|
Post by wesk on Oct 8, 2023 11:34:17 GMT -5
You are at 100% injector duty, and your VE is totally unreasonable. It looks just like fuel delivery issue.
|
|
|
Post by wickettoby1 on Oct 8, 2023 12:30:28 GMT -5
What do you mean by the the VE table being totally unreasonable?
|
|
|
Post by wesk on Oct 8, 2023 13:55:37 GMT -5
Higher than reasonable values under boost. Very typical when out of fuel system.
|
|
|
Post by wickettoby1 on Oct 8, 2023 14:02:51 GMT -5
Those VE #'s are the same as what's been in there since the chassis dyno tuning a couple of years ago.
|
|
|
Post by wickettoby1 on Oct 8, 2023 14:03:41 GMT -5
This is a 60mm turbo on a 2.5 stroker with a set of 60lb injectors.
|
|
|
Post by wesk on Oct 8, 2023 14:57:08 GMT -5
Those VE #'s are the same as what's been in there since the chassis dyno tuning a couple of years ago. Again, impossibly high values, and indicative of being out of fuel system then. Marginal then and now something has mechanically changed.
|
|
|
Post by wickettoby1 on Oct 8, 2023 15:02:24 GMT -5
Just fyi.....It's got stock lines and a 255L intank pump.
|
|
|
Post by wickettoby1 on Oct 8, 2023 15:03:43 GMT -5
It made 335hp and 350ft/lbs on 20lbs of boost when on the chassis dyno.
|
|
|
Post by wesk on Oct 8, 2023 15:47:39 GMT -5
Just fyi.....It's got stock lines and a 255L intank pump. You need to measure fuel pressure while driving and under boost.
|
|
|
Post by wickettoby1 on Oct 8, 2023 16:05:41 GMT -5
So here's a new development, the fuel gauge only showed a 1/4 tank so I went and put another 7 gallons of fuel in it thinking that its possible that there may be something wrong with the fuel pickup. Well on a 3rd gear pull it definitely didn't go lean but I'm still seeing that the duty cycle is way up there at 140% which still isn't good. Is it possible that the enrichment isn't aggressive enough? Ultimately I know i have a little safety margin built into the VE table (commanding mid 11's afr when I could be at 12:1 and still be safe) but I'd rather not lean out the fuel table until I know all of the other issues have been sorted out. I also need to invent a way to monitor fuel pressure while driving. I know the tank is still going to have to be removed and the pickup/pump investigated but here in Michigan were getting to the end of the "fun car" season so that may wait till winter. Thanks for your help.
|
|
|
Post by Stinger on Oct 8, 2023 23:57:52 GMT -5
I don't think you're getting it. This IS NOT a tuning issue. This is a mechanical issue, period. The issue existed whenever that VE table was created. You can't fix "out of fuel" with tune changes when your injectors are already at 100% DC (or 140%). You can datalog and theorize and such but it's all a waste of time until you are able to monitor fuel pressure under load, and fix the fuel supply issue.
Stock lines, 255 pump, etc. can all support way more than 335hp so assuming the lines aren't kinked/dented somewhere and the pump is working as it should, those items are fine. The 60lb injectors are likely near the limit regardless (we rate them for about 350hp) but regardless, you can monitor fuel pressure under load with a $40 fuel pressure testing kit (connect kit to Schrader valve, hose runs through gap at the rear of the hood, tape gauge to windshield or zip tie it to the wiper arm. Obviously a temporary solution but it's a very common method.
|
|
|
Post by wesk on Oct 9, 2023 5:56:07 GMT -5
If you look in the last log you posted, fuel is on target/rich of target at peak boost onset, and 3700 rpm with a VE value of (136 the high side of reasonable if the tune is set to "not incorporate AFR target). As rpm climbs it continues to get rich relative to target, but for some reason whoever tuned kept ramping fuel/VE in it. At 4000 rpm it is at 100% duty cycle (as they have put 20% more fuel in it relative to thigh side of reasonable) and it begins to lean out with rpm. In that log, above 4000 rpm it continues to lean out linearly with rpm to 11.9@ 5300 rpm. At 5300 rpm the VE in the able is 166. Whenever the car was tuned some one put 30% more VE in the table after it was out of injector, and just left it there even though it didn't/couldn't do anything. I would guess making that last entry 140 and just interpolating between the 136 value and that would run exactly the same as it does now.
The previous logs you posted looked like fuel pump, or "out of gas" as you found.
If you find with testing your fuel pressure is holding in there, you can bump fuel pressure up a little and just decrease required fuel by whatever amount your change calculates out to to get a little more head room.
|
|
|
Post by wickettoby1 on Oct 15, 2023 12:51:35 GMT -5
Wes, thank you for the advice on the VE table. I reduced the high rpm/high load VE numbers and the duty cycle dropped with no negative effects on the AFR. The duty cycle is still up in the high 120's as far as percentage goes so a more in depth investigation of the fuel delivery and injectors will happen over the winter. My current question is going back to the strange idle issues. I thought I had everything figured out (good starting, predictable warmup, steady idle, no surging, minimal idle change when load is added) then all of a sudden this idle surge shows up out of no where. The surge will happen during warmup like in the log attached but it will also happen when the engine is up to operating temp and after 10 or 15 minutes of driving. I've seen quite a few forum posts that talk about shielding of the TPS wiring is crucial for an accurate TPS signal, is the same shielding crucial for a quality IAC signal? The idle PWM seems to be steady and the curb idle is set to 950 with the engine at operating temperature and the IAC unplugged. I will take another log with the idle functioning correctly later today and add it to the post. Do you see anything in my idle control settings that would explain this phenomenon? Like always thank for your help and thoughts. Attachments:CurrentTune.msq (120.61 KB)
Startup Idle.mlg (411.2 KB)
|
|
|
Post by wesk on Oct 16, 2023 5:17:05 GMT -5
You have closed loop idle set to "use last value" (no idea why, "use initial values table" is only thing we ever recommend) and your activation settings are such it is in a place it can not activate. Try the attached file. Do a "compare tune" to see what was changed. Attachments:2023-10-16_test.msq (120.57 KB)
|
|
|
Post by wickettoby1 on Oct 25, 2023 1:18:05 GMT -5
Wes So I did a compare from the tune I sent to the tune that you sent back, I saw a few major changes and a few minor ones. Unfortunately the suggested changes made the engine not run unless the throttle was held open. The engine would start but immediately the idle would drop and the car would stall. I was confident that I accurately made all of the suggested changes but just to confirm I loaded the complete tune that you sent, same result. The engine will not stay running unless the throttle is held open and this was on a cold (50's F) vehicle. When I set the curb idle I did so with a warm engine, the IAC unplugged and set the RPM to 950. Looking at the tune you sent I narrowed it down to the differences in the closed loop initial value table that's causing the not staying running and stalling condition. Can you please explain why the PWM is so low in the lower RPM range? Is the closed loop idle initial value table that you configured one that is typical and has been the norm in the past? I did lower the idle valve closed duty % to the 14.9 like you suggested but the engine didn't seem to like it. I implemented most of the other changes that you suggested but put the closed loop idle initial value table back to like it was. At this point I still have a cold (50's F) surge on startup that I'm hoping to alleviate. Please take a look at the attached log and tune, hopefully you see something that I've missed. Thanks Justin CurrentTune.msq (120.64 KB) Startup and Idle 10-24-23.mlg (251.31 KB)
|
|