To check the Vacuum of your engine.....
05-27-02, 12:05 AM
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To check the Vacuum of your engine.....
I was wondering when you check the Vacuum at idle, when your in neutral or when your in first gear? anyway i notice that engine trembles slightly at idle and on the boost gauge when the car is in neutral the vacum reads 20 but the needle shakes rapidly, when I have it in gear it well the needle doesnt shake at 20. Now when I turn my fans on the car will tremble and engine will kind of idle up and down and then the vacuum needle well shake and go up towards 15 and then come down to 20 and settle down. What is causing this, and what could be the cause of the engine trembling? The idle on the rpm needle sits just below the 1000 at idle and it doesnt move but the car is slightly shaking? any ideas?
05-27-02, 12:31 AM
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I'm a CF and poop smith
how are you turning on your fans?
if by turning on the A/C then its putting a load on the engine and the engine will have to work a little harder and the vaccum will go down. If at idle/ netural you are pulling 20inhg, the Id say your engine was in pretty good condition. Normal is about 16-18inhg
if by turning on the A/C then its putting a load on the engine and the engine will have to work a little harder and the vaccum will go down. If at idle/ netural you are pulling 20inhg, the Id say your engine was in pretty good condition. Normal is about 16-18inhg
05-27-02, 12:38 AM
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Yes, it sounds like youre air bypass at idle is off. You either have a vacuum leak, a miss adjusted air screw, or messed up fast idle mechanism. If you have installed anything like an intake, DP, exhuast, or have removed your UIM then you may need to adjust the air adjustment screw or fast idle screw until you equalize your idle air-to-fuel mixture.
You see, the ECU sends a set amount of fuel to the engine at idle and if your air bypass is messed up, you will get those thumps and bumps in your idle - although most rotarys have one bump or two at idle.
I disabled my Fast idle actuator and now it runs like **** when cold. I'm working on an alternative to the coolant actuated fast idle. So far I am using the double throttle solenoid with a vent on it to add a little extra air in at cold start, but it's not nearly as much as cracking the throttle valve (that's what the fast idle does). Anyway, good luck.
You see, the ECU sends a set amount of fuel to the engine at idle and if your air bypass is messed up, you will get those thumps and bumps in your idle - although most rotarys have one bump or two at idle.
I disabled my Fast idle actuator and now it runs like **** when cold. I'm working on an alternative to the coolant actuated fast idle. So far I am using the double throttle solenoid with a vent on it to add a little extra air in at cold start, but it's not nearly as much as cracking the throttle valve (that's what the fast idle does). Anyway, good luck.
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