All wrapped up and back together. Ended up repairing my broken dipstick tube also. It runs great again and isn't setting any codes.

I checked the compression on #9 cylinder with the engine running immediately after reassembly and the compression was only at 60 psi. That has me a little concerned but it isn't throwing codes and runs the same as normal.

I'm wondering if the low compression had anything to do with all the carbon that came loose in the cylinder while running compressed air through it (lots of condensation). I am thinking possibly some carbon was keeping the valves from sealing completely. I plan to check it again in the near future and see if compression recovers.

 

Awesome, glad to hear it's running smooth again! And good job on the diagnosis of the problem, with as clean as the top end of the engine appears to be it has a lot of life left in it.
I wouldn't worry too much about the compression on #9 just yet, I would suspect as you did that there is probably some combustion chamber crud affecting the valve sealant. If it was actually only making 60psi I would very much doubt that it would even be firing and you would still have a misfire.

 

I'm not sure if I should start a new thread but I'm back with another idle issue. I thought it would be appropriate to just add to this one since it has the background info for the vehicle.

The idle issue only occurs within the first 5 minutes on a cold start. It's not entirely an idle issue though...if I drive from a cold start it stumbles for the first couple minutes and nearly dies and low throttle. After it warms up it idles smoothly and everything seems normal.

No CEL and no codes stored.

My first guess is the coolant sensor reading incorrectly. Thoughts? I believe I can monitor this with my obd ii app but not sure what values to look for.

Also, I don't believe it would cause the cold start issue but the tailpipe is breaking out of the muffler. I just wanted to throw that out there in case it could be a contributing factor. I'd rather repair the cold start problem before paying for exhaust work unless the exhaust is/could be contributing to a cold start problem.

 

The coolant temp sensor would certainly be a good place to start since it takes around 5 min for temps to come up to normal.
With your OBD2 app the temps should start at ambient and climb to the thermostat open setting which is probably around 190 deg.
I would at first say check the IAC valve and vacuum lines, but I think you already replaced/checked them.
Also, check the throttle position sensor, TPS.
What is the system voltage doing, is it staying consistent while things are coming up to operating temp?

 

I just checked and the coolant sensor did start around ambient temperature and steadily climbed as it warmed up. When I started it idled normally to begin with then began to stumble for maybe 10 seconds before it started running right again. I checked the engine load as it was beginning to run normal and it was at 72% then dropped to a little over 50% as it began running right. Is it just me or does that seem pretty high for engine load at idle?

It didn't run as rough as it normally does though from cold start. I'll try to grab some reading again in the morning.

 

I didn't notice the system voltage. I was focused on getting the readings from the obd2 app and forgot.

I was taking screen shots of the readings for reference and noticed the Throttle Position was reading 20% after starting. I just purchased the "Pro" version of the app that is supposed to log all of the readings. I'll see how that works out next time.

I didn't happen to capture it while it was stumbling or afterward. I'll have to try to capture that in the morning also.

It takes a bit for the app to connect after starting so the readings in the screen shots were probably 20 seconds after startup and maybe 10 seconds before it started stumbling.

 

The first thing I always do with these engines with any misfire/stumble is pull the COPs and look for moisture on the plug boots.

 

Check the IAC valve if you haven't.

 

I may have missed it, but what app are you using and how are you connecting your phone to your truck?

 

I don't know about him, but this is what I use:
App
https://play.google.com/store/apps/d...l.torque&hl=en
Bluetooth adapter
https://torque-bhp.com/wiki/Bluetooth_Adapters

 

Somehow I must have missed out on the notifications when you guys replied. It started running better on its own and I started driving my company truck more so I hadn't put much more thought into the Ex until today.

I'm not sure which app those were from- I have 3. I connect to a dongle via wifi. I'll have to check and see which dongle it is.

The apps I have for obd2 are: Fourstroke, OBDCardoctor and iobd2.

I'm currently waiting for a tow truck to bring the Ex home. It's been a long day...the exhaust actually fell off onto the way home and was dragging on the interstate until I found a place to pull off and get it out from under it. Then I was almost home and it died, I sat beside the road for about 45 minutes waiting to be towed, only to learn that the roll back couldn't make it up my driveway due to a dip where it comes off the road.

On to what's wrong now. I haven't really been able to troubleshoot anything yet, but it began dying while I was driving. If I accelerated above about 1200 rpms it would die. I limped it about a 1/4 to 1/2 mile until it died completely. It almost seems like a fuel problem...maybe. After it cooled off it would start back and die within a couple seconds.

It seems really odd that it decided to die just after the muffler and tail pipe fell off, but I don't see where that should cause it to die. I probably ran it 25 minutes missing the muffler and tail pipe before it died. Could the loss of back pressure have an ill effect that quick??

I gues the first thing I will be checking is fuel pressure followed by compression. Looks like I will have the pleasure of pulling spark plugs again soon. I'be been planning to buy a 08-10 V10 super duty this fall. Just wasn't quite ready for the the Ex to give up on me.

 

I was actually able to start the Ex and drive it the rest of the way to my house. I knew the problem wouldn't just go away, so I left it idling for about 5 minutes- until it stalled. No codes, I was looking at the sensor data when it stalled.

I checked fuel pressure and it was "0", then took the pressure gauge off and no fuel came out. Since the problem was intermittent and fuel pumps can act strangely when they are dying I went ahead and replaced the pump and filter. So far so good. I let it idle for about 20 minutes after changing the pump and it appears to be fixed.

While I was working on it I noticed the muffler is the only thing that supports the catalytic converter so I decided to not drive it until I fix the exhaust. I ordered a muffler and tailpipe so it should be good to go in a few days.

This will be my first experience with Walker exhaust but it seems to be a pretty reasonable setup for home exhaust repairs. I ordered the muffler and tailpipe from Amazon for $165...and it is supposed to bolt in place of the OEM exhaust and use the original hangers.

 

I put the Walker exhaust parts on this evening. The parts I ordered were the muffler, tail pipe and 2 clamps. I reused my old hanger insulators. The muffler went on pretty easy.

The tail pipe was a little more difficult. I had some trouble getting it to slide all the way up onto the stub coming out of the muffler. I couldn't get it closer than about 1/2" from the muffler itself. That last 1/2" would have made it clear the gas tank skid plate a little better. The tail pipe hanger would actually bump the skid plate when I shook the exhaust...so I did something that's probably not recommended. I put a little sideways pressure on the exhaust by pushing the hanger through the insulator as far as it would go and putting a hose clamp around the hanger to keep it from sliding back away from the insulator. That solved my issue with the hanger bumping the skid plate but I'm not thrilled about putting the pressure on it.

I believe it would have been a perfect fit if they had expanded the pipe a couple thousandths more to get it to slide up onto the muffler stub a little easier/further. If I had an exhaust pipe expander I would have expanded it just a bit more myself. If it gives any trouble I will get one and try that but I don't really expect any issues with it.

The replacement exhaust sounds like factory exhaust without comparing it directly. I'm sure it is a little different but I can't distinguish the difference from memory alone.

 

Are you still having issues at idle? Based off your scan this is what I can tell..

TPS is supposed to read 20% when closed at idle or .092v with a multimeter. Check
Short Term and Long Terms 02's look good. Check.
Engine Coolant Temp I assume is right. Check
IAT should read about ambient Temp. Check
Engine RPM looks a little high... Idle screw adjustment? Also check TPS with a multimeter to verify with Key On Engine Off the voltage, this can change your idle depending on the position/voltage.
You cleaned your IAC and put it back on?

 

I finally drove it the first time Sunday and it seems to be running fine now. Maybe the exhaust leak was contributing to the fluttering? Dunno.

I believe engine RPMs were up because of initial startup. It's doesn't idle high once it warms up a bit.