Full Version: Rich mixture
I have a 75 1.8. Seems to be running very rich. I replaced some relays on the board, both having to do with fuel. Im getting alot more fuel. When I drive her. At higher RPMS the engine seems bogged down and sputters a little. Too much fuel? How do I change my air fuel ratio? Theres no nob on the computer like a 2.0. I have good fuel preasure. Seems to read right on 35.7.
Have you checked to see if the air flap is stuck?
Geoff
Geoff
How do I check to see if the air flap is stuck? I found the adjustment screw on my air flow sensor. The is no apoxy so I assume someone has already adjusted it. I dont have access to a smog dyno right this second. Would it be worth messing with? Which way is lean and which is rich? Im definetly experiancing air restriction or a rich mixture.
Before you start adjusting things lets make sure it is a rich mixture buy taking out the spark plugs and looking for a lot of dry black soot all over the plug. It is normal for the 1.8 to have black soot around the edge of the plug. A rich sign is when the plug almost flowls because everything is covered.
My 1.8 had bad Injectors. I replaced them and it helped alot. Also check the Head Temp Sensor on the passengers side near #3. It should have 2500 ohms or more cold and 100 ohms or less hot.
Then its back to basics. Check the dwell, timing, vacuum at the plemum, Compression, and make sure all hoses are not leaking vaccum. Check the Distributor "Mechanical advance" by making sure the dizzy snaps back when moved a little by hand. Make sure the pots can hold a vacuum on the retard and advance canisters.
Once all that checks out then look to the AFM. A stuck flap is easy to check for. Take the plastic cover off the top and gently rotate the flap. Check for any area it seems to get harder to move or sticks at. I have actualy run the car with the plactic cover off to see how it moves. I could tell mine was sticking just above idle making it run really rich at that level.
The adjustment screw you see towards the throttle will effect richness at idle only. Screw it in for more, out for less.
After all was said and done on mine I found that it ran much better with a new AFM installed. But that was after I did everything else.
Welcome to the dark side!
My 1.8 had bad Injectors. I replaced them and it helped alot. Also check the Head Temp Sensor on the passengers side near #3. It should have 2500 ohms or more cold and 100 ohms or less hot.
Then its back to basics. Check the dwell, timing, vacuum at the plemum, Compression, and make sure all hoses are not leaking vaccum. Check the Distributor "Mechanical advance" by making sure the dizzy snaps back when moved a little by hand. Make sure the pots can hold a vacuum on the retard and advance canisters.
Once all that checks out then look to the AFM. A stuck flap is easy to check for. Take the plastic cover off the top and gently rotate the flap. Check for any area it seems to get harder to move or sticks at. I have actualy run the car with the plactic cover off to see how it moves. I could tell mine was sticking just above idle making it run really rich at that level.
The adjustment screw you see towards the throttle will effect richness at idle only. Screw it in for more, out for less.
After all was said and done on mine I found that it ran much better with a new AFM installed. But that was after I did everything else.
Welcome to the dark side!
At idle. It has little backfires every now and then. Gets worse when accelerating. Im going to do plugs and the things you mentioned after work. Mabey its just timing. Smells way rich though. Thanx for all youre help!
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