Surging IDLE bad when cold and when coming to a stop + TUNE

I was having an issues with my car dying when I came to a stop because of the VSS. I recently got my VSS hooked up (but reading high) and now it want's to surge when cold starting and when coming to a stop. I tried using some Russ K Base Idle Airflow .cfg but it didn't seem to work for me. I was reading it could possibly need adjustments in the throttle cracker/follower but since they are based off the RAF I shouldn't touch them until I assure that they are correct. This motor is a complete stock GEN III 5.3 with 80lbs injectors. The cold start is not included in this log as I tried the Russ K .cfg and never safed it.

The other issue I am having is that the car keeps wanting me to subtract around 20%-25% fuel at idle. When I do this and reload the tune it again will settle and want to subtract another 20%-25% of fuel at idle. It is just that my injectors are already running at the minimum pulse width at this time or should I keep taking away fuel and see what happens? They are fairly large injectors for my application.

Please take a look at my tune and let me know if you see anything odd. I am still trying to get everything dialed in as I learn but also stay on the safe side to not cause problems. I've done a few minor WOT pulls and it seems I need to start taking some fuel away to hit my correct AFR.

In Fuel>Tansient Fuel Qualifications, set Min Fuel Milligrams to .015 to lower the min inj PW. The 80's flow too high for the stock settings. Log IPW before and after.

WOT fueling is not to bad...maybe -3 to -5% rich. Rich is better than lean :-)

Ed M

Thanks! I changed that. I will load it up tomorrow and see what happens. Could this be the issue of my surging idle and it wanting to die when I come to a stop?

Also I added IPW Bank 1 & IPW Bank 2 to be logged removing barometric and control module voltage.

And yes my EXACT thoughts. I figured I would rather be rich learning to tune than lean. I can always slowly take fuel away!

Also I enable rolling idle RPM but I imagine it will not work as my car isn't sending a signal to the ECU to let it know when in neutral nor when the clutch is pressed in.

I put in 0.015 for that value and I could not get it to run at all after that. What else should be changed along with it? Should I raise the VE table back up since I've probabaly taken away so much fuel?

I got the fuel min miligrams lowered to 0.015, raised the VE table back to where my stock tune was and started from there. Runs WAY better now and the surging is 95% gone. It stills does it a little when I let off the clutch while driving. Drops to around 400 or so then raises back up to 750 and sits.

I am having this issues like I am hitting some kind of limiter and it's cutting fuel (which is bad!). I think it's the speed limiter but I can't seem to bring my VSS speed down. The car is using a 1990 300zx trans and I'm not sure what info to put in. I found a site that said 17 for trans/rev but that didn't seem to lower it. I've also tried raising it higher. @ 11:21:24.650 my AFR goes full lean and the car basically cuts off for a second. I think this is a speed limiter because it will do it just cruising down the highway out of boost and in boost. It seems to do it around 80mph. Is this what I am hitting?

hi Ed , can you give us an advice on how to get that number for different injector flows ie 42s 60s etc? this change when using another intake like a fast?

i was reading a 5.7ute post that reads

Quote:

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Originally Posted by 5.7ute

It all boils down as to what value your tuning tool applies to the hex value at a certain address. For example, if the hex value at the address for minimum fuel in mg is $0064 (which is 100 in decimal) The tune tool will display the value 0.04883. ( my last post was ass about as HPTuners uses 0.0004883 as the scaler).
The correct value that should be shown is 1.5198 which is the correct scaler for ms. (0.015198)
This puts the tune tool out by a factor of 31.124308.
So as a work around, divide your injectors minimum pw by 31.124308 & place this value in the minimum fuel in mg & this will prevent the pw floor from being hit with large injectors.
One thing to remember though is if this low pw value is hit it will not use the default minimum pw value. If you want it to switch to the default min pw you need to set this value lower than your min pw table.

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is this a good practice?
98 f body tunes are zeroed at this value
thanks