First off, 90 rex si with B16. I just bought the car, and noticed that when the car is sitting at an idle, with or without the break pedal down, the idle seems to drop down from idle (800 or so) then jump back up. It doesnt do this all of the time, I was just wondering if anyone has had the same problem, or knows of any suggestions.

P.S. Does anyone have any hints for getting rid of some ot the notorious dash rattles in the car?

 

Check your hoses for any vacuum leaks.

 

you could have a tps problem startin get it checked

 

It does not do it all of the time, and I can sometimes get it to stop by playing with the throttle a little bit. Any other suggestions?

 

DID you check the tps and vacuum lines?

 

I have the same problem, but i was thinking it is the Engine Coolent Temp sensor, because it is REALLY hard to start when it is below freezing.

 

I am new to working on cars, and an unsure what TPS is, and how you check it, along with the vaccum lines?

 

TPS=throttle positon sensor.
The vacuum lines are all the black hoses underneath the Hood, there is manifold vacuum and Ported Vacuum... I can explain but its not importnt, if they are mixed up, just take it to a shop.

Why is the TPS such a popular option for the other answers?? Does this happen alot?

Also, more info, I know I have a bad o2 sensor, but it is not the problem becuase it does it when the engine is cold also. Plus, i know I am rich because someone said there is black smoke comming from my exhaust when I nail it, and I only get like 18-20mpg. Please help!!

 

i have a hesitation issue w my b16,but it runs really well for the most part.a little rich though i put in a walboro fuel pump-no differenceany ideas

 

First off everyone needs to quit being post ****** and stealing this guys thread, no one really cares if you have a belly button and whether or not its an inny or an outie.

To the guy who posted the problem.....make sure your idle screw is seated and not loose, you also might want to reset your idle. Have you noticed a difference when at night with the lights on and other accesories..???

 

It does the problem equally during the day and night. I also have a hesisitation issue with mine, it runs great unless you are just barely on the throttle. Im not sure if these things could be related, just curious.

How do you reset the idle?

 

Well im not going to post how to reset the idle do a search it will give you a chance to familiarize yourself with it. Or buy a haynes manual you can atleast get one for a crx which will tell you how to do it since its virtually the same intake manifold as the b16a but just so you know you can get a del sol manual to for the b16

If you cant find it anywhere say so then Ill help you out in a p/m or via email.

Did the engine have a tune-up before or after teh swap to your knowledge if not go for it, you prob. need one anyway.

 

The car was recently tuned up. It has an ACT strage 3 racing clutch and a flywheel. Could this be why it is hesitating?

 

Dash rattles will be real time cunsuming but you can do it. One rattle at a time.

Idle issues.... Slew of things it can be. Air pocket in cooling system.......... vacume lines hooked up wrong........

Wrong octane gas. Mine idled likle **** with 87 octaine, but no knocks, 93 octaine and it runs far better. There is no simple one answer fits all with an idle problem, you have to do a search and disprove each and every possibility until problem is fixed.

 

clean you iacv, i had the same problem, once i cleaned it idled like new. if not it could be your throttle angle sensor on you TB.

 

Try this..

Look inside your throttle body and you should see a small hole just outside of the butterfly on the side closest to the firewall. If so, get your car up to running temperature, then try putting your finger over that whole with the engine running. If the idle settles down to normal, then it's your fast idle valve.

I had a similar problem, so maybe I can help you with yours.

 

is there any was to turn the idle up a hundred rpm or so?

 

Ok, So I was able to determine that the idle only drops when the engine is warm, and it still does not do it every time. If i pull up to a red light with the clutch in, and the engine is idleing normally, as soon as i give it any gas, the car will start to drop down to 300 and come back up to around 900

 

Ok, i am not sure if you have the same problem as me but here goes....

Mine also had a problem at idle, when i sat at a light it would go from like 250rpm, stall sometimes, to like 2000 rpm. when it is dead cold out it would stall if I tried hitting the gas without warmng the engine up.

So, today I finally got the check engine light to come on and it was a 6 flash code. Signifiying ECT sesor (i was right!!) So I just cleaned the connecter, checked it with a ohm meter just to make sure the sensor was still good, and it was. So, plugged back in, reset the code, and its been fine ever sense. If you want more infor just ask. GOOD LUCK!!!

 

having your 02 sensors backwards/ improperly hooked up results in the described hesitation issues. Ryan

 

so the car would still run fine at an increased throttle if the O2 sensors are wired backwards?

 

Yes, when the throttle is open the car will run fine. If you are at light throttle or at a constant speed, the sensors are trying to lean out or richen up at the wront times. It creates bogging. Ryan

PS, just swhich them at the ecu, and see if it helps. I bet it does.

 

You are running both sensors, right? Ryan

 

ill have to check it out tommorow, but I think that they are. Im running a first gen B16 with OBD-0

 

Tell me which one is going to which, and I will compare it with mine. Ryan