On the hot start issue, if you turn the key on and off to prime it a few times before starting, does it help the issue? Wonder if the lines are losing their prime, could verify with a fuel pressure gauge, to make sure the pressure doesn't drop when vehicle is off. I would also check to make sure the fuel lines aren't touching/near anything hot.
i thought the same exact thing...ive tried to on/off a few times to ensure prime (first thing i thought too) and it doesnt help. if i blip the throttle during hot, it will hold where i put it but as soon as i let off, it falls to under 450 and then recovers, but bouncing until it comes to. i added 8% to the Initial Adder vs. ECT and it didnt seem to change.Originally Posted by twenglish1
im comparing a stock file and my current and in the Park/Drive Enrichment Initial Adder vs ECT on the stock file, it has values accross the chart but mine is 0'ed out at 111-241. i couldnt screenshot the tables but the top is stock and the bottom is my file
0.650390625 0.650390625 0.650390625 0.599609375 0.349609375 0.1201171875 0.0595703125 0.0595703125 0.0595703125 0.0595703125 0.0595703125 0.0595703125 0.0595703125 0.0595703125 0.0595703125 0.0595703125
0.2001953125 0.150390625 0.099609375 0.080078125 0.0751953125 0.0703125 0.0654296875 0 0 0 0 0 0 0 0.099609375 0.099609375
That may be an artifact of your original "tune" that has not been fixed yet. Probably can't hurt to try stock settings on that and see what happens. You can always change it back if needed.
Ya that’s kinda what I was thinking. But was unsure. Figured I’d ask someone who knows more than I do. Working on getting the wideband installed. Acquired some pins from the dealer yesterday. Thinking of swapping my plugs out for a new set for giggles and regap to .060. Running delco coppers.
I know it’s been a little bit since I’ve been on. I’ve been slowly getting things done at the house with the chickens and ducks along with getting some stuff done on the truck that HAD to be done. She now has new shoes, new socks, and might as well say new feet too. lol.
Dropped a trutrac unit in with the 4.10 gears, new moser axles, diff completely rebuilt., new tires, new brakes, and a east coast drive line 86-1/2” 5” aluminum driveshaft. Working on getting the aft pinned in the ecm along with the 2nd stage high speed fan wire afr gauge is just gonna sit on the dash for now.
Make sure you use the gear/tire wizard to update the speedometer calibration, it will also scale your transmission parameters so it shifts correctly. Its under the "Edit" menu at the top, enter new tire size if they are different(height in inches) and the new gear ratio
Ya I did. Question… just finished getting the gauge wiring done and when I fired it up with the gauge installed, it idles weird and it’s showing hella lean. Do I need to change something in the tune?
At least I thought I did. Took it for a spin and I either didn’t save the file or just uploaded the same one. Lol
Here's the log and the current tune with the Wideband logging thru the EGR. The log is sitting in park and to operating temp. No drive was done.
Was actually pretty easy to set up, once you know how to set the math up. (brushing shoulder off)its really lean. No idea what im doing after this as far as making changes.
I got a weird vibration somewhere. im hoping its something stupid....feels like its in the front but the only thing i did in the front was get the header off the frame (pass side), new brakes on the front.
Rear got everything. Including a new driveshaft. Whole rear diff is new. Bearings, seals, carrier, gears, and brakes. i had a busy weekend. truck was on the lift for over week waiting on parts to come in.
Last edited by Chris miller; 02-09-2025 at 10:16 PM.
There is alot of mixed opinion on it, but alot of people agree that the WBO2 should be ignored at idle/part throttle, it will be a good reference at part throttle as a sanity check, should read whatever EQ is being commanded by PCM in closed loop fueling, but don't use for tuning and just let the fuel trims handle it, PCM will constantly slightly over/undershoot 1 lambda or whatever the commanded EQ table says, if the trims are within +/- few percent of 0 then don't worry about what the wideband reads, however wideband is critical to reference during power enrich conditions because they PCM switches to open loop fueling and relies strictly on the VE table with no active NBO2 feedback(fuel trims).
Last edited by twenglish1; 02-10-2025 at 07:24 PM.
ive been playing with histograms and charts. i now have the AFR error and WBo2 recording and im making changes ever so slightly. looks like im getting the afr where it needs to be. hopefully itll be in the next 2-3 drives before i start doing MAF tuning
Just make sure you are applying the data correctly or you will be running in circles, AFR error chart can only be applied to VE when it was logged in open loop/power enrich, since you are using the fuel trims for part throttle fueling, you can filter the data that gets logged to this chart to only record data when commanded lambda is less than 1, and engine coolant temp is above 140 or so, this will ensure afr is only logged during power enrich, i think it was mentioned before, but always remember to merge the primary VE with the secondary VE
I’m running ve only. Everything is off. I think I’ve watched over 4 hours of hp tuners training vids and others. It’s getting better and better as I go. Trial and error. I’m on log and change # 12 and I’m within 4%
i have been going at this and maybe im getting somewhere..... i think im lacking spark advance timing etc. here is the log and the tune file. i finally got the stock file from him, at least i believe it is and did VE the best I could and did MAF the best i could and blended the 2 onto the stock file with all of the DIAG etc taken care of.
Can someone chime in? i kinda did a WOT to verify it was going int PE and it is, but i did it from a dead stop and it lit the tires up, pegged the limiter and after it shifted it fell on its face....recovered and went back to normal.
Vibration ended up being the driveshaft. When we measured, we didn’t account for the stub shaft being 1/2 longer.
Always shoot for slightly negative trims overall, otherwise the PCM will dump additional fuel in at WOT by whatever the positive trim is.
I had a discrepency between my wideband and narrowband for a while that recently started becoming more and more noticeable.. Started by replacing the Wideband 02 sensor since it is a 12-13 year old AEM kit on mine. Same reading. They replqced the Narrowband 02s since they were also about the same age. One of the narrowbands had a broken wire for the heater circut where the wires enter the sensor. Been about 3 weeks now and my fuel mileage around town is up about 2 mpg. Does not seem like much but I was getting about 13 to start and now I am getting 15 mpg around town. Highway mileage was unchanged because of reasons that give me better mileage when I am at a steady speed over ~55 mph. Resolving a 10% discrepency between Narrowband and Wideband fueling was worth 2 mpg in my case and it runs both smoother and with more part-throttle response and power.
Last edited by Fast4.7; 3 Weeks Ago at 02:38 AM.
Very interesting, i don't think i knew about trims being added to the PE fueling, what determines which trim value is used, the last trim before entering PE? Or does it reference the stored LTFT values and apply them to the PE accordingly?
Last known LTFT trim value if it is a positive trim is what is used. If you have lean transient fueling that causes it to lean spike to say +10% LTFT it will add 10% at WOT everywhere. Negative values are ignored and the PCM applies Zero correction to the base fueling. GM has been like this since the TBI era. This is why it is important to have good fuel trims, the VE and MAF and transients dialed in before you touch WOT. I have seen LS1 F-cars with only a SLP lid that were running +20% or more LTFTs and had been tuned via PE table to 13:1 commanded and 30* of timing. Some real tuning made them run so much better.
Last edited by Fast4.7; 3 Weeks Ago at 01:11 AM.
everytime i tried to log maf err, i would request closed loop off and it wouldnt. looks like ive been chasing my tail with ltft and stft. ltft were off but it seems like stft i overlooked. correct me if im wrong but maf tuning with the wideband, everything is off and in open loop, same with ve when dialing it in?
ive turned stft and ltft off and ive gotten 100x closer to 14.12 as commanded without going into PE. slow steady throttle all the way up and backing off when it goes a little lean, do the multiply % - half and adjust the graph up and relog. im on log 6 and across the histogram it looks really good, or at least i think it does. im up to 8500hz...how far do i need to go?
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