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Thread: Coolant Temp Enrichment vs A/F Ratio Offset

  1. #21

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    81TransAm - I've made a few datalogs this way. I did a cold & hot datalog today to look over.

    Danny- I'll look at them this evening. It seems like it needs more air, but I'm not ready to say that's it yet. I'm going to turn the Injector End Angle table off and kind of reset everything and verify idle timing, fuel, etc., in the morning. I have such little TB opening for a DBW setup. I may have to go in and do custom on the IAC setting.

  2. #22
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    IEA can cause some issues as well. I started this thread detailing my experience with IEA: https://forums.holley.com/showthread...4470#post94470

  3. #23

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    OK, here's what I've done. I went back and turned the IEA table off to eliminate that is an issue. I put my original columns back in my Fuel & Timing table and corrected the tables to match. Basically everything is back where I started a month or two ago. I put CL & Learn back to 100% again and went for a long 60+ mile drive to get a descent amount of correction in the idle/part throttle areas. I also stopped for gas, so I got a hot start but it was only a short cut off time. The car started fine here.

    Next I let the car sit for about 45 minutes or so. I turned CL off and I added fuel to the AFR Offset to see if that would correct it. It did not surge which is good, but it was very lean. With the adder I was requesting 13.4 AFR and the mixture started at 15.4 and slowly came down to 14.4 over a period of 90 seconds. No adders other than the Offset are active, so that means the Base Fuel Table is lean, correct? However, if you're out driving idle AFR is sitting at the Target of 14.1 with minimal correction. I'm not sure which way I need to go on this yet. Cold crank is on a different area of the map.

    OK, I updated my Base Fuel Table with the corrections from earlier to help center the fueling for my idle area. I took another 30 mile trip and then brought the car home still running. At this point, I let it idle in gear as it was for about a minute. Once correction was zero I did the same out of gear. There was only 3% difference at best, so I closed Learn to 2% in that area. That's the correct fueling per the wideband feedback. CL correction is still high, so it should be able to correct for any temp variances. I'll do a cold start in the morning and see what happens.

  4. #24
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    The AFR Offset does not add fuel, it only modifies your Target AFR based on engine temp. The CL & Learn modifies your Base Fuel Table. I would never turn CL off. With the CL off, the ECU has no way to modify your Base Fuel Table, so it can't reach your target AFR.
    I have my idle limits at 5% so it has a little room to move around. Turning the IEA table off, does not eliminate it as a cause. If this is a sequential MPFI system, your IEA has to be somewhere. Datalog your cold start and post it and your Global File. You can zip the file and post them here. Datalog it all the way to fully warm.

  5. #25

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    Yep you're right. I forgot when I turned CL off, the AFR Offset basically did nothing but change the target. The ECU wasn't going to try & correct to reach it. CL was turned off to see exactly what the AFR would be reading directly off the Base Fuel Table. It should've been 14.1. Hopefully the work I did today will pay off.

    Well that didn't do it. I also stopped it after it finally stabilized on it's on. The cell(s) the engine is idling in are different from hot idle as it's cold. The two idle cells in my Base Fuel Table are 800/35 for out of gear, and 800/40 in gear when fully warm. Those values are correct unless the WBO2s are junk, which would be very odd. I've attached the datalog & Global File hopefully.

    I've smoothed my fuel table manually, but I haven't touched it in VE. I just looked and it doesn't look right. Maybe this is the area of concern. Also this was not an issue when I first got the car running.
    Last edited by JST4FN; 09-17-2017 at 01:36 PM.

  6. #26
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    You're not giving the engine what it wants as it warms up. You have your Target AFR at 14.1 when it's cold. It obviously doesn't like this. You have your CL limit at 100% at idle, this is part of the problem as well. The engine starts to run lean so the CL adds a bunch of fuel and overshoots your target, then it goes rich and the CL pulls a bunch of fuel and it goes lean. This happens over & over.
    Do you have your knock sensors setup properly? They are not picking anything up.
    I made a bunch of changes to this file. Load it in and datalog a start. Don't give it any throttle when it is cranking. Your TPS was at 6% when you were cranking. Let it warm all the way up, so the Learn turns on. Then wait a day and do another cold start with the same file, and datalog it as well. Then post the results.

  7. #27

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    Don't forget I moved CL back to 100% it was at 8%. Also it did the same thing with CL off (cold start). That was my original guess. I did do a hot start with CL off and it did not surge. It idled from 15.4 down to 14.4 in 90 seconds.
    I don't touch the accelerator pedal while it's cranking. If it's at 6% that's because it's asked for that position. It starts every time on its own. I never touched the pedal the entire datalog. No, I have not set the knock sensors up yet.
    I can't remember for sure when it started to happen. I remember my base tune fuel table was very lean, so I tried to make it closer to reality by using a N/A dyno. I can see by looking at the VE Table I didn't do this correctly.
    Last edited by JST4FN; 09-18-2017 at 07:29 AM.

  8. #28

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    To update, the changes made to my file were way too rich (9.3 AFR), but I pulled fuel manually to what it was commanding as it warmed up. It didn't surge while doing this, so it does need added fuel to warm up. I'm slowly lowering the AFR Offset until it stops completely (small surge right now), and then I'll correct the Coolant Temp Enrichment table. I'm not sure why this didn't show up in the beginning. The only thing I can think of is, as the Base Fuel Table became closer to correct and I narrowed the correction it became a problem. I'm not sure, but I believe I'm going in the right direction now.

  9. #29
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    Quote Originally Posted by JST4FN View Post
    The only thing I can think of is, as the Base Fuel Table became closer to correct and I narrowed the correction it became a problem.
    In post #2, I stated, "The Base Fuel Table must first be well tuned, before any modifier tables."
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  10. #30
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    I find it easier the tune from a rich condition and lean it until it starts acting up, then go back a little.

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