Terrible gas Mileage on 1986 Monte Carlo!

[Lorenzo]

For the USA folk that's 186 miles to 13.74 gallons...or 13.5 MPG for the 300km/52 litre tank or 8.8 MPG on the 195 km tank

I suspect that the electronic components of the CCC quadrajet are in need of attention....assuming it still has one on it.

Tough to diagnose without knowing a lot more about the situation.....driving style/type of trips/idling time/state of tune/overall engine health.

My personal experience with the OEM QJ on my 83 Bonneville was that after almost 30 years, it had deteriorated to the point that I was getting about 10 MPG. The TPS and the idle solenoid were both dead players. After installing a completely remanufactured unit, MPG went to 16 on my daily commute.

Are there any codes stored? Even if there is no check engine lamp on, there may be codes being generated/stored...some people (like the previous owner of my Bonneville) seem to believe that removing the bulb will "fix" that annoying light

And BTW, "plugged jets" would make the car VERY lean, assuming it would run past idle at all.

Well its an electronic feedback carb with the electric choke. Ive had to clean the connecter on the choke before because it wasnt work properly at all. As for my driving habits i dont push it very far to the floor unless i need to pass a car or go up a very steep hill which is very rare. I havent checked for any codes because i dont have the software to do so. Also funny you should say it runs lean because it kind of does sometimes. When its cold outside the car starts with one turn of the key and a couple of pumps of the throttle and it starts up and idles fine. but when its warm outside the car will start then stall, so i have to start it back up and then it will stall again. The third time is when it can actually idle on it own. Usaully when i put it into drive or reverese or any other gear i have to give a quick pump of the gas otherwise the car will stall. Once i do that the car will run fine. Usaully when im idiling it does idle low and the car does shake a bit too. Also once the car hits 4th gear it seems to bog down, i have to push very far down on the accelerator just to get it to 80. Hope this helps a bit! Thanks!

 

[Clone TIE Pilot]

Have you tried checking your m/c dwell with a dwell meter?

Im sorry i have no clue what that is lol.

The mixture control solenoid, you check it's duty cycle with a dwell meter. Sounds like you need to study some repair manuals for your car. As already said you should also check for trouble codes.

 

[85GPLef41]

you can pull the codes with a paper clip and count the check engine flashes...try this website
http://www.extreme-check-engine-light-c ... ecoder.htm

 

[Lorenzo]

Have you tried checking your m/c dwell with a dwell meter?

Im sorry i have no clue what that is lol.

The mixture control solenoid, you check it's duty cycle with a dwell meter. Sounds like you need to study some repair manuals for your car. As already said you should also check for trouble codes.

Well i do have the Haynes reapair manual and it doesnt say anythiing in there about the the Mixture Control solenoid. Where would i be able to see this part on my carb, and how can i check if its running properly.

 

[Lorenzo]

Is this what the connector looks like? I tried attaching a paper clip and a wire between a and b and no light came on when i turned the key or when the engine was running?

 

[Ribbedroof]

Obviously, won't work if they pulled the bulb/it's burnt out from being on all the time.

If you turn the key "on", engine not running, does the check engine light come on?

Also, Haynes and chilton manuals are a joke for anything beyond the most basic changing a water pump type operation, spend the money for the real GM manual.

 

[Pontiac455]

Remove the carb, pull the top off, I bet the power valve is sticking which will make it run rich esp during cruse. Take it out give it a ligs scuff with some fine grit emery, give the bore a little rub as well. While yer there throw a kit in er, and pop out those plugs so u can adjust yer idle circut. Reason why GM put those plugs there was because they set em up a little too rich for emissions this caused a slight miss at idle.

 

[Clone TIE Pilot]

That is weird since mine says quite a bit about the m / c solenoid, info for it should be in the fuel system chapter in the carburetor section. Maybe Haynes down sized their manuals? My Haynes explains how to check the m/c solenoid using a dwell meter.

 

[Lorenzo]

Obviously, won't work if they pulled the bulb/it's burnt out from being on all the time.

If you turn the key "on", engine not running, does the check engine light come on?

Also, Haynes and chilton manuals are a joke for anything beyond the most basic changing a water pump type operation, spend the money for the real GM manual.

Well when I turn the key, the only thing that lights up is the fasten seat belt light. Maybe I shoulda checked if it was burnt out when I took the cluster off before 😛 I'll check that tommorow

 

[Lorenzo]

Obviously, won't work if they pulled the bulb/it's burnt out from being on all the time.

If you turn the key "on", engine not running, does the check engine light come on?

Also, Haynes and chilton manuals are a joke for anything beyond the most basic changing a water pump type operation, spend the money for the real GM manual.

Ok so today i went out and bought new bulbs. Replaced the one for the check engine, and still nothing happend? There is only 3 bulbs behind the dash too, is that normal? Thanks