Electronic carb wierdness
02-13-2003, 05:08 PM
#1
Drifting
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Electronic carb wierdness
Okay, here's a strange problem...
I've adjusted the idle screws and the rest of the electronic carb adjustments.
So if I let it sit and warm up, the carb has a nice dwell (35-40) and the O2 sensor
reads about .4-.5 volts (.47 is ideal.)
So if I go for a run and then let it idle, now the dwell is up around 50 and the O2 sensor
is around .6 volts. BUT if I turn off the car and then turn it back on, the dwell and
O2 sensor will read the good (above) readings. :confused:
So now what can be happening that turning off the car (cutting the electricity) and
turning it back on now makes the carb run fine?
I am assuming that turning off the car and back on will not change the air plates
in the carb. I assume there is no mechanical change - thus this leaves the
electronic solenoid and the power piston as a possibility.
Could this be getting stuck/out of line that it doesn't close all the way down?
What else can be wrong that fixes itself with turning off/on the car?
:confused:
02-13-2003, 05:33 PM
#2
CFOT Attention Whore
Re: Electronic carb wierdness (adam)
wow! that is way beyond my e4me (?) knowledge. i just turn mine till she runs nice and off i go! do you have the book by doug roe? that would probably be the best your going to get in that respect.
02-13-2003, 10:03 PM
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Re: Electronic carb wierdness (adam)
I think you have a problem of some kind in the ECU, your carb is probably fine. I'm not an expert by anyone's standard, but I don't think that the carb has anything to do with control of the dwell.
02-13-2003, 10:43 PM
#5
Drifting
Re: Electronic carb wierdness (Smokehouse69)
Adam,
Letting the car idle will not produce the same engine temp as driving. After you test drive the motor is hotter requiring less fuel which is why the dwell is so high. The 02 is trying to lean it out but can't. You may have a weak 02 sensor. Have you ever seen it above .8 volts? One other problem is your air management valve is gutted preventing the air pump from switching airflow. When you shut it off and then restart it the comp is back in open loop cooling off the exhaust and 02.
Mike
Letting the car idle will not produce the same engine temp as driving. After you test drive the motor is hotter requiring less fuel which is why the dwell is so high. The 02 is trying to lean it out but can't. You may have a weak 02 sensor. Have you ever seen it above .8 volts? One other problem is your air management valve is gutted preventing the air pump from switching airflow. When you shut it off and then restart it the comp is back in open loop cooling off the exhaust and 02.
Mike
02-14-2003, 12:14 PM
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Re: Electronic carb wierdness (tracdogg2)
Hey Mike;
The reason I think something is wrong with the carb is that when I restart
the car (after it's nice and hot) the dwell and O2 readings are in good shape.
But if I drive off and then idle again, the ECU can't get the mixture down (the
O2 reading stays high) so it hunts to drive it down - the dwell climbs to 50,
the O2 reading fluxuates as the mixture fluxuates, etc.
Hey Mike, its nice to hear from you again - we'll have to get together on this...
The O2 sensor should be fine - I replaced it a while back.