1997 F150 supercab longbed 4wd 94Kmiles on 4.6L engine.

A couple months ago I had some exhaust work done and the sparkplugs changed. (don't know if that matters or not)

Last night, out of nowhere, the thing starts sputtering and feels like it is missing on several cylinders. Check engine light is flashing.

I was only about 200 yards from home so I drove it home.
Checked later that night - still missing.

Checked this morning - still missing.

Bought myself a code scanner - came home, hooked it up and got P0308.
So I guess it was a misfire on cyl 8 only.

BUT - the darn thing seemed to run fine now.
Drove around the block - everything is fine.

I parked it and looked under the hood with the engine running.
(it was dark so I couldn't see much)
There's a constant nonstop clicking coming from somewhere near the throttlebody (I think)

Sounds like a little solenoid of valve just clicking non stop.

Any ideas?
I guess I'll try and take a closer look tomorrow.

Thanks in Adv.
Scott

 

Look for white spots on your #8 spark plug wire. Sounds like it has a burn spot thats making contact with metal and redirecting some of your spark voltage. What kind of plugs did you have put in?

 

Well - I drove it to work today - figuring it was half way to the repair shop I use, so why not.

The problem came back quickly just a mile or so into the trip.

I somehow don't believe it is just a misfire on #8.
The effects seem much worse than one of 8 cylinders not firing.
I've got a couple old british sports cars, and I've driven both of them with a disconnected ignition wire. In those cases it was 1/4 or 1/6th of the cylinders not firing - and it didn't seem as bad as this.

The constant clicking noise (figure 5 to 10 clicks per second) is coming from the area where the DPFE sensor and EVR solenoid are.

I think I mentioned exhaust work last time it was in a couple months ago.
The EGR pipes (sort of a trident looking manifold of tubing) were replaced.

Obviously I'm going to take it back to the guy who fixed it.
I'm just wanting to learn as much about it as I can first.

 

My 98 4.2L f150 is doing the same thing cyl1 missfire runs good at first than when it warms up same sh*t your having WTF is it.

 

The more I'm looking at and reading the Haynes Manual - the more it is making sense.

There's an EGR valve - which does just what it's acronym says - It recirculates exhaust gas back into the intake manifold to mix with the incoming air / fuel mixture.

The AMOUNT of exhaust gas is apparently fairly critical.
It says TOO MUCH weakens combustion, causing the engine to run rough or stop. It can cause it to stop at idle after deceleration. If the EGR is wide open all the time, it may not idle at all.

TOO LITTLE makes combustion temperatures get too high during acceleration and high load conditions and can cause knock, engine overheating, and emission system failure.

GREAT. GOOD TO KNOW.

Looks like basically, there's a special pipe/manifold, a sensor, the actual EGR valve and a EGR regulator that actuates the EGR valve open and closed.

One of the key parts for me in reading this stuff is that the computer is only going to tell that regulator to start working once the coolant temperature gets above 113degF. (plus some other stuff)

So when I restarted my truck immediately, or shortly after the problem - the coolant was still warm and the system would be actuating the EGR valve.

Last night when I checked it, the truck had sat for a day and everything was cool. I didn't drive it long enough to really warm it up. So things didn't get warm enough for the computer to take control of the EGR system.

This morning - once again, the engine is cold, it runs okay for a mile or two.
Then it warms up and stuff starts going wrong.
Once it warms up . .. the computer starts controlling the EGR valve.

So . . . now my only thing is .. . that damned clicking.
If it is the tiny solenoid that allows vacuum to get to the EGR valve and actuate it . . . then I'd think that it'd be toublesome right from the get go.
(cause it is clicking all the time)

 

Well, Only if things worked out as they theoretically should - then that would matter more .

Unfortunately , that isn't the case the majority of the time IMO. Congrats on investigating and searching out things as you have - most don't

Tell you what- heres a very imformative link about your EGR if your really interested -

http://www.fordscorpio.co.uk/egrmonitor.htm

Being familiar with these motors , I bet your problems would go away replacing both coilpacks on your motor. Simply because you generated the 308 - Coil packs don't age well and need to be replaced , if you don't they can cause many headaches on down the line .. If your using anything other than Motorcraft plugs in your motor - that's TROUBLE..

NOTE: Before purchasing anything for your motor ASK where to do so - One very good thing about this site is that it can save you lots of $$$ there. Specially with ignition parts..

Whats clicking , you don't say ? The EVR ?

The only thing that clicks is a relay trying to reset, which IMO is your fuel pump relay .

The BIGGEST and most troublesome sensor in these EGR systems would definitly be the DPFE reporting bogus signals back to the PCM. Where replacing the DPFE with only a dealership one will work . NO third party venders carry the correct sensor for these trucks at this time..

NOTE: I only spent this time because you have used the search bar - if we could only get the rest too ( :

 

he says it runs ok when its first fired up though, if the coil packs were misfiring it they wouldn't just do it after it warmed up.

 

Coil is Misfireing - The OBD 2 Scanner has reported this . Coils will short momentarily. There starting to go and are weak.

Right now he's getting robbed with performance and economy because of weak coil packs...

 

If it was the coils, they would do it at startup and fail continuously. They would also get worse the more/harder you drove it.

 

NO - WRONG

Apparently you haven't been around these motors much

The thermal layer breaks down and becomes weak - EVENTUALLY getting totally compromised..

This tends to happen sooner in Coil Over Plug (COP's) applications. Never the less , it applies to both applications. The thermal wall is thicker in a pack is all..

They become very volnerable to moisture as well - A plug wire, boot or pack seam, all seams need dielectric grease (tune up grease) or there like naked and moisture will find its way in there.

Now, you can reboot, retest and restart the misfire monitor and usually this will make your motor run smoother for a time because your still within default parameters so the monitor will report and you'll get an overall better adjustment - it's short lived , but it works for time.. That's what makes it difficult to diagnose. A coil pack section has to just about be dead before falling out of set parameters - meaning, Primary and Secondary faults ..

Coil Packs are cheap nowadays and he has indicated a failure , you can't get around that . That spells it out for me because it's difficult just getting to that point in these ignition systems..

Also , I 'm not saying that's his only prob - I don't know what he means by clicking , that's a different problem on top of the coil pac issues..

 

JBREW - give him the link to your post months back on your coil over problems. I read it and guess what all my problems went away with the 03 coil pack! The knowledge gained from others problems is immensly helpful!

 

Fix cylinder 8 first. A flashing cel is raw gas getting to the cats.
Is the boot on the plug? Is the wire good? Is the coil good? Easy to see if there is spark using an external test plug.
Any other codes?
The EGR doesnot operate until you get into a cruise condtion. The PCM uses speed, rpm, throttle opening and a time interval to make a logic decision to enter that routine. When it does, the fuel is cut back and the ignition timing advanced for that interval of operation with EVR allowing vacuum to the EGR.
The DPFE gets into the act by monitoring the gas pressure accross a restriction in the main tube. This is the 400/1400 series codes.
A stethoscope with the tip rod removed should find the location of a click, as you discribed it.

 

Yeah, I've been looking for that

 

Bluegrass -

 

I've only been around them since 1993, but I guess that's not long enough. I've never seen this happen on any of my 6 Fords/Lincolns over that time...

I did have it happen to my '92 Bonneville, however. It was a slightly different setup, but same effects.