"new to me" 2004 with a p0304

[modelageek]

I compared the injectors using my stethoscope. They sounded the same, best I could tell.

I bought an Acton cp7828? Comp tester and will do another test asap.

I noticed that if I am idling at a long light the CEL will eventually flash and stop flashing once I start driving . I did an experiment and held my idle at about 1300 for over 3 minutes there was an occasional hiccup but the CEL did not flash.

 

[RonD]

Compression test will give you more information and you can go from there.
And remove 1 spark plug(at a time) or all spark plugs for the test.

Compression heats up the fuel/air so it can ignite properly, if compression is too low then ignition is partial or not at all, and this "missing" cools off the cylinder so it misses even more.
As you raise RPMs, compression in all cylinders goes up, so a lower compression cylinder will usually start to ignite again.

 

[modelageek]

I am struggling with time, but I was able to pull the #4 plug and test it. . This time I pulled the TB hose off and propped a screwdriver in the butterfly. I used my new acron tester. I got 158 dry and 193 wet. Hopefully soon I can pull all the plugs and test all 6.

 

[RonD]

That's more like it

160 would be a "normal" compression reading on a V6

So I doubt compression is the issue

 

[modelageek]

That's more like it

160 would be a "normal" compression reading on a V6

So I doubt compression is the issue

OK, so right after I did the compression fest on #4 and got 158 I changed the oil. I used Dino 5w30. I also added a can of Restore. The flashing cel went off for about a week. The truck did run better but still a little rough at idle. The Cel has flashed a few times the last dew days. I did discover a roughed up wiring harness with a loose wire next to the obd port that kept my temp gauge from working. I also might have noticed a little white smoke from the exhaust. Oil and Coolant look fine. All thoughts are encouraged. Should I do a combustion gas test?

 

[modelageek]

OK I guess you are all waiting for me to do the full correct compression test. Hopefully I can do it soon. Truck still running rough at idle. No codes for about 5 days now. I have been researching this and it appears that most likely it is the heads. If I determine the heads are bad does anyone have an opinion about Dover heads. I called them and they say they have the correct new heads with the hardened steel valves/seats. Total cost with gaskets and bolts $425.

I have driven about 700 miles since the oil change and the oil seems fine and does not appear to have used any oil

I was thinking of changing to M1 full synthetic 5w20. If I have the valve issue would the FS 5w20 be better?

All ideas are appreciated.

 

[modelageek]

Oh and I changed the coil pack and the p0304 still came back. When I get new bolts for the upper intake manifold I might hack the old ones off and replace the injector. I figure if I do need to change the heads I will have to deal with the rusty upper intake bolts anyhow.

Any chance I could have a leaky upper intake gasket? I have sprayed crap around to see if the idle changes and it is hard to tell.

 

[RonD]

Yes, a vacuum leak near one cylinder could lean it out enough to misfire.

Ford fuel injectors can be tested with an ohm meter, it is not definitive but would ID a bad injector.
You need to test all 4, not just #4
Set ohm meter to 200
Remove injector connector
Put ohm meter probes on the injector's 2 pins
11-18 ohms is the "OK" range
Should be about 14.5 ohms

testing OK doesn't mean injector is not clogged or sticking, just that its windings are OK.

 

[modelageek]

Thanks Ron. I can't get to the injectors with the intake on. I will get some new bolts and remove the intake and also try to do a full compression test.

 

[modelageek]

still not solved:

Here is what I have done.....

change the plugs.

swapped wires

cleaned everything I could think of and added Techron

new coilpack

I pulled the upper intake off and installed a new injector on #4 and 3 new intake gaskets.

I put a vacuum gauge on the engine and it is pretty steady moves between 18 and 18.5.

when I gun it at idle the vacuum gauge drops to 0.......if i hold it there it goes back up

I did a compression test again on #4( I know I should be doing at least that side if not all of them) I got 160#( i let the engine cool for 20 minutes and then I cranked it for 3 or 4 seconds....I relived the pressure and did it again......3 times in all.......all about 160)

I have done some reading and talked to a few mechanics and this is what i have heard...they said that if I had compression of 160 it should not be a valve issue...that 160 is good enough.....
they also told me that if I had a valve issue my vacuum gauge would fluctuate rapidly 4 or 5#
I also was told that the wet test is "old school"....and out of date...
one last thing.....I notice on occasion a tap, tap from the lower end.......I put my scope on it and I can here a little tap, tap......I know I my lima 2.5 the lower end made a little noise for the 80k miles I owned it......it never failed....

I can do a compression test on all of them but i am not sure what it would tell me.....the guy that told me about the vacuum gauge moving also told me that as long as the cylinders were within 25% of each other I would be OK......He said I could have a lower intake vacuum leak.....I tried the propane trick and could not notice anything......

I took a picture of the plug in #4 it has 3k miles on it. I will try and post it.
all thought are encouraged.....

 

[RonD]

"Wet test is old school", lmao

Young pups think all the old tests are worthless, wait til their fancy test gear has a dead battery, "closed for the day", lol

Anyway, compression is good, 160psi cranking with starter is what you want to see.

So we will assume mechanics are ok.
You could have an intermittent lifter or broken valve spring, which might not show up on a compression test but you would hear the "ticks" when it was effecting that cylinder.

So you have fuel and spark left on the table.
Spark is easy to test, use an "old school" timing light on #4 spark plug wire, this will tell you if it is getting spark regularly from coil, steady flash, if its got some missing flashes then could be PCM or ignition module goofing up, since coil is new.
Also swap spark plugs with a working cylinder, I just replace a spark plug that was less than a year old and was dead, looked perfect, but dead as a doornail.

Fuel is tricky to test with fuel injection, obvious test is for OHMs at injectors, I think 14 OHMs for Ford injectors.
Next is to listen to each injector with engine at idle, small hose works, steady "tick, tick, tick"

Next would be to swap injectors around to see if problem moves with the injector.

 

[modelageek]

"Wet test is old school", lmao

Young pups think all the old tests are worthless, wait til their fancy test gear has a dead battery, "closed for the day", lol

Anyway, compression is good, 160psi cranking with starter is what you want to see.

So we will assume mechanics are ok.
You could have an intermittent lifter or broken valve spring, which might not show up on a compression test but you would hear the "ticks" when it was effecting that cylinder.

So you have fuel and spark left on the table.
Spark is easy to test, use an "old school" timing light on #4 spark plug wire, this will tell you if it is getting spark regularly from coil, steady flash, if its got some missing flashes then could be PCM or ignition module goofing up, since coil is new.
Also swap spark plugs with a working cylinder, I just replace a spark plug that was less than a year old and was dead, looked perfect, but dead as a doornail.

Fuel is tricky to test with fuel injection, obvious test is for OHMs at injectors, I think 14 OHMs for Ford injectors.
Next is to listen to each injector with engine at idle, small hose works, steady "tick, tick, tick"

Next would be to swap injectors around to see if problem moves with the injector.

thanks again for the help Ron..For the record I am 53....the 2 techs that i talked to were 35 and 45 respectively. they both thought the wet test was a little outdated......I am only reporting what they said.I don't have an opinion on the wet test myself.....I am a pretty good backyard mechanic other then knowing a ton about the actual workings of the engine.

I just did a compression test on #5.........I cranked it for 3 seconds and it went to 179......I cranked it again for 3 seconds and it went up to close 195....I then added oil and cranked it for 3 seconds it went to 205..I cranked it again and it went to 240.......I will report back when I can get to all 3 on bank 2
and for refreshers.........

-#4 was 160 dry and 185 wet.....
-I replaced the #4 injector and I can hear it clicking.......I also replaced the upper intake gaskets....
-the coilpack is new.

 

[Rearanger]

Compression tests should be done with hot engine. For reference my 67K 03 has compression from 185-195. I doubt your 240 #.

 

[modelageek]

Compression tests should be done with hot engine. For reference my 67K 03 has compression from 185-195. I doubt your 240 #.

I let the engine cool about 20 minutes. Dry test cranked for 3 seconds. 179. I cranked another 3 seconds 200. I removed the hose and added exactly 1 tablespoon of dino 5w20. I cranked for 3 secs 205 cranked for 3 more secs 235- 240.

 

[Rearanger]

Dry test cranked for 3 seconds.

I admit working with a hot engine is a pain but can be done with gloves. By the time you pull all the plugs it's about 20 minutes anyway.

For compression test you should just let it crank over until the gauge maxes out. No specific time. Throttle should be full open. When hot there should be enough oil in the rings for seal so extra oil won't really tell you much. As well when cranking over there is oil flow.