Has anyone messed with the Q Jet on their 81 or is this something that is better left alone. I have a HyperTech Chip installed.
The reason I am asking is that when the car is hot {I mean HOT in the Arizona Afternoon and Summer is not even here yet} and you floor the gas pedal the car dies out like it starving for fuel. The car runs fine until you floor it and then just goes BLAHHHHHHHHH but if you drive like a normall person no problem . Do not have this problem in the cool mornings. Maybe I need to go East for the Summers.
VAPOR LOCK ?????????
Later
Ken

 

tham -
Ive heard/read that you arent supposed to mess with the mixture setting. It is set at the factory and
not to be changed.....

but ....as a fellow 81'er , I will throw you back to the top :D

 

I rebuilt mine, runs much better now. I also picked up a set of the tools at Napa to make sure everything was set right.


[Modified by stickboy, 10:03 AM 4/4/2002]

 

stick - did you rebuild it to stock?.....did you mess with the mixture setting?

Kevin

 

Hi, Ken,

I rebuilt my E4ME about 6 years ago with a basic kit from NAPA and a book from PepBoys called "Rochester Carburetors" by Doug Roe. It's not particularly difficult, if you have the patience to deal with instructions and some skill with tools. After the rebuild, my Q-jet performs beautifully. The throttle response is the sharpest of any carbureted car I've ever driven. The rebuild included complete disassembly, so of course the idle air screws and the mixture control solenoid all had to come out and be cleaned and reset. That involved fabricating a couple of tools, nothing complex, as described in Doug Roe's book. That book is an excellent resource. My carb has recently developed some additional problems; the fuel bowl leaks down over a couple of days, and the high idle cam sticks on startup, so I'll be pulling it off to do another rebuild soon.

There are a lot of different things that could be causing the WOT bog you're experiencing, so I won't speculate. I think you've got to take a systematic approach to diagnosis on that.

One thing you might think about: There's a place in Mesa called "Carbs R Us" that does a LOT of Q-jets. Their phone number is (480) 461-1690.

 

Sounds like the HEI module has failed. I've had this happen twice. Rotor fails causing spark to pass through center of rotor to shaft (signs of brown/orange dust will be on advance weights under rotor). Stray spaks can hit and damage HEI module over time.

Took me ages to figure this out on an older Trans Am I had. Im the morning it was find, but once warmed up, the ignition could not fire the richer mixture beyond light throttle. I finally got the engine hot and allowed the distributor to come up to temp (running bad), then sprayed electronic component cooler on the distributor near the module to cool it and the motor then ran fine.

Replaced the rotor and HEI module and motor ran like new again! It's worth a try and is common to mistake this for the carb. This also happened to my vette a few years back and also a friends.

Good luck

 

Yes, I rebuilt it to stock, the ECM will handle most of the mixture settings. It looks like you vette is completely stock except for the chip, which shouldn't hurt you in any way. I would say rebuild your carb, make sure you buy a new float (I forget the part number, Lars gave it to me) and make sure the mixture setting are correct. You may want to check to make sure your ignition system is up to par too. I will post the numbers of the float and tools later when I get home :cheers:

 

Here is more info on rebuilding the E4ME.

Lars suggests getting an Echlin (Napa) brand NitroFill float (not a brass float)

This page describes the tools for adjusting the E4ME, http://www.aros.net/~rbuck/tech/carbtool.html, these tools are still available at NAPA and the tools/gauges cost me about $30

 

You need to readjust your Air Bleed Valve setting. On the passenger side of the carb there is a flat head screw, with an allen head setscrew underneath. Loosen the set screw while holding the ABV flat screw with a screw driver. Turn the flat head screw until the tension in the spring is totally relieved. Now turn the screw back until the spring touches the retainer and turn past that point 1/8 turn. Try it out, you shouldn't have a bog. If you still have a bog, turn the screw further, like a 1/4 turn (and so forth), until the bog is gone. That is one of the more pronounced sympotms of the E4ME carbs. I know these carbs like the back of my palm, since they are also equipt on '82-'87 Camaros. :cool: Good luck!

 

I'm confused???? Aren't you talking about the tension on the secondary butterflies? Or is air bleed different than idle air bleed, which would be a screw in the center above the primaries.