Having 292k on my motor, I'm planning on replacing some things on my motor.

My truck runs fairly smooth, drives decent, but in my opinion tows kinda crappy and really drops my mileage even with smaller trailers. My mileage is the worst running stock, but does decent with my superchips on high for everyday driving.

I've bought a set of almost new stock injectors I'm going to install. While i'm under the valve covers i was planning on doing glo plugs and a compression check and also oil rail end plugs that are leaking.
I know there are some low compression 7.3's out there with worn rings, but what is the probability of having pitted or improperly seating valves? I'm trying to think of what might be causing a fairly good running truck to "wimp out" with a trailer possibly from low compression. I'd like to get AE for doing buzz tests and checking my hpop but its not really in the budget right now.
anyone want to throw out a few suggestions or opinions?

 

What are your boost #'s and EGTS? I wouldn't be running the truck without gauges if you are using a tuner/chip. How much blowby do you have? If you take the oil filler cap off, is there a lot of mist/vapor or is it a steady but light stream? How do your intercooler boots look? Are they clean or leaking oil? Of course, make sure your filters are good as well. While you are under the valve covers, I would get the revised under valve cover harnesses with the retainer clips. Also, check the torque on your rocker arms and injector hold down bolts. They should be around .


https://www.ford-trucks.com/forums/9...cap-video.html

https://www.ford-trucks.com/forums/8...ing-sound.html
(Note, in lbs and ft lbs torques.)

 

not sure on my boost and egt numbers without gauges. I checked blowby a few months ago and my cap just vibrated off after a little while. I'll check again for the misty vapor stuff. I keep my intercooler boots cleaned twice a year to keep the oil off them. I wonder if new boots would help me. I think one of my spring clamp springs is busted now that i think of it. I should make a IC turbo leak checker out of pvc or something.

 

Where did you get these almost new injectors? If it were me, I wouldn't waste my time with injectors unless you have a reason to think yours are bad. What kind of air filter or intake do you have?

Yes you can build a boost leak detector with a PVC cap and air compressor fitting, but if you've got a loose clamp and the superchip on high won't blow the tube off, then we really need to introduce you to what a chip is supposed to be. If you're a Texas truck, we'll get you in touch with Tony.

In the mean time, check the clamps on all 6 boots for the intercooler plumbing, and check your up pipes. I'm guessing you've got leaking up pipes.

 

I got the injector set off CL. I'm using the 6637 filter. I've blown boots off before with superchips. I might try hooking up a temporary boost gauge to see what I'm running. I'll give it another checking over to see if I can find anything obvious.

 

I think changing the injectors is worth the effort based on the miles you have so far. I had 240k on my engine and it seemed to run fine. I was down on power but didn't know it because it's hard to notice when it gradually happens over a long period of time. Turned out my injector nozzles were not flowing anywhere close to factory spec but the truck still ran fine.

I had the nozzles replaced and injectors rebuilt and the difference was shocking. I have all my power back now and the truck runs great. If I was a betting man, I would bet that your nozzles are pretty worn and need replacing so if you have a newer set of injectors, I would give them a try.

 

Sorry, but need to hijack for a minute. What other symptoms did you have that made you want to swap injectors? Did your MPGs start to fall off a bunch? Power get incredibly low finally? Engine get too much knocking? Other symptoms I'm not thinking of? I'm still running my stock injectors, but power and MPG's seem the same as when new (aside from the switch to ULSD) so I'm leaving things alone for now. Also, who did your injector testing and work?

 

Oddly enough, my MPGs increased slightly. I went back through my fuel logs and noticed about 8/10th mpg increase beginning at the 190k mark. Engine power seemed about the same unloaded but I sure noticed the power was down when towing my fifth wheel toy hauler. I figured it was just because I kept stuffing more and more stuff into the RV and it was getting pretty heavy. However, the engine seemed to run fine, no SES light so I just kept driving around as if nothing was wrong.

Eventually, around 145k the SES light came on and my AE said that #7 injector was not contributing like the others. I pulled the VC and solenoid to find the armature screw was loose. I tightened it up and the SES light went away the truck ran normally. I ended up ordering a replacement injector anyway and replaced it a few weekends later. With the new injector, the truck ran rougher and the rotational velocities were all over the place. A few weeks later, one of the nozzles split on #5 and I pulled all the injectors and sent them to Jim at Rosewood. He flow tested them all and found that the new injector was flowing at 140cc as expected but the other injectors were only flowing in the 80cc to 90cc range.

Long story short, I paid him to rebuild them with new nozzles, pressure and flow test and I wish I would have done it about 50k miles ago. Once I got the rebuilt injectors back in the truck, I hooked up my RV and towed it around a bit to test the engine. It pulled so easy and nice that I was kicking myself for not realizing my injectors were worn out. I am looking forward to camping season this year.

 

I wouldn't have expected that, but thanks for sharing your info. I'll keep that in mind.

 

well I found out why my truck tows horrible and why I get bad mileage.
I installed a temporary boost gauge and took it for a spin. I've got 0-1 psi boost at 55 mph and maybe 2-3 at 65mph. this is with superchips tow perf. my max boost at WOT is around 16-18psi with a jumpy needle. pretty bad huh?
I used my leak checker and couldn't find any obvious leak yet but hear air rushing down below the spider. a year ago i thought it was going past the intake valves but now I'm thinking I have a split boot on the bottom of the spider or a blown plenum gasket.
I'll probably buy all new boots from clay to start with.

 

If your boost numbers are when you're driving around empty on level ground, they sound pretty normal. Stock tuning will get you around 15 - 16 psi I think so the superchips has given you an extra psi or two. I don't think you'd see 18 psi with a split boot or blown intake plenum sealant.

You did check the up pipes for soot stains, right?

 

yea, like this...........

 

will my up pipes do that with the new bellowed up pipes? I've looked a few times but couldn't find any soot.

 

If you have bellowed up pipes then you're safe. They fix the leaking gasket donut issue.

 

Before going into injector replacement, I would try diesel purge.
The MOLY stuff is sold in local independent shops or on ebay and I had some good luck with it on high mileage Mercedes, although it did zip on smoking CAT.
This shows blowby on my PS with 217k on it. Yes it is a napkin.