C'mon, admit it. Many of us have stepped in it with their rig, and I don't mean the testostopedal.

While I have seen many threads and posts that provide useful information on what to do, how to do it, and when to do it - I have not yet found a collection of DON'T's. Since I sometimes feel I'm the grand poobah master of how not to treat a 7.3L, I thought it only fitting that I should share the "don'ts" I've learned along the way (sometimes the hard way), and invite others to share theirs. While it may not help to troubleshoot a hard/no start, it can help prevent that scenario following some do-it-yourself work - it might even prevent real damage, injury, or (heaven forbid) death.

Here is the first example:

Number 1: Don't even wave a picture of a wrench at that driveline without first chocking the wheels (that's not mine, but it's too important to bury in a list).

Speaking of "key" don'ts, whitetmw will share in the thread below: Don't let those keys out of your pocket, unless you have a very specific test that needs to be done with a hot PCM. With the key on, many circuits are now energized and the truck should be running, were it not for the lack of the engine spinning. A wrench in the wrong place can make it spin and start - even if that wasn't the intent. Testing hot circuits has its own set of hazards - you really need to know what you're doing, or have detailed instructions from a competent source.

Since the word "Don't" will show up everywhere, I'll just make a small list here with the understanding that each is to be avoided.

Don't...

• tighten injectors without an inch/pound torque wrench (0-240 in/lb wrench is ideal).
• crank the engine quickly to evacuate cylinders of fluids after injector work.
• put the glow plugs back in without first ensuring the cylinders are completely evacuated.
• put the VCs back on without running the engine up to full temp, making observations, then re-torquing the hot injectors.
• take the cleaning of the heads lightly for cup replacement. The factory installed cups on pristine-clean heads, we need to do the same.
• power up (chip, program, or otherwise) without first making sure the truck is 100% and has gauges to monitor the powertrain's reaction to the new power levels.
• get it in your head that powering up is a simple and inexpensive task - more power always throws something out of balance.
• let car alignment guys align your 4500-pound nose - truck shops seem to be the only ones who understand the dynamics, and are equipped to do the work.
• expect the dealership (or any shop, for that matter) to have mechanics old enough to know these rigs. Many of today's mechanics were breaking their voices about the time the last 7.3L made a brand new Superduty sink the suspension.
• get in a hurry when starting a cold truck in the winter - that "Wait to start" light is a reminder, not a timer for the glow plugs.
• take any one person's word on the forum as gospel (especially mine) without verification. Rumor, lack of direct experience, misinterpretation, or even a typo may be the root source of that "word".
• believe that the most popular product of the day is the "best" product for your truck. Many products have fallen out of favor as time/experience passes, and the long-term effects are realized. Do your homework, ask questions, and use your head. Cliché, I know - but there it is.
• button up the truck and drive on until you can verify the fix/upgrade is solid (where practical). My Hutch mod had an air leak, and it caused me all manner of grief until I finally discovered and addressed it.
• assume the 50-cent mod is a permanent fix. New UVCHs grip so tight that the locking mechanism isn't even put to the test.
• take the keys out of your pocket (or even off the dresser or key hook) when pulling/installing the chip. This fits right in with one of the first rules, but it is such a common mistake that I mention it again just for chip handling.
• forget to put the HPOP reservoir plug back in before cranking over the engine. While the Old Faithul-esque oil spout may be spectacular, the moment is not worth all the cleaup.

That's what I have until somebody chimes in to remind me of something else... or the coffee kicks in. Have at it guys, I know you have some good stuff to share.

 

Don't assume rust is a problem that you can deal with at a later time. As soon as you get that truck, coat the bottom of it with something! Used oil, fluid film, liquid wrench, or any host of other rust inhibitors! And unless you has something that is applied once and works, plan on doing that at least once a year, if not twice! My truck is falling apart around the frame. Bed is shot. Front doors and rocker panels are toast. Mechanically, it's great!

 

that's an awesome list!

 

Preach on Brother!!!

 

Rich, good idea for a post that will probably attract a lot of dont's. My lesson Don't forget to check the hub selector lock rings after installation to ensure that they are firmly in place. I lost both hubs somewhere!

 

Do Your research,some aftermarket parts can be a disappointment.

 

Don't fall prey to "forum cheerleading".....Its your hard earned money, do yourself a favor and spend it wisely.

 

Don't
-Think you are immune to PMS, once you give in it can take over quickly.
-Ignore the little leaks or repairs, they have the potential to turn into major repairs or leave you stranded.
-Use non OEM parts, unless it is completely unavoidable, you will spend the same if not more by buying cheap-o parts due to frequency of changing.

Just my 2 cents worth
Robert

 

I wish he would bring it back so I can write it down correctly, but Cleatus12r's signature definition of a proper upgrade was something like:

"As good or better performance and quality as good as OEM"

 

The one thing that stands out I just can't forgive myself for is LEAVING THE KEYS IN THE IGNITION, IGNITION ON, WHILE I WAS TESTING A CIRCUIT which back-fed the PCM. I still have the pay stub: -$800.00 for Customer PCM Damage. Dam! That was ten years ago!

I could list a 100. But, that's the one that gets me.

I teach Electrical Troubleshooting to Tech Students on occasion for the High School. No pay, just do it to help the school. That's the first slide and the last slide!!

 

Don't even wave a picture of a wrench at that driveline without first chocking the wheels!

...(that's MINE, and I would even suggest using wheel chocks every time you start any... yes, ANY maintenance task just because you never know what rabbit trail you'll end up chasing in the process of doing "just one little thing under the hood"!).

 

Experience can be a very painful teacher!

 

Ouch! I have been trying to wrap my brain around gasoline engines lately, and I am having a hard time understanding fuel trim both long term & short term, fuel pulse width, and how it all relates to the 02 sensors and cats. Is there a good online site that I can study up?

 

Rick Great Thread !! The title had me wondering what the heck is he talking about. But par for the course. LOL This is one of them threads that should be read before everytime I head out to turn wrenches. Because to this day even after turning wrenches for over 25 yrs I still find myself doing something "Stupid" every now and them. I wish I was 21 yrs old again because back then I knew everything.

Like it was once said "It is better to burn out because rust never sleeps." I don't think that statement is true but I do know for fact that rust never sleeps.

That truely is a "Don't Do" and I too have had bad things happen with the key on but not $800 of OOoopppss
I have one equally a " Don't Do" and that is DON'T use a Power Probe to power up relays or circuits unless the you are 100% positive you have the right relay or circuit and you are 100% positive you have the CORRECT wire. Trust me on this one "Bad things can happen"
Myself after learning the hard way if I am not 100% sure I leave the Power Probe in the tool box and stick to a DVM.

 

Wow, I could spend hours on this. In a nutshell. The STFT maintains everything as close to 0% as possible. The LTFT learns from the STFT. Both are logged by the ECM.

Either a rich/lean bank condition affects the 02 Sensors input to the ECM or vice-versa (Bad 02) causing the opposite effect by commanding the injectors pulse with for that bank. Then there is up-steam and down-stream systems, Wide / Narrow Open / Closed Loop, band systems, and older generations such as the 1980's GM's and such.

There is a guy on you tube named scanner danner. He explains it pretty well. I bought his book because of his graphics, primarily of the Scope Snap-Shots so I could use them teaching.

I've communicated with him several times and he is a teacher at a Tech School and does his own business like I do contracting with Dealerships and Shops In the Area. Great Guy!