dc97

Cleaned my iacv yesterday, since then, when my car is fully warm its idle is at 750. When i slightly tap the throttle not even a full rpm, it drops to 650 and sometimes if im lucky 500... before i cleaned it, there were days that it would drop below 500 where the car wants to stall... during the night it idles at 1000.. in the day, 750... any ideas.?

DAmunster671

i have the same problem, view my post for wierd idle jump in this forum! i haven't got time to attack the problem but i this issue is irritating!

also the idle plays when you are in neutral or press the clutch in? let me know, because like i said i have the same problem!

check engine light on? slight back fire?

dc97

Nope, only what i posted

skylerreniger

had the same problem with my car. mine was a 1993 honda civic. my idle would always jump up and then go down. replaced the ecm and now it works perfect. maybe you can take it someone and get the ecm tested. hope that helps you

el crapitan

when the rpm dips after you blip the throttle, how long does it stay low?
it's normal for the idle to dip briefly when you do this. basically, the ecm is commanding the iacv to "hunt" until it finds its "happy place". it'll do that for about a second. same thing happens when you put an auxilliary load on the engine, such as AC or even brake switch or clutch. the IACV is there to smooth out and maintain optimal idle speed. any load will interrupt that, and the IACV must close or open a certain number of "counts". it can take a second for the ecm to interpret and command. hondas, and most imports, are actually pretty slow when it comes to command speed, since they run on a relatively slow protocal compared to most domestics.
same thing happens when you coast and let off the throttle to brake. if you pay attention, you'll see the rpm jump briefly. that's the iacv opening, as commanded.
it becomes really clear when you can view the iac PID through a datalogger, what's going on

dc97

when i "blip" the throttle and im idling at 750, and the rpms drop, it goes down to either 650, 600, 550, and itll stay their for 2 seconds... so im just like uhh..

also PID through a datalogger? can you explain that a little more for me please

one more thing, the other day i was doing a canyon run and I was in 3rd gear staying at 4000 rpm, and when i tried to punch it, my car started to bog, like it didnt wanna past 4k rpm, almost like if it was its redline or something.. so i would have to take it out of gear and throw it back in and it was good. It did this a few times.. im wondering what sensor could be causing this or something... this is the first time i experienced that

fcm

Normal idle RPM, [when engine is at running temp.] is 750 RPM +/- 50 RPM, and other then you bog on your "canyon run" everything sounds normal.

When was the last time the fuel filter was changed on your car?

What is the MM&Y of your car?

Or do we assume it is a 97 Integra, if so, what trim level and any mods? 94

dc97

Yes its a 97 integra, with an intake, headers/full exhaust, stage 3 clutch, the motor is a 2000 spec LS.... ive had the car for a year and a half.. and as for the fuel filter i dont even know if it was ever changed, but its unmounted from the broken bracket and just dangling in the engine bay

DeCePtEgRa

Well its bracket being broken could mean that is been changed at one time, but if unsure of when it is a cheap easy replacement to see if it will help idle. I'd check FPR next if you pull vac line going into it a fuel cones out diaphragm is cracked. Fuel pressure at idle needs to be correctly regulated for engine performance to be correct.

fcm

Then change it, a clogged fuel filter may be your problem, even if it is not, the older the fuel filter is, the harder it is on the fuel pump.

The most common cause of fuel pump failure is a clogged/old fuel filter.

I replace the fuel filter on my 94 RS every spring. 94

el crapitan

what i'd do:
check for codes. always always always. regardless of an illuminated cel.
your problem may be fuel related, ignition, or an input (sensor). as mentioned, your idle sounds fine. the bogging is an issue.
as mentioned, if you're unsure of the last fuel filter change, it's worth the 10$ for peace of mind at least.
run a dynamic fuel pressure/flow test:
install a fuel pressure gauge at the filter outlet (you can keep this installed for future diagnostics. a great tool to have on hand). at operating temp, idle, pressure should read roughly 35-40psi. now, pinch off the vac line going to the regulator. do not remove it. pinch it. pressure should rise roughly 10psi. if not, reg or vac line to reg is bad. what you just did there is simulate WOT. if good, proceed. line pinched, snap the throttle 3 times. pressure should decrease no more than 2-3psi. this is the flow test. if more than 2-3, there is either a restriction, ie, filter, or the pump is weak.

if that all checks out and you have no codes, load test the ignition. buy an HEI tester and install it as per the instructions. super easy to use, cheaper than dirt, and a great tool to own for future diagnostics.

as for the PIDs, it stands for parameter identification. it's a visual of inputs or actuators interpreted through the ecm, with a scan tool.
basically the datalogger allows you to view a list of PIDs which show exactly what the sensors and actuators are doing at that time. you can command an actuator through the datalogger to qualify its functionality. or check for irregularities with a suspected input or actuator

dc97

Well its just hanging off the bracket, I kind of over exaggerated on that, but ill give that a try though, thanks for the idea.

damn. after reading this, ill replace the fuel filter with another for sure next paycheck which is next friday.. right now i have not even $20 to spend lol.. is it recommended to change it that often? the fuel filter on my car is from Fram.. ill probably get another Fram, unless theres something a bit better like K&N or if anyone can suggest?

what would you say though about my rpms dropping from 750 to 600 - 550 sometimes? if its still normal, ill live with it but the car does sputter a bit when it gets close to 550...

Thanks a lot for the troubleshooting tips, I will try that out, and probably on my next paycheck ill buy the fuel pressure gauge along with my fuel filter.. but I will try all that when i get the chance, and when i have time at work ill plug in the computer.. i do have a check engine light but since i last checked it was just for my speed sensor which i already knew, but maybe something else came up...

DeCePtEgRa

Changing it on a regular basis is good usually it's roughly 30-60k but gas stations have sediment in there main tank and if you fill up durning or right after they fill it more chance of it going in your tank.

skylerreniger

also I got to thinking that maybe your throttle cable could be sticking a little bit. does the throttle cable look old, worn out, or maybe a little rusty? my throttle cable would stick when I pressed the gas and then at a red light I would sit there with it idling way to high looking like a idiot because it was sticking. put a new throttle cable on it and it fixed it.

dc97

So i changed my fuel filter, really didnt notice much except that i couldnt really blow air through the old fuel filter... i have been noticing aftee my car warms up it idles at 750 fine but when i start driving it and i keep coming to stops it idles at 1100 wtf?

95 integra

iTrader: (2)

The higher idle after the car warms up can be caused by low coolant levels or air in the coolant.

The bogging when you jump on the gas can be caused by a bad ECU tune or a bad/dirty MAP O2 or TPS sensor. Usually that means that you are running rich or lean either due to the tune or a bad/dirty sensor.