If I'm not mistaken that's the tester catching a cylinder that isn't contributing correctly.

 

Yes, I'm going to check the #3 plug, plug wires and hope that is the problem. It could be a problem with the #3 injector and I may need to run a compression test for that cylinder. I hope it is something simple and cheap. The older I get, the more I like to drive a vehicle and the less I like to work on it..

 

code 30 for cylinder 3 is saying it didn't pass the cylinder balance test. You have to tell the reader to run the balance test in KOER mode. KOEO test MUST be cleared before you can run the test. The test is ONLY for engines with sequential injector firing and I believe your year is batch fired. Actually in most publications code 30 is not even a trouble code. I would run the entire test again before thinking about code 30 as I can't see how it would even exist on your truck.

Your two KOEO codes are suspect for false codes if the engine was not up to operating temp when you tested KOEO. KOEO and KOER should always have the motor to temp when testing.

There is a relearn procedure for ECMs that have been battery disconnected and I think your new one may apply to this needed step. It is the idle relearn test.

Follow these steps to complete an Idle Relearn:

1. With vehicle at a complete stop, set the parking brake.
2. Put gear shifter in "P" (Park), turn off all accessories.
3. Run the engine until it reaches normal operating temperature.
4. Allow engine to idle for at least one minute.
5. Turn the air conditioning on and allow the engine to idle for at least one minute.
6. Release the parking brake. With your foot on the brake pedal and the A/C still on, put the vehicle in "D" (Drive) and allow the engine to idle for at least one minute.
7. Drive the vehicle to complete the relearning process. Just make sure you drive easy for the first 30 miles, so the PCM can re-learn and adapt to your driving style.

 

sandymane

That's news I can use. I did NOT clear my KOEO test before I ran the KOER test. So, I will redo that. I now remember reading about the relearn procedure for the replacement ECM, I did not run that procedure with the replacement ECM. Tomorrow I will warm up the engine, perform the relearn procedure and run the KOER test. I will check the manual to see if I have to rerun the KOEO test and clear the result before I do the KOER test. Thanks!

 

I think you are on the right track. You don't just clear the koeo codes to run the balance test. It means the KOEO codes be cleared before it will run the test. Again, I don't think the test is applicable to your truck if it is batch injector fired. Actually there is no need to even run KOER test until you clear Koeo hard codes as it is not the correct procedure.

Most of this is in chapter 4 of the reader manual.

 

Cylinder Balance Test is only valid for vehicles that use sequential injection, it does not apply to batch fired injectors that these trucks use. Code 30 is not listed as a valid KOER code (or any other tests) in any of my Ford service manuals.

I wonder if the code reader is interpreting the cylinder ID, a single digit and is frequently displayed wrong on aftermarket readers, as two digits.

 

I'm no expert with these but I have the Innova scanner. Been pretty happy with it but has made mistakes a time or two. If I were you I'd run the test a time or two and see if it still comes up with that. Make sure the truck is at operating temperature when you run the test otherwise the scanner will think something is wrong and throw a code for coolant temp. Good luck!

 

In your “ Coolant in oil” thread, you stated that you found that the head was bad and that you replaced it with another used head. What happened after that? Did you do the test that hav24wheel suggested? You never responded after that post.

In the “Ford 4.9L” thread thread you asked if everyone has else’s engine runs rich. Is that why there is a misfire?

In “What did I miss?”, you were told by two people to remove the schrader valve in order to check fuel pressure. For some reason you think removing the valve to install the pressure gauge will make the truck burst into flames. Hook up the gauge, turn on the key and check for leaks before starting the engine. In that thread you were also under the impression that the air injection system and the EGR systems are the same thing. So is the EGR system also disabled/ removed or only the air injection system? Are the vacuum hoses and capped off? What about the air pipe that goes to the catalytic converter? Do you now have a large exhaust leak? That will screw with the oxygen sensor causing the computer to add more fuel.

Next you want to know how to remove the computer because you think it is a computer problem. Now in this thread you have replaced the computer and seem surprised that the misfire is still there.

 

In his defense the electrical can cause a miss. When my computer started acting up it made the truck run rich and cause a miss. Although it didn't fix it it certainly didn't do the truck any favors for him. Maybe it is the result of it running rich which in that case might check the idle air control valve and throttle positioning sensor. Pull the plugs and inspect each one to make sure one isn't soaked in something. A good plug will be dry and have a tan ish haze to it.

 

OK, my4Fordtrucks, let me catch you up on my 1988 journey. I will try to answer all the questions. The second head that I got came from a large national parts house and they claimed the head had been rebuilt and tested. It appeared they were true to their word, because I installed the head with a new gasket and it has functioned perfectly.

Now regarding the fuel test port and fuel pressure test. I have taken the suggestions under advisement. Yes, I am concerned about a fuel leak. A few months ago when I started to install the fuel rail I discovered the Schrader valve was missing. I called all local parts stores and my nearest Ford dealer to inquire about a fuel rail specific Schrader valve. No one listed that particular part individually or as part of a kit. I ended up trying a valve from a farm cart tube and "bingo" it worked and is still working. This might explain why this non specific valve stem will not function with the fuel pressure test kit I used. Either the configuration of the valve allows it to sit deeper in the test port and/or the stem length of that valve is too short or, maybe the fuel rail test port is a non-conforming. My last concern would be the seals on the valve I used and how they react to fuel over time. Before I get real serious about removing the valve I would like to have a new valve in hand. Anyway that is how I roll.

The air Injection system was missing and was not replaced. The EGR plumbing was also mainly missing or so badly corroded that it was not used. ALL holes were plugged or capped in the exhaust system, and intake manifold and an EGR delete plug was used to eliminate that issue triggering the "Check Engine" light. I seems to be working fine. Engine vacuum is steady at 18-19 Green area on my vacuum gage. I installed a new exhaust system and have no exhaust leaks.

Lastly, I did ask about replacing the ECM and how to remove it. I got some great advice and turns out, it was super easy to access the ECM and remove it. I replaced the ECM for a couple of reasons: First I have no clue of the pedigree on the ECM in the truck. It could be the original unit, or something pulled from another vehicle that just fit or, it could have been an ECM that was partially fried or damaged by water. I did some online research and ran across an article that listed 5 symptoms of a failing ECM and my truck exhibited every symptom to some degree. I ended up getting a refurbished ECM (Amazon $115 delivered from vendor Cardoneno with no core charge or return) that was supposed to be an exact replacement fit my pickup. When I pulled the ECM from my truck, I found the Engineering Code on that ECM matched exactly the Engineering Code on the Cardone replacement. I replaced the ECM, performed a relearn procedure on the replaced unit and I am driving the snot out of the truck right now. It still has an occasional/erratic miss and it still "smells" like it is running rich. I have run a scan that may be pointing to a problem on #3 cylinder that may be related to the miss; however, I'm going to do another scan because I may have done the scan improperly....yes, I'm still surprised I have an occasional miss. I am sending the removed ECM to BSE for R&R and keep it as a spare.

 

ECM failure on these trucks are more likely than a person would think. I think you did the right thing just because if it wasn't failing yet it was going to eventually. My new ECM fixed the dozen of problems my truck had and also was showing signs of ECM failure. It had to be electrical because if it was something mechanical it would most likely be constant instead of coming and going. It's very easy to overlook the computer chasing down an issue and even though it may not seem like it can very much be the problem. All it has to do is send one wrong signal to the system because of the wrong voltage going through the computer and make the entire system get confused.

 

A great and interesting comment, as least as fas as I am concerned. I never stopped to ponder how fuel was delivered to an engine of this age and ilk. So, do I understand correctly that all batch injection system injectors fire at the same time? I realize at road speeds the fuel intake by individual cylinders would be mere fractions of a second apart in the firing order; however, that would mean, in the case of the Ford 4.9L engine, the fuel atomization would be better for the #! cylinder, first in firing order, than the #4 cylinder, last in the firing order? It is likely a moot point. It is just an interesting scenario I had never thought about. I love this forum.

 

I came to the same conclusion. I think it would be better if there were a more efficient and comprehensive diagnostic tool available for these old truck; however, one must play the hand they are dealt. There is a shortage of engine tech/mechanics in my area that have the specialized tools and willingness to tackle one of these old road warriors. This is the main reason I tap into the expertise of this wonderful forum. It reminds me of the question: How do you eat an Elephant? Answer: A bite at the time!
I will keep on trying until I get it right!

 

On a 4.9L engine the injectors are fired 3 at a time, 1/3/5 then 2/4/6. V8 engines the injectors are fired 4 at time. On a Speed Density system using batch fired injectors there is no way for the computer to fire only one injector at a time, therefore the computer cannot do the Cylinder Balance test. Code 30 in your scenario is a red herring bunny hole. Why your Innova is displaying that is anyone's guess and the reason why I speculate the Cylinder ID test is not displaying correctly (which happens frequently).

 

I don't have to be smart, I do need to kow smart prople! Thanks ria205!