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Thread: Help with overfueling issues!

  1. #1

    Default Help with overfueling issues!

    Hello all, I am having a frustrating issue with my Sniper setup. On a cold start, the car will act like it is super rich. It will crank for 5 seconds or so, and I need to rev it myself, or it will surge up and down, and usually die out a few times, requiring restart. Looking at the handheld, it looks like the engine is swinging super rich (9.6 AFR), and the Sniper is trying to compensate. During this, the IAC is also very high, usually at or around 100%. Once it reaches operating temperature, it seems to run well, but the IAC is still high (90-95%), and the RPM are lower than they should be (550 RPM vs 850 set RPM). Once the car gets good and hot after driving for a bit, the IAC comes down to where it belongs,a round 5-6% and seems to restart well. When driving while hot however, even when running "well" it still seems like it wants to go down to 9.6 AFR, then it will try to compensate. It never seems to settle around the Target AFR, it always seems to be on the rich side. This tells me it is a tuning issue, but for the life of me I cannot find out how to tune for this. Based upon some advice from someone else who has a Sniper, I adjusted the A/F Ratio Offset to a much leaner setting. It did not seem to make a difference. I realize it may be a WBO2 issue as well, or an injector issue. Can you all point me in the right direction on how to start figuring this out? I have tried to attach what I believe is my Global Config File, but the forum says it is an invalid file type (it is a .sniper file, not sure if that's correct.) I can also post datalogs if needed. Thank you so much in advance!

    Engine details:
    462 Pontiac
    Kauffman Heads
    10.9:1 Compression
    230°/242° Roller Cam, .605" total lift
    Holley Street Dominator Single-Plane Intake
    Full length long tube headers
    WBO2 is 12" after pass side collector.

    Fuel setup is as follows:
    Tanks Inc tank and pump. Pressure line feeds into a Holley filter/regulator, mounted above the differential. The return line feeds right back to the tank. This setup is VERY loud, and when priming, it sounds like a creaky hinge. I wonder if this is part of my problem. I plan this winter on ditching this setup, and running a traditional return line that I will run front to back, since I have heard this "dual regulator" setup is noisy, as I'm realizing. Thank you!

  2. #2
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    Default

    Zip the files and post them.

  3. #3
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
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    Originally Posted by Danny Cabral
    For further assistance, post your Config File and a short datalog of this occurrence for us to analyze.
    Also, review the datalog and inform us of exactly where in the datalog (time/seconds) the problem occurs.
    Datalog & Global Files can be linked to a document hosting website. I use Dropbox.com.
    Files can also be "zipped" (compressed zipped folder) & attached directly to a forum post ("Go Advanced" & "Attachments").
    Your Config File is in the "Documents", "Holley" folder, "Sniper" folder, "Config Files" folder (.hefi file).
    Your Datalogs are in the "Documents", "Holley" folder, "Sniper" folder, "Data Log" folder (.dl file).
    Someone will analyze/troubleshoot the problem & offer advice.
    https://www.youtube.com/watch?v=iqHOtDNiTNA (How To Record & Email A Datalog)
    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.

  4. #4

    Default

    OK, here's the Config File and the Datalogs I took.
    "Cold Start #1" is a cold start. As you can see, the car starts, then stumbles and dies.

    "Cold Start #2" is restarting the car immediately after the stall in "Cold Start #1". You can see the AFR bouncing between 9.6 to the 30s. The end of this datalog is when I give the car throttle, it stumbles and dies out.

    "Hot Idle" is after the car has been nursed to operating temperature. As you can see, it is much more stable as far as running on its own without the need to two-foot it. However, please look at the AFR, which is still all over the place.

    Some of my settings (such as Coolant Enrichment and A/F Ratio Offset) may look odd, as I have adjusted them trying to correct this issue, but I have obviously not been successful. Any assistance you can offer would be greatly appreciated!
    https://www.dropbox.com/sh/6pz42lw68...jxW827pia?dl=0

  5. #5

    Default

    HI Bandit. So far I've only looked at the Config File and the cold start datalog, but I have some feedback. First, you need to make major changes to the A/F Ratio Offset table in the Startup Enrichment section. I know you adjusted it like that in hopes of getting rid of the super rich (9.6 AFR) section, but you need to understand what modifiers are at work in that section. In the area where it's super rich the system is in Open Loop. Therefore the ECU will NOT be trying to make adjustments based on the actual AFR nor try to move it towards the target (which includes the offset). Based on your A/F Ratio Offset table you have a target AFR of over 15, which is probably not going to work well for a cold engine. Danny will post his link to startup tuning. Read it closely and do what he did. The A/F Ratio offset should be always negative (yours is positive) and never greater than about 0.6. Tuning Coolant Temp Enrichment is more important than A/F Ratio Offset, although they do work together.

    So you are probably wondering why the AFR gets so rich after start and is killing the engine? It is the "After Start Enrichment" table that's at work here. If you know how to add & remove fields from the datalog, be sure to add "Fuel Flow" and graph it. You'll see very clearly that once the engine starts the fuel rises a huge amount then has a slow gradual decline. It's in this area it runs super rich and often dies. The length of the decline is based on the "after start decay rate" table. The length of the decay is not too much of a problem typically but the baseline Wizard Config Files are overly rich on the "After Start Enrichment" table. My advice for starters is to just lower the entire "After Start Enrichment" table by about 10% and try it. You'll most likely want to lower the cells even more than that in the 60-80°F area.

    I'd also raise the Target Idle Speed in the areas cooler than 80°F. Maybe add a couple hundred to each.

    I also notice that above 200°F you have zero Cranking Fuel. Is that because when the engine gets that hot you do not want it to start? I guess the prime shot may be enough to get it running, but you may want to at least add a little fuel here. Maybe 7 lbs? Try out those changes and grab another datalog and post it.
    69 Camaro
    400 SBC, ProCharger D1SC

  6. #6
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    23,085

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    Quote Originally Posted by gregs69rs View Post
    Danny will post his link to startup tuning. Read it closely and do what he did. The A/F Ratio offset should be always negative (yours is positive) and never greater than about 0.6. Tuning Coolant Temp Enrichment is more important than A/F Ratio Offset, although they do work together.
    If you take the time to study this, you'll be a startup tuning expert, and read the "TIP" in post #6:
    http://forums.holley.com/showthread....6254#post36254 (Good Starting Advice Thread - Especially posts #2, #4 & #6.)
    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.

  7. #7

    Default

    If your tune is way off then just build another one using the Wizard and start over. Pick street cam this time and give it plenty of timing at idle, if you're controlling timing. If you aren't controlling timing, you should. Controlling timing with the Sniper is almost mandatory when running a performance cam. I don't understand your fuel system, but I doubt that's your issue. Sounds like you have a regulator feeding a regulator? Not sure why you would want to do that.

  8. #8

    Default

    Quote Originally Posted by gregs69rs View Post
    HI Bandit. So far I've only looked at the Config File and the cold start datalog, but I have some feedback. First, you need to make major changes to the A/F Ratio Offset table in the Startup Enrichment section. I know you adjusted it like that in hopes of getting rid of the super rich (9.6 AFR) section, but you need to understand what modifiers are at work in that section. In the area where it's super rich the system is in Open Loop. Therefore the ECU will NOT be trying to make adjustments based on the actual AFR nor try to move it towards the target (which includes the offset). Based on your A/F Ratio Offset table you have a target AFR of over 15, which is probably not going to work well for a cold engine. Danny will post his link to startup tuning. Read it closely and do what he did. The A/F Ratio offset should be always negative (yours is positive) and never greater than about 0.6. Tuning Coolant Temp Enrichment is more important than A/F Ratio Offset, although they do work together.

    So you are probably wondering why the AFR gets so rich after start and is killing the engine? It is the "After Start Enrichment" table that's at work here. If you know how to add & remove fields from the datalog, be sure to add "Fuel Flow" and graph it. You'll see very clearly that once the engine starts the fuel rises a huge amount then has a slow gradual decline. It's in this area it runs super rich and often dies. The length of the decline is based on the "after start decay rate" table. The length of the decay is not too much of a problem typically but the baseline Wizard Config Files are overly rich on the "After Start Enrichment" table. My advice for starters is to just lower the entire "After Start Enrichment" table by about 10% and try it. You'll most likely want to lower the cells even more than that in the 60-80°F area.
    I'd also raise the Target Idle Speed in the areas cooler than 80°F. Maybe add a couple hundred to each.
    I also notice that above 200°F you have zero Cranking Fuel. Is that because when the engine gets that hot you do not want it to start? I guess the prime shot may be enough to get it running, but you may want to at least add a little fuel here. Maybe 7 lbs? Try out those changes and grab another datalog and post it.
    Thanks for the feedback! I spent some time making the recommended changes in your response, and in the thread you linked. While it does seem better, I'm still experiencing a surging idle, where the engine will die out, requiring restart to nurse it to operating temperature. I'm wondering if it seems better since the ambient temp is colder than last time (60°s vs 80°s), and the engine tolerates a rich mixture better. Overall it seems like the Sniper is very confused in regards to fueling this engine. I have posted two more datalogs, linked below. "9-27 Revisions" is the new config file, with the changes we discussed. "9-27 Cold Start" is the cold start, and ends with the engine stalling out. "9-27 Warm" is warm (not hot) idle. One thing to note with all of the datalogs (previous ones and these ones) is that the IAC is almost always pegged at 100%. I added the RPM to the areas you specified, but the engine cannot reach them, since the IAC is maxed out most of the time. I intend to do another cold start this evening, while watching the timing at idle. I'm wondering if my vacuum advance may be coming into play, skewing the idle stability.

    Quote Originally Posted by andyf View Post
    If your tune is way off then just build another one using the Wizard and start over. Pick street cam this time and give it plenty of timing at idle, if you're controlling timing. If you aren't controlling timing, you should. Controlling timing with the Sniper is almost mandatory when running a performance cam. I don't understand your fuel system, but I doubt that's your issue. Sounds like you have a regulator feeding a regulator? Not sure why you would want to do that.
    I intend to purchase the HyperSpark very soon, but it's sold out for the next month or so. In regards to the fuel system, it was done this way because my car ('70 Firebird) does not have a return line of adequate size. So I mounted the regulator in back, and has its "return" line go right back into the tank, making the return line only a couple of feet long. The regulator output then feeds the Sniper. The Sniper return is plugged, so its regulator does not come into play pressure-wise. I intend to ditch this setup for a traditional return line, as the Holley filter/regulator is LOUD!!! https://www.dropbox.com/sh/6pz42lw68...jxW827pia?dl=0

  9. #9

    Default

    Bandit, I think you have something really wrong either mechanically or with your Sniper. A maxed IAC for the entire datalog seems odd. Even more odd is your AFR will be 9.8 which is super rich and the Closed Loop Compensation is still dumping in 30%+ fuel? That makes no sense. Better give Holley tech a call and send them your datalogs.
    69 Camaro
    400 SBC, ProCharger D1SC

  10. #10

    Default

    Greg, thanks. I tend to agree with your assessment. Unfortunately, that's what I was afraid of. I'll call Holley tomorrow. Mechanically, I believe the engine is fine, as it runs great when warm (except for favoring the rich side of AFR). This seems to me to be a Sniper issue (but I may be wrong). Thanks for the advice, I'll post here with a fix if/when I figure it out.

    UPDATE: Hey all. I just wanted to stop by to give a quick update on this issue. I spoke to Holley Tech, and after a few basic checks, they had me replace the WBO2 sensor. I did so and now the car runs great. All issues are taken care of. I hope this helps somebody who may be experiencing something similar!

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