okc lube man

In the past I have done extensive work on ignition and fuel system with exception of injectors. I have pulled all injectors left on fuel rail. If key is on and fuel to rail, if they were going to, the injector(s) could be leaking.?

Not happening. So I assume that part is good. Is it possible to apply power or ground to injector(s) to see if they are spraying fuel? If so which wire would it be? I believe the choice is red and yellow or white.

Thanks Mike

Chris_1

iTrader: (1)

I think it may actually work that the power is there and the computer provides a ground. Most of the things the computer does is by grounding.
That said, I don't know the answer to your question.
I do know that you can check if they're getting a signal but you need an LED test light.
Check easyautodiagnostics.com - they have a lot of useful info on testing things there. Maybe they have something that will help with your issue.

okc lube man

OK here is what I have done. I bought one of nicer to me test probe with detachable leads. I took the lead that you can hook the wire and then pierce it and put a jumper with clips on its threads to engine ground. All injectors seem to be firing. Although they appear to be more of a stream than a mist. I need although they are all firing to check the resistance, just cause.

What however seems strange to me is that with harness in tact to injectors and the key on to supply power to injectors as I apply the ground to #1, 1,4,5,8 spray, the same goes for 2,3,6,7. This seems strange and a waste of fuel. I do not have a wiring diagram, however for a ford van it seems as all grounds go back to pcm.

If they should not all fire like that then I would assume I have a faulty pcm, although just replaced.

Is there anyone out there with knowledge of how this should be? If it is as it should be?

Thanks Mike

Chris_1

iTrader: (1)

That would be a speed density system (as opposed to MAF). It's how they work - 4 injectors and then the other 4 injectors.
MAF fires only the injector right beside the intake valve that's opening.
Speed density is not as efficient, but it still works fine as the computer will back off on supplied fuel if the O2 sensor shows that the motor is running rich. Called fuel trim.
The injectors will put out a different spray pattern depending on fuel pressure, which is determined by the fuel pressure regulator (vacuum operated)
Basically, they provide a softer spray at idle and coast when the air is moving slower and a really hard jet when the air is moving fast (throttle open) and a bit of variance in between.
So your system seems to be operating properly from what info I read.

okc lube man

Thanks Chris 1! Would think that since I have it down this far and I am in not to much of a rush that it would be worth having injectors serviced off of the truck?

Chris_1

iTrader: (1)

Not a bad idea if you think they're in need of servicing - they rarely fail, but they do get dirty.
New screens and O rings would help at least.
Check out mrinjectorparts and mrinjectorus - not sure where all the dots and coms go there. Guy's name is Bill Johnson I believe. I bought kits from him before to service injectors on my son's truck. Interesting site.

Chris_1

iTrader: (1)

Check out mrinjectorparts.com - good info site. I've bought kits from him before. Good service, no issues.

NOW my first post loads !!?!

Tfraser

When I had my mustang, I tested the injectors by taking them out to check the spray pattern. Basically you just get two wire connectors and make your own positive and ground then you just touch the wires accordingly to a battery. There is a small list of stuff you will need besides that though. You need a can of something to spray through the injector that won't hurt it. Not sure what I used as it was a while ago. Then you need a valve step, the one used on your tire to put air in. Take the actual valve thing out. Put the bottom part that goes in your rim around the furl injector and use the tip from the spray can in the top. Put power to the injector and spray the can of whatever in. Be careful not to give it complete pressure as the valve step will pop off. Might have to get a bit creative but it's basically a diy bench test on a budget. Pm me if you have any questions.

okc lube man

Sent them off Wednesday. Hopefully they will be back by end of the week and the truck will run like it should. If not back to shootin.

It was truly a sad thing that even with the shipping cost I could not find a local shop to do the same job and spend another $80.