7G idle problems help!!!!

**stormbringer** · 05-12-2009, 07:44 PM

I still have this idle problem on my ride, hope somebody with the similar problem have theirs fixed and share it with me.
1994 galant AT

1. when I start the car, idle runs smooth at 800 rpm
2. when I turn on the aircon, the RPM goes down a little and slowly rises up for the engine not to vibrate
3. when I STEP on the BRAKE and put it on DRIVE or REVERSE, the RPM drops to 400 or 500 RPM that makes the engine vibrate.
4. the RPM will drop more if I turn on the headlights.
5. When driving with aircon on, and on a stop, the engine vibrates and RPM is on 400-500. and sometimes the idle pulsates up,down,up,down.

Things that I did:

1. Cleaned the throttle body ( I made sure its free of dirt).
2. Cleaned the IACV
3. Checked and tested the IACV motor. ( IACV motor runs fine. it goes up and down when tested on a 9 volt battery)
3 Cleaned the MAF.
4. Checked all the vacuum hoses (no leak, seems ok)

I have done all this things so far that is connected to the idle problems. But the problem remains. can anybody help me or give me an advice what to check next. I was also thinking of the ECU if its sending signal to the IACV to activate ( I did'nt checked the continuity yet). but before I go to that conclusion please somebody help me if there is still other things to check before I go to the ECU. thanks and please help:

**Galanttuner10** · 05-12-2009, 08:24 PM

raise the idle via the biss screw cuz it seems everything else is in check

**stormbringer** · 05-12-2009, 11:09 PM

thanks for the reply. which one is the biss screw? the one that controls the air or the one that is connected to the cable accelaerator pedal?

**Galanttuner10** · 05-12-2009, 11:28 PM

Originally Posted by stormbringer

thanks for the reply. which one is the biss screw? the one that controls the air or the one that is connected to the cable accelaerator pedal?

its on the throttle body right on top u will see it as its a really noticible screw.. loosen it a little and it raises the idle if that doesnt work let me know

**kamenfaiz** · 05-13-2009, 10:11 AM

if i were you i will check the charging system on the alternator and battery

**Galanttuner10** · 05-13-2009, 10:20 AM

Originally Posted by kamenfaiz

if i were you i will check the charging system on the alternator and battery

if it were that the battery would have died by now

**kamenfaiz** · 05-13-2009, 10:28 AM

just check the charging system it might be the alternator is not charging enough

**Galant306m** · 05-13-2009, 12:17 PM

Well everything you are describing shows that you are putting the engine under load while you are having the problems. Seems kinda normal if you ask me. I mean your RPMS will drop when you turn on more accessories, and when you pump the brakes it should drop and then go up to normal because of the vacuum booster.

Have your alt checked see if it putting out the right amount, and have your bat checked just to be sure.

**Galanttuner10** · 05-13-2009, 04:37 PM

Originally Posted by Galant306m

Well everything you are describing shows that you are putting the engine under load while you are having the problems. Seems kinda normal if you ask me. I mean your RPMS will drop when you turn on more accessories, and when you pump the brakes it should drop and then go up to normal because of the vacuum booster.

Have your alt checked see if it putting out the right amount, and have your bat checked just to be sure.

it cant be the alternator.. after everything was cleaned and such it coud have changed the idle as everything is clean.. if it was the alt his car would be dead by now i know from experience.. mine went and 2 miles later the car was dead

raise the idle as it only seems like you have a low idle as mine in drive is 700 rpm

**stormbringer** · 05-13-2009, 06:57 PM

i was thinking of the alternator too, coz of too much load the RPM will drop. but on the second thought galanttuner is also right that it should be dead by now if the alternator is not working well. I have a 4 month old battery and up to now its working fine.I will have it checked anyways, a friend nearby can check it for me. i was also thinking of the electrical continuity of connection from ECU to IACV. like I said, I tested the IACV with a 9 volt battery and I saw it go up and down by changing the polarity( I saw this test on youtube). It works on a 9volt directly,but what about on the car connection? im thinking of a bad connection to the IACV. How do I check the continuity of this connection? I raised the idle as advised by galanttuner, I raised it to 1000rpm with no other accessories on. smooth though, but still vibrates a little when put on drive when the AC is on and on gears. anyway,what is the ideal RPM on a normal engine without any accessories on like AC, radio etc.? thank you people for the advice.

**Galanttuner10** · 05-13-2009, 10:33 PM

my idle is 700 rpms give or take some i have no ac but with the music up headlights and all on its the same just a quick dip whne the accesories are turned on.. battery would be dead if it was a bad ground or if the alternator was completely dead.. it might in fact be on its way out

as for the iac.. if it had anyhing to do with that it would not hold idle at all on start up u have 2 hold the idle where its supposed to be until its warm if it were that.. i had 2 change them on both my 7gs and i hate IACs on these cars but u show no symptoms of that