Question about 1990 Honda Prelude
I have a 1990 Honda 2.0 si Fuel Injected Prelude. When you first start it up (cold) is when it's the worst, it will idle real high (4,000) rpm for about 45 seconds, then it will fluctuate between 1,500 and 4,000 rpm until its warmed up. It will then only fluctuate between 1,000 and 2,500 rpm. I have bled the cooling system about 5 times for 30 minutes apiece, and have tried the tool that pulls a vacuum of 25 - 26 psi and them sucks coolant in. I have also replaced the temp sensor by the thermostat housing. Is this problem even cooling system related? Does it have to do with the ECM?
This problem is a little bit hard to coz you need to check the following throttle body, fast idle valve & the IACV valve. First the throttle body it must fully closed during idle and the TP sensor voltage must be 0.5 volt. The fast idle valve is wax type there is a 2 small hose pass below of this valve, if the coolant water is not circulating the valve will not closed. You can check it by touching the lower portion of this valve after 1 min. Regarding the IACV you can check if this is the fault by removing the hose connecting the throttle body and air filter. there is 2 small hole near the opening of the throttle body, while the engine is running at idle close one by one and see which one cause this problem.I hope this will give help to your problem.
Posted on Sep 23, 2008
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Posted on Jan 02, 2017
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