Rough Idle when put in gear
August 13th, 2011, 03:49 PM
#1
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Rough Idle when put in gear
Please help any info will be apreciated. I have a 1967 olds cutlass with a 330 ci motor it has a rochester 4 barrel quadrajet carburetor. I just got done with a full tune up points,plugs,wires,air filter. I adjusted the carburetors air and fuel mixture screws per specs and adjusted the base idle screw and the car is perfectly idled while in park.As soon as she goes in gear it starts to bog down like it wants to stall and does stall but not every time. can it be the fuel filter? i havent changed that. i also put a new pcv valve. any help would be apreciated im hoping its not a full carb rebuild i need.
August 13th, 2011, 04:57 PM
#2
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Location: The Hudson Valley
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Sounds like you set the idle too low.
You said, "I adjusted the carburetors air and fuel mixture screws per specs and adjusted the base idle screw and the car is perfectly idled while in park.As soon as she goes in gear it starts to bog down like it wants to stall and does stall but not every time."
That seems to imply you adjusted the idle while in Park.
The idle specs were to be adjusted in Drive.
If that's what you did, it's an easy fix.
- Eric
You said, "I adjusted the carburetors air and fuel mixture screws per specs and adjusted the base idle screw and the car is perfectly idled while in park.As soon as she goes in gear it starts to bog down like it wants to stall and does stall but not every time."
That seems to imply you adjusted the idle while in Park.
The idle specs were to be adjusted in Drive.
If that's what you did, it's an easy fix.
- Eric
August 14th, 2011, 09:41 AM
#4
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Join Date: May 2011
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MDCHANIC is right. I did the same thing several years ago and could not figure it out. Simple error I ended up doing a full tune up and then still could not figure it out. After having a nice martini it was like a large lightbulb went off in my head, sure enough put it in drive put the ebrake on, adjust the idle and bang, perfect. Wish I had this forum 10 years ago.
August 15th, 2011, 05:55 AM
#5
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mdchanic i tried ur solution of setting the idle while in drive but to no avail the idle had to be set so high when it was put back in park it was reving way to high. i had a friend come over and look and we found a leak in the intake manifold gasket.could that be the reason for rough idle in park and a slight miss in the motor?
.
August 25th, 2011, 12:01 PM
#7
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well the intake minifold leak is fixed but the car is still rough ideling in gear and now is changing on its own. i drove it about 30 miles yesterday and it was ideling fine but when i got off the interstate it was ideling so high i had to hold the brake hard to keep car from taking off. i checked the carburetor and it has a serial number 7026250 which indicates its a 66 model carburetor and my car is a 67 so its not original to the car. could this be the problem? i read somewhere that pre 67 carburetors were prone to problems? should i just buy a holly or edelbrock for it? i seen a site where they are charging almost 400 dollars to rebuild a rochester quadrajet and fix the 42 factory problems. are there really that many problems with a factory carburetor from that year?
August 25th, 2011, 12:12 PM
#8
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Sounds like you may still have another vacuum leak.
Go around all vacuum lines and parts, and intake and carb joints with a propane torch (not lit) or a can of car startin' ether - if it speeds up where you spray, you've found your leak.
- Eric
Go around all vacuum lines and parts, and intake and carb joints with a propane torch (not lit) or a can of car startin' ether - if it speeds up where you spray, you've found your leak.
- Eric
August 25th, 2011, 01:28 PM
#9
Be VERY carefull when doing this and do it outdoors. Propane and Ether are both heavier than air and can fill up all the little pockets and valleys waiting for a spark or ignition source to light them.
I usually prefer brake cleaner as it evaporates very quickly and is not nearly as dangerous. Its also easier to spray on the joints.
I usually prefer brake cleaner as it evaporates very quickly and is not nearly as dangerous. Its also easier to spray on the joints.
August 25th, 2011, 01:29 PM
#10
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Location: Rogues Island, USA
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My 66 carb has been a nightmare. Especially with fuel entering the bowl unmetered. The needle and seat design on those 1st generation Rochesters is a poor design. In addition to the needle and seat is a little tower along side it on the passenger side that also leaks if not sealed off correctly. Only the addition of an aluminum plug and JB Weld finally stopped that from leaking. Since you can't see any of this it's maddening to say the least. Is the upper bowl gasket wet and leaking? If so I'd look at the two things I just talked about.
Once fixed it will run like a dream though. The one saving grace of a Rochester 4bbl.
Once fixed it will run like a dream though. The one saving grace of a Rochester 4bbl.
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