there any other pathway back to the elec system not through the relays?

Tampa 928s

Looking at Schematic not my year tell me if I'm correct!
12v from Fuel pump relay
Out from central elect system pin 13
12v commom to cyl 1-4
12v common to Cyl 5-8
12v to idle speed Reg
12v to oxy sensor
With relay removed all return path to ground should be lifted I am showing 1.3 ohms.

Tampa 928s

Pulled the idle speed reg same low ohms showing on 12v center pin !

Tampa 928s

86
Anyone with a car in pieces with Inj easy to access?



If you have been following my inj post I need to know if there is any connection from 12v pin on the inj connector to ground. My trigger side that goes to the Lh which is ground is fine but my 12V is showing a short on all inj. I traced the Skem and removed all the relays and devices that are connected to it Ox Sensor and air Regulator. It still shows 9 ohms to ground on the 12v side. If you could test one or two injectors from the pins to earth or ground and see what reading you get. Both should be open with no pathway to ground. If this is so there is a short in my 12v lead to the injectors. I dont want to start tearing things apart untill I know for sure this is the correct reading I should be seeing.
Thanks

Tampa 928s

On my intake there is a sensor "not the one in the air box", and it is showing 4.5 ohms to the 12v Inj connector. I'm sure this is not right trying to find what this is called to trace it down. This shares the same cable as the Inj harness.

Tampa 928s

I guess I am talking to myself today!

Has anyone removed the connection rake at the bottom of the Fuse/Relay panels? Does it pull stright out or do you require a tool?

ROG100

Mark,
What do you mean by "connection rake"?
Roger

Tampa 928s

The bottom of the relay panel where all the wires attach each has several wires on it its vertical. Called wire harness plugs a-x

Tampa 928s

For all of you that ever run into this problem and the rest that could care less I thought you maybe interested in why I am doing this.
My **** troubleshooting procedure has been based on 25 years in the Electronics business. My time on this 928 has been a few weeks which forces me to analyze a problem so I really understand how it works rather then taking a guess. That all said, with the symptom of loss of power after adding the new Ford Inj everything pointed to an Inj issue. I will know next week when my rebuilt ones come back. But on to the Wiring Harness with all the moving around after the intake rebuild the spector of a shorted or broken wire was a possibility. I found the 12V Inj pins were showing not an open but a 3.9 Ohm to ground indacating a short. I have since removed the wire loom connector x and the short went away. This tells me one of two things, either the shared power circuit is loading the meter down giving a false ground or another device on that circuit is loading it down. For the sake of logic there is no way the car would run with a shorted 12v on the Inj. I hope this helps someone in the future so not to go through what I did and use this trouble shooting procedure.
I still do not know if it will run right next week but I know what it is not wrong. I now have a very good, not total but good understanding of engine management now.

Tampa 928s

I have unloaded fuse 42 and the short on the 12V Inj went away.
Looking at this Skem it seems the Fuel pumps are in series and would create the load on the 12v showing a short although non was present. Please review and add any comments please!

Tampa 928s

I received my rebuilt injectors installed started and it barely ran. Motor starts runs on a few cylinders and when trying to restart just turns over.
All connections are correct and hooked a Fuel Pressure gauge reads 39 lbs at start. The fuel pressure will drop over time and return to zero over a long while not sure if this is normal.
The LH and Ezf Amp connectors were out along with W of the Ceb vertical connector of course the inj and all sensors wiring for testing.
At this point I am going to put a scope on Control signal on the Ezf to check for a signal. Is there any thing else I can check with a scope such as injectors it is impossible on an 86 to get to the Injector connectors.
This car ran great before I fixed it!
It ran Ok, low power after I added the new inj and intake rebuild.
It now does not run after putting in the original Injectors and playing with the wiring.

Tampa 928s

Tested one Injector on harness reads 12v with relay xx bypassed seems ok!

John Speake

Pull back the boots on the injectors connectors and make sure there are no bare wires that can short out the injector.

Tampa 928s

Ok will do!
I am getting 12v to ground on both sides sure looks like an inj harness short, am I correct?
If I pull the boots back they will be destroyed they are very brittle !
Is there a way to test them installed, an 86 is a pain and I would have to remove the side intake and fuel rails again.