Long story short, my truck does not make the pressures I read about other guys claiming they make. My truck had the stock 15* pump and I would see 2300-2400 on a hard pull. I put a 17* in there, and it runs like a freight train. I still only see max of 2400 on a hard pull. I am not sure if the tuning has anything to do with it and I am not real concerned because he runs and pulls so well, but should I be? I get the P1211 all the time, but Cody tells me that is how his tuning works and I believe him.

Anyways, been curious about this for awhile now.

 

Yep. It has to do with asking for too much from the injectors. Put some 80% nozzles on the injectors and get the same "freight train" feel with 2/3 the pulse width. Asking for 60+ more horsepower from stock nozzles is too much to ask.



EDIT:
Just to put it into perspective, small horsepower gains (like 40-ish additional horsepower) from stock nozzle'd ABs or ADs are realistic and keep things happy. They keep the pulse width in the 2.5-2.8mS (actual, at-the-nozzle) range. Any more than that and not only do you run out of usable injection window for efficiency and power production but you also run into mechanical limits and that magical 3mS number. With the same capacity and an 80% nozzle your injection time goes down to 2.2-2.5mS (again, actual) and your injectors are empty and you are making 60+ more RWHP efficiently. Sadly, the problem with short injection times is that it's typical to miss out on the midrange torque compared to long injection times (like the 3.3-3.4mS actual) like your tuning has. Keeping the injection pressure low to raise pulse width results in a bit of inefficiency though so the mapping for the injection pressure is kept high and if a system will keep up with it all the better. Most trucks won't do that though.

Unfortunately, it's one or the other and it's usually the other.......

 

Thanks Cody. I was hoping you'd chime in. Makes sense to me. But the pressures? Are those normal for my setup? Why are others seeing 2700-2800?

 

See my edit.

Without firing up my tuning computer (hit or miss these days as far as booting up), what pulse width numbers are you seeing on your datalog? It should be in the 3.6 to 3.7mS range (commanded, not actual nozzle pulse width). That would be somewhere in the neighborhood of 60 RWHP at the top end.

Another thing, kind of off-the-wall though.... Stock injectors WILL make an additional 80-100 RWHP. 60 RWHP isn't the limit. Horsepower is a function of torque and RPM. WHERE that additional horsepower is made in the RPM range is the factor . No matter how much additional power is made and what pulse width is jacked-up above stock levels, stock injectors will almost ALWAYS make the same amount of power above 2900 RPM up to the max of 3300 RPM. 6.0mS of commanded pulse width (after figuring in the reduced injection pressure) may make 100 RWHP above stock between 2200 and 2500 RPM but it will fall off stupid-quickly and the injection pressure will tank and never recover before the maximum RPM. Not to mention EGT will be pegged somewhere above 1500 degrees...... A calibration that tops out around 3.2-3.4mS of actual pulse width (at a given injection pressure) may make the injection pressure fall a few hundred PSI but the horsepower level will be maintained at the same level the uber-high pulse width tune makes above 2800 RPM without the idiotic level of EGT through the midrange.

Keeping the pulse width at a respectable level and not expecting to make ridiculous amounts of power between 2000 and 2800 RPM is realistic, not to mention better for the engine in the long run -- with the main trade off being that there are more shorter injection events using that high pressure oil in a given amount of time at higher RPM. These engines are rated from the factory with maximum power between 2500 and 2700 anyway but then they are programmed to start cutting back fuel whereas aftermarket tuning nullifies that so they pull harder at higher RPM.


My 2000 with ADs and that pulse width (all stock at 260K miles) would run in the same neighborhood as yours although my 1973 with as-of-now (but have a set of AD 80% injectors waiting on the shelf) stock ADs will run 2600-2800 PSI with that pulse width (still with 3000 PSI commanded). With 250/200% injectors (now at 287K miles and a stock high pressure pump), the 2000 will run 3000 PSI at 1.8-2.0mS actual all day long and make likely 400+ HP doing it (but the rest of the drivetrain won't take that for more than a few seconds at a time......or very often). Look at some people running 100-120 HP (advertised) tunes only being able to maintain 1800-2000 PSI on a pull. UGH.

If you want, I can lower the pulse width (or make you another tune with less pulse width) but it won't be very much fun or freight train-like.

 

Cody, first I will say I am extremely happy with the tuning and how it runs. I don't want or need any changes, but I very much appreciate the offer. I just don't think it needs it. Now that you explain to me how the pressures work in conjunction with the pulse width, it makes total sense and I'm not worried about it.

I don't completely remember what the pulse widths are.... my truck is down right now and I'm fixing some leaks, but I believe I remember the pulse with being 3.3 or 3.4 at WOT. As soon as I am back up and running, I'll pay attention to those and see what they are.

Now that I know the pressures aren't pointing to any fault in my high pressure oil system and they are where they're supposed to be, that answers all of my questions. I've had a couple of friends ride in my truck that own 7.3s and they are always amazed at how much power the truck has, especially in 3rd and 4th gear pulls. No it's not like a sled puller, but for the setup it has and how well it runs, it pulls pretty dang hard.

I very much appreciate you explaining it in detail. I understood everything you said and have a bit more knowledge now of how it all works together. I had never considered injector pulse width as part of the equation.

 

You're welcome.

By the way, pulse width sold A TON of unnecessary aftermarket high pressure oil pumps 5+ years ago.

 

Why am I not surprised?

 

Good information guys. Your so lucky Byron to have Cody's tunes.

 

 

It is, sadly....LOL. Honestly, when I was looking for a Superduty, I didn't know there were two version or I would have got a Late 99 or 2000. I may be trading up this Spring because I am needing a crew cab as well. I just don't know.

 

my question is , if the p1211 DTC triggers when the programing calls for more fuel than can be delivered at the command PSI and PW why not scale back on demand to what the Hpop can deliver at a given PW ? is it a matter of lazy programing and not wanting to do the math or did programers not understand or just not care ?

 

I think what Cody is saying, if I understand him correctly, is that it isn't possible to combine both with stock nozzles and get the desired results while having custom tuning and asking more from the injectors. I'd have to change nozzles to 80 percenters to achieve this.

 

Not to be rude, but I am having trouble following this so I'll get into how I think it reads:

P1211 is set when the actual injection pressure from the injection pressure control sensor (ICP) input to the PCM is compared to what is actually desired by the calibration and the difference is 290 PSI more than desired or 406 PSI less than desired for 7 seconds. It's not a code that directly correlates to a specified amount of fuel that can't be delivered. In the aftermarket tuning world, it's more in line of "your injectors are out of fuel and are becoming an oil leak". Technically, by Ford standards and calibrations that are designed to NOT tax the high pressure oil system, it's a code that tells you there is an internal high pressure oil leak somewhere or other anomaly occurring wherein the mapping in the PCM for desired high pressure oil pressure isn't what is actually happening and there's an issue.

P1211 doesn't only arise from high pressure oil deficiencies though. Plugged fuel filters or weak fuel pumps can also cause it and this is a big eye-opener because our vehicles are not equipped with any kind of fuel pressure monitoring hardware. Potatoes stuffed in the exhaust pipe can also cause the code to trip.

As far as "fixing" the problem through tuning, I will go through the possibilities:

1: Shorten the pulse width to a level that gets along with the high pressure oil system. This is easy. This also reduces the power output. However, it is also vehicle-specific as not every 7.3L is going to be able to deal with the same amount of pulse width. Some can't touch 3.0mS while others are good to 3.5mS. It also depends on the driver. Since 2012, I haven't personally had a reason to run the wheels off of a vehicle while using more than 40-ish additional horsepower since I hate fixing broken stuff and I baby my equipment.

2. Lower the desired injection pressure under load. That is also very easy to do but it's not a viable option in practice. But again, to what extent is each vehicle going to tolerate? How will it affect power since the desired mass fuel rate has to be maintained to see the perceived power in the butt dyno? The pulse width has to go up when the injection pressure goes down to maintain a specific mass fuel amount. This can turn into a vicious cycle because now the pressure is starting out at (for all intents and purposes) 2200 PSI instead of 2900 PSI but to maintain mass fuel rates the pulse width has increased to 3.5 mS from 3.0mS. What happens when the high pressure system can't maintain 2200 with the higher pulse width? At nearly full load at a constant mass fuel rate, stock programming at 2900 PSI calls for 3.03mS. Dropping down to 2500 PSI, the PCM commands 3.12mS and dropping another 300 PSI to 2200 PSI it commands 3.44mS.........and so on. The more the pressure drops, the higher the pulse width goes. The higher the pulse width goes, the harder it is to maintain pressure.

3. Turn off the code. This is extremely easy to do in a couple different fashions. Either extend the error time to something ridiculous or change the code-setting pressure deltas.

4. Fiddle-dee-dee with the IPR mapping. Want a really snappy, responsive engine? Make the ICP go artificially high on tip-in right from the get-go by slamming the IPR shut as soon as the engine is loaded. This does work for a few seconds but it's akin to a higher-rate fuel pressure spring. No matter how high your fuel pressure starts, once the pressure starts dropping there is nothing that can make more pressure other than more supply. If you start out with a stock spring and 60 PSI of fuel pressure at idle but your pressure drops to 20 under load, changing the spring to something that starts you out at 70 PSI only delays the subsequent drop to 20 PSI again by a second or so.

Here's my take on the P1211. It's not hurting anything and it's useful when there is actually a problem. However, this code has been around since the dawn of aftermarket tuning and injection pressure fooling devices. The real reason for its presence has only been realized within the last half-decade but it's never been an actual life or death problem. Larger nozzles aren't the end-all solution either.....the solution is knowing what the injectors are capable of and either tuning accordingly (not expecting more power than reasonable and that more than 3.0mS at 3000 PSI on 160/80% injectors is going to start causing high pressure oil issues) or being aware that long hard pulls are going to cause a little amber light to come on for a few minutes. Thankfully, there is enough recent information on the code throughout the interwebz that people don't usually just throw a $500 pump at the issue anymore.

I hope this helps. I really didn't know where to go with this one.

 

It doesn't matter. The pulse width limits are exactly the same between AB and AD injectors because they are identical. If I were to find a 2001 pickup and put ABs in it without the owner knowing that I did so, he'd NEVER know that the injectors were different regardless if he had aftermarket tuning or if it was all stock.

The things people lose their minds over.......