Remember my AC problem with the car (1993 Civic Si with 215k miles) almost stalling. Well now I noticed that if I keep the fan on #1 the car sits nice. When I select #2 the car's rpms drop a little. On #3 the car starts to stutter and rpms drop really low. On #4 the whole car shakes and feels like it's about to stall. I cleaned out the ICV last month and that didn't solve anything. What's going on here? Alternator going? Something is not charging right?

Also at the last autocross my 1st run my car's temp was fine. But runs 2, 3, & 4 the temp gauge would shoot up after driving the car hard in the first 10 seconds. I saw the temp gauge almost touch red every run. I bled the coolant for almost 30-40 minutes, refilling it when the themorstat opened up. Our event back in June I had the same problem, but I bled the system in the parking lot, and had a co-driver. He went out and the temp stayed perfect. What's going on here? Water pump? Timing belt? Accessory belts?

Also noticed the rpms climbed (to almost 1500 rpms) when I pumped the brakes at the start line and then return to normal.

I think my car is cursed

 

You might have a combination of problems here. The fan switch thing definitely sounds electrical. There could be a short or something that's draining the system. I'd put a volt meter on the battery with the car off, then with the car on and verify that the alternator is providing a good charge. Then I'd turn the fan switch on and see what happens. If the voltage drops with every click, then either the alternator is bad or there's probably a short somewhere. Theoretically a short should blow a fuse, but I've seen cases where the fuse was too big for the application or it had been bypassed with hacked up wiring on a race car. If all of that checks out, then I'd start looking at possible vacuum leaks.

The RPMs jumping up when you hit the brakes sounds like a vacuum leak at the brake booster. There's a way to determine if the leak is at the check valve or in the booster itself. The troubleshooting procedure is in the factory service manual.

Good luck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FlyZlow &raquo;</TD></TR><TR><TD CLASS="quote">The RPMs jumping up when you hit the brakes sounds like a vacuum leak at the brake booster. There's a way to determine if the leak is at the check valve or in the booster itself. The troubleshooting procedure is in the factory service manual.</TD></TR></TABLE>
He said *pumped* the brakes.. It's 100% normal for RPM's to rise when you pump the brakes. The brake booster is "powered" by vacuum, so you end up "pushing" a bunch of air into the intake manifold with each release of the pedal.

For the overheating, could be a water leak or headgasket. Try a leakdown test to see what happens.

I think the fan thing is IACV, whether you cleaned it out or not. Try a new one. If the RPM's drop really low the voltage will drop too, so I don't think that'll be a real good test unless you hold the RPM steady with the throttle.

 

Mike,

I had the idle same problem along with some cold weather stalling upon startup with my car a few years ago. I ended up replacing the IACV, FITV, and IAT sensor with new and it has been fine ever since.

I went through everything I could (including a known good used alternator) before I decided that new honda parts were the only fix. With 240,000 miles on all but the engine itself, I couldn't be sure what the exact problem was. The engine probably only has 100,000 miles on it by now, but it is 16 years old and I have only owned it for 7 years. I did the diagnostic tests in the helms a million times, and even that was inconclusive as to the exact problem. Have you tried the tests? They will help to determine if the idle issue is a result of a faulty switch or sensor, although all of those sensors (PS, A/C, fan, etc) provide information to the ECU which in turn tells the IACV wat to do as far as idle speed is concerned. In my situation, the IACV did not appear to be faulty as per the helms test although I'm 99% positive that ended up being the cause anyways.

Don't worry about the brake booster vs. RPM situation, like others said, its normal.

Did you try a new thermostat or radiator (stock size) for the overheating? Have you flushed the cooling system since you bought the car?


Modified by smichael at 8:46 AM 8/15/2007

 

Well I replaced the thermostat back in May. Radiator is new since it had a crack, all the coolant hoses are new (replaced those in March).

Some other also recommended replacing those pieces you mentioned. You have part numbers?

 

my parts were for a 1st gen b16a, so the numbers won't help you much.


http://www.slhondaparts.com lists the 3-part honda part numbers. Look under engine&gt;throttle body for the IACV. http://www.hondaautomotiveparts.com seems to have better prices though they don't show you the actual honda part number until you place your order.

I'd do a leakdown/compression test like Chris F said if you've already replaced the thermostat. Just curious, did you flush the block with a garden hose or something when you replaced the radiator?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by smichae &raquo;</TD></TR><TR><TD CLASS="quote">I'd do a leakdown/compression test like Chris F said if you've already replaced the thermostat. Just curious, did you flush the block with a garden hose or something when you replaced the radiator?
</TD></TR></TABLE>

When I first purchased the car I did flush the system back in June 2006.

Well lol. When I thought I had a headgasket leak I put this stuff in the raditaor (before it was replaced) that is supposed to stop the headgasket leak, recommended from a friend who works at Honda. Found out it was a rear seal leaking instead. When the raditator was replaced the system was flushed though, but I do not know what type of fluid my sponsor used.

Have not done a leakdown/compression test yet.

 

Well I didn't get a chance to do what all you guys suggested, since I've been working crazy hours.

But here's something I saw. I was reading about Samco hoses and how some Civics while doing track days or autocrosses I saw somewhere about the radiator hoses collapsing under load. The hoses I installed are not Honda hoses, got them at some local shop so I don't know the brand. I'm wondering if the hoses are getting so hot they are collapsing? Has this happened ot anyone?

I'm thinking of replacing the thermostat again (with a lower temp one), thermo switch (with a lower temp one) and replacing hoses with Samco or some other reinforced hose.

Going to try an autocross on Sunday to see one more time.

 

I'd try an OEM Honda hose if you're concerned. I'm 99.9% positive you would be wasting you money with the Samco.