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Thread: Random Huge Lean Problem

  1. #11

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    My fuel pressure is rock steady. Because I'm running a supercharger, I set the fuel pressure at 50 psi. I'm using a Holley 12-846 with a Holley fuel pressure transducer, so I can monitor the fuel pressure at the same time I'm monitoring the A/F Ratio on test runs. I told the computer that the fuel pressure is 50 psi. I've turned the WBO2 off (Open Loop) for a test run, would it still be the WBO2 sensor? The change occurs like hitting a switch. Runs good, hit switch, runs bad, hit switch other way. Instant change from one to the other, which leads me to believe it is electrical in nature. It does the same thing in all parameters. Idle, cruise, and light to medium acceleration. WOT seems to be OK. Although scared to go WOT for any length of time, if goes lean at WOT, not good. New fuel filter installed also. P.S. 50 psi is my max or WOT fuel pressure. Set with key-on/engine-off and jumper across the fuel pump relay. Using Terminator to trigger stock fuel pump relay. Running fuel pressure (out of boost) is 43-44 psi.

    No other ideas? I would really appreciate a reply of some sort. If you do not know or have any other ideas, please say so. I'm still making payments on my credit card for not only the Terminator system, but the Weiand supercharger also. It would really be good if I could drive & enjoy it. Talk to your other tech reps, your supervisor, anyone that you think can help. I do not have the money to shotgun this. I need some educated, knowledgeable suppositions please. I have also made a test run in open loop (already stated) with no change. So how can the WBO2 sensor be bad? Your two suggestions of the WBO2 and the fuel pressure have (I think) been covered. What next? Am I on my own?

  2. #12
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    Quote Originally Posted by jsmith View Post
    I've turned the WBO2 off (open loop) for a test run, would it still be the WBO2 sensor?
    Yes, because a failing WBO2 sensor will corrupt the Learn Table. If the Learn Table is corrupted, you can't just run it in Open Loop mode, or replace the WBO2 sensor, and restart the engine.
    You must upload the last "known to be good" Global File, upload the base calibration, or at the very least, clear the Learn Table of the corrupted values from the defective WBO2 sensor.
    http://forums.holley.com/showthread....1842#post61842 (Learn Table - Diagnostic/Troubleshooting Tool)
    http://forums.holley.com/showthread....ension-Harness (Read 4th paragraph under "Wideband O2 Sensor Notes".)
    http://forums.holley.com/showthread....7370#post47370 (Closed Loop & Learn Table - Especially posts #2, #6 & #11.)

    The change occurs like hitting a switch. Runs good, hit switch, runs bad, hit switch other way. Instant change from one to the other, which leads me to believe it is electrical in nature.
    This means it could also be some other intermittently failing sensor (or its wiring) or an ignition related problem (such as ignition module). Ignition misfires cause a false lean condition, which show up as momentary full lean spikes. The WBO2 sensor is an air (oxygen) sensor, not a fuel sensor.
    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.

  3. #13

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    I understand this. When I upgraded the computer's firmware, loaded the known good tune, the first thing I did was go into Open Loop for a test run. And why I replaced all of the ignition parts. No change. But if you are fairly certain it's the WBO2, I'll purchase one. I believe the NTK is the best one for boost as stated in other places on the forums. I also (when first installed the system) made a copper heat shield for the WBO2 to protect it from extraneous heat. I annealed the copper as it is now the seal on the header. To test for leaks, I've used an old aviation mechanic procedure. You put the exhaust of an industrial vacuum on one of the exhaust pipes. Tape it on (doesn't need to be air tight, but as best as possible) and tape up the other pipe (if dual exhaust). Turn the vacuum on and pressurize the engine. Mix up a soapy solution in a spray bottle and test for leaks. This is a very good way to test for leaks and the engine remains cool. You don't get burned. None found.

  4. #14
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    Quote Originally Posted by jsmith View Post
    But if you are fairly certain it's the WBO2, I'll purchase one.
    WBO2 sensor testing procedure at end of "Wideband O2 Sensor Notes": http://forums.holley.com/showthread....ension-Harness (WBO2 Sensor Information)

    I believe the NTK is the best one for boost as stated in other places on the forums.
    Yes: http://forums.holley.com/showthread....ension-Harness (WBO2 Sensor Information)
    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.

  5. #15

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    If jsmith loaded a known good tune with known good VE table, and then set it to open loop so no change should occur, why would the WBO2 sensor still be the suspect?

    I don't yet have my Holley HP running on my current project, so I have no direct experience yet. But from all the other EFI systems I've tuned (all GM OBD1, OBD2 & modified variants) by definition, going into true Open Loop disregards WBO2 sensor feedback (in that case narrowband sensors). Does the Holley not have true Open Loop operation?

  6. #16
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    Quote Originally Posted by alan91z28 View Post
    If jsmith loaded a known good tune with known good VE table, and then set it to open loop so no change should occur, why would the WBO2 sensor still be the suspect?
    That's not the order in which he was advised. My statement to upload the last "known to be good" Global File (post #12) was in reference to him simply turning off Closed Loop (post #11). He then stated he had uploaded a known good tune in Open Loop in post #13. So if that was in fact a "known to be good" Global File, then the intermittent problem isn't with Holley EFI.

    Does the Holley not have true Open Loop operation?
    Yes, Holley EFI has a true Open Loop option, which ignores the WBO2 sensor and runs off the Base Fuel Table & Modifiers.
    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. #17

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    Thanks for the clarification.

  8. #18
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    You're welcome.
    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.

  9. #19

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    Well, I tested the WBO2 in accordance with YouTube video. It did not act exactly like the video, but was unstable. So I ordered an NTK and the Innovate Motorsports HBX-1 bung extender. Loaded Global File and started over from scratch. Just went for test drive, problem worse than ever. Still goes lean, completely undriveable. At wits end. Parked, don't know what to do. Desperate for a fix. Any other ideas?

    P.S. Originally when I installed the system, I had a brand new DUI distributor. When I start it the first time it acted just like this. Completely uneducated on these systems at the time. Read forums. Found a post where you said use all GM parts. Robbed module out of old distributor. Ran great for 1.5 years. Then this. Figured module old, so bought a new one. No change. Changed all ignition parts. Pickup coil in distributor, module, ignition coil, all stock GM. Replaced distributor cap & rotor with Taylor parts. Replaced plugs, went from NGK BKR6EGP to E3s, E3.56. Upon removing plugs, all look good. Using DUI Live Wire plug wires. Tested with VOM while vibrating wire. All tested good, reinstalled. All to no avail. Still switches back & forth. One second runs good, next bad. If mechanical issue would think it would run badly all the time. Have check compression,150 psi all eight. Plus or minus 5 psi. Still think acts electrical in nature. Either ignition or EFI. But all new parts other than ECU or injector itself. If had a carb would try, but do not. See no sense in buying one just for troubleshooting. I'm on my own. None of friends gear heads or have no experience with this. Again, any other ideas?

    P.P.S. Could it be the TPS? I've read that it can cause weird problems. I have a the original trucks good GM TPS. Is it compatible? Part number 06681. The truck is a '95 GMC C1500. Originally TBI system. Have removed it completely including old wiring harness. Story for another day.

  10. #20
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    Quote Originally Posted by jsmith View Post
    Could it be the TPS? I've read that it can cause weird problems.
    Well, does the Data Monitor indicate it's operating properly? 0% at idle, and gradually increases toward 100% at WOT? Does the Data Monitor display legitimate values for all other sensors?
    http://forums.holley.com/showthread....2193#post72193 (EFI Software/ECU Firmware Problems)
    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.

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