Is there a mechanical bypass in the throttle body that's letting more air into the engine than you need?
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1975 Plastic fantastic aka Corvette
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lots o gear ... I guess with teh Super T10 ratio spread it should be interesting. I'd cube the hell out of it, but that's me. I see where KMJ has Howard's 100% USA forged Chevy cranks on sale for 550.00 - 6" rod in a 350 with a modern lightweight piston should rev like crazy if you want it to.Flying south, with a flock of bird dogs.
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Originally posted by TheSilverBuick View PostWhat thumpr cam did you put in it? It'd drive me nuts idling around at ~1,400+ rpm.
Brand:COMP Cams
Manufacturer's Part Number:CL12-600-4
Part Type:Camshaft and Lifter Kits
Product Line:COMP Cams Thumpr Hydraulic Flat Tappet Cam and Lifter Kits
Summit Racing Part Number:CCA-CL12-600-4
UPC:036584181224
Cam Style:Hydraulic flat tappet
Basic Operating RPM Range:2,000-5,800
Intake Duration at 050 inch Lift:227
Exhaust Duration at 050 inch Lift:241
Duration at 050 inch Lift:227 int./241 exh.
Advertised Intake Duration:279
Advertised Exhaust Duration:297
Advertised Duration:279 int./297 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.479 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.465 in.
Valve Lift with Factory Rocker Arm Ratio:0.479 int./0.465 exh.
Lobe Separation (degrees):107
Camshaft Gear Attachment:3-bolt
Grind Number:279TH7
John has a good idea - I'm going to mess with the IAC a bit more before I give up.... strangely, it did idle fine the last time I drove it - so that may be round one, go drive it 20 or so miles.Doing it all wrong since 1966
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Granted I don't know small blocks for crap, but I would expect that to at least idle down to 1,000. I'd be looking for either a vacuum leak that the EFI is compensating for and checking the IAC settings to see if at idle the valve is all the way closed. Or maybe in the software settings there is a target rpm setting that is fubar'd? Can you get a read out of what all the sensor are reporting to the ECU? Incase it's an issue like Tartis(sp?)'s friend's van and the temp sensor. I know how mine is programmed if the temp sensor wiring comes loose or grounds out it'll report cold, making it run rich AND idle up the car to 1,200 because it thinks the engine needs to warm up.Last edited by TheSilverBuick; December 28, 2012, 09:23 AM.Escaped on a technicality.
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Originally posted by TheSilverBuick View PostGranted I don't know small blocks for crap, but I would expect that to at least idle down to 1,000. I'd be looking for either a vacuum leak that the EFI is compensating for and checking the IAC settings to see if at idle the valve is all the way closed. Or maybe in the software settings there is a target rpm setting that is fubar'd? Can you get a read out of what all the sensor are reporting to the ECU? Incase it's an issue like Tartis(sp?)'s friend's van and the temp sensor. I know how mine is programmed if the temp sensor wiring comes loose or grounds out it'll report cold, making it run rich AND idle up the car to 1,200 because it thinks the engine needs to warm up.Doing it all wrong since 1966
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Originally posted by SuperBuickGuy View Postnew differential
2.73 gears..... posi is in good shape, needs a left yoke; or simply a shim....we'll see which one I go with....
So I dinked with the car tonight, working on tuning it.... I've come to the conclusion I think I made a mistake by putting the 1.6 ratio rockers on it.... it won't idle under 1400 rpm, even with the rockers at 1/8 turn past zero lash..... ah well, I can fix this pretty easily
good score!! not sure what i could come up with on the idle problem, but, i think you got a handle on it...Patrick & Tammy
- Long Haulin' 2008, 2009, 2010, 2011, 2012, 2014...Addicting isn't it...??
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SBG, you idled before, therefore there is nothing wrong with your cam.. Something went "off" ..
I ran the "280H" cam in my flatbed.. Power band started at like 1200rpms it idled at 800-850 warmed up.. Didn't have a choke either and it would run at maybe 600 rpms till it warmed up..
I always wanted to know what that cam woulda done in a car.. Moved the flatbed pretty good!
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Originally posted by SuperBuickGuy View PostAnd the biggest clue, when I was checking for vacuum leaks, I disconnected a direct port while the motor was running - and the idle speed went upEscaped on a technicality.
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I think Randal may have run without IAC for a while? I'd turn the minimum idle screw in on the TB with the IAC disconnected and see if that will let it idle lower. Busted IAC function is .. no idle. If you force it to 850-900 with the throttle blade and IAC undone, I'm thinking it's a clue.
Is a stepper motor IAC?Flying south, with a flock of bird dogs.
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Originally posted by TheSilverBuick View PostOn EFI I'm not sure that is diagnostic of anything as any way you add air to the system it's going to add fuel, thus up the rpm. It doesn't really care what the throttle blades or TPS is doing.
or, put another way, I've yet to find the control for the IAC on the tuner.Last edited by SuperBuickGuy; December 28, 2012, 06:48 PM.Doing it all wrong since 1966
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Originally posted by Bob Holmes View PostI've run my '86 Mustang with the IAC unplugged. Just fiddled with the idle screw on the throttle body. Early EEC IV Fords have horrendous idle "hunting" issues.Flying south, with a flock of bird dogs.
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My Mustang has the IAC deleted (I made a solid gasket), and I set the idle to 600rpm. The 1200rpm idle was driving me nuts, made parking lot driving awkward, and made the car sound horrible.1997 Ranger 5.0L HO, GT40 heads/tubular intake, 65mm TB, 1.7rr, B303, Tri-Y headers, dual 2.5" exhaust, Flowmaster mufflers, T5 trans, Tri-Ax shifter, CenterForce Dual Friction clutch, 8.8 Traction Lok 3.55 gears, Cobra 13" front brakes, Cobra 11.65" rear discs.
1997 Mustang GT
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