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View Full Version : Multiple System Issues on a stock '91 240sx


Spikuh
09-13-2009, 11:38 PM
Hello, although this is technically my first post on this forum, I have been lurking for a while here and on a few other forums getting myself educated in preparation for starting a project that has been on the back burner for 7 years now. Finally have the ability to turbocharge my KA motor, but that is not the purpose of this post.

So…straight to the point. Over the past few days I have been having some serious trouble with my car running smoothly and need some help getting these issues pinned down to get them looked into asap so I may get my plans back on track. I’ll try to break down the problems in as much detail as I can.

The car is a 1991 240sx SE model with all the options from the time that I know of including the HICAS system, the LSD, and ABS. Everything on the car is stock except for a Cold Air Intake.

The first issue I ever had with the car occurred a long time ago, probably 6 moths after I began driving it. The issue was an idle issue that would periodically show up and then disappear for months on end only to come back and then go away. What happens is the car can’t hold at idle (tach reads it at just over 1k for the iddle) and begins to bob up and down until it dies. There is another also another thread on what appears to be this same problem, but as this is not my only issue, so I decided to go ahe adand mention it. I have read the other thread (http://zilvia.net/f/engine-tech/277282-dying-idle-problem.html) and will be investigating some of the possible solutions suggested.

The next issue is probably just minor, but has to do with the HICAS system. The HICAS light has on occasion come on, but has never stayed on. It, like the idle problem, comes and goes as it pleases. Since I have never experienced any handling changes or problems with the light on as opposed to off, I have just assumed there was a problem with the sensor or it was just covered in junk. Does anyone have any experience with the HICAS system and how to check if the system is running properly?

So now for the third problem. This is the big one and the main reason for this post. I am having a problem with my brake system and it’s a confusing one…for me anyway. Here’s the situation. Whenever I first start the car after leaving it parked for some time (few hours at the least), the brake pedal works normally when I first apply the brakes. However, after the first engagement, the pedal becomes progressively harder and harder to push in until it is basically impossible to move the pedal. This usually happens between the 3rd and 5th pedal press. At this point, one would assume the problem is the Master Cylinder not backing the calipers off from the rotors, but this is not the case. The calipers appear to be backing off just fine because the car will accelerate like normal.


To make matters worse, while the car is busy doing this, the first problem seems to have reappeared to go along with the break issue, so I can’t rule out the possibility that one is causing the other.


I am at a total loss on this issue, so if anyone could give any insight on solutions, I would greatly appreciate it.

As for myself, I am taking the car to an autoparts store tomorrow to have them run their diagnostics on it to see if that turns up anything. Not sure if this will just prove a waste of time because I have no idea how good this stuff is, but my dad suggested it couldn’t hurt so who knows.

Thanks for any help.

Spikuh
09-14-2009, 05:30 PM
Woke up this morning, and had an odd idea strike me while I was in the shower. I remember that I changed the oil a few days ago, just before these symptons started showing up and decided to go check and make sure I had retightened everything properly.

After making sure everything was plenty tight by making it all more tight, I started the car and have not had a repeat issue of the brakes being wierd and they seem to be functioning fine now. That really just leaves the idle issue. Hopefully the brake issue does not come back.

I went ahead and took the car to Autozone anyway, but they told me they couldn't do anything unless the engine was throwing codes, which it is not.

So I guess now, I get to clean the engine bay and start testing/inspecting everything. Unless the brake issue comes back, I'll just follow the other idle issues threads and not add to the clutter.