Number 1 and 5 cylinder indicating miss fire. Plugs changed. All coils tested. Injectors rotated from other cylinders with NO change. Visually checked spark on both plugs from 1 and 5. Plug in 1 is very sooty black. Plug 5 is black but not so sooty.

A friend has computer which gave me the below readings:

Below readings at IDLE in park.
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Bank 1 O2 V ranges from 2-7 usually around 6 O2 ranges from 5-22% usually around 10
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Bank 2 O2 V ranges from 2-7 usually around 6 O2 ranges from minus 2 to 22% usually around minus 1%
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Throttle Position 19%
Timing ranges 8-26 but usually around 10 Fuel Trim B1 ST minus 1.6% Fuel Trim B2 ST ranges from 7-15%
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Am wondering if the O2 reading should be so different?

Any help out there for this Back Yarder? Am on an island in Alaska. Thank, J

 

time to replace the COPS and boots. Plugs are not firing correctly, maybe on 02 sensor as well but I would start with the COPS. O2 sensor would not make it misfire.

 

Check and clean your IAC also.

 

I'm having similar issues... Is there any write-up on how to check and clean the IAC?

BTW alaskang, welcome to FTE!

 

I know the engine pictured in the website is a 4.6L, but this will give you an idea of what you are looking for.

Autoclinix.com: Free Do-It-Yourself Repair Instructions

While the IAC is critical, if you're throwing misfire codes a bad COP is probably the cause.

 

Thanks for the help. Unfortunately I have completed all of the above. Or at least I think I have.

I have removed each COP and tested them per the ford specs. I have also taken switched them around but still got the 'intermitten' misfire codes on 1 and 5 only. I have also sprayed out several time the IAP if you are talking about the one just down stream of the airfilter. the small wire appears intact and clean. I have also taken out the injectors. sprayed them with carb cleaner, cleaned off the carbon and rotated them with NO change in the rough idle. I have measure the temp at the exhaust manifold using a laser reader and all cylinders are hot at idle except 1 and 5. Number 1 plug is very sooty and number 5 is black and wet. I have also changed out those plugs (only 2000 miles on them) with new autolite platinum tips.

So, I am really confused as i thought it would be plugs, COPS, Injecters or IAP.....

What is really puzzling is that the problem is in the front tow cylinders...

Thanks for any idea, Jimmy

 

Sooty plugs on 1 and 5 are a strong indication of a misfire or a rich condition, especially if the other plugs looked OK.

Since you have changed the plugs and moved the COPs around but are still seeing sooty plugs up front, there must be something else going on.

A few things might be worth checking.

How is your PCV valve? Is it stuck open? Isn't it routed to the front of your intake manifold?

Has your intake air temp sensor been checked? How about your engine temp sensor? If the CPU thinks the engine is not warmed up it might keep you in the rich starting cycle, but you'd think you would see sooting on the other 6 plugs if this was the case.

 

I guess at this point in am with reford, check the PCV valve, it you can get to the 02 sensor you could change that out but they are pricey.

 

An O-2 sensor will not cause the concern you are having. They cannot have an effect on only one cylinder per bank.

Have you checked base compression? A quick way to get a very general idea of compression is to make sure the vehicle is in park and then jump the starter solenoid to crank the engine without it starting. If there is a cylinder with low compression, you will be able to hear the difference while the engine is cranking.

In your case, I would check the injector circuits to make sure you don't have a short to ground or a stuck injector driver. It's easy to do, free, takes only a minute or two, and only requires a test light (not a DVOM.) Turn the key to the 'on' position and disconnect the suspect injector connectors. Connect the test light to ground and check the terminals at the connectors and you should find one wire that has power on each connector. On many Ford vehicles, this will be a red wire but it does vary. Next, hook the ground lead of the test light to the POSITIVE terminal of the battery. This allows you to check for a ground path on circuits. Touch the test light to any grounded piece of metal and it should light. Now, probe the opposite terminal in the injector connector, the one that didn't have power during the last check. The test light SHOULD NOT LIGHT. If it does, then there is either a short to ground in the wiring harness or the injector drivers in the PCM are defective. To determine which is the case, disconnect the PCM connector and check the circuit again. If the light still lights, the harness is shorted. If not, the PCM is bad.

Jay

 

Thanks Guys....I have a friend who has a compression tester so I will do that and I will also check the circuits. I have a volt meter so that should help. On the possible short to ground....shouldn't I be able to read the Ohm meter to check that side out?
I also have another Excursion which is an O2. is it likely that they have the same PCM? WOnder if I could also switch them if the other tests don't turn anything up?
Finally, Can you tell me where the PCM is? and how to get to it if is not out in the open. I have been reading tons on the internet but have not found that answer yet.
Thanks, Jimmy
PS: Two excursions...yeh...it is VERY icey here in ALaska and the FORD beast does the best of most any vehicle when outfitted with studded tires.

 

REDFROD, I have already checked the PCV valve. But thanks for the Temp sensor Idea. I will hook up the machine and see what the sensor is reading for temp at start and then after it is warm. Jimmy

 

I just completed the check but got hot circuits on both ie concluded that PCM is bad or ground fault is indicated in the harness....but I tried the same test on the other excursion and got the exact same results and it runs fine. So I am wondering if I am misreading your instructions. Bottom line is that I get 11.5 volts from ground to rt side of injector plug and 0 volts on other side. Then I tested from Positive terminal on battery to to the left side (was 0 volts from grnd) and got 11.5 volts on that side? I know that you said i could use a light tester....does that mean I cannot use my voltmeter? Thanks for putting up with my questions...and probable operator error?

 

Senix, See you are up on Turkey day. Can you tell me where the PCM is located in my excursion (F250 body). Thanks, Jimmy

 

should be behind the ash try area, way up there. let me check and see if I can verify

 

The ECM, which is mounted behind the engine on the
passenger side cowl, uses sensor inputs to control
actuators and send fueling commands to the fuel inectors.
• The ECM controls the fuel and air manage

This is for 6.4