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Thread: Need help getting car to idle when cold

  1. #1
    Fuel Injected! Dukenukemx's Avatar
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    Need help getting car to idle when cold

    Since I put a cam in my 02 Vette I can't get it to idle unless I let the car warm up. It'll idle just fine when I crank the engine, but it's when I shift into gear it just stalls. Once I warm it up this isn't a problem, but it takes a while to warm up like at least 5-10 minutes. I've increased the airflow and the idle but doesn't seem to matter since putting it into drive or reverse will just stall it out. What other values can I change in TunerPro to correct this? The OS is 12221588.
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    Fuel Injected! ralmo94's Avatar
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    Did you ever get a wideband o2? If you did, you could tune the warm up enrichment
    If not, what are your O2 readings before it goes cl, pegged, or almost 0?
    Is it cl when it does this? Maybe keeping ol longer, or going cl sooner would help?
    No need to re-invent the wheel. But we can make it better

  3. #3
    Fuel Injected! Dukenukemx's Avatar
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    Quote Originally Posted by ralmo94 View Post
    Did you ever get a wideband o2? If you did, you could tune the warm up enrichment
    If not, what are your O2 readings before it goes cl, pegged, or almost 0?
    Is it cl when it does this? Maybe keeping ol longer, or going cl sooner would help?
    No wideband yet. I figure that's for next year when it isn't so cold. I do have the trans cooler but not installed for the same reason. I don't have a garage to park my car in. I never looked to see what the O2's are reading. I'll give it a try tomorrow and see what they say.

  4. #4
    Fuel Injected! Dukenukemx's Avatar
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    I did a quick startup at idle and logged it but it didn't report short term or long term trims until it warmed up a bit which took a few minutes. I then saw it report -22% and then slowly climbed up to around 0%, which I then put the car into drive and reverse and it didn't stall. So I guess that means I'm running too lean? Is this something I adjust in the VE table or there's another set of variables that control startup idle? I would have guessed it ran too rich just from the smell of the exhaust.
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  5. #5
    Fuel Injected! ralmo94's Avatar
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    Quote Originally Posted by Dukenukemx View Post
    it report -22% and then slowly climbed up to around 0%,
    So I guess that means I'm running too lean?
    I would have guessed it ran too rich just from the smell of the exhaust.
    -22, means it is taking 22 percent out, that is rich.

    Quote Originally Posted by Dukenukemx View Post
    Is this something I adjust in the VE table or there's another set of variables that control startup idle?
    There should be a table of commanded ratio per engine temp, and possibly a warm up multiplier?
    You don't want to change VE, you already tuned it.
    No need to re-invent the wheel. But we can make it better

  6. #6
    Fuel Injected! ralmo94's Avatar
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    I found a Stock file on HPT Respository
    Here is the table and HP description

    [ECM] 12430 - Open Loop F/A vs. Coolant Temp vs. MAP: This table is used to determine the commanded AFR when in open loop mode. It divides the Stoich AFR value. AFR is determined by 14.7/table value. Example: 14.7/1.30 = 11.3 AFR
    Open Loop FA.jpg
    I don't know how it is labled in UP
    No need to re-invent the wheel. But we can make it better

  7. #7
    Fuel Injected! Dukenukemx's Avatar
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    Quote Originally Posted by ralmo94 View Post
    I found a Stock file on HPT Respository
    Here is the table and HP description

    [ECM] 12430 - Open Loop F/A vs. Coolant Temp vs. MAP: This table is used to determine the commanded AFR when in open loop mode. It divides the Stoich AFR value. AFR is determined by 14.7/table value. Example: 14.7/1.30 = 11.3 AFR
    Open Loop FA.jpg
    I don't know how it is labled in UP
    I think I found it. I think it's called B3605 Open Loop Commanded Fuel. Should I just decrease everything by 20%? I have an original bin I found to compare and it does seem like the values were increased, but slightly. On average it's a good 0.20 higher than the factory settings.
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  8. #8
    Fuel Injected! ralmo94's Avatar
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    I would just set it to the stock values, and adjust from there, IF NEEDED.
    No need to re-invent the wheel. But we can make it better

  9. #9
    Fuel Injected! Dukenukemx's Avatar
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    Quote Originally Posted by ralmo94 View Post
    I would just set it to the stock values, and adjust from there, IF NEEDED.
    I set it to stock then lowered everything by 20% and the car wouldn't run in park. Went back to stock and increased it by 15% which made it idle so much better. Still stalls if I put the car in drive or reverse unless I give it a good 2-3 minutes. But yea it idles far better now, so I lowered the idle and park RPM as well as idle air flow. Maybe I could increase it another 5% to see if that corrects it or maybe it needs an idle relearn? Maybe I should lower the temp needed for closed loop? Also I noticed that B4206 STFT Open Loop Enable is enabled while the original setting was off. Not sure what that does?
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    Hey Duke,did you ever determine what B4206 does I'm curious also. What became of your idle issue, fixed?

  11. #11
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    Quote Originally Posted by Trgrhpy View Post
    Hey Duke,did you ever determine what B4206 does I'm curious also. What became of your idle issue, fixed?
    I haven't done anything to the Vette since as I've also been busy dealing with my other cars which need fixing. I did flash yet another change to the tune as I did increase the open loop table by another 5% and I also smoothed it out. It didn't help so much for the idle but it drives better until closed loop. As it is right now I gotta wait a good 30 seconds before shifting the car when cold. In the summer this isn't an issue. I'll upload what I did last to the tune. As for B4206 I never did turn it on. It allows open loop to use the O2 sensors, but I'm not sure if that's a good idea or not? I doubt it'll solve my cold start idle. More specific it'll idle just fine in park or neutral, just not when I shift into drive or reverse. 30 seconds is an improvement compared to before, especially when compared to Chucks tune. Had to give the car a good 3 minutes or more before shifting it into gear. Still haven't bought a wideband sensor yet, but form the looks of the prices, that might have been a good thing. Prices have come down a lot last I checked. I don't plan to make it a permanent part of the car, mainly because I'd want to use the wideband on my Porsche 928 as well, if I can ever find a way to tune that car. I think I now have a way to tune my uncle's 07 Tahoe as well, and try to use what I've learned here to boost his performance and MPG. Next year.
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    Duke, I loaded your bin in TunerRT, sourced a 12221588 xdf and took the attached screenshot. Doesn't it show that B4206 is enabled? This xdf describes the 4206 very well, the xdf for my car doesn't have a description at all. It seems the xdf can make a huge difference. Some xdf's reference table temperatures in C and some in F, some a mixture of both. Doesn't matter as long as you know that and don't assume all tables are one or the other. I attached this xdf file in case you want it.
    Attachment 18769
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    Last edited by Trgrhpy; 12-23-2022 at 12:52 PM.

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    Hiya,
    Did you ever post your stock file? I can modify your stock file that will probably run better than you can purchase, so can many here and get you a good starting so you can fine tune.

    No offense, but, you are focking around in areas you shouldn't be. Just because you have software and a laptop, doesn't make you a tuner. Again, no offense. It's truly why older facks don't even reply.

    When I get hired to tune, very many times it is because they have paid some other fack to do it...Of course they believe because they don't know anything. It sucks to go into a job and charge twice as much as they have already paid to some fack.
    Last edited by In-Tech; 12-23-2022 at 01:18 PM.
    -Carl

  14. #14
    Fuel Injected! Dukenukemx's Avatar
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    Quote Originally Posted by Trgrhpy View Post
    Duke, I loaded your bin in TunerRT, sourced a 12221588 xdf and took the attached screenshot. Doesn't it show that B4206 is enabled? This xdf describes the 4206 very well, the xdf for my car doesn't have a description at all. It seems the xdf can make a huge difference. Some xdf's reference table temperatures in C and some in F, some a mixture of both. Doesn't matter as long as you know that and don't assume all tables are one or the other. I attached this xdf file in case you want it.
    Attachment 18769
    That's one of the XDF's I've been using. I tend to switch between some, and even use Universal Patcher. I guess I turned on B4206? I don't remember doing that. Looking at previous bin's, it looks like I've had that on for a while. Probably a desperate attempt to get it to idle better.
    Quote Originally Posted by In-Tech View Post
    Hiya,
    Did you ever post your stock file? I can modify your stock file that will probably run better than you can purchase, so can many here and get you a good starting so you can fine tune.
    Don't have a stock file because I trusted a guy named Chuck from Westchester Corvette to do the tune. Then when I actually drove the car for a long distance it burned so much fuel and didn't operate the way I wanted. After a lot of help from the community I then realized that Chucks tune sucks. I honestly think he went onto HPTuners repository and grabbed whatever he could find and made some changes for my car and then charged me $1k.
    No offense, but, you are focking around in areas you shouldn't be. Just because you have software and a laptop, doesn't make you a tuner. Again, no offense. It's truly why older facks don't even reply.
    You have no idea how many times I've heard that phrase, only to end up knowing more than those that do. If you don't fock around, then how do you not find out? I liked it when I did lap the valve's on my Vette's heads and I called it a "Valve Job", machinists would chime in and remind me that a proper valve job is this and that. Ok then I will call it a lap job. I don't care to be called a tuner if my car runs the way I want it.
    When I get hired to tune, very many times it is because they have paid some other fack to do it...Of course they believe because they don't know anything. It sucks to go into a job and charge twice as much as they have already paid to some fack.
    At this point my Vette feels faster and I'm getting so much better MPG. More importantly, it's more drive-able. A remote tune without any data log isn't going to do me much good without me feeding you data constantly. At this point I need a wideband and to log it, and then let Trimalyzer further adjust the VE table. Maybe mess around with Power Enrichment some more.
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  15. #15
    Electronic Ignition!
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    what size cam did you swap in? you may need a stall converter? I'm not sure what trans you're running or if it has some stall built into its converter? the stock 4L60E has 1650 but I'm not sure if that's your setup or not just my 2cents, hope you get it lined out

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