Carb 2.8 Runs rough

[Casper]

My Celeb has a 2.8 with an E2SE carb. It is hard to start and won't idle for 3 minutes after starting. After that, it idles up and down, and bogs HARD(to the point of cutting off, sometimes) in gear at anything over 1/2 throttle. In park it bogs, but not as badly. I'm thinking Carb. I've done a tune up (cap, rotor, good used plugs and wires) and I only paid 400 bucks for the car. Any thoughts on how to remedy this situation?

[sky81]

Make sure the choke pull off is actually pulling the choke plate open.
It should also not pull it open too wide or the car will not run well when the engine is cold.
It should pull the choke off just a little bit.
This is most likely what is wrong from what you're describing.
I assume the bog when accelerating is when the engine is cold also, not when warmed up?
If it's doing it when it's warmed up, I'd think it would be the accelerator pump.

It might not be the carb though.
How are the vacuum lines?
Are any cracked or broken?
Vacuum leaks will cause all kinds of driveability problems and make it seem like it is the carb when it is not.

[Casper]

The choke is coming all the way off. This car does this worst when cold, but It also does it at operating temp. And I've fixed all the vacuum leaks, and it still does this. I was thinking accelarator pump, but when I crack the throttle hard, I can see fuel squirt in, like it is good. Also, the O2 sensor has come out of it's ring (the element and wire seperated from the housing that screws into the exhaust) But it hasn't thrown a code.

[sky81]

I'm wondering if the float is either mis-set or is sunk in the carburetor.
It's either delivering too much fuel or too little.
The hard starting might be due to the carburetor flooding if the float sank in the carb.

Do you know how to rebuild one of these?
They are a little complicated but not impossible to rebuild.

Sounds like it's a good idea to replace the O2 sensor even if it hasn't thrown a code.

[CamoDeafie]

isnt there also an Idle setting screw somewhere on them?

[sky81]

Do you mean the idle speed screw or the idle mixture screw?
Yes, the E2SE has an idle speed screw, which sets the slow idle on the 2.8 V6.
The fast idle screw is separate and is used for when the choke comes on.
On the 2.5 4 cyl, they used an idle speed control motor for the slow idle (when the choke is completely off).
The idle mixture screw on the E2SE is in the back of the carburetor but it is capped from the factory to prevent adjustment in the field.
You'd have to remove the carb and cut the cap off to get at it.

But I don't think the idle speed setting or the idle mixture setting are going to have any effect on whether the car bogs down under acceleration- hot or cold.
In this case it is happening under both situations. So it is most likely the accelerator pump or the float setting. Or the float having taken on fuel and become too dense for proper regulation of the level of the fuel inside the float bowl.
It's also possible that there's a bad air horn to float bowl gasket.

He's pretty much covered ignition, and he's saying he's looked for vacuum leaks.

Is the carburetor tight on the intake manifold? Don't over-tighten it- just snug it down.
If it's loose you'll have a vacuum leak there.

It's worth changing the fuel filter insidethe fuel inlet nut, also.

[Casper]

I'll check the carb's tightness today when I work on it. This car had sat up for a while (I don't know how long) before I bought it, so I wouldn't doubt that the float has sunken. Do rebuild kits have floats? or will I have to scavenge one? I'l probably rebuild it, either way. Any way I can check the Float's position? How would I get to it? I know nothing about these carburetors, Holleys, Edelbrocks, I can do, but these feedback carbs are a whole new realm for me. I've got a good O2 sensor from my dad's old van(rebuilt the motor and put all new parts on it) so I'll do that too. I'll also do the Filter, I was thinking that may be it. Thanks for the help so far guys!

[sky81]

Here's what I recommend you do. Haynes has a very good book called "Rebuilding Rochester Carburetors". It is excellent and will give you step by step instructions with photographs. There is a chapter in there on the Varajet carburetor (another name for the E2SE).
Feedback carbruetors are not any different than regular carburetors, except they have a mixture control solenoid instead of a power valve, and they have a throttle position sensor. All you have to do is pull these parts out and put them aside- there's nothing you need to do to them. Everything else you can take apart and clean out, just like a regular carburetor.
What is cool about the E2SE is that you can take the little vent off and you can stick a gauge in there and figure out what the float setting is, without even taking the carburetor off the car! Just don't drop the little screws inside the carb when you do it!

No, a rebuild kit will not have a float included, but it will have the float gauge I just mentioned.
A rebulld kit will probably cost $25 at NAPA, and a float will cost probably $10.
It really isn't worth re-using an old float from another car, if that's what your problem really is.
If the float is just mis-set, you can try bending the tang on it to adjust the level (you have to take the carb apart to get to it- the vent removal tric is just for checking the float _level_. BTW I think you have to do it with the car running, but don't quote me on that- read the Haynes manual and rwad the rebuild kit instructions.
The E2SE is actually a fairly straightforward carburetor, other than looking a little weird because it's a rectangle.
But it has your standard 3 pieces- an air horn, float bowl, and throttle body.
A lot of the pieces to it aren't serviceable anyway (e.g. the idle mixture screw is supposed to be plugged with a cap; there's a rich mixutre screw inside the carburetor [not an idle mixutre screw- it's meant for crusiing fuel delivery] that isn't adjustable- you just unscrew it from the bottom of the float bowl. Mxture control solenoid and throttle position sensor are not adjustable).

The main things you'll have to replace are the needle and seat and the accelerator pump and check ball.
And check the float adjustment, re-set the sdjustment or replace the float.
You also might want to check the adjustment of the choke opening, and check to make sure the choke vacuum break is holding vacuum and is working as it should. If the car has a/c and it's an 83-86, it should have an idle load compensator on it.
You just check to make sure it holds vacuum- that's it.

I assume you have a vacuum gauge handy to test these things with.

Clean it out, put in new gaskets, a new accelerator pump, a new needle and seat, possibly a new float, do the choke adjustment, check the vacuum break and possibly the idle load compensator, set the idle speed set screw, a new fuel filter, and you should be good to go!

BTW you might need a set of Torx screwdrivers (attachable to a socket wrench) to unscrew the pieces of the carburetor.
They didn't use regular screws unfortunately.

[Casper]

Thank you sky! only one last question. What's the setting on the float supposed to be? And I plan to get that book. Hopefully it's just mis-set. :) I have a vac gauge, but don't know where the heck it is O_o

[sky81]

Unfortunately it's been a while since I rebuilt one of these, so I really don't remember the setting.
I can tell you that the setting they list is the distance from the top of the float to the top of the float bowl (i.e. when you're rebuilding it).
If you try to measure it with the carb still on the car by taking the vent screen off, you're measuring to the top of the air horn.
That's a different reading, so check the instructions and see if it has both settings in there.

I thought of one other thing. When you do the rebuild, they will give you self tapping screws in the rebuild kit that hold the choke coil to the housing. If the carb has not been rebuilt before, the choke coil will be riveted to the housing. You need a drill and a drill bit (forget what size) to drill off the rivet heads. There's a little notch in there that is supposed to index where the choke coil sits in the housing. But, if you're not happy with the setting (i.e. the choke comes off too quick or it stays on too long) you can adjust the choke coil clockwise or counterclockwise to get more or less length of time that the choke stays on. If you don't think the choke is the problem, you can skip this step.

The reason I bring this up is because after many years, the bimetallic coil that holds the choke coil tends to wear out and leaves too much slack. It can allow the choke to come off too fast and cause stalling when the engine is still cold. If you can turn the choke coil whichever way gives more choking action, you'll have fewer problems with stalling when the engine is cold.

I don't think this is your problem though because you say the car bogs down even when the engine is warmed up. But, it could be a contributing factor.

Older Rochester carburetors had a marking on them that said "<-Rich Lean ->" so you knew which way to turn it, but your car will have an electrically heated choke so it will not say that on it. You'll need to figure out what setting works best. You might need to take the drill and drill back the index in the choke housing (it should be aluminum) so you can turn the choke coil to the setting that works best for you.

The 2.8 V6 does not need a lot of choking, compared to the 2.5 4 cyl.

[Casper]

You're a godsend Sky. You've given me a TON of info. I appreciate this a lot. I'll rebuild it. It's a mess. There isn't really any gas in the bowl, so It's waaayyy lean. I figured it was, cause there was no raw gas smell fron the tailpipe.

[85_Ciera_Rebuild]

hard to start and won't idle for 3 minutes after starting

Always check fuel pressure....and if there is a volume test, that too.

Usually, hard to start means (1) No fuel in carb, cause it leaks down, or (2) choke is not working....if timing & computer are working fine.

I don't know this vehicle, if it has a distributor, then the module will start vehicle, and transfer control over to computer....but go to automotive store and see if you can get a code....if your computer has shot craps....well.

[Casper]

Well, I picked up a carb from a Skylark today, looks a lot better than mine, but we'll have to wait till I put it on to see what happens. Also I'm going to check the timing.

[Casper]

Put a newer o2 Sensor on it since the old one was broken completely out of it's metal ring. I unplugged it before, and got no check engine light, even though there was no o2 sensor. Now with the new one in, it has a lit check engine light, but idles and runs a tad better, starts quicker, but still bogs hard. I was wondering, since I made a carb gasket for a 5 horse briggs and stratton out of a cardboard shoebox lid, and it worked great, could I do that for that for this car? The intake/carb gasket.

[Drop Top Olds]

A factory service manual will also provide very detailed information on rebuilding your carb. It is your best investment.

Check out Helm on the internet. They have pretty good prices on GM factory service manuals.

[sky81]

I would think the reason you're getting a check engine light now, with the new O2 sensor put in, is because it is detecting a very lean or very rich mixture condition.
I wouldn't make a carburetor mounting gasket myself. You need it to seal well, and if it doesn't, you'll have vacuum leaks and you'll continue to have driveability problems.
A new carburetor base gasket will come in the rebuild kit (approx cost $25). Or you can buy a carburetor base gasket alone, which will probably be something like $5 or $6.
Also, if you don't use the correct carburetor base gasket, you run the risk of tightening the mounting bolts too tight, and you can crack the throttle body.
The correct carburetor base gasket will have strengthened areas around the bolt holes that a fabricated gasket will not have.
I have actually seen this happen on a 2SE carburetor when the incorrect carburetor mounting gasket was used and the bolts were tightened too much.

[Casper]

Ohh, sounds like bad juju. I'll have to order the gasket. NO ONE in town has it. Not even the Napa warehouse. I'm gonna go work on it tomorrow. Hopefully the old one will be okay. I'll check and see. I'm gonna jump the diagnostic terminals and check the timing. The car's at my friend's shop. He's the one I bought it from and He was just the broker. The crotchety old man wo owned it before me let it sit for a while, finally he needed it, he threw some new tires on it(400 dollars worth) and it ran like crap, so he sold it. The main reason it ran so badly is the fact that the plugs were literally worn to about a .100 gap. I'm surprised it ran at all. If the old gasket is bad, I'll just have my buddy order it with his commercial discount and put the carb on another day.

[Prospeeder]

u tried spraying brake cleen all over the gasket surfaces like the intake manifold and carb for vacuum leaks? if the engine light is on, pull the codes, alls u need a paper clip, look online

[Casper]

For some odd reason, The light went away. and the car has a master disconnect switch, which my a**hole friend decided to flip right as I was going to pull the codes stored in the computer. I have tried that. And to no avail. I'm just going to swap carbs once I get a gasket. I also noticed today, the secondary on the carb isn't opening. Would it open without a load on it? I know my junkyard carb will open just by pulling the throttle linkage past halfway. Maybe that's my problem!

[83STE]

Definitely do the above carb rebuild and other work as posted above. A few pointers on the carb rebuild: You will need to have a set of Torx bits. When you remove the carb use some bolts as standoffs under the throttle body, so you won't rest the throttle plates on the bench and bend them. If you dip the carb, you may have to remove the throttle plates to prevent damage to the bushings. As alternative to dipping you can use carb cleaner and canned air to clean the passages, which is the method I used.

On my car besides the dirty fuel bowl, the other source of drivability problems was the throttle position sensor that was out of adjustment. To adjust this use a small slide hammer or a self-tapping screw and mini pry bar to extract the plug which covers the adjustment screw. The plug is located in the area of the accel pump plunger, but be careful as the carb metal is weak. .Back probe the TPS plug at the plug terminals with a digital voltmeter across the center terminal (B) and the bottom terminal (C). With the ignition on and the engine and A/C off, turn the adjustment screw until you see .26 volts on your meter.

You can also adjust the primary fuel mixture by adjusting mixture control solenoid duty cycle using a dwell meter or duty cycle function on a multimeter. Instructions should be able to be found on the web or your rebuild kit. Most like this is not the problem, but I thought would include it.

[Casper]

Well Thanks STE! I don't think it's my problem but I'll check it. I'm pretty sure my problem is the secondary not opening, but we'll see.