Nissan Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
greetings,
my b12 90 sentra has been a good boy for the past year, but then it started to stumble and die on stops. to remedy the problem I 've searced for ways to adjust the idle. there's a nut/bolt/spring combo on the outer part of the throttle linkage, and it hits a shock absorber looking thing (it may be a decel absorber, so the throttle closes slowly). I adjusted it to where the idle is higher, but maybe too high, I might've just opened the throttle plate more. it wouldn't stumble and die tho, for a day.

next day driving to work on the freeway, I feel what felt like a fuel cutoff (like if you hit the speed limiter, but not as bad) for a second, then went back to normal. but it happened again and again, randomly, speeds at 65-70mph, sometimes even at lower speeds. this I found a solution for: fuel filter. popped in a new filter and never did that again, BUT, the idle is WAY TOO HIGH now! I haven't checked with a tach (my dash doesn't have one) but it feels like at least 2krpm. I could let go of the clutch and the car would roll (in gear).

I've replaced: plugs, wires, cap, rotor, and corrected timing to 7degrees. Nada. I've also blown out the idle wax area or whatever where coolant passes, still nothing. I don't know anymore!

I checked the ECU and noticed some writing on it, it says Idle control or whatever on it. How can you adjust the idle with the ECU knob?

Please help!
Thanks.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #3
my throttle body doesn't have an IAC valve (according to the manual), only an AAC valve (aux air control) which doesn't really do anything until my A/C comes on.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #4
anybody please? it doesn't feel like something is clogged, more like something is stuck open. is a vacuum leak possible? the idle doesn't hunt, it's like it's always on cold start idle. HELP!
 

·
B12 Enthusiast
Joined
·
844 Posts
Have you pulled the codes from the ecu to see if anything shows up ? I was checking the FSM the other night there are several things that could affect this. one of the things that they wanted you to check was the fast idle cam & linkage to make sure it is not binding up and oves freely. :rolleyes:
 

·
Registered
Joined
·
5 Posts
Discussion Starter #6
thanks astream, no ecu codes on mode 3, I only have a haynes manual. You know I was tinkering with what looked like the fast idle cam, there's a spring loaded cam right beside the throttle body, and a protruding shaft that looks like it should retract so the cam could rotate, and that thing is STUCK. It's also where some coolant lines go into, i guess where the famous wax area is, I've already cleaned that out but the shaft won't retract/move freely. Does it say in the FSM how to get it loose? maybe torch? thanks again.
anthony
 

·
B12 Enthusiast
Joined
·
844 Posts
there is a roller that rides the bottom of the cam. that roller is attached to an arm with is connected to the throttle valve. the top part of the cam rests against the thermo element. as the engine warms up, the thermo element moves in or out, moves the cam, thus changing the position of the throttle plate. you need to let the engine warm up, and then check the position of that cam/plate to make sure it is moving. if not, that element may be bad. not 100% sure, but the thermo element and wax pellet are one in the same ? Your sure that you got those lines cleaned out good ? did you blow air back towards the motor too to make sure the lines themselves were clear ? if that coolant doesn't get up in there like it should, that system will not work. :rolleyes:
 

·
Registered
Joined
·
5 Posts
Discussion Starter #8
yea that's it. I adjusted the bolt that rests on the thermo element, and that lowered the idle. now I don't know how the element should move: should it push out to lower the idle? because I couldn't push it in any more, but I can pull the shaft out freely. and also I adjusted the bolt to the farthest it'll go, I don't think that's good. yea I blew the lines out both ways, but I only used compressed air in a can (duster) :thumbdwn: I'll get to a real air compressor and try to blow it out again.
thanks!
 

·
B12 Enthusiast
Joined
·
844 Posts
Didn't look at the unit on my car, but from the FSM, looks like it moves outward because they talk about measuring the distance it moves. You definitely need to use a compressor for that.I don't think an air can has enough force to clean it out properly. after you do that, see what happens and make sure you put that set screw close to back where you started. :thumbup:
 
1 - 9 of 9 Posts
Top