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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: MY340]
#443807
08/24/09 11:41 AM
08/24/09 11:41 AM
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Joined: Jan 2003
Posts: 75,003
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,003
U.S.S.A.
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Quote:
 You guys are so funny!
Maybe my Edelbrock 750 thinks it's a Holley? 
You know like a wolf in sheeps clothing.
Plus my mild combo runs high 12's with slicks and as the previous owner included several times slips with the receipts.
don't take offense , sounds like you PURCHASED it setup , or have you confirmed that the carb is BOX STOCK ?? I'm curious , I played with one for a bit , it never ran right , finally switched to a rebuilt original number correct AVS and the car ran so much better .
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: JohnRR]
#443808
08/24/09 11:56 AM
08/24/09 11:56 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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I'ev never had one I couldn't tune. Some people give up. Some people don't like not throwing more fuel on it. I've had bad carbs from Demon/BG, Holley, Edelbrock, and Carter. They could all be tuned into good performers when the time and knowledge were applied. It sounds to me like you need to first examine the timing curve and setup on that engine. If it's totally stock... Does it have points? If so, you start with setting point dwell. Then set initial timing, then seet total timing, then tune the carb for idle quality and speed, then get the strip kit and tune for drivability. If you don't go in that order, you've got a good chance of getting PO'd and giving up because you WILL have to go back and fix what was overlooked. Holleys run well because they throw fuel at everything until it runs good. Or feels like it to the driver. "Well Tuned" doesn't care who made the carb.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: JohnRR]
#443809
08/24/09 12:05 PM
08/24/09 12:05 PM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
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Wow lots of activity here over the weekend! 
I ran the car on Sunday, intake vacuum was 8-9 inches of vacuum at 700 rpm low idle. I moved the mixture screws out an additional 1/2 turn (now 3 turns out), and switched the vacuum advance to the full vacuum fitting, instead of the ported fitting, and the car seemed to run slightly better, but not much. I've been reading the Edelbrock manual and looking for direction there as well, lots of info and combo's for tuning, but no mention (That I found) on off-idle changes.
I would put it back to the ported position or you'll have to much timing when it's not needed .
I disco the vac advance completely and lock it in full at 36-38* at 2400 and be done with it. If you want a "stockish" look use the 800 thunder.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Mr.Yuck]
#443812
08/24/09 11:55 PM
08/24/09 11:55 PM
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Joined: Feb 2003
Posts: 10,205
Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
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Posts: 10,205
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Quote:
Quote:
Quote:
Wow lots of activity here over the weekend!
I ran the car on Sunday, intake vacuum was 8-9 inches of vacuum at 700 rpm low idle. I moved the mixture screws out an additional 1/2 turn (now 3 turns out), and switched the vacuum advance to the full vacuum fitting, instead of the ported fitting, and the car seemed to run slightly better, but not much. I've been reading the Edelbrock manual and looking for direction there as well, lots of info and combo's for tuning, but no mention (That I found) on off-idle changes.
I would put it back to the ported position or you'll have to much timing when it's not needed .
I disco the vac advance completely and lock it in full at 36-38* at 2400 and be done with it. If you want a "stockish" look use the 800 thunder.
Why throw away MPG? 
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Mike H]
#443813
08/24/09 11:57 PM
08/24/09 11:57 PM
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Joined: Feb 2003
Posts: 10,205
Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
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Posts: 10,205
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Quote:
Would the 1406 have the same problems as the 1407?
I had one on a low po 383 and it was great. Ran very well all the way around. That was in the 69 RR vert that got such good mileage. If you have a hopped up engine I don't know, but others have said they have done ok for them.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: SomeCarGuy]
#443814
08/25/09 06:02 AM
08/25/09 06:02 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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All of the Edelbrocks are typically lean once you get to the point of tuning the main fuel circuit. Regardless of cam, compression, gearing, convertor, or any differences in engine builds, I've never had to change squirtors on a Edelbrock or Carter. If you have one, get the timing curve set properly (and unless it's a full on race car you need a curve rather than a locked out set timing amount and should run a vacuum advance off the ported vacuum port) and get it idling right witht he right step up springs, jet/rod it right, and they will outperform almost any Holley or holley based product on a street car.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: SomeCarGuy]
#443815
08/25/09 07:16 AM
08/25/09 07:16 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Quote:
Quote:
Quote:
Wow lots of activity here over the weekend!
I ran the car on Sunday, intake vacuum was 8-9 inches of vacuum at 700 rpm low idle. I moved the mixture screws out an additional 1/2 turn (now 3 turns out), and switched the vacuum advance to the full vacuum fitting, instead of the ported fitting, and the car seemed to run slightly better, but not much. I've been reading the Edelbrock manual and looking for direction there as well, lots of info and combo's for tuning, but no mention (That I found) on off-idle changes.
I would put it back to the ported position or you'll have to much timing when it's not needed .
I disco the vac advance completely and lock it in full at 36-38* at 2400 and be done with it. If you want a "stockish" look use the 800 thunder.
Why throw away MPG?
hahaha MPG and a BB Mopar, I mean really...is it that important? if the car is tuned the vac advance isn't going to net you much better MPG if at all.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: moper]
#443816
08/25/09 07:59 AM
08/25/09 07:59 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
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Grand Haven, MI
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Quote:
All of the Edelbrocks are typically lean once you get to the point of tuning the main fuel circuit. Regardless of cam, compression, gearing, convertor, or any differences in engine builds, I've never had to change squirtors on a Edelbrock or Carter. If you have one, get the timing curve set properly (and unless it's a full on race car you need a curve rather than a locked out set timing amount and should run a vacuum advance off the ported vacuum port) and get it idling right witht he right step up springs, jet/rod it right, and they will outperform almost any Holley or holley based product on a street car.
the 1406 I put on my 360, stock long block with a comp XE262, headers, and RPM air gap was way rich with stock jetting. I actually had to drop the secondaries down to .089 jets, put the original secondary jets in the primaries (IIRC they're .092") and go one step richer on the cruise needle (OOTB is .075x.047, I used the .073x.047), and I needed to drill the primary plates with 1/8" holes to lean the idle out to reasonable (~14:1). all tuning was done with a friend's LM1 wideband 02 sensor. I used the stiffest step up springs, and I used the middle hole on the acc pump for summer, usually had to go to the closest hole in the winter.
put the same carb on my rebuilt 318 a couple weeks ago--stock long block, mag heads, 259/259 adv, 208/208 roller cam, headers, same intake, that setup was way lean, took it back to stock jetting, is running much better, should get my friend's LM1 tomorrow to fine tune it. I do have a slight bog nailing it, even with the acc pump on the nearest hole.
personally, IMHO you really need a WB O2 sensor to fine tune a street carb, otherwise you're doing a lot of stabs in the dark, especially when tuning the transitions between different circuits, and may be going in the wrong direction.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: patrick]
#443817
08/25/09 08:32 AM
08/25/09 08:32 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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"personally, IMHO you really need a WB O2 sensor to fine tune a street carb, otherwise you're doing a lot of stabs in the dark, especially when tuning the transitions between different circuits, and may be going in the wrong direction".
puuuuufst, no need to spend hundreds of dollars on something like that for a mild street car. get a vacuum gauge and a good timing light. That's all you need. If you choose to stay w/ the Eddy carb buy the tuning kit. The Eddy 750 will never be as good as the 850DP. Personally I'd use the 850 and get a drop base so you can use your air cleaner assembly. I'd also turn the fuel line backwards towards the fire wall, or get the split fuel line. It's not rocket science.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Mr.Yuck]
#443818
08/25/09 10:28 AM
08/25/09 10:28 AM
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Joined: Aug 2005
Posts: 697
Central IL
70Sbird
OP
mopar
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OP
mopar
Joined: Aug 2005
Posts: 697
Central IL
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I had a little time last night after the kids were in bed and decided to check out the rods and springs in my carb to see what there. Imagine my surprise when I found .070/.047 rods and plain springs! those rods only show up on my 1411 tuning chart with a jet change going in the lean direction. There should have been .075/.047 and orange springs as the "factory" calibration. Apparently this carb has been "tweaked" previously. I suppose now I'll tear it apart tonight and see what jets I have as well, then get a baseline to begin tuning. Note to self - even if you know the person that sells you a carb and have added a rebuild kit "just in case" verify the setup! 
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: 70Sbird]
#443819
08/25/09 11:26 AM
08/25/09 11:26 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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It may not be the person selling it. I have seen factory out of the box ones with the wrong parts in them. This is why you look and tune, rather than throw parts at it until you get lucky, borke, or angry enough to say "it's fine!" 
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Mr.Yuck]
#443820
08/25/09 12:00 PM
08/25/09 12:00 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
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Quote:
"personally, IMHO you really need a WB O2 sensor to fine tune a street carb, otherwise you're doing a lot of stabs in the dark, especially when tuning the transitions between different circuits, and may be going in the wrong direction".
puuuuufst, no need to spend hundreds of dollars on something like that for a mild street car. get a vacuum gauge and a good timing light. That's all you need. If you choose to stay w/ the Eddy carb buy the tuning kit. The Eddy 750 will never be as good as the 850DP. Personally I'd use the 850 and get a drop base so you can use your air cleaner assembly. I'd also turn the fuel line backwards towards the fire wall, or get the split fuel line. It's not rocket science.
to tune a car to run good, no. to FINE TUNE (get it running good and optimize mileage) yes. if you tune for max vaccuum, 9 times out of 10, I bet it's tuned slightly fat, and you're sacraficing some fuel mileage. for someone who drives his car every day, a 2-3mpg difference can add up relatively quick.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Mr.Yuck]
#443823
08/25/09 08:19 PM
08/25/09 08:19 PM
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Joined: Feb 2003
Posts: 10,205
Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
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Someplace you aren't
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Quote:
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Quote:
Quote:
Wow lots of activity here over the weekend!
I ran the car on Sunday, intake vacuum was 8-9 inches of vacuum at 700 rpm low idle. I moved the mixture screws out an additional 1/2 turn (now 3 turns out), and switched the vacuum advance to the full vacuum fitting, instead of the ported fitting, and the car seemed to run slightly better, but not much. I've been reading the Edelbrock manual and looking for direction there as well, lots of info and combo's for tuning, but no mention (That I found) on off-idle changes.
I would put it back to the ported position or you'll have to much timing when it's not needed .
I disco the vac advance completely and lock it in full at 36-38* at 2400 and be done with it. If you want a "stockish" look use the 800 thunder.
Why throw away MPG?
hahaha MPG and a BB Mopar, I mean really...is it that important? if the car is tuned the vac advance isn't going to net you much better MPG if at all.
You must be really rich. If I took the vac advance off I would have easily went from 15 MPG to 12 or less real quick. In other words, 20% less, if not more.
I drove over 6000 miles in the RR this summer.
I'll let you do the math. Remember to take off the dollar or so that the hose cost to run the advance.
I'm really not sure why ANYBODY would say it isn't worth it to run on a street car. It is easy to adjust so ????You wouldn't tell somebody to leave the wrong jets in a carb, why is vac advance any different?
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: SomeCarGuy]
#443824
08/25/09 08:53 PM
08/25/09 08:53 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
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Posts: 12,675
Columbia, CT
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Quote:
I'm really not sure why ANYBODY would say it isn't worth it to run on a street car. It is easy to adjust so ????You wouldn't tell somebody to leave the wrong jets in a carb, why is vac advance any different?
Just different people, different opinions of "tuned", and different levels of knowledge.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: SomeCarGuy]
#443825
08/25/09 09:16 PM
08/25/09 09:16 PM
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Joined: Nov 2004
Posts: 1,760
Port Alberni, British Columbia
MoparDonny
top fuel
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top fuel
Joined: Nov 2004
Posts: 1,760
Port Alberni, British Columbia
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Quote:
If I took the vac advance off I would have easily went from 15 MPG to 12 or less real quick. In other words, 20% less, if not more.
I drove over 6000 miles in the RR this summer.
I'll let you do the math. Remember to take off the dollar or so that the hose cost to run the advance.
I'm really not sure why ANYBODY would say it isn't worth it to run on a street car. It is easy to adjust so ????You wouldn't tell somebody to leave the wrong jets in a carb, why is vac advance any different?
Exactly !!! 
I actually modified ( drilled ) my primary metering block on my 800 Double Pumper so I have a vacuum advance. Works Great. Last Highway drive I did got me 15 mpg with my 3.91's and 235/60/14's.
You don't get any kind of mileage when you're turning 3000 RPM at 55mph so I'd say I'm doing OK.
Don.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: MoparDonny]
#443826
08/26/09 01:53 PM
08/26/09 01:53 PM
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Joined: Aug 2005
Posts: 697
Central IL
70Sbird
OP
mopar
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OP
mopar
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Central IL
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OK, I got the carb off last night and pulled the jets out to verify the base combo I'm working with. As I was surprised with the rods being changed, so were the jets. I had .104 main jets, combining this with the rods, I found this combination on the Edelbrock calibration chart and this combo represente two steps lean on the cruise mode and three steps lean on the power mode!  Now, would that cause a lean off idle condition? I'm probably going to start from scratch at this point and begin as recommended above, new spark plugs and reset base timing (MP electronic ignition so no points)and set the carb at baseline, or possibly a step or two rich. or is there a better place to start other than the baseline factory settings? I'm still thinking I probably need to move up to the .043 acc pump nozzles from the .035s on there now
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