Running Rough . . . . But Only Sometimes . . . . .
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Im guessing the 82's would have a couple more
Thread Starter
Racer
Joined: Aug 2007
Posts: 290
Likes: 0
From: Marietta GA
Update . . . . .
Here's an update . . . . . and another question. Next on our list was to replace the fuel filter. Since the carburetor is an aftermarket (replaced with an Edelbrock), I looked up the manual online. Seems this carb uses an in-line fuel filter; however, whoever replaced the carb didn't bother installing one. We're installing one, but what kind of problems will we be facing since it ran so long without one?
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Probably explains your intermittant problems.
With a car that old and sitting for periods, you may well have junk in the carb bowl. Hopefull not too much.
To remedy would require disassembly.
Try this first.
When installing the inline filter, remove the coil wire.
Put a section of hose on the carb line coming out of the fuel pump and put the other end into a bucket. Have someone crank over the engine until you get at least a half gallon into the bucket.
You will then see how much junk you are getting.
With an old car it's good to do this every time you change the gas filter. Will help it last a little longer too.
Get some Chevron Fuel Injector Cleaner and put in the tank and drive it. Great for dissolving gum etc. Best shot without repair.
Then just drive it and see what happens.
With a car that old and sitting for periods, you may well have junk in the carb bowl. Hopefull not too much.
To remedy would require disassembly.
Try this first.
When installing the inline filter, remove the coil wire.
Put a section of hose on the carb line coming out of the fuel pump and put the other end into a bucket. Have someone crank over the engine until you get at least a half gallon into the bucket.
You will then see how much junk you are getting.
With an old car it's good to do this every time you change the gas filter. Will help it last a little longer too.
Get some Chevron Fuel Injector Cleaner and put in the tank and drive it. Great for dissolving gum etc. Best shot without repair.
Then just drive it and see what happens.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Can you post a picture of the fuel line from the fuel pump to the carb?
This will give us an idea of what needs to be done to install an inline filter.
I also agree with noonie. Any damage has already been done so just drive it and see what happens
This will give us an idea of what needs to be done to install an inline filter.
I also agree with noonie. Any damage has already been done so just drive it and see what happens
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
Sounds like dirt in the bowls. Choke on or running above idle you probably won't notice any problem, but idling improperly could be a result of the dirt obstructing fuel flow. I'd clean the bowls out.
Pro
Joined: Jun 2005
Posts: 725
Likes: 1
From: FL.
you havent had the Bowls off yet for a Look?? Everything youve said indicates Taking the float bowls off, likely youll see crapola in there
. Bite the bullit, Have it cleaned and rebuilt. Sorry, gotta do that or your otherwise great car may just decide to plague you ..
. Bite the bullit, Have it cleaned and rebuilt. Sorry, gotta do that or your otherwise great car may just decide to plague you ..
Thread Starter
Racer
Joined: Aug 2007
Posts: 290
Likes: 0
From: Marietta GA
Yeah, that's what I was afraid of. The car sat more than it was driven by the previous owner. We were *hoping* that since it was a fairly new carb that using some carb cleaner would do the trick (it's helped, believe it or not!). However, now that we know there isn't a fuel filter, guess we're going to have to get it rebuilt. Dang. Gonna try noonie's suggestion first just out of curiosity.
Did get a couple of pics of the fuel line, but couldn't get a picture of it coming from the fuel pump. Previous owner had cut the original line and replaced with a short piece of rubber hose. Did y'all still want to see the pics?
Someone had mentioned an external fuel filter - anybody have any experience with installing one? Is there any value to having it over an in-line fuel filter?
Thanks!
Did get a couple of pics of the fuel line, but couldn't get a picture of it coming from the fuel pump. Previous owner had cut the original line and replaced with a short piece of rubber hose. Did y'all still want to see the pics?
Someone had mentioned an external fuel filter - anybody have any experience with installing one? Is there any value to having it over an in-line fuel filter?
Thanks!
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Gonna try noonie's suggestion first just out of curiosity.
Previous owner had cut the original line and replaced with a short piece of rubber hose. Did y'all still want to see the pics?
Someone had mentioned an external fuel filter - anybody have any experience with installing one? Is there any value to having it over an in-line fuel filter?
Thanks!
Previous owner had cut the original line and replaced with a short piece of rubber hose. Did y'all still want to see the pics?
Someone had mentioned an external fuel filter - anybody have any experience with installing one? Is there any value to having it over an in-line fuel filter?
Thanks!
Post the pics of the fuel line so members can give a recommendation.
Installing an external fuel filter is probably one of the more simple tasks you will ever have to deal with on a C3.
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Racer
Joined: Jul 2006
Posts: 337
Likes: 10
Had same issues....seemed like it was rough at night, sometimes. Last Friday night upon departing, the driver headlight would not go up.....blown shaft seal. In capping off the vacuum at the manifold until my parts arrive.....I have found the engine idles 100% perfect...every stoplight, all the time now. I will be rebuilding both actuators and checking the system for leaks. I suspect the headlight switch could be a leak.
Pro
Joined: Mar 2005
Posts: 683
Likes: 4
I had a problem like this with my 75 and it drove me nuts! Here's what I found. The vacumn advance for the distibutor that looks like a bell and sits on the passenger side of the car and the vacumn hose attaches to has a small rubber diaphram inside it. When the car would warm up the diaphram would start leaking and thus would not advance the distributor. When your car is at operating temp remove the vacumn hose from the distributor. If there is no effect than you have a leak.
Good Luck,
Steve
Good Luck,
Steve
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Manifold vacuum will pull the advance in at idle but ported source will need some throttle to start moving the advance.
The easiest way to test the can is to pull the hose off the carb and suck on it. If the can holds a vacuum then its good.
Of course a hand vacuum pump works fine and is a great tool for any Corvette owner to have.... not very expensive and doubles as a vacuum gauge too.
Thread Starter
Racer
Joined: Aug 2007
Posts: 290
Likes: 0
From: Marietta GA
Thanks for all your suggestions and your patience. I'm so car illiterate. 
I can tear down a computer, figure out why it's not working and bring it back to life, but not with a car - at least, not yet! But I have my assembly manual, a good ol' Haynes manual and the internet (I now know what an actuator is! 
), not to mention my hubby knows his way around cars pretty well! (but he's out of town this week)
Anyway, I was going to buy an Edelbrock 8873 in-line fuel filter, which was recommended by Edelbrock (of course). I haven't gone to get it yet, so don't know what it looks like. After doing some research, I thought maybe I should get a "glass" filter, unless an "external" filter is a better choice (and I know nothing about external filters). What do you think? Here are the pictures of the fuel line from the carb:
This is where it ties into the original line (no comments on the red hose, please - it's on my "list"
)
I can tear down a computer, figure out why it's not working and bring it back to life, but not with a car - at least, not yet! But I have my assembly manual, a good ol' Haynes manual and the internet (I now know what an actuator is! ), not to mention my hubby knows his way around cars pretty well! (but he's out of town this week)Anyway, I was going to buy an Edelbrock 8873 in-line fuel filter, which was recommended by Edelbrock (of course). I haven't gone to get it yet, so don't know what it looks like. After doing some research, I thought maybe I should get a "glass" filter, unless an "external" filter is a better choice (and I know nothing about external filters). What do you think? Here are the pictures of the fuel line from the carb:
This is where it ties into the original line (no comments on the red hose, please - it's on my "list"
)
Drifting
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: Oak Ridge NC
Here is a page of what inline filters look like.
http://www.google.com/products?q=inl...num=1&ct=title
Glass can brake...quite a few of of will tell you not to use a glass in line filter...others will say it is no problem...I would not use glass.
http://www.google.com/products?q=inl...num=1&ct=title
Glass can brake...quite a few of of will tell you not to use a glass in line filter...others will say it is no problem...I would not use glass.
Thread Starter
Racer
Joined: Aug 2007
Posts: 290
Likes: 0
From: Marietta GA
) Thanks for the info about the glass filter - kinda wondered how "fragile" they were . . . . .
Drifting
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: Oak Ridge NC
Thanks, SmokinBBC. Guess I should have clarified - I know what an in-line fuel filter looks like, just didn't know what the Edelbrock one looks like! (One of the few things I do know! ) Thanks for the info about the glass filter - kinda wondered how "fragile" they were . . . . .
) Thanks for the info about the glass filter - kinda wondered how "fragile" they were . . . . .http://www.edelbrock.com/automotive_...l_filter.shtml
IMHO..replace that rubber/hard line feed line with a new hard line if you can get one..looks better. I don't know if the Edelbrock fuel inlet is the same as stock, but if not then that may be why the rubber line was put in. Put the correct filter in the carb inlet and forget the inline filter..just my humble opinion.
Racer
Joined: May 2007
Posts: 370
Likes: 0
From: Cherry Hill N.J.
Stalling Sometimes
Have You Checked For Vapor Lock....i Have The Same Carb,was Having A Problem With Stalling After Long Runs On Interstates.
Seemed The Problem Went Away After I Installed A Carb Spacer And Insulated The Rubber Fuel Line.this Was 4 Years Ago And I Have Not Had A Problem Since. Good Luck!
Seemed The Problem Went Away After I Installed A Carb Spacer And Insulated The Rubber Fuel Line.this Was 4 Years Ago And I Have Not Had A Problem Since. Good Luck!
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Sizie
You have 3/8" fuel line. Buy the 8873 filter and two new clamps then follow the instructions in this video (it's a big download) and you'll be fine
http://www.edelbrock.com/automotive_...on_PT3_320.wmv
You have 3/8" fuel line. Buy the 8873 filter and two new clamps then follow the instructions in this video (it's a big download) and you'll be fine
http://www.edelbrock.com/automotive_...on_PT3_320.wmv
Le Mans Master
Joined: Aug 2006
Posts: 7,423
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Don't Play With Fire!
Hi suzie-q, on page 254 in the AIM you can see that your car came with a Q-Jet, the fuel inlet is at the bottom front right side, your new carb inlet is at the right top rear. My guess is that the last owner took a shortcut and used rubber.
Call Edelbrock and get an "in carb filter" ( ask them if you need a spring too ) and a hard line from the pump to the carb.
That will be a good start, but there may be whatever inside that carb so it may have to be overhalled. ( If so contact Lars )
You say your Vette was parked for a long time, use a mirror and look into the tank, see if the bladder is bad it may let the tank rust get into the system.
Hope that helps, Pete.
Call Edelbrock and get an "in carb filter" ( ask them if you need a spring too ) and a hard line from the pump to the carb.
That will be a good start, but there may be whatever inside that carb so it may have to be overhalled. ( If so contact Lars )
You say your Vette was parked for a long time, use a mirror and look into the tank, see if the bladder is bad it may let the tank rust get into the system.
Hope that helps, Pete.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Also, I don't believe Lars rebuilds the Edelbrock 1400 type carbs but I could be wrong on that one.
Thread Starter
Racer
Joined: Aug 2007
Posts: 290
Likes: 0
From: Marietta GA
Sizie
You have 3/8" fuel line. Buy the 8873 filter and two new clamps then follow the instructions in this video (it's a big download) and you'll be fine
http://www.edelbrock.com/automotive_...on_PT3_320.wmv
You have 3/8" fuel line. Buy the 8873 filter and two new clamps then follow the instructions in this video (it's a big download) and you'll be fine
http://www.edelbrock.com/automotive_...on_PT3_320.wmv
Now, to find someone who can rebuild my carb . . . . .