Are you running stock fuel rails?
Are you running stock fuel rails?
I am.
Can you guys please try to log your fuel rail temp channel and see what you get?
I have been going back and forth with support about this and might have hit a dead end. The original 'rail temp' channel I saw, wasn't supported by my FPDX strategy, so it caused a data drop out on all other channels when logging.
They managed to remap a different channel which is supported, and I can now log that channel. However, it reports 60.000*F constantly.
I am going to try a test tune, where I keep the injector offset multiplier value from 60*F the same and pivot that curve about this point. I want to make it a steep slope to show whether the table is in fact being used with a different channel that is changing temps.
If anyone else could please log the rail temp channel they have and report results, it would be nice to know what other strategies are doing here.
I've never gotten rail temp to log since it's inferred on 11-17, on the 18 it works fine though since they have a pressure/temp sensor on the rails.
Originally Posted by Jn2
Being inferred doesn't mean you can't log it. Load and MAP are both inferred too.
My Whipple strategy has similar behavior - very rich in first cold start - doesn't fully correct until well after warm - seems to take 10+ min or so sometimes longer. Definitely well after head, oil, and coolant temps are normal. I have never tried to log this and I don't remember seeing it but im going to look for it now for sure. My car will actually run rich long enough to start trending in the LTFT, Only to revert and go back. seems weird.
There is no sensor right, so if the rail temp model in the cal doesn't fit reality that might cause this? Can this be calibrated?
definitely seems to be effected by ambient. Once temps dropped below 60 it was more noticeable. I'm actually going to back out a couple changes I made likely in error trying to account for this as the last time I drove the car it didn't like hot starts. I had to keep it at 900 rpm manually for 20 seconds to keep it from dying.
Last edited by superman07; 11-20-2018 at 07:01 PM.
Well HPT support seems to be pulling the plug on helping with this.
They are adamant that the current "rail temp" channel they have mapped is "100% the right one", even though it never deviates from 60.000*F
I decided to test this out by only changing the two "____ vs rail temp" tables, and comparing logs. My theory is that after a long period of cruise, fuel rail temp will be low (lots of cooling and moderate fuel flow). Once you pull to a stop and idle, the rail temp should steadily increase (rising underhood temps, plus lower fuel flow allows more heat absorption).
In the first picture, you can see my latest tune provides a pretty flat STFT during idle after a long period of cruise.
railtemp2.png
In this log I kept the 60*F value constant and pivoted the rest of the table to create a steep slope around the 60*F value. If the steady 60*F rail temp channel they currently have mapped was being used, there should be no change in the STFT behavior. This was not the case.
railtemp1.png
To me this proves that the tables are functional, and that they are being driving by an inferred rail temp channel that HPT is not able to log.
Please make some noise and ask support to work on this. Any table that modifies injector slopes or offsets is super important to the tune. Any parameter driving those tables needs to be logged.
I agree 100 percent.
I agree that anything modifying the fuel inj offsets or slopes needs to be able to be logged, however, I don't see the rail temp changing very much at all, with differing setups, to need tuning. Maybe there's a different scenario I'm not thinking of?
In other words why would this need changing?
I guess you could ask that question about many parts of the tune. Like, why would you take a well calibrated MAF sensor and change the transfer function?
Many times, the stock calibrations are good middle-of-the-road values, but for us, we are optimizing for a specific build; generally quite different than the stock car.
Many of the aftermarket tunes just wipe these tables out with all '1's. I'm guessing they don't care enough to spend the time tuning them, much like the speed density tables (also very important). When I have those tables set to '1's, I can see very obvious, slow swings in fuel trims as temperatures change and as the car drives and idles.
My stock GT calibration uses a 15% multiplier range on the offset vs rail temp table. But now I am using the '13 GT500 MU52 injectors. The GT500 cal has an even bigger range of offset multipliers, 45%. But I'm pretty sure it uses a physical rail temp sensor. So what are the odds that the inferred rail temp in the GT strategy matches the reality of a GT engine, with GT500 injectors stuck into a custom DoB intercooled manifold, and an M122 blower on top? Not great. Then factor in varying amounts of engine bay venting, which will affect the actual rail temp as well.
I think especially because an inferred value is driving these modifier tables, we need to see the correct inferred value. Imagine trying to tune speed density without being able to log calculated MAP.
Please email [email protected] and request that they get the 'rail temp' channel functioning! I'm just one annoying guy at the moment, that has been hounding them for 6 months on this.
Both my GT500's don't have a fuel rail temp sensor, 2010, and 2014.
I read some posts where people were referring to the rail sensor as a pressure/temp sensor. No idea if that is true or not.
Either way, inferred or measured, it is important.
If anyone has the SCT advantage software and could check for a functioning Coyote rail temp channel, that would be great!
They both have the rail pressure sensor, not sure if it measures temp too or not. I'll look see how many wires it has, if three, most likely it's only pressure, if four, I'd say it's both.
The sensor is a four wire, so it must be measuring something other than pressure. If it's measuring temp and reporting to the pcm, it must have a PID. I'll look see if I can see it in the scanner, maybe plug another sensor in and warm it up a bit with a hairdryer or something, see if it changes so I know it's live and not inferred.
Sweet, thanks man!
GT500s actually have a temp sensor built into the pressure sensor. Its pin 3 on the FRPT connector C106.
The coyotes (atleast 2013/14 in the shop manual I am looking up) shows .5 hours to replace but does not list a part number, connector or location for the fuel pressure sensor.
Last edited by Sleek98; 12-08-2018 at 07:38 PM.
Forgot to mention that the fuel rail temp is pin 26, the fuel rail pressure is pin 23 on the PCM side of the engine harness and listed as 5.4/5.8 only. I am guessing the 5.0 does not have an actual temp or pressure sensor since the regulator for them is in the tank I believe. Doesnt the 5.0 use a pop off valve in the tank to control their pressure?
Bump!
Still looking for people running different Coyote strategies to find and log Rail Temp, and post what results they are getting.
If you find the same fixed 60.000*F channel, please email [email protected] and request that they find the correct channel.
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