Are you seeing the same issue with a loss of rpm signal from an inductive pickup on the dyno?Originally Posted by FlyinRyan
Are you seeing the same issue with a loss of rpm signal from an inductive pickup on the dyno?
We wanted to resolve the issue before setting it up on the dyno. Reason being, the shop I'm tuning it for is using a dynapack....alot of work to not finish the job . The miss also wreaks havoc with the knock sensors, which makes my job very difficult.
Any chance you ever figured this issue out. Just had the exact same problem on a 2016 Procharged Challenger 5.7 Shaker with a set of ID1300's. Changed out the injectors for a set of stock 6.4 injectors (running very low boost right now) and that fixed the problem. I emailed ID because I believe it is an issue with something in their tables, but wanted to see if you ever got this car situated.
Thanks
We had the same issue as it turned out after quite a bit of experimentation the problem lies with the PE threshold Voltage which is adjustable , the lower you set it the worse the problem my recc would be not to go lower than 2.7 V where it disappears , thats the lower limit but you can go anywhere above this
Not sure it is the same problem....its true, if the PE threshold is set too low it can cause a cough/stumble but happens at almost any lower rpms if/when the threshold is passed.
But the OP seems adamant his only stumbles at 2500rpm and is already in PE...
Yes, the OP and the car I am working on both have the same issue. I can be at WOT at 1400 RPM and it will be fine until 2500. It misses (actually almost acts more like it is shutting off) for a split second, then runs right to redline without hesitation. I think I'm going to do some logging of the issue and post the tune and log on here to see if anyone has any ideas. This is obviously not an isolated incident. I'm also going to put an O-Scope on the coils and injectors. I really believe they are shutting down by the way this feels, and I believe someone earlier in this thread actually mentioned they thought it looked like the coils were shutting down for a split second. I actually questioned it, thinking it may have been their dyno pickup up a dirty signal due to a misfire. Now that I am running into the same issue, and feel what this one is doing, I'm thinking they may have actually been seeing a situation where the computer is shutting things down for some reason.
Last edited by mxatunerjg; 07-17-2017 at 07:35 AM.
I'd be logging and checking for maybe tagging a tq limit also.
Desired vs calculated...if the calculated gets too much above desired, the PCM will 'clip' it back by pulling throttle, fuel or spark.
Pretty easy to run into on blown stuff.
I had looked at that before with the same thought. The only issue is with stock 5.7 injectors and stock 6.4 injectors it does not do it. Only when I install the ID1300's. On all three injectors the car runs great, just with the 1300's it gives the issue at 2500 rpm and only 2500.
Tried checking the calculated vs desired tq. Did not find any issues there. Also tried this without any boost (disconnected the bypass valve). Still had the exact same problem. Installed a set of brand new ID1050X injectors. Same problem. Installed the 6.4 injectors again and the problem goes away. The values are exactly what ID wants us to be using, even went as far as sending them a copy of the tuning file and they verified the values.
Next step is to install a set of Hellcat injectors and see if they will work or not.
Our thought at this point is there is a some sort of limiter, maybe like a minimum pulse width vs rpm, in the computer that we do not have access to.
So I just tested this car with a set of Hellcat injectors. Car runs great with no misfire issues at 2500 RPM and the fuel trims are near perfect. I have one more idea to test with the ID 1300 and ID1050X injectors. If it does not work then I am going to contact HP and ID about this issue. It is coming to a point where it almost has to be an injector data issue or a table we do not have access to. Anyone have any other thoughts?
Some more info on this issue. If PE values are set to 0 the car runs great. That said it is running dangerously lean, so it cannot be set this way. It is also interesting that as soon as the PE value becomes anything more than 0 the misfire occurs again. So for example if I set all of the PE values from 0 - 3200 rpm to 0 the car runs perfect (other than being lean) at WOT right up until 3201 rpm, then it misfires as the PE tables start to add fuel. So to test I moved this back to 2800 and at 2801 it occurs. Then I moved it back to 1900 and it did not misfire until 2500 just like it did with the whole table populated with normal values. So the actual amount of fuel is not the issue. I also went to the point of running .020 across the board in the PE tables. The purpose was to test if a specific pulse width could be causing an issue, maybe a "harmonic" in the fuel system. I tried this because I noticed a similarity with the previous tests of the misfire occurring at the point where the pulse width values hit 3.5. This test proved inaccurate as the misfire still occurred at 2500 though the pulse width exceeded 3.5 at a lower RPM, around 1900 if my memory is correct.
All of this led me to another theory, that being if the PE tables are populated across 2500 rpm range it will misfire at 2500 regardless of the PE value. So I tested this theory by putting the lowest possible value, which is .0002, in the PE tables from for all rpm points up to 3200 rpm. As expected the car misfired at 2500 rpm even though it was running approximately the exact same lambda as it was with 0 in the same cells. This also solidified the results of the previous test that the 3.5 pulse width is not the issue since it did not hit 3.5 until around 3200 rpm.
I've tried all of these tests with Neural Network on and off with both scenarios yielding identical results.
This is really interesting. I appreciate your approach to the whole thing.
Another interesting point to make here. While testing the PE enrichment tables I noticed the ignition timing seemed to change as well. In the RPM range that had 0 it ran an ignition timing much different (higher) than if those same cells were populated. I also have not been able to trace the source of those ignition values, though it has not been a major concern since this is not how the car will be run once I figure out what is needed to make these injectors work.
So to expand on this more...I disagree with Diablo's approach to the injector tuning, but I have also contacted them about this situation. All I got for a response was "It's because the scale wasn't retained". So assuming they are meaning the injector scaling I decided to adjust the injector pulse width tables based on their method. I got everything running well using only the Fuel Mass columns, leaving the pulse width columns the same as they were from the factory. Fueling was as needed but still had the same stumble at 2500. So again I set values in the PE tables to 0 with the exact same results as before.
I do know a way I can probably make this work on the fueling side, and that is to set all PE values to 0. Then either turn off NN and tune based on only the VE tables, or tune fueling using only the Pulse Width tables creating a slope that accounts for the changes as RPM and boost increase. I don't want to do this because this is a street driven vehicle, and since the VE tables at 0 seem to cause ignition timing changes I would really need to figure out where those values are coming from.
More to come from that drama that unfolds!
Who are you talking to at ID? Have you been able to talk to Paul yet?
I have been dealing with Tony, but Paul is involved.
Exact same scenario here. Any luck finding the resolution?
Same here. On a 2015 Whippled SRT GC.
I have a small throttle oscillation due to exceeding expected tq, but I'm dialing that out.
The real issue is that 2500RPM momentary cut/ hard stumble.
Cheers,
Brady
You guys should state the mods instead of just, same problem here...we need to find a common denominator, to see if it's a tune/software issue or hardware problem. mxatunerjg is on the right path with his tests, tells me once again it's an injector problem, why would ID be the only injector that needs an extra table to tune properly? Sadly good luck getting answers on that one, even suggesting an issue and you get trashed, even though they have more data points on squats in the gym than their injectors...apparently. Haha
I ran into this on my buddy's 2014 Charger with ProCharger.
Mods: D1 Procharger running around 9psi, Jay Greene stage 3 cam, JBA long tubes, 80lb injectors and meth.
I set the Part throttle VVT table to match WOT
I rescaled the injectors with ANN off and got trims in the 5-7% range before fine tuning with the VE tables.
WOT thresholds for PE and Throttle body are at 3.00v
I read this thread and initially zero'd out PE in the lower ranges as described but later saw during a scan that the TB was closing, causing my stutter. I found this having the owner put to the back of the parking lot at the track and gun it quickly to grab scans. I set the adapts high enough to get that to stop.
She still had a stutter to her so I scanned again and found that it was because she was lean where I had zero'd out the PE tables. I added fuel there and boom.. it all went away. I then bumped up timing and sent him to the staging lanes. On launch he made a smoke show due to roasting both tires. He's happy, I'm happy and we are anxious to get him back to the track to get a launch with DRs now.
2013 Dodge Challenger RT Plus - Shaker
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