Ford Forums banner

Dead Injector?

2K views 7 replies 5 participants last post by  MADNC_8 
#1 ·
The XF is running again (idling only :dead:) but missing. It gets perfect spark through all leads and plugs and the valves/pushrods etc looked alright when the head was off.

Since there were no other problems I could see, I started un-plugging the injectors one by one whilst it was idling (like checking the leads). I found that it made no difference when I un-plugged a certain injector.

Now my question is, is there anyway of testing the operation of a fuel injector?? i.e. How do I tell if it is clogged or dead?
 
#2 ·
Maybe try backprobing the injector (installed to the fuel rail and harness) with a multimeter to see if there is a current pulsing through there. If there's no current, then probably the injector wiring is dead (injectors are connected in parallel no?).
Although if it is an electrical problem, it should show up if you run an ECU diagnosis. Can't help you out on how to do that tho, sorry, but it should be really easy and in a gregory's book.

If there is a current going through it or no fault comes up in the diagnosis, then I would say that your injector is not opening properly sand you would need a new one.

Hope that helps you out a bit.
 
#3 ·
Tickford6 said:
Maybe try backprobing the injector (installed to the fuel rail and harness) with a multimeter to see if there is a current pulsing through there. If there's no current, then probably the injector wiring is dead (injectors are connected in parallel no?).
Although if it is an electrical problem, it should show up if you run an ECU diagnosis. Can't help you out on how to do that tho, sorry, but it should be really easy and in a gregory's book.

If there is a current going through it or no fault comes up in the diagnosis, then I would say that your injector is not opening properly sand you would need a new one.

Hope that helps you out a bit.
Yeah checked the voltage not the current at the connector, should this make much difference? (i.e you can still tell if its getting power) All seems fine so I guess the injector is the problem.

I also tried listening for 'clicking' through the handle of a screw driver, but the slight rocking of the engine as it missed and the noise from the EGR made it hard...

On the subject I ran the ECU diagnosis and came up with a code 22 (MAP (vacuum) or BARO signal out of range). Not exactly sure what this means though. :shrug:
 
#4 ·
As a stab in the dark, I'd say it may be a result fo the dodgy injector, but funny the injector didn't come up in the test.

I'd get an injector from a wreckers and see what happens when you hook that up. Or, try another injector in the place of the bad one and see what happens.

Good luck
 
#5 ·
Map sensor has a vacuum hose attached to it. If this vacuum hose slips off or you forget to connect it back up, then you will get a very rough idle.

I think the MAP sensor is bolted to the firewall. Make sure that the vacuum hose is connected properly with no leaks. Also check the electrical connection to the sensor.
 
#7 ·
Snake8 said:
Why don't you swap the injector with another in the engine. That should help to isolate the problem.
Yeah did that, put it on cyl 1 so that I can get to it easier. Checked the resistance of the injector itself also and its in range so maybe its severely blocked.

This EFI XF is proving to be a lot of 'fun' to get going properly.

As for the MAP sensor... I can't find the bloody thing. Anyone got a pic of what it looks like??? Can't see anything bolted to firewall that has vacuum hoses and power going to it???
 
#8 ·
sorry no pics but its on the left (passenger) side at the top of the firewall its a little black thing bout 4 cm wide by 1.5 to 2 cm high with a green 'plug' type thing in the bottom it has a vacuum hose which goes to the plenum and 3 wires (i think) make sure the wires arent corroded and that the vacuum hose goes from the sensor to the plenum (it tells the computer manifold absolute presure - MAP) so hte computor can sompensate for things like idle, cold starts, etc
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top