1990 Integra surges while idling.

I have a 1990 Acura Integra that I have been having problems lately
with, I was hoping you could shed some light on the issue for me. It is
surging every now and then when it is sitting and idling. I was driving the other day and my battery light came on and I had to replace the battery because it was completely shot. Now that I have new battery in the car it still surges. I took it in and had a electrical system test done where they hook up a load to my battery and check the system that way. They told me that it could be the alternator or it could be a bad electrical connection. I have done some diagnostics myself and found that sometimes the car runs ok when I disconnect the battery and other times it dies. Normally when you connect a voltage meter with the vehicle running you should see 14.4v, when it surges I am seeing anywhere from 14.4 to 14.0v, I don't know if this is a good
ndication or not because I don't know if my volt meter can respond as fast as the surges happen. Have you heard of this problem with this vehicle before?

Any help you can give would help me out tremendously.

First...you should never disconnect the battery from the car while it is running...older non computerized cars can handle that..you are taking a great chance by doing that...
I dont think your problem is electrical, surging is caused by the computer trying to keep a hold on the engine but there is something going on...does it surge all the time?
what rpm range is it surging at...
Have you checked the coolant temp sensor and the air temp sensor?
Is the throttle body assembly clean?

BTW the voltages are just fine from what you have told us....

The surging only happens when the car is idling about 1500 rpm's. it will drop to about 1000 rpms. While the car is running and you disconnect the wire harness on the alternator the car then runs correctly, it smooths out. That is why I think there is something wrong with the alternator.



First...you should never disconnect the battery from the car while it is running...older non computerized cars can handle that..you are taking a great chance by doing that...
I dont think your problem is electrical, surging is caused by the computer trying to keep a hold on the engine but there is something going on...does it surge all the time?
what rpm range is it surging at...
Have you checked the coolant temp sensor and the air temp sensor?
Is the throttle body assembly clean?

BTW the voltages are just fine from what you have told us....

The car should idle around 850..is this when you start it upp and it runs at 1500 then drops to 1000 and stays there or does it go back up to 1500??

The car is here in Colorado so when you start the car up inthe cold it will idle higher than normal, so when I start the car it idles around 1500, then when is starts to surge it drops to 1000 and back up to 1500 and it keeps doing this unless I pull the wire harness off the alternator.

does it do this after the engine is warmed up?

yes

you can pull the alt out and have it checked. but also check the idle air control valve and test the resistance on the coolant temp sensor..

I had the electrical system tested by Autozone and when the battery light is on this is the only time it suges and the findings were that when the battery light was on and the car was surging the battery was not being charged (real weak trickle charge from alternator)

How do I test the idle air control valve and the resistance onteh coolant temp sensor. Also where are these items at?

After driving everyday I have to put the bran-new battery on a charger to charge it because the car is only running off battery power.

if the battery light is on the alt is not charging the battery...change it out...
The coolant temp sensor in located in the water passage on the intake..it has a brass base with a connector on top..pull the connector off and see what happens to the idle...the idle air control IAC or ISC is located behind the throttle body.

Start by changing the alternator out...then see what happens..

I appriciate all the help, i have been trying to avoid changing that alternator out becuase everyone I have heard talk about this means i have to pull my half shaft off. I purchased a new alternator already. I think i am going to try and see if I can put the new one up through the bottom without pulling that half shaft off.

You should be able to get it out without pulling the half shaft off..if i remember correctly..you have to take all teh brackets out of the way first...its been a while since i messed with one of those acuras

Would a leak from your header or pluging the wrong vacuum hose to your intake manifold can cause your acura to idle like a mf.

a leak from the exhaust..not likely...but the wrong vacuum hose connected can cause lots of problems..especially the egr system..

i had that problem and i tried diconecting my baterry while the car was on the only thing that does is fry your alternator. change your alternator an easy way to do it is through the bottom. take off the driver side front wheel remove the well cover and it should be there

what is the egr system.