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Author
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Topic: Richness Problem
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-08-2002 07:26 PM
   
Need help locating the cause of a richness problem.  I have changed several things, like:New Taylor wires,
New plugs and gapped to 47,
Downsized the jets (its a Holley 650 dp),
New primary float and adjusted lower. Could a bad power valve cause richness yet still run good at WOT? Its supposed to have a blowout preventer. How would I check it? We did not have this problem until after the tranny swap (Tremec to C4), but I don't see how that could affect the engine richness.
We did switch to AR-93 plugs but they fouled out in no time, so we went back to the 104s we ran all last year and the first half of this year. Now they too are fouling out. The set I just removed were black as midnight after 4 passes at the track and some street driving.  I am about to take it to shop, but hate giving up. So, I need all your wisdom, suggestions, hints and trouble shooting ideas that you care to share.
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V8 Thumper
Gearhead Posts: 3467
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 11-08-2002 07:37 PM
What jets are in it now?
What is the stall speed of the converter?
What cam/intake/heads do you run?------------------
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 [This message has been edited by V8 Thumper (edited 11-08-2002).]
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-08-2002 08:24 PM
63/71 (were 65/73)
3900 stall. Converter was supposed to be 3500, but on the transbrake it actually stalled at 3900
The XB3 crate engine set up. GT40 heads. B cam and rpm performer intake.
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V8 Thumper
Gearhead Posts: 3467
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 11-08-2002 08:57 PM
Jeez, those are plenty lean.I had a float hang up and just dump fuel down the venturis  , so bad it wouldn't run under 4K , but that was a vac. secondary carb, not a dp. A power valve problem would also richen the snot out of it. What # p/valve(s) are in it? Got another one in your toolbox you could try? ------------------
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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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-08-2002 10:17 PM
P.V. is a 6.5. I think I will remove it and have it tested. A local performance parts store has a tester. I have a 4.5 but did not try that yet. We changed the jets because the last dyno f/a was 12 or 12.5. With 63/71 jets it should be running rich at all.
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65_289
Gearhead Posts: 761
From:
Registered: Jul 2001
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posted 11-08-2002 10:38 PM
The jets are 65/71, down from stock 67/73. 
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-08-2002 10:58 PM
Opps.  My mistake.
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-09-2002 02:01 AM
ttt
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Fordwiser
Gearhead Posts: 217
From: Metamora, Illinois
Registered: Dec 2000
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posted 11-09-2002 09:44 AM
When you pull the metering block off the main body, if the well behind the power valve is wet, then the power valve is leaking. If it's dry the power valve is fine.
Roger
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-09-2002 11:41 AM
Power valve checked fine.Ran out of things to try. Need suggestions.
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-09-2002 01:15 PM
One more time. Can a coil be 1/2 good? In other words, can it generate enough fire to run, but not enough to properly burn all the fuel. Besides buying another one and trying that, is there a way to test the coil's output (which should be about 40,000 volts). The new plugs I put in yesterday are black on all surfaces today after a 10 mile road test.
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Moneymaker
Administrator Posts: 19704
From: Lyons, IL, USA
Registered: May 99
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posted 11-09-2002 01:26 PM
Try the 4.5 PV with the previous jets please. ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-09-2002 08:11 PM
I guess I will take it to a shop next week. Can't seem to isolate the cause.
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-09-2002 11:48 PM
quote:
Originally posted by Moneymaker:
Try the 4.5 PV with the previous jets please.
Help me with the thinking on this. We have been running for 1 1/2 years with the 6.5 PV and 67/73 jets. Now, all of a sudden, it goes rich so we go down to 65/71 with the 6.5. How would going back to the 67/73, but going down to a 4.5 power help? Help understand it before I foul out another set of plugs. Also, I thought power valves were supposed to be 1/2 of the vacuum at idle. We have 13 so 6.5 is 1/2 of 13. I don't mind rejetting and going to the 4.5, but just need to better understand why. Thanks.
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Moneymaker
Administrator Posts: 19704
From: Lyons, IL, USA
Registered: May 99
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posted 11-10-2002 01:14 AM
I just guessing, but I am suspect that your air bleeds are pluged up and a shorter PV would help prove this theory by not allowing enrichment until you are closer to WOT. If you can't understand that, then by all means take it to a shop.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
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Fordwiser
Gearhead Posts: 217
From: Metamora, Illinois
Registered: Dec 2000
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posted 11-10-2002 01:17 AM
Maybe check that the air bleeds aren't clogged up. Spray some carb cleaner down them and compressed air.
Roger
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-10-2002 02:01 AM
Air bleeds. That's what I was looking for. Something that could have happened recently that would explain the richness. Not just at idle, but throughout the range. I will work on that tomorrow. Thanks for giving me another thing to look at.
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Glens67
Gearhead Posts: 325
From: Petaluma
Registered: Mar 2002
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posted 11-10-2002 02:13 AM
What is the Vacuume at Idle? Your Power valve should be 1/2 of that. Look for a vacuum leak that you may have covered by tuning the carb. The power brake booster is a good place to start looking. ------------------
Glen
67 GT 390
65 Galaxie 500 XL 4 Speed
It was not a Red Light they gave me a Slow Tree [This message has been edited by Glens67 (edited 11-10-2002).]
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65_302
Gearhead Posts: 239
From: Bixby, OK
Registered: Jul 2001
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posted 11-10-2002 12:40 PM
quote:
Originally posted by Glens67:
What is the Vacuume at Idle? Your Power valve should be 1/2 of that. Look for a vacuum leak that you may have covered by tuning the carb. The power brake booster is a good place to start looking.
Vacuum at idle is 13. No power brakes. I have not, as yet, removed the carb just the primary fuel bowl. Where could I have missed a vacuum leak? I am going to remove the carb today and clean it throughly.
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