QuestionQUESTION: 1995 sidekick jx 16v 5 speed.
Mr.Scott,
You have helped me a great deal in the past and I hope you can give a hand here.
You helped me solve a heating (cabin) problem by reverse flushing system, and then I contacted you with a floating idle situation that you said could only be remedied with a factory manual. You mentioned that there is a bipass tube in the throttle assembly somewhere that may be affected by temp and I took a guess that by restoring a proper radiator heat, after having the car adjusted to running colder for so long something was just a bit off so I tried adjusting my air mix screw several small times and finally got the idle to settle around 1000 rpm except when it is cold then it still lopes a bit, but since then my gas milage has dropped. I use my car to deliver papers and I travel the same route every night, with my milage I'm using what would seem to be an extra 25 more miles of gas over 3 days time and some power. Should I restore the idle screw to where it was and let it lope or loose the extra gas and no lope. also I appear to have a pinhole leak in radiator somewhere on bottom will this get bad in a hurry or just smell a bit, there is no drip just an occasional smell of coolant while driving.
I have a complete head from another jx should I just replace the throttle or the whole air intake section that it is attached too?
ANSWER: One of the issues that is seldom considered in fuel mileage changes is ambient temperature. In the winter, the engine is cold longer, thus using more fuel until it is warmed up. Additionally, the oil is colder, requiring more energy to pump it until warmed up.
When considering your vehicle, I assumed it was a U.S. Sidekick with injection, which has a relatively complicated procedure for setting idle speed. Mixture is controlled by the engine temp sensor, mass air meter, oxy sensor, and the engine control module.
If yours has a carburetor, and as you have said, a mixture screw, all bets are off, for I have no knowledge of your fuel system, and the accompanying devices.
As for the pinhole leak, you can only monitor it closely, and see if it is getting worse quickly, and act accordingly.
You could replace the throttle body (assuming it is injected), and see what happens. At the minimum, there's an even chance it could work better.
scotty
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QUESTION: I'm sorry I should have said that it is the 16v fuel injected. When looking at the motor from the front the air intake tube goes to the throttle which has (I'm assuming is the mixture) screw on top right by the throttle sensor. If its adjusted counterclockwise the motor revs up but then it lopes more. I marked the metal where the screw was set then turned it clockwise until the idle came down and it lopes less and stays around 1000 except when cold then it stays high until I guess it reaches op temp. This loping only began when we flushed the radiator.
The metal housing that the throttle is attached to that sits over the injectors ( the unit that has the vacuum hoses and egr brass tube attached to it) what is that called and what does it do? could it become clogged. Could it be cleaned or should I try the old one?
And lastly the pinhole, until I can replace it its not going to burst or anything like that?
ANSWER: I think that is the screw that opens and closes a bypass passage that allow gross idle speed to be set. I don't believe there is a mixture screw, because the injection makes all of the decisions regarding mixture. I suspect the loping is a fuel shutoff for decelleration that usually starts at about 1200 to 1400 rpm when the throttle position sensor indicates idle position, and the bypass screw allows too high an idle speed.......
I have never worked on a 16 valve, and am not familiar with it. I can't translate your description into technical terminology, and advise you as to what to do. It's sort of like target practice by braille. That's why you NEED a shop manual.
The leak will just gradually increase, how fast, I have no way to foretell.
scotty
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QUESTION: you said the mixture is controlled by a temp sensor and since this began to happen with a change in my coolant temp maybe I should try fixing this first? where is it located?
also on the part where the throttle body is mounted( the air intake manifold?) on the right side of it there is a unit that has 2 small coolant lines that run in and out of it with a electric plug is this the temp device for the throttle?
anywhere online I can view a factory manual?
Thank you
AnswerOk here goes...
IF the coolant is too cold(bad thermostat, or IF the coolant sensor "believes", and sends a signal to the effect that the coolant is cold(relatively so), then the idle will stay high, a symptom you have said is not the case with your vehicle, so that's another theory to discard as not applicable in this particular case.
The inputs to the computer are:
the coolant temp sensor
the intake air mass meter
throttle position, usually both idle on and off, and a variable signal that reflects throttle opening percentage
engine speed, usually a distributor signal
the oxy sensor in the exhaust, that is a feedback signal telling what the functional mixture is
These all work together in combination to generate an injector opening duration to vary the fuel delivery quantity according to all the varying conditions of load, engine speed, temperature, both internal and external......
The device you describe may be the throttle body, and the tps, or not, because I don't have a "picture" of the engine in my mind, as I would if I had worked on one. I can only describe the devices that I'm fairly certain your vehicle has, being an electronically injected Japanese vehicle..
I do not have access to a manual, either on paper or online, and have never seen that kind of copy protected book containing that kind of information available any way but for sale.
I must incessantly and stubbornly repeat that you need to have access to the factory procedures in order to set the idle correctly, and determine if and what device or combination of devices and adjustments are the source of your issues. I would have to read and follow the procedures myself, and consult the manual for measurement values to do adjustment/diagnosis myself
