Hesitation while driving & Electrical Problems

[Toddles82]

Car: 1995 Nissan 240SX SEMileage : ~108,000

The car hesitates and bucks while driving, but not all the time. It primarily does it when the ambient temperature is warm. By hesitation and bucking, I mean that while cruising the car acts as if it hits a fuel cut, and will lurge, and the gas pedal doesn't do anything. When it does this, it will even sometimes die. So you can be driving down the interstate at 80, have the car lurge, die, and then you have to use the clutch to kick start it (push the clutch it, and pop it back out). One dealership told me it was the computer ($1000 is what they wanted) another dealership is telling me its the AIV valve (I think that's the one) and they want 800. Don't be mislead when I said fuel cut. It may not be a fuel cut but that's what it feels like. Like you've hit the rev limiter, but at odd ball RPM's 4000, 3000, etc.

The first time it did I was coasting to a stop, put the clutch in, went to first and went to slowly accelerate from a neighborhood and it bucked on me. I about hit my head on the steering wheel. It did it again after I ran the car to 95 on the highway (chasing down a race prepped SAAB :rool: so I turned around and went back home.

The car drives fine when it's not bucking like a wild stallion. I can run in through the gears (providing it doesn't buck) no problem. I've only noticed it on accel but I would imagine decel would be the same story. Happens anywhere from 0-100% throttle, which includes cruise control. The car will immediately crack up with the key with no hesitation.

Things we did to try and fix it: -Tested new wires, ECU, and MAF (brother has the same car) -New Fuel filter -Sprayed Carb cleaner down some of the tubes -New cap and rotor -Oil was changed a bit ago.

We are considering dropping in another stock KA for the price everyone else wants to fix it.

The other issue is really the troubling one. An electrical short. When you turn the hazard lights on: (car on or off) -Temp gauge bounces in rythmn with the hazards -Radio Antenna goes up and down in rhytmn -Interior lights blink in rythmn When you first press the hazards in blinks 1-2 at normal speed then goes double time.

When you press the brakes: -The gauge bounces (if you press the brakes fast enough you can make the temp gauge climb) -Brakes on = Antenna moves down (direction I'm not sure about since it broke in the up position some time ago, but I can hear the motor turning) -Brakes off = Antenna moves up

Both stimulus cause an EXTREME current draw and the interior lights become very dim.

The short is the most recent installment of "what's wrong" when I was trouble shooting the hesitation about 2 weeks ago.

Due to me being at school and my car being at home, this probably has now plagued me for about a month. Any insight you bring to the table is most welcome.

The problems did not start at the same time, hesitation first and then the short several weeks later. The car was not driving hard prior to it starting. I just drove across town. I went to leave for a concert in a nearby town, and my car decided it didn't wanna take me.

It is VERY predominate at warm ambient temperatures. I was barely able to drive 40 miles (OKC to Norman) in 85-90 weather. At night when it was ~70 it didn't hesitate until I was nearly home ~ 80 miles. Now that I think about it, the lights on the stereo were dim while driving, but none of the above short problems were noticed.

The car is stock mechanically, airbox and all. Car has 110,000 on it and the plugs were replaced ~95,000.

Do you guys mind double posting? I want to post this in the 240SX section, because I think the foot traffic is different between the two forums.

[s13sr20chris]

the short problem sounds like one of two common probs. 1-bulb has melted contacts. i would pull every bulb out of the car and check for melted contact points and check the socket too.2-alternator is going out. this is less likely but possible.

the driveability condition is prob not the idle control valve. its possible but i am doubting it. bucking can often be traced to a distributor(they hate heat by the way) doing funny things with the timing. stalling can often be related to maf or ect issues.

[p00t]

In addition to what s13sr20chris said:

bucking could be timing, or TPS. you will need to check the TPS with a multimeter to make sure its in its propper range and has no quirks or drops as its moves.

Timing needs to be checked with a timing light, should be 20 degrees BTDC for premium, or 15 BTDC if you run 87 octane. But you can also do a quick visual check... look at the distributer, you should be facing the exhaust side of the engine. You turn the distro clockwise (towards the firewall) to retard timing. And you turn it counter clockwise to advance timing. Make sure the distro is not pegged at full advance, meaning it cannot be turned counter clockwise any more. Im started to see more nissan motors like this and Im very confused as to who has been working on these cars. Typically the distro is 1/4 from full adjusted to 1/4 from full retarded, depending on how the previous mechanic set it.

[benemorius]

I've seen blown fuses cause similar electrical problems. Do be sure and check them...all of them.

[Toddles82]

I checked all of them.....

Wierd thing is, today the car didn't act up at all. No hesitation, no electrical problems.

WTF is going on?

[jsr240sx]

you may also have a faulty stater(ignition module) I used to have a 95 mustang that kepted bucking and stalling on me, even while driving on freeways, it would just turn off and and it would not start again unless it cooled down. i replaced three times, because you need special instructions to connect it (get them from the merchant)

[Toddles82]

For future refrence to those that search.

I believe it turned out to be a loose ground. THe screw that holds the main negative cable nearest the battery on the passanger side strut mount was loose. The current had arced the threads right off of it.I sanded the area and replaced the screw and everything seems perfect. We'll see what happens when it gets 100 degrees tho.