Injector Misfire, Sticky IPR, HPOP, ?...

Turk.919 said:

I’m going to have to read through this a few more times and do similar tests. My 03 does similar and I had an issue with the IPR being too tight and binding recently. Mine might be a chafed injector harness though, or an issue with the plug at the FICM

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I see in your signature you have a 2003 - Before the fuel injector harness concern was identified and corrected, the harness most commonly rested in several of the intake manifold bolt heads. This caused chafing and direct shorts on the bolt heads and or internal harness chafing and shorting to the grounded shielding. The most common symptom was sudden stalling. To check for this, I used to take the same wooden dowel and gently press down on the harness with the truck running. Concentrate on the driver's side near the FICM up toward the intake tube where it also becomes compressed. Any stall or hiccup should be considered confirmation of a harness concern. REPLACE the harness. There was also a manifold bolt with a stud that needed to be moved but my memory fails me at this moment. I think it had to do with a retainer taped to the new harness. Again my memory is fuzzy. If I remember and have time I'll look for any bulletins relevant to the harness. There was also a recall at one time too.

Torque Wrenches - I have a couple click type from Harbor Freight, but those are probably not accurate enough for this job, correct? Any recommendations besides ones that cost $500? Also, where did you guys get your extended T40/45 Torx in 3/8 or 1/4 drive?

I have the torque specs are as follows (please correct me if i'm wrong!):

1. Injector hold down (mine's an '05, so i'm assuming it's a T40) - 24ft lbs (26ft lbs for T45's)
2. Oil Stand Pipe - 60ft lbs (don't need to install new ones, right? Mine are the updated 12mm's)
3. Oil Rail Bolts - 120in lbs (10ft lbs)
4. Valve cover bolts - 80in lbs (~6.5ft lbs)

I'm 7/8ths of the way to being ready to change this thing LOL

-jokester

I played the calibration game for 30 years at work. Our electronics shop at the dyno test facility used to do cal's for both us at vehicle testing and the dyno lab. They had a nicely made deadweight tester. Then I set up one at our facility, too; we were 100 miles away. We still did our "official" company test at the lab.

This was no different than when we had to run a field test at TRC in Ohio. The Transportation Research Center in Ohio was also where NHTSA did its tests. They used a deadweight tester before ISO. In fact, they did deadweight testing with all the load cells.

When our company adopted ISO certifications, we had to send the wrenches out routinely, which we did to Snap-On. All of our instrumentation had to be sent out, and we had a lot of test instruments; we could run over 20 test vehicles. I spent thousands of dollars every year.

We had several torque wrenches of every size so that we could rotate out without loss of use, since built test vehicles every day of the week. But I still had my guys do our dead-weight check before and after they went to Snap-On. Trust, but verify. The deadweight tester followed Snap-On, including with one failure. We just didn't have a nice calibration graph for our records.

It's pretty easy to build a DIY deadweight tester; I did a video of mine at home.

It's pretty common to understand that torque wrenches and almost any pressure or force reading instrument has a best range, typically at the center of the range. Better tools are tighter at the extremes, and often we try to get the tightest spec we can.

This is always something I find interesting with bolt tightening since every engineering textbook out there shows that using torque for tensioning ranges from about +/- 25 to +/-35% of target due to friction of the threads and contact under the heads, nuts, and/or washers. That includes lubricated. The data has been backed up with strain-gaged fasteners. So with a +/- 2% tool, the range maybe 23/27% or 33/37%. It's why Torque/Angle is a better methodology if someone has properly measured the tension. And why the torque tightened bolt is set to the "clamp load", well under the yield point, so that wide range won't yield the fastener.

That being said, I still check cal on my torque wrenches on a routine basis or when I am about to do something critical. But, of course, the quality of the test is totally dependent on the quality of the setup; by me. But I can certainly understand sending them out, but it shouldn't be the only option if calibrating is not part of the business or your job..

T40 Torx (I would get a 3/8" Torque wrench - I don't like adapters when torquing):

or

or

Also, some cheap Torx sockets have too much "play" for my liking.