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Author
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Topic: Cant get a good idle..
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Jace
Gearhead Posts: 148
From: Killeen, Texas
Registered: May 2002
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posted 08-14-2005 05:41 PM
 
ive got a 65 mustang w/ a 289 4v engine. i got the motor rebuilt a few months ago and havent got the idle/timing locked in right. the mechanic i had do the engine work was kind of shady, and i probably shouldnt have had him do the work but oh well. any ways, he had a timeline set out, but he failed to tell me he was already a month overdue. so i guess i rushed him when i said i wanted it, and he just set it enough to run "good." here are the up grades-
Performer 289 intake
600cfm Edelbrock carb
Performer-Plus cam (Cant recall the specs on that)
MSD 6A ignition
MSD Billet distributor
flat top pistons
"head work"
those last two im not sure of, but its what the machanic said he did. my biggest problem is that i do not have a timing light... i have been trying to get it timed by ear. none the less this week i will buy one. i cat get it alright, but the idle flucuates between about 500rpm to 900rpm. never above and never below those two at idle. and it seems to cycle between those two every 5 seconds or so. also when i rev it up, i will sometimes stall out when i let off the gas. if any one can help i greatly appreciate it. like where do i set initial timing, how to figure my advance curve. and why the heck wont my elec. choke work lol! thanks to those who can help, and ill help out as much as i canJace
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Tom G
Gearhead Posts: 1069
From: Bethlehem, Pa USA
Registered: Nov 2001
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posted 08-14-2005 06:38 PM
First thing make sure no vacuum leaks. Intake or a hose collaping to the power brake booster. Another source of vacuum leak is rear port on back of carb, make sure it is a tight fit. Is the 600 new or rebuilt? Base timing to start is 10 degrees make sure you get a light with a advance wheel or digital advance so you can tell where the timing is all in by.
I see ou are running a mSD dizzy try the silver bushing with the silver and blue light springs installed this will give you 25 degrees total advance add 10 intital and you get 35 which should get you in the ball park. We were running the stock heavy springs big silver and black and the total advance didn't come in till almost 5000 rpm. You should have recieved a spring and bushing kit with your distributor. If not summit racing sells the same thing for about 12 bucks.
Electric choke needs a ignition switched 12 volt source use a test light to find it watch out for resistance wires such as for old ignition wiring. these will cut down voltage and choke may never fully open. Also make sure you have a full 12 volts to MSD box or will cause an idle problem. BTW all this stuff I've been tellin ya. "been there done that"------------------
67 Mustang F/B 302 GT-40X FMS engine RPM Air Gap 650 Holley DP Crane 1.7 roller rockers, Edelbrock Performer Nitrous system, Dynomax ceramic coated headers T5, cable clutch Flows X Pipe 3.89 9". Clearwater Aqua GT Clone Vintage wheel works 40 series 16X8 225 front 255/50 rear drag radials 308 hp at the rear motor only 13.25 @103mph
92 VERT triple black 5 speed, 88 GT 5 spd 77k original miles Red and Silver
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Jace
Gearhead Posts: 148
From: Killeen, Texas
Registered: May 2002
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posted 08-14-2005 06:56 PM
Tom G- thanks! i have checked all of the vacuum ports on the carb. the two up front, and i have two behind the carb(one is on the spacer). i have replaced three plugs with those black rubber plugs, and the carb has a metal theaded one that is secure. the 600 is new. i have the heavy silver and blue springs on now. but i will put the silver bushing on. as for the timing light, i suppose i could find one with an advance at most parts stores? the choke worked on the engine before i had it rebuilt. i got the carb earlier and couldnt wait until the rebuild.. so i dont know why it wouldnt work now unless it was damaged or..? but thanks again with your help and i will get back to you with the results.Jace
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Jace
Gearhead Posts: 148
From: Killeen, Texas
Registered: May 2002
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posted 08-15-2005 09:25 PM
ok, so i did one of things mentioned above. i installed the silver spacer, and it did help alot with the timing. during idle and acceleration that is. but when i cruise at a steady speed, between 10-40mph, the engine sputters and jerks and surges... quite annoying driving around town. so i have another question, does it do this because of my set up? or is something still messed up? thanks againJace
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V8 Thumper
Gearhead Posts: 4777
From: Phoenix, Arizona
Registered: Dec 2001
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posted 08-16-2005 04:16 AM
That performer package is a good little setup, and if installed correctly should run good; low-rpm torque, great throttle response, and power from off-idle to 5000-some rpm.What is the voltage source for your MSD box? If sourced of a 40 year old wiring harness, chances are it's not getting full current that it needs. For the 'hot' lead, that should tie directly into the positive side of the battery (or starter, as that's hot also). On the ignition lead, I've always had best results relaying that circuit to insure full current to the box. If you're confident of the MSD's wiring you might concider having your alternator tested, or you may have a voltage regulator problem. I just read Tom's post, brilliant minds think alike  ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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BornInAFord
Gearhead Posts: 610
From: Bend, OR, USA
Registered: Dec 2002
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posted 08-18-2005 12:10 AM
Kinda sounds like a classic vacuum leak with the surges and all... You probably have several issues (including a vacuum leak), one of which you fixed with the more appropriate dizzy springs. A vacuum leak will cause your enging to run lean. Does the exhaust smell like it's lean? Does the engine overheat quickly?
Daniel
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BornInAFord
Gearhead Posts: 610
From: Bend, OR, USA
Registered: Dec 2002
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posted 08-18-2005 12:18 AM
Jace, wow! We're practically neighbors. Maybe sometime when I'm in town, I'll swing by to take a look.
Daniel
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Jace
Gearhead Posts: 148
From: Killeen, Texas
Registered: May 2002
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posted 08-18-2005 10:54 PM
Daniel,
i thought it would be a vacuum leak as well, but i really dont know where it would be leaking from. latley i have been working +12hr days and i just dont have the time to investigate. in a few weeks i will be able to do more. i appreciate the offer to swing by sometime, but im in the military, stationed in texas. i grew up in albany and havent changed the info. but i cant think of anywhere i would have a leak at, i dont have any vacuum assit brakes or power steering, and all the ports in the carb are plugged. any other ideas? thanks for the helpJace
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