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Thread: Cutting Out Under Load

  1. #111
    Join Date
    Dec 2009
    Location
    Connecticut
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    22,898

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    Quote Originally Posted by jbeemer View Post
    Just went for two different rides, 5 miles each way, same route both times.
    1st run with wideband in the right bank, 2nd with it in the left bank.

    AFRs are the same as far as I can tell on two separate runs.
    One thing I did notice is the AFR gauge is way more steady with the carb.
    I wonder if your Terminator throttle body had an intermittently failing fuel injector or injector wiring. I'd Ohms test (multimeter) the throttle body wiring while wiggling the wiring around.
    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.

  2. #112

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    I wonder if your Terminator throttle body had an intermittently failing fuel injector or injector wiring. I'd Ohms test (multimeter) the throttle body wiring while wiggling the wiring around
    Not a bad idea. It did run good for the one week, after it was unplugged & moved when I found the intake bolts. However, I have done a lot of "wiggle" tests and nothing ever came up.

    On another note, I had a good engine guy that has concern about the valve springs. This engine had sat, which means some valve springs have sat compressed for a long time. Could have valve flutter causing weird airflow and the unbalance. The carb wouldn't know because it adds fuel based on air flow.

    Did a compression test tonight, all cylinders within 5 psi. Going to swap the valve springs this weekend, and measure the ones that are in it now. Just to be safe.

  3. #113

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    Started swapping valve springs tonight.

    I had a set of two year old Vortec springs that only had 2000 miles on them, from a new set of heads that I bought.

    First I lined them up and checked the height, new springs all the same. Then I set a digital scale on the floor, and made a PVC spacer to wedge under my vise, that's welded to a building column. The "new" springs were all 120.2 to 125.4 lbs when compressed with the spacer, which is about 5/8".

    The springs that came off the driver side were all visually the same height. Five were within the 120-125 lbs. One was 116.2 and two were 115.0.

    I didn't check all of them for lash when I took it apart, but the several I did were about 3/4 of a turn past zero lash.

  4. #114

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    Swapped out the rest of the valve springs this morning.
    On the pass side: six of the springs were in the 120 to 125 lb range.
    One was at 117.2 lbs, and the exhaust valve on number eight was 111.1 lbs.
    So at 5/8" compressed they are within 12%.

    The next "test" I did was to shorten my preload stick, so that when in the scale they were at about installed height.
    All of the springs were 74.5 to 79.2 lbs. That puts them less than 8% spread.

  5. #115

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    Got my ECU back from Holley yesterday. They ran it on their test machine and in a car. Said that it tests good.

    I installed the throttle body and computer again this morning. I left the large cap HEI in to eliminate that variable. It runs like it did before. The right bank is 2 to 3 points richer under load. I put the Holley wideband in the right bank, plan is to put it in the leaner bank eventually, but the unused bung was on the right. It ran good at first. After I started to drive, the Learn started pulling fuel in the upper map, which led to lean misfires on the left bank. I stopped and turned the Learn off in the upper map, and cleared the Learn table. It went back to running OK. After a few more miles I turned the Closed Loop off and ran off the fuel table. It ran good other than a few spots in the table, mainly off the throttle coasting is lean.

    Not sure which way to go next? Overall, if I run the AFR table lean in the upper, with the wideband on the left, or rich with the wideband on the right, it runs decent. But it's not balanced and can be way better.

    It's better than a carb now...but I know there's a lot more there.

  6. #116

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    Just a quick update to this old thread to hopefully help others. After lots of changes it's running right now. Here's a very short run down of changes & modifications. Drove it last summer as it was, and dealt with it. Last winter, I changed to another set of heads, a LT4 hot cam, and 1.6 roller rockers, didn't change the uneven left & right at all.

    This spring I pulled the GMPP dual-plane intake off, and installed a short dual-plane Summit intake I had. No change, maybe worse. Last week, I put together a RHS single-plane with port injector bungs welded in. I installed Bosch 42 lb/hr injectors, but haven't wired them yet. RUNS GREAT, EVEN LEFT & RIGHT.

    Two years of testing & changing, and it was the dual-plane. Has to be something with the turbulent air in the intake. When I took both of dual-plane intakes off right after running. There was pooled gas in the bottom of the intake. After all this, the single-plane is night & day better, even before tweaking the tune at all. Now for the multi-port injection & Coil-Near-Plug ignition.
    Last edited by jbeemer; 07-07-2016 at 12:01 PM.

  7. #117
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,898

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    Thanks for the updating this thread.
    http://forums.holley.com/showthread....0913#post70913 (Terminator TBI & Dual-Plane Intake Manifolds)
    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.

  8. #118

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    I'm really amazed at the difference. The Learn leaned out everything under 4000 RPM 5-15%, and added about 5% above 4000 RPM. The difference at cruising speed is very noticeable. Not only less fuel for maintaining the AFR, but I went from about 80 kPa to maintain 65 MPH, to about 60 kPa to maintain 65 MPH. So it's working less and more efficient. Should be way better gas mileage.

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