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sprinkles08
sprinkles08, ASE Certified Technician
Category: Ford
Satisfied Customers: 22134
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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I did a minor tuneup on a 1989 ford econoline 350 with a

Customer Question

I did a minor tuneup on a 1989 ford econoline 350 with a 460. It ran fine, the next day started it and it was missing on number 3 changed plugs to make sure I didn't crack one. Checked timing to make sure it didn't jump time.Checked firing order 3 times. Ran compression on the cylinder 160 psi.Next cylinder was 165 Went and put a second set of wires on it and new second cap and rotor. Then replaced injector on number 3 no change on situation. Put a injector pulse tester on number 3 as well as number 2 no light but I had a kit and another pulse tester from a gm fit when it had the wrong configuration on the pins for the ford one. Is a test light the same as a pulse testor?
Submitted: 4 months ago.
Category: Ford
Expert:  Juan Crespo replied 4 months ago.

Hi there.

A regular test light has very low impedance and might actually damage the injector driver inside the onboard computer. Noid lights are recommended for quick injector pulse checks (click here to see example)

Please let me know if this helps solve your issue or if you need further assistance.

Best Regards.

Customer: replied 4 months ago.
I used a noid light it didn't light
Expert:  Juan Crespo replied 4 months ago.

Try the Noid light on an injector you know is working; if it works there, then the driver for the other one is probably shot.

Customer: replied 4 months ago.
I tried on another injector no light. Is the noid light bad they are new
Expert:  Juan Crespo replied 4 months ago.

If you tried the Noid light on an injector you know is working and it did not flash, then it is bad. Make sure the Noid light is made for testing Bosch-type injectors.

Customer: replied 4 months ago.
Ok I have a Bosch type but it has different pin spacing can I run jumper wires
Expert:  Juan Crespo replied 4 months ago.

Yes, you can.

Customer: replied 4 months ago.
Its raining like hell here. I will need to continue tomorrow.
Expert:  Juan Crespo replied 4 months ago.

I'm usually online 2-8 PM weekdays. Hope to hear from you then.

Best Regards.

Customer: replied 4 months ago.
cool thanks,is that eastern time
Expert:  Juan Crespo replied 4 months ago.

Sorry, I don't work weekends. I'll opt out so other experts can look at your question. Please don't reply until another expert responds.

Best Regards.

Expert:  sprinkles08 replied 4 months ago.

Hello and welcome to JustAnswer!

Do you still need help?

Customer: replied 4 months ago.
Hi I am going to hook up a bosch noid light and check to make sure I have a pulse. I will get back to you as soon as I do that. Thanks
Expert:  sprinkles08 replied 4 months ago.

You're welcome!

Customer: replied 4 months ago.
The Bosch noid light does not lite on no 2 or 3 1 and 4 lite
Expert:  sprinkles08 replied 4 months ago.

So you have four cylinders that aren't running?

Customer: replied 4 months ago.
It seems 3 and 4 no noid on either there is spark through to plugs on those jugs. When I pulled the wires no change
Expert:  sprinkles08 replied 4 months ago.

Do you have an incandescent test light?

Customer: replied 4 months ago.
You mean a 12 volt test light? Yes
Expert:  sprinkles08 replied 4 months ago.

Is it an incandescent bulb?

Customer: replied 4 months ago.
yep standard napa test light, with a bulb like are in flashlights
Expert:  sprinkles08 replied 4 months ago.

Can you see if the red wire at the injectors not working will light the test light brightly when the engine is running?

Customer: replied 4 months ago.
Connected
Expert:  sprinkles08 replied 4 months ago.

I don't believe your whole post made it to the page, all is see is 'connected'.

Customer: replied 4 months ago.
Leave the wire connected to the injector or test disnonnected
Expert:  sprinkles08 replied 4 months ago.

You'd have to disconnect it to contact the pin in the connector.

Customer: replied 4 months ago.
Ok,thought you wanted me to probe througb
Customer: replied 4 months ago.
Hot to both
Customer: replied 4 months ago.
Red and blask
Customer: replied 4 months ago.
Steady light
Customer: replied 4 months ago.
On both injectors
Expert:  sprinkles08 replied 4 months ago.

Connect the alligator clip end of the test light to battery positive and probe the terminal for the second wire in the connector. With the engine off does the test light illuminate?

Customer: replied 4 months ago.
The black or red by second black?
Customer: replied 4 months ago.
Do you meAn the black,wird
Expert:  sprinkles08 replied 4 months ago.

You already tested the red wire and now are testing the second wire.

Customer: replied 4 months ago.
The second wire was hot also
Expert:  sprinkles08 replied 4 months ago.

You tested both wires for power rather than just the red?

Customer: replied 4 months ago.
When I
I probed the black,it was hot Lso
Expert:  sprinkles08 replied 4 months ago.

So you connected the test light alligator clip to battery negative, unplugged the injector and touched each terminal individually and they both lit the test light?

Customer: replied 4 months ago.
Expert:  sprinkles08 replied 4 months ago.

Does power on the second wire go away when cranking?

Customer: replied 4 months ago.
ill go check
Customer: replied 4 months ago.
Dims does not go away after it starts
Expert:  sprinkles08 replied 4 months ago.

Compare that to what you're seeing at cylinders that aren't having an issue. Does that not happen on the others?

Customer: replied 4 months ago.
No
Expert:  sprinkles08 replied 4 months ago.

Do you have a digital voltmeter? You're going to need to disconnect all injectors and the ECM and test for continuity between the two wires in the two affected injector connectors. You either have an internal failure in the ECM or the wires are shorted together somewhere in the harness.

Customer: replied 4 months ago.
I need to check the other injector characteristics. Disregard the no on the top answer. What I was thinking is that if that is only happening to the 2 injectors.. Cutting the 2 black wires that run to the injectors and running a new ground. I aint there yet lol. Where is the ecm located?
Expert:  sprinkles08 replied 4 months ago.

It's in the right side of the engine compartment under the blower motor area.

Customer: replied 4 months ago.
Just checked known good injector. Black stays solid light, red wire shows pulse in light. So it appears there is no pulse to the 2 red wires on the bad injectors
Customer: replied 4 months ago.
Thanks for sticking with me on my little twilight zone lol
Expert:  sprinkles08 replied 4 months ago.

The red wire is a constant power feed, ground is pulsed on the opposite wire to control the injector.

Customer: replied 4 months ago.
hmm seems that the pulse was on the red wire.
Expert:  sprinkles08 replied 4 months ago.

The driver wire for 3 is black/white, 4 is light green.

Expert:  sprinkles08 replied 4 months ago.

The same red wire powers all injectors and a handful of solenoids together. The driver wire to each injector that pulses ground is the wire that is not the same color at each injector.

Customer: replied 4 months ago.
I will need to double check It looks like the each injector has a red and black wire. I will verify. I am away from the motorhome
Expert:  sprinkles08 replied 4 months ago.

Each injector has a red wire which is the power feed. The driver wire varies for each injector and is pulsed ground to control it.

Customer: replied 4 months ago.
should I unbutton the wiring harness. or just run countunity tests on the affected wires? The color coded wires run al the way to the ECM correct? Could the fault be at the distributer?
Expert:  sprinkles08 replied 4 months ago.

The distributor is not related to the fuel injectors.

Yes, the ECM controls the injectors.

If the two wires going to the affected injectors both have positive voltage all the time and the behavior doesn't match what you see at the others then you need to unplug the ECM and injectors to test for continuity between the circuits. If ok then the ECM needs to be replaced.

Customer: replied 3 months ago.
where is the ecm on the rig
Expert:  sprinkles08 replied 3 months ago.

It's in the right side of the engine compartment under the blower motor area.

Customer: replied 3 months ago.
It was inside the pass side how do I get it to come out
Expert:  sprinkles08 replied 3 months ago.

Correct, that's the right side of the engine compartment if you're in the US.

You don't need to remove it, just unplug the connectors.

Customer: replied 3 months ago.
Got it
Expert:  sprinkles08 replied 3 months ago.

Great!

Customer: replied 3 months ago.
I tested for continuity for 3 is 2nd row 1 and 2 from right. cyl 2 is top row 2nd from right and top row first pin to the left of the bolt hole
Expert:  sprinkles08 replied 3 months ago.

You tested continuity between the injectors and ECM?

Customer: replied 3 months ago.
to the pins I described
Customer: replied 3 months ago.
from the non red wires
Customer: replied 3 months ago.
yep
Customer: replied 3 months ago.
it showed 2 live on each injector
Expert:  sprinkles08 replied 3 months ago.

Did you unplug the injectors and ECM and test for continuity between the driver and power feed wire at the two affected injectors?

Customer: replied 3 months ago.
Customer: replied 3 months ago.
Had,continuity between non red wires,on, 2 an3
Customer: replied 3 months ago.
To the 2, pins on each I described earlier
Expert:  sprinkles08 replied 3 months ago.

If you have continuity between the two circuits with the injector and ECM unplugged then the wires are shorted together in the harness.

Customer: replied 3 months ago.
what I meant is that Testing the non red wires 2 pins were active for each injector tester on the ecu
Expert:  sprinkles08 replied 3 months ago.

You don't need to do anything at the ECM other than unplug it.

You're unplugging the ECM, unplug the two affected injectors and check for continuity between the terminals. If there is continuity with the ECM unplugged then the circuits are shorted together in the harness.

If they are not shorted together or to power or ground with the ECM unplugged then replace the ECM.

Customer: replied 3 months ago.
Bear with me on this. So I unplugged the affected injectors. I mran a jumper wire from the non red injectors on the unpluged injector wires to the ecm I had continuity between thise wires to the ecm pins and have continuity29 November 2016 09:51
So I tested for continuity for 3 is 2nd row 1 and 2 from right. cyl 2 is top row 2nd from right and top row first pin to the left of the bolt hole. There is continuity there
Expert:  sprinkles08 replied 3 months ago.

Unplug the ECM.

Unplug the injectors.

One test lead goes to one terminal in the injector.

The second lead goes to the second terminal.

If continuity is shown then you have a wiring problem.

If an open circuit is shown then you need an ECM.

Customer: replied 3 months ago.
I disconnected the ecm I tested for continuity on each injector. 2 female pins on the harness were live for each cylinder, So does it go non red into the ecm through the processor and out and back to the injector. which would explane conttinuity on 2 lines
Expert:  sprinkles08 replied 3 months ago.

You unplugged the ECM and injectors and found two wires in the injector connector had continuity to each other?

Customer: replied 3 months ago.
ya but after passing through the ecm like continuity into the first pin on top and 2nd pin on top. So if it was plugged in it would be juice in then through the ecm and juice out. Does this make sence
Customer: replied 3 months ago.
ya need juice into the ecm then through the processor and timed joice out or vice versa
Expert:  sprinkles08 replied 3 months ago.

You're not concerned with the engine controller. You're testing the wiring with the controller unplugged.

Customer: replied 3 months ago.
correct again thanks for your patience on this issue
Expert:  sprinkles08 replied 3 months ago.

You're welcome!

Customer: replied 3 months ago.
yep ecm unpluged testing continuity on the female end of the connection block. had continuity on 4 total like I said must be hot from the injector then through the ecm back to the injector from each of the 2 injectors. Am I correct on the assumption. I need to go fix another rig I will be back this evening. Again thank you
Kevin B
Expert:  sprinkles08 replied 3 months ago.

If the two wires in a connector show continuity with the ECM and injector unplugged then the circuits are shorted together in the wiring harness.

Customer: replied 3 months ago.
is there a likely place for a short. In the event I can't locate the short. can I run wires to bypas it?
Expert:  sprinkles08 replied 3 months ago.

The short could be anywhere in the harness. Yes, cutting the old wires and running new is acceptable if you're not able to find the problem area.

Customer: replied 3 months ago.
I had to take the day off
Expert:  sprinkles08 replied 3 months ago.

Ok.