Question: Another E4ME question

[LannyL81]

Hello to everyone....I found my way back.

Anyways, short story is that I have my '81 up and running...sort of...have a problem with running way rich.
Am I correct that if I see fuel dripping out of the primary nozzles at idle that I have the float too high?

I stuffed cotton swabs on the nozzles and had the idle mixture screws all the way in...and the engine still ran the same. I don't know where it was getting fuel from...but it is. About ready to just get another carb or send this one off for rebuild and I did everything according to the book...with possibly the exception of the float level.

Any suggestions???

Thanks in advance,
LannyL81

 

[Sensei]

Float level is one possibility. Another is the way you hung the needle valve on the back of the float. Where you hang it has two holes, and it looks like you should hang the little wire hanger in a hole to keep it from falling off. If you do this, the valve will stay open and overflow fuel. This is a common "oops". The good news is either way, float or needle valve, the fix is easy. You don't even need to take the carb off the car. Just take off the air horn, fix the problem and go!

God bless, Sensei

 

[LannyL81]

Yep, know about the float needle valve hanger and those two holes. I have rebuilt several Q-Jets over the years and that aspect is all the same....stay out of those holes.

So unless it slipped during reassembly or something..it should be correct. And you are right, just taking the airhorn off is all I need to do. I have had that airhorn off so many times....even have a extra gasket ready for this. The only thing that gives me a problem is the gasket around the mixture control solenoid connector.

Guess I should go get busy and do this.....only takes 30 minutes to do.

Thanks for the reply.

 

[LannyL81]

Checked the float level....it was good...maybe at the most 1/64 high.

I put a new air horn gasket on it and tightened all the screws in order and the fuel dripping out of the primary nozzles stopped.

Adjusting the aif fuel mixture screws...still have no effect though. Tried carb cleaner and cotton swabs....got alot of black stuff out...but no difference.

Still working on it.

 

[GerryLP]

Lanny,

Great to hear from you again, pal.

If the float is ok, there is got to be something forcing the fuel in (or out )of the nozzles. By chance you still have a mechanical fuel pump right? Not an electrical fuel pump without a regulator? right? The carb can only take between 6 - 7 PSI at idle and no more than 9 PSI at WOT.

Just asking, you know?

AT idle I see fuel dripping from the nozzles as well. It is not a constant, nor evenly spaced dripping, it seems, but I can discern the fuel drops just as well.

Have you attempted to check the air valve adjustment of the carb at idle with a dwell meter? The L81 manual has the procedure, and when read from the 6-cylinder scale, the needle should "hunt" (vary back and forth small distances) near the 30 degrees on the scale.

GerryLP:cool

 

[LannyL81]

Gerry,
Before I took the air horn off (again), the fuel coming out of the nozzles was a fair amount. Now its all dry until I open up the throttle plates. Even got the secondaries to open up....never done that before.

As far as the dwell setting...I have tried, but unable to stay in closed loop at this time due to the headers/sidepipes. Have a heated O2 sensor on the way to fix this and once I put this in, I should be able to try to adjust the dwell. Currently it just stays fixed at about 27. Hope the heated O2 sensor fixes this and leans out the mixture.

Thanks for the reply buddy,
Later,
Lanny

 

[LannyL81]

Does anyone know for sure what the idle mixture needle screws at the E4ME base adjust.....air or fuel???

 

[6880 Mike]

Does anyone know for sure what the idle mixture needle screws at the E4ME base adjust.....air or fuel???

I don't know, but Doug Roe does.

His book includes a section on the E4ME.

 

[GerryLP]

Lanny,

Here is an image of my E4ME manual 9D-5-1:

The end of that paragraph on the next page mentions the anti-tamper fuel needle plugs and that the calibration procedure on page 15 "must be followed exactly" after a major carburetor overhaul.

GerryLP:cool

p.s. let me see if I can get it loaded larger...
View attachment 18346

 

[Sensei]

You can look in the primary bores and see the idle needles sticking into the bore as you screw them all the way in. They intersect a fuel passage outside that point (in the throttle plate) and then form a restriction in that hole leading to the primary bore. As you screw them out, it allows more fuel to flow into the primaries.

God bless, Sensei

 

[LannyL81]

Mixture Control Solenoid connector question:
Which way do the wires face coming out of the connector when mated to the carb? Do the wire face toward the carb airhorn or away from them???

Maybe I have my connector on backwards....it will go either way. But one way I get an error, the other way I do not...so I think I have it correct....but still running way, way, way too rich.

Lanny

 

[Sensei]

Mine has a clip that will only allow it to go on one way. If you had it plugged in backwards, you may have damaged the MCS.

God bless, Sensei

 

[LannyL81]

I have the Doug Roe book....read over it again yesterday. Did not find my answer yet.

My MC connector did have a clip on it....but it broke off. One way the harness connector fits over the carb bolt head just fine but it looks to me like its on wrong. But the other way, the harness connector does not fit over the carb bolt head very well, bolt head interfers with connector body, but where the clip was appears to line-up.

So I really need a close-up picture of this connection.

Anyone with a camera?

 

[Sensei]

Sorry, no digital picture (a 1981 computer controlled carb is as close to high tech as I get). But I did look at my connector, and If yours is like mine, the wires come out of the connector to one side. That side is toward the front of the car (not inward toward the carb). Hope this helps.

God bless, Sensei

 

[motorman]

if your corvette still has the computer controlled carb you need the gauges to set the M/C lean stop,the rich stop and the idle/air setting. here are the gauges you need.

 

[LannyL81]

Sensei: got it....that is what I needed to know...wires are towards front of car, not inward towards carb. That is what I thought as well.

Motorman: I have the set of carb tools....not quite the same as yours...a newer version...but they work...just cheaper made.

I am going to check the lean setting of the M/C solenoid again. That is the only thing I can think of that might be off. I know I have 4/32" travel, but if I set the lean level too low, then I would be on the rich portion of the metering rods all the time. I am sure I used the lean gauge, but if this is not the problem, then I will probably just get a rebuilt carb from somewhere.

I did the Lars lean/rich test and removed the pump lever and the engine accelerates much better...so it is getting way too much fuel...I just do not know from where??

 

[LannyL81]

Is this the correct way the MC connector should go??

 

[bradfordsvettes]

if the air mixture screws are to far out this can also be a problem. If my memory serves me right all the base settings start at three truns out from being bottomed that is the adjustment in the cover bowl and base plate the idle air control is set with the tool and os basicly determined by the rich lean stop settings . check and make sure your float is not soaked with gas and heavy and needle and seat are ok float level is correct Steve

 

[Sensei]

LANNY! It looks like you are missing the vacuum brake for the secondaries! It is a little metal "flying saucer" just in front of the choke housing that connects to the secondary air valve. If I'm remembering correctly, this would cause problems when going to WOT.

God bless, Sensei

P.S. Yes, the connector is plugged in right.

 

[LannyL81]

Correct in that the initial idle mixture screw setting is 3 1/3 turns out from all the way in. Have done all the settings, new brass float, level is correct.
However it makes no difference where the screws are at, unless all the way in which will stall the engine after about 2 minutes...or all the way out, which stalls the right away.
It appears that I am not going into closed loop as the dwell just does not vary, it is a steady reading. I can hear the MC solenoid clicking away when I go into test mode, and I have no Check Engine lite now that I have the O2 sensor wired-in better. The MC solenoid resistance checks good. There is 12 volts at the connector when in test mode. I am taking an O scope home this weekend to see what the signal actually looks like at the MC connector.

And I took off the secondaries choke hold-off....thought I might get better throttle response. But since I am running so rich...I do not even need the secondaries to open at all. More than enough fuel comes from the primaries.

Anyone want to loan me their computer for a week?