intermittent power, lots of idle noise

[POWER-STRUCK]

bad things could happen! engine will be out of balance and that cyl will recieve more fuel

 

[Copracr]

Well, if thats the case I thinkk I'll swap out #8 and #4 and see if the CC test fails 4 - just to be sure. I don't have any guessing money this time of year.

 

[POWER-STRUCK]

did you measure any of the injectors? how many replacement injectors do you have?

 

[Copracr]

did you measure any of the injectors? how many replacement injectors do you have?

No, i'm in the middle of doing 4 back to back 12 hour shifts so I wont get to play with it till the middle of next week.

I have 7 AD's and 1 AE sitting on the shelf, but besides looking fine I know nothing about them. I was thinking I should disassemble them all the way down and take a look at everything and clean them up.

That might take a while cause I've never rebuilt injectors so I'll be going real slow and meticulous.

 

[Copracr]

And I should probably do the switch on my current injectors to verify I need to do all that. Could be a while, but I will post up results

 

[Copracr]

Alright, I finally had a little time off to get something done.

I figured I'd swap out #8 injector to see what happened.

I fired it up and it was running pretty rough, as expected. No unusual noises though. I started getting pretty happy and figured I'd drive it around and purge the air. I got about a quarter mile and the noise returned, sproradic at first but now its all the time.

I figure this rules out my flywheel as the problem, but I kinda knew that anyway. It's almost always present at idle, goes away around 1500 rpm, never does it on decel, and comes intermittent on accel. It runs rough and loses power when the noise comes, and it has something to do with #8 cylinder but its not the injector.

I got a bad motor?

 

[Copracr]

http://www.youtube.com/watch?feature=player_detailpage&v=khuIOhJqmqc

 

[POWER-STRUCK]

almost sounds like a roller ball missing from a rocker arm or a bad lifter

 

[Copracr]

http://www.youtube.com/watch?feature=player_detailpage&v=aGHcSOlBGfU

This is first startup this morning, not plugged in. It has a good miss, and around 7 seconds you can hear the noise start. Pay no attention to the tach, it reads high. You can hear it real clear again around 1:20 when the idle comes down after revving it.

While I was out there I ran a buzz test -sounded good. I swapped the under valve cover harness with a spare and put my original AB injector back in. Before I start it back up I was wondering how much of a mess would it make to run it with the cover off? I'm thinking of unplugging one injector at a time till the sound goes away. Then I can at least narrow down which cylinder I'm working with.

 

[mandkole]

Defintely have an unhappy cylinder(s) and sounds very much like an ICP issue. Angry IPR, pressure leak (oring), etc. I would think that the ICP reading is going wild while its idling.

Running the motor with the VCs off gives you more to work with and see. It doesnt make too much of a mess, but can get a little oil splash, collect at the bottom of the head and try to spill over. Pulling one injector at a time can help determine if an individual injector is at issue. You can also look for oil bubbling up around an injector

Have you pressure checked the oil rails' ability to hold ICP? Deadhead each head and pressurize through a check valve to 3K. Should hold for 4-5 minutes.

 

[Copracr]

Have you pressure checked the oil rails' ability to hold ICP? Deadhead each head and pressurize through a check valve to 3K. Should hold for 4-5 minutes.

I doubt I have any way to do that, no tools.

Today I ran it with the driverside valve cover off. I unplugged each injector and the noise remained. I put that side back together.
I was at a loss so I decided to look at my oil pressures again. ICP is around 500 at idle, icp% is around 10. I tried a cyl contribution test again and now #1 and #8 fails. During the contribution test the noise disappears for a few seconds too.

So I'm thinkin: pull passenger side cover, check #1 compression, if bad then check rockers/pushrods, if good then swap out an injector for a spare.

Any other suggestions? I'd like to put a gauge on my high pressure oil but I don't have one. But the ICP values look good and rise very linear with RPM's so I'm hoping they're OK.

 

[mandkole]

its just sounds like similar ICP issues Ive heard on my truck. Did you clear the 1211? If so, is it coming back?

I went back and read again and you did put a new IPR in. It is likely working fine. The moving around CCT results are interesting as well...

If you had bad compression on a cyl, you'd have an audible miss and possible smoke. The miss becomes more defined as the rpm increases.

Check the pass side, but not being in front of it, Im running out of ideas..

 

[POWER-STRUCK]

we had a freak occurance years ago where navistar left an intake bolt laying inside of an intake runner and it took 70,000 miles for it to bounce to an intake valve and rubbed there till it got small enough to pass the valve and drop into the cylinder

 

[Copracr]

I haven't had much time to work on this, but here's what I've done.
Checked compression - 325-ish every cylinder.
I made an injector BOB and killed one cylinder at a time - noise remained.
Let it sit for 2 weeks, then started it up and the noise was gone. It came back in 20 minutes though. I istalled a port to check fuel psi and it was good. I filled up the tank and drove it to work 45 minutes. By the time I got to work the noise was gone and hasn't returned.

I found out my water in fuel light doesn't work, and I think I got some bad fuel and drained the water when I installed the gauge port.

Now it idles perfect, but when I accelerate there is a definite miss and it's still down on power. I've put 200 miles on it hoping it would sort itself out.

 

[Copracr]

Found it, turns out the fuel pressure was all over the place and the fuel pressure regulator o ring was screwed up. Had a spare in the garage and swapped it out, not it runs almost perfect. I think some damage was done to some of the old AB injectors, but it runs about 95% smooth now and has quite a bit more power.
One stupid o-ring.