Hello everybody, been too long since I have been on here but been busy..

My truck shutters accelerating and very occationally while at cruising speed. Not at all when cold just when up to temp. So today I thought I would do the standard stuff, pulled valve covers to do the 50cent mod. (went very well thanks to researching here THANKS )Nothing was loose and the connectors were in nice shape but I did the mod anyway to save future headaches. (planned on doing it last fall but winter snuck up on me and the truck just sits then anyway) While I had each valve cover off I started it up and checked that each injector was squirting oil from the little spout and they all were. While this doesn't rule out injectors by any extent there was nothing obvious like one not firing at all.
I checked the IPR nut and it is tight, Checked the ICP for oil in the plug and it is dry. I replaced the CPS last fall with one from Clay when the issue started (new dark blue one) I also replaced the fuel filter as it was time anyway and everything was nice in there.I haven't done anything in the tank yet but it is on the list.
The next thing I was thinking of exploring was the fuel pressure. Kind of wondering if I have a weak/dying pump as it appears to be origional pump or at least its been on there a while. The truck is about all stock, I haven't changed anything at all with the engine. The PO did the exhaust work.
I do not have AE, I wish i did but I don't have the cash right now to buy a laptop and the software and fix whatever is wrong with the truck.
Anybody's thoughts are appreciated for sure! If there is anything else I should check I missed feel free to chime in..

 

I forgot in the original post, no SES light has ever come on.

 

How old is the oil? Doesn't really sound like fuel. Low fuel pressure would be more of a sputter and lack of power while accelerating, usually accompanied by a knocking sound as pressure got real low.

Any difference in how it acts between a cold and hot engine?

 

The oil has about 2000 miles on it. I change every 4k so about half way. It runs pretty good cold but gets worse when warmed up. Kind of sounds like hpop related doesn't it. It is also starts better cold than hot. Not really long crank but longer than when cold.

 

Don't have an answer, but here's a bump. My truck does the exact same thing. It's an intermittent slight shudder from about 1200 to 1800 RPM, also only when at temp. I located and corrected a larger torque converter vibration a few months ago, but that only revealed this new one.

I also have no check engine light, and have tried swapping CPS, IPR and ICP with no change. There is some variation in the injection pressure reading but it's too fast to be clearly seen on the AE plot. I'm thinking the problem might be a high pressure oil pulsation, but I don't know what's causing it.

 

I wondered about drivetrain vibration somewhere else too but I can hear the miss in the exhaust tone which still leaves me with a miss in the engine.

 

Runs better when cold and worse when hot can be the sign of a bad or worn o-ring. Maybe on the IPR or possibly on an injector. When you watched for squirting oil, did you watch with the engine warmed up since that's when the problem shows up? Notice any oil bubbling from the base of the injector where it seats in the head? Does your fuel filter look like it's stained with oil? If you sniff the dipstick, does it smell like diesel any? Those would by injector o-ring symptoms.

 

I watched it while it warmed up for a while and it wouldn't miss then just idling without a load. I didn't notice anything really around the injectors other than the the oil coming from the spouts. There is no hint of fuel smell in the engine oil at all, just smells like oil no tell-tail diesel smell. The fuel filter wasn't that bad looking really, it had about 20K on it. I didn't really notice anything that looked like oil but I will go look at it again in the morning. It is still sitting in the drain pan in the garage.
I suppose 180K is probably about time to start thinking o-rings, so I guess it wouldn't be too much of a shock if that ended up being the problem.

 

I guess I will order a set of injector o-rings from clay and try to get them in next weekend. Even if it isn't the cause of the problems it won't hurt to change them after 180K. and its cheap. The only thing I would add is the exhaust does smell kind of rich, both cold and warm. and It does puff blue for the first few minutes after starting but not really thick, or billowing. The smoke goes away after warming up. I just figured it was bad glow plugs (which I replaced 3 yesterday that ohm'd bad.) Could that be an indication of O-rings a sticking injector, or both. The smell is most certainly fuel, not engine oil. Plus this thing doesn't burn hardly any oil. Maybe 2qts per 4k oil change interval.
BTW, the fuel filter looked good, no sign of engine oil, just fuel crud.

 

I believe you might have a weak injector. Tugly would be the one that can help pinpoint this a little more. I don't think it would show up on a buzz test but with AE you might be able to see something somehow, like I said Tug will know what to look for.

The reason I say this is because I have about the same deal with mine. However mine is a little more erratic. It will run smooth when cold but certain times it will have a slight miss (not a full miss) when warm and at idle/slight throttle and I can hear the injector knock down by the oil pan when listening.

I reO-ringed my motor hoping that would take care of it and it hasn't even though I found a couple bad O-rings on injectors.

I am also around 165K miles, did 50 cent mod, changed oil, dead head fix, the whole bit.

This is one of the reasons I am looking for an injector to tear down and learn on so some day I can order the parts and more injector O-rings and go at injector rebuilding some day.

 

Oh yeah, if you get or find someone with an AE please let me know, I would like to check my 7.3 as well!

 

I guess when I pull the injectors to re-ring I could maybe spot the injector in question by gunk on the tip showing poor combustion. It is far from scientific but if one stands out as caked with junk it would be a pretty strong hint its the one. My other question would be this, If I understand correctly a person doesn't have to replace an AE long lead injector with another AE, you can put in an AD like the other 7 right? The AE was just an attempt to quiet the motor a bit right? IF that is the case I will order another AD with the o-ring kit to have on hand if I spot one that looks suspect and it could go in any hole it needed to.

 

You are correct.

Another option is to get the riffraff FRx so the number 8 isn't starved any more for fuel totally taking care of the number 8 injector deal.

I built my own version of it and have noticed a nice reduction in noise and much better slow speed throttle control. I am very happy with the mod!

 

I see they have it on sale right now too. Might pick one up and install while everything is apart.
I will go ahead and order up the parts and hope next weekend I can get it done. I hope this clears it up.

 

Nice deal! I'll be watching to see what you find!