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Carb Issues with Edelbrock Performer by BullRider
Started on: 09-25-2007 06:21 PM
Replies: 12
Last post by: mafv8 on 09-26-2007 07:09 PM
BullRider
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Report this Post09-25-2007 06:21 PM Click Here to See the Profile for BullRiderClick Here to visit BullRider's HomePageClick Here to Email BullRiderSend a Private Message to BullRiderDirect Link to This Post
Hey guys! My car is finally running alright, and now I've noticed a very annoying issue. Any time that I corner, accelerate, or decelerate hard, I lose power. If the clutch is in, it will get as bad as to stall the car altogether. Under hard acceleration, the car will hesitate for a second and then kick in with the power. Cornering stalls the car if its a hard corner with the clutch in. It sounds to me like the car is getting starved for fuel when the engine gets some g-force applied to it in any direction. If it does stall out, I need to pump the gas to get it started again.

Engine is a mild 350SBC crate engine with a Edelbrock Performer carb.

What the heck is up and how do I fix this issue? I'm not carb-saavy.

Thanks, in advance, guys!


Bob
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craigsfiero2007
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Report this Post09-25-2007 06:34 PM Click Here to See the Profile for craigsfiero2007Click Here to Email craigsfiero2007Send a Private Message to craigsfiero2007Direct Link to This Post
 
quote
Originally posted by BullRider:

Hey guys! My car is finally running alright, and now I've noticed a very annoying issue. Any time that I corner, accelerate, or decelerate hard, I lose power. If the clutch is in, it will get as bad as to stall the car altogether. Under hard acceleration, the car will hesitate for a second and then kick in with the power. Cornering stalls the car if its a hard corner with the clutch in. It sounds to me like the car is getting starved for fuel when the engine gets some g-force applied to it in any direction. If it does stall out, I need to pump the gas to get it started again.

Engine is a mild 350SBC crate engine with a Edelbrock Performer carb.

What the heck is up and how do I fix this issue? I'm not carb-saavy.

Thanks, in advance, guys!


Bob


What size carb do you have? Did you just take it out of the box and bolt it on to the engine or did you adjust it? Edelbrock carbs are already adjusted for a mild Chevy 350, so you don't have to adjust it.
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Russ544
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Report this Post09-25-2007 07:09 PM Click Here to See the Profile for Russ544Send a Private Message to Russ544Direct Link to This Post
I'm betting it's a 750? I say that cause I hate those things. the 600 is pretty good, but the 750 sucks. anyway...... I'd recomend that you either buy an angled spacer that gets the carb sitting more level, or adjust the floats so it sees a little more fuel in the bowl.

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CTFieroGT87
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Report this Post09-25-2007 07:35 PM Click Here to See the Profile for CTFieroGT87Click Here to Email CTFieroGT87Send a Private Message to CTFieroGT87Direct Link to This Post
I had a similar problem till I had it dyno tuned. Soon I'm getting rid of the Edelcrap and putting on a dual feed Holley 650cfm.
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craigsfiero2007
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Report this Post09-25-2007 07:41 PM Click Here to See the Profile for craigsfiero2007Click Here to Email craigsfiero2007Send a Private Message to craigsfiero2007Direct Link to This Post
 
quote
Originally posted by CTFieroGT87:

I had a similar problem till I had it dyno tuned. Soon I'm getting rid of the Edelcrap and putting on a dual feed Holley 650cfm.


I had one of those on my 1980 Chevy Camaro, it wasn't worth the money. It never worked right. Hated every minute of it. I have a Edelbrock 650 on my mild Chevy 350, the best carb I have ever owned. I just took it out of the box and bolted it on the engine and the engine fired right up and has ran great since.
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Jake_Dragon
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Report this Post09-25-2007 07:44 PM Click Here to See the Profile for Jake_DragonSend a Private Message to Jake_DragonDirect Link to This Post
Mine does the same thing, what is your fuel pressure set at? I was told mine may be too high but that doesn't fit what its doing.
Mine is a 650 by the way running 5.5 PSI

[This message has been edited by Jake_Dragon (edited 09-25-2007).]

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CTFieroGT87
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Report this Post09-25-2007 08:39 PM Click Here to See the Profile for CTFieroGT87Click Here to Email CTFieroGT87Send a Private Message to CTFieroGT87Direct Link to This Post
Edelbrock is easy to bolt on and just go, but they are nothing compared with a Holley. I will never call myself a carb tuning guru, but my dyno guy is a Holley freak and can tune the hell out of them. I would never have thought of a Holley because of the difficulty tuning them, but since thats no longer a problem, I'm going as soon as possible.
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Arns85GT
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Report this Post09-25-2007 09:44 PM Click Here to See the Profile for Arns85GTClick Here to Email Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
Two things. Holley is not hard to tune if you do a little reading. Also, the Holley 1-800 guys are great help if you need it.

Also, the problem you're talking about sounds like the float setting. If it is too high, the fuel in the fuel bowl will slosh around and cause the float to lift when you are in a maneuver.

I'd lower the float some and try again. Of course, my experience is with the Holley carbs.

Arn
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Oreif
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Report this Post09-25-2007 09:51 PM Click Here to See the Profile for OreifClick Here to visit Oreif's HomePageClick Here to Email OreifSend a Private Message to OreifDirect Link to This Post
Having driven a Fiero with a Holley carb and one with an Edelbrock, I can definately say the Edelbrock in my opinion works better.
First off, when using a Holley you need to buy the Moroso anti-slosh kit or even a regluar turn may cause a stumble. The Holley with the side hung float bowls was designed for a "north-south" mounting. Putting it transversely sloshes the fuel more and causes fuel starvation. On my 3.4L I had this same problem until I installed the Moroso kit. It did greatly improve it, But on a road course or a 270* ramp of a highway it would occassionally still stumble. Note that the Holley carb was a single feed dual float bowl 390cfm 4-bbl carb. I don't know if a dual feed will have the same issues. Either way the anti-slosh kit does work very well.

The Edelbrock I have uses a center hung float in a center float bowl which works great. I have not had any problems on the street or the track. I am running 6.5psi to it which gives me a 5.5 psi constant line pressure. In BullRider's case it sounds like the float bowl float is set incorrectly (if carb is at an angle this affects the float setting) or he has low fuel pressure. To help him figure out what the issue is, I need to know what fuel pump he is using, What regulator he is using, and what his fuel pressure is at the carb. at idle and at WOT. Does the carb look like it is tilted when the car is on level ground?

The fuel pressure during WOT needs to be at least 5psi. The fuel pressure at idle is not the same as WOT. Depending on the fuel pump and regulator it can be .5 to 1.5 psi of difference from idle. Anything less than 5psi and it could cause an issue when cornering.
Too high of pressure (around 7psi or higher) could cause the fuel bowls to overfill during cornering and the fuel will leak out the vent tubes causing a stumble from too much fuel. On a final note, The farther away from the carb a fuel pressure gauge sits, The more inaccurate it can be.

Hope some of this info helps.

------------------

Happiness isn't around the corner...
Happiness IS the corner.

ZZ4 Powered !!

[This message has been edited by Oreif (edited 09-25-2007).]

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project34
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Report this Post09-25-2007 10:40 PM Click Here to See the Profile for project34Send a Private Message to project34Direct Link to This Post
 
quote
Originally posted by BullRider:

Any time that I corner, accelerate, or decelerate hard, I lose power. If the clutch is in, it will get as bad as to stall the car altogether. Under hard acceleration, the car will hesitate for a second and then kick in with the power. Cornering stalls the car if its a hard corner with the clutch in. It sounds to me like the car is getting starved for fuel when the engine gets some g-force applied to it in any direction. If it does stall out, I need to pump the gas to get it started again.

Engine is a mild 350SBC crate engine with a Edelbrock Performer carb.

Although the Edelbrock Performer carburetor comes in a wide range of sizes, from 500 cfm, to 800 cfm, the symptoms you describe don't necessarily sound to me like the carburetor sizing issue suggested early on in this thread.

I suggest visiting Edelbrock's website, and accessing their 26-page, "Edelbrock Performer & Thunder Series AVS Carburetor Owner's Manual." The direct link to this owner's manual currently is at http://www.edelbrock.com/au...rb_owners_manual.pdf
However, if you have a really slow computer, be forewarned that direct link takes you to a 1.83 MB file.

In any case, you could start with looking at page 22 of that Edelbrock carburetor owner's manual, the "Troubleshooting Chart" covering their Performer and Thunder carburetors. There, using a grid format, Edelbrock lists which of 19 "possible solutions" might be applicable to which of 15 different "symptoms."

For example, for the 3 "symptoms" listed below which you'd alluded to earlier in regard to your own car, the number of "possible solutions" Edelbrock shows is:
  • 3 for "Bogs,"
  • 5 for "Stumbles or loads up," and
  • 7 for "Lack of power."
Good luck with your carburetor project!


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BullRider
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Report this Post09-26-2007 10:57 AM Click Here to See the Profile for BullRiderClick Here to visit BullRider's HomePageClick Here to Email BullRiderSend a Private Message to BullRiderDirect Link to This Post
Wow!! Thanks, guys! Once again, Pennock's is the place for Fieros!
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Arns85GT
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Report this Post09-26-2007 11:10 AM Click Here to See the Profile for Arns85GTClick Here to Email Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
On the fuel pump and fuel pressure issue, as I said above, I run mine at 6.5 psi. With my system I am using the stock Fiero v6 pump and I run it into a Mallory bypass regulator. What this means is that the fuel pump runs wide open all the time at maximum flow, and the regulator bleeds off just what it needs, at 6.5. The fuel pressure just doesn't move much at all. It might drop 1 psi at the very most because hand operating the throttle to WOT and off scarcly moves the needle on the gauge.

Oreif is pretty much bang on. If Edelbrock had a 350 cfm carb I'd likely try it out.

Arn
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mafv8
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Report this Post09-26-2007 07:09 PM Click Here to See the Profile for mafv8Click Here to Email mafv8Send a Private Message to mafv8Direct Link to This Post
Bullrider, if you need an angled carb spacer I have one I am not using, I had it on my 350 SBC with an edelbrock performer, and it put the carb almost exactly level, I think is was about 5 degrees off level before this, let me know if interested.
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