92 crx b18b1 problem

[k-customcivic]

i bought a 92 crx with this swap but it is idling around 4 grand and i tried the replace the idle air control but it still does this, i was looking at my map sensor and noticed it was crack toward the middle of it could this cause the weird idle? and if so i order a map sensor for a 94 intergra right? thanks for your help

 

[norcalgsr]

First of all there is no 92 CRX, and I would check for a vaccum leak before I started replacing things.

 

[dtob]

First of all there is no 92 CRX, and I would check for a vaccum leak before I started replacing things.

I'd have to agree with this guy. Must be a HUGE vaccum leak but ya look for something like that. Could even be a bad manifold gasket.

 

[norcalgsr]

Yeah I've seen those same symptoms from a bad intake manifold gasket.

 

[k-customcivic]

my mistake

sorry bout that what i meant was a 92 b18b1 in my crx, anyways how can i check the intake manifold gasket for cracks? someone told me to spray either starting fluid or ether arround it! will this work?

 

[JWL54]

a large vacuum leak wouldnt go to 4000. they are like maybe 2500 and they run really crappy. is it setting any codes?

 

[norcalgsr]

You're wrong.. a large vacuum leak leak at the intake manifold will rev that high. I've fixed a car with that exact problem that had a large leak at the manifold mating surface to the head and it was idling around 4k rpm.

 

[JWL54]

youre missing what isnt being said. there should be codes if there was a leak. he also didnt mention its running rough like a large vacuum would cause. with a swap situation there could be something as easy as the throttle cable is missadjusted.

 

[norcalgsr]

Actually you're assuming things that are not necessarily true all the time. You can have a vacuum leak that doesn't cause a CEL depending on where the leak is. Especially with Honda engines if you have a leak that is after the MAP sensor the ECU may not even know it is there because the sensor is reading normally (such as a leak at the intake manifold gasket). It might be something simple, but overlooking certain things just because you're assuming something that isn't correct is not a good way to diagnose a problem.

 

[JWL54]

where the map sensor is located if there was a leak at the intake gasket there would be less vacuum at the map sensor because the engine is sucking from anther spot not past the throttle plate. the map sensor would read a load on the engine and adjust accordingly. which would make it run rough, high idle, hunting. either way, every manifold leak no matter where will always effect the map reading because of its location directly behind the throttle plate before any gasket . if it was my car i would look for vacuum leaks first too. but a check engine light is always a valid question. it could help identify if there are other issuses. so what if a vacuum leak not even the problem or the whole problem? im simply trying to give him other things to look at/think about.

 

[norcalgsr]

I'm just saying that I have personally worked on a car that had a leak at the intake manifold gasket and it didn't throw any codes and held a very high idle around 4k due to that leak. So those symptoms are not necessarily correct 100% of the time. Other than that I do agree with what you are saying.

 

[k-customcivic]

no it is not throwing any codes, but when you drive the car it rough at first but the as the rpm climb it smooths out. its kinda weird but i am planning on replacing the intake gasket and all vaccum line this friday not sure if that will solve my problem but atleast i can eliminate vaccum leaks!