I guess its that time in a 7.3's life that is starting to make me a regular thread poster on this site.


My feed truck (2001 ext cab 4x4 7.3 198k) had a cold starting issue I fixed with new gp relay. Now I noticed when it gets down below 30 degrees it has a cylinder miss until motor warms up. I don't doubt injectors are in my future. I was wondering though if that is common for worn injectors or if maybe something else has gone haywire and how long can I run it like that before somethine else tears up? after about 7-10 min the miss goes away and I don't notice it. I would like to get through the winter before messing with it or having injectors put in it... whats every ones thoughts? Thanks in advance.

 

Ya worn injectors are probably the bad guy here. Hoping the group. There is a post that'll that talked about re shimming the amerature on top of the injectors and this problem going away for a while. I was gonna look into it. Would be worth while to search it. Also what oil do you use? If you go synthetic it will help this too sometimes. The 5W40 synthetic isn't as thick. You can pop the valve covers off and actually see it. The injector will not pass oil until it's warm. I have about 3 of them on my truck so I feel your pain.

 

this is the post that Firefighter1406 is takling about . I am about to do this on mine and Orings.

https://www.ford-trucks.com/forums/1...when-cold.html

 

aww ok, I will do a little research on the shimming. Thanks for the article post. I have just been using the motorcraft 15-40 diesel. The funny part is its not throwing any codes or anything it just shakes and misses for about 10 minutes then clears up. I was really not wanting to yank my valve covers till this summer when I had time and warmth (un insulated shop)...then I would just drop injectors uvwh, gps, etc while I was there. I might try the lower weight oil until then. Running it that way shouldn't hurt anything other than my mpg and injectors right? Where is a good place to buy stock injectors?

 

Stock injectors I would say Clay at Riffraff, plus customer service is great. I wouldn't think it is hurting anything since the cylinder walls are not getting washed down since the injectors are not firing, but honestly I am not 100% sure. My truck has been doing this during fall-spring for years and she is still running.

 

Thank you for the link sir.

 

after shimming your cores might be junk aka no value if worn to much

 

I do not think any harm is being caused, if you want to wait for warm weather.

 

I've got an E99 stroker.

I too suffer from a miss, probably inj knock til it warms up.

Degas bottle is clean, oil is synth, no problem. Runs like an ape after warm up. Been doing this for many Michigan winters.

I would go with, "ya it's getting old, but it still hauls the mail"

I wouldn't be too concerned with a simple miss til it warms up.

Just my two cents.

BTW, went to get a few groceries today, truck was ready and willing with 12 degrees, 30 knot winds and I'll be damned if I didn't step outta the truck because it was too damned cold out.

Yep, cold has a limit.

Run it and watch your degas bottle for a stain and keep your oil up and smile.

Denny

 

I've had the cold startup miss for the last 3-4 years, worse in winter, but there all year round. Was planning on doing shims and o-rings over the holidys, but didn't get to it. Will do it in the next month or so.

However, I did an oil change in early December and went back with 0w40 (CJ-4), and the thinner 0w oil at startup has significantly reduced how long it takes for my tired injector to start firing again (the miss goes away MUCH faster, even before the engine gets warm).

 

I see in his post that Denny is already running synthetic oil. Grayson what are you running? Some have had luck going to syn or a thinner oil in the winter to smooth out the eng when cold.


EDIT: Looks like Pete and I were typing at the same time

 

Do you tow or plow in the winter? Is over heating an issue with the thinner oil?

 

Poppet wear is a well known weakness of the design.

Poppet Valve.pdf

Would a reputable rebuilder not replace poppets and machine or replace seats on all cores. Uhh, some simply replace the internal shim and call it "rebuilt". This sort would likely reject your shimmed cores.

All the more reason to go only with new OEM injectors!

 

Hey guys thanks for the reply's...I think with what ive heard I am going to wait till warmer weather....if its much above 30 I have no miss, its only when it gets in the 20's like it has this week, and I don't ever plug my truck in so maybe it would help if it did? I just use the motorcraft 15-40 oil...might try some lighter oil as well like you guys mentioned. I just use my truck few days out of the the week to run back an forth to the farm and to feed hay. .......I know this is way off topic and for another thread but I saw where Colorado Horseman mentioned only using NEW oem injectors. I was looking at the reman injectors on RIFFRAFF...is that a no no?

 

No towing or plowing.

Overheating will not be an issue with 0w40 oil for two reasons.

First, because the 0w represents the oil's viscosity only for cold oil. Once it gets to operating temperature, it has the same viscosity as a 5w40 or 15w40 because the "40" is the nomenclature for the oil's viscosity at operating temps.

Basically, as oil warms up, the viscosity drops. "Multi-weight" oils have a XwY nomenclature as compared to "single weight" oils which have a Xw nomenclature (i.e. 10w40 multi-weight or a 10w single weight). The multi-weight oils have viscosity modifiers added to them to allow them to have an "easy flowing" viscosity when cold but not lose too much viscosity as it warms up. In the example of a 10w40 in comparison to a straight or single weight 10w oil, below are the viscosity specifications for both cold and hot oil temperatures, and you can see that the multi-weight oil has a much higher viscosity at hot temperatures.

The single weight 10w oil has a viscosity range of about 32-54 cST @ 104°F and 4.2-5.2 cST at 212°F.
In comparison, the multi-weight 10w40 oil has the same 40°F viscosity range, but has a 100°F range of about 12-18 cST which is 3x higher than that of the single weight oil.

Secondly, the "overheating" issue has to do with ONLY your engine combustion and cooling characteristics, not the baseline oil viscosity. The only potential problem you could get with an excessively low oil viscosity is a lower oil film strength which allows for a physically thinner boundary layer of oil coating internal parts. If thee viscosity of the oil shears down low enough to allow too thin of a boundary layer, the impact forces of contacting surfaces will "push past" the boundary layer of oil and end up with metal-to-metal contact. That's why used oil analysis tests include both viscosity and wear metal values so you can see how well the oil is holding up and maintaining the proper hydraulic boundary layer of lubrication while the engine is running.





Good points, but to put it simply, everyone does not always have the financial luxury of ONLY considering "new OEM injectors".