# 240sx 1990.. NEED HELP Engine vibrating, electrical problems: dash light, brake light



## raboyto2 (Nov 8, 2005)

Hello, ok well heres my situation, im 16 and i just got my license and i was forced to buy my own car with my own money because my parents suck. I dont know much about cars, so what i learn is from the Internet or my own experience. So, i went to the auto auction, and bought myself a 1990 240sx. ya, ya i know....**sports car + new driver + rwd = bad things**... but i couldn’t help myself, the car is so sexy. Anyway, im on a small budget and i have some problems with my car (what do you expect from an auction) The car has 214,000 kms on it and was driven hard by the previous owner. (really hard) Here are my problems, hope you can help! 

Engine Problems: 

**1** My engine vibrates at a low rpm, around 1000rpm. So when its idling at a red light, it will start vibrating. Well i figured that since its a 4 banger, one cylinder must be miss firing, and making it go out of balance (i know it is the 3rd cylinder), . So i changed the spark plugs, nothing. Checked the wires for the spark plugs, nothing. Changed the fuel injectors (11$ for 4 of them off ebay, i have to brag because there $240 each at Canadian tire.) But i still have the same problem. It is on and off, some days, even runs like a dream, some times it feels like someone is bouncing on the car. (when it gets really bad i keep the revs up... at like 2000, cause the vibration stops, im sure it cant be good for my motor mounts) I got the compression checked, turns out the 3rd cylinder has a compression of 105 and the rest have 135. Now what could cause that? (my guess, valves, valve relays, cams) Now, would those cost alot? im guessing yes. But could it be anything else? 

Electrical Problems: (be warned, this stuff is just weird)

**2** My dask lights dont work. (doesnt seam like anything big right ? ) Well they turn on and work perfect after about 8-10kms. (since my speedometer is digital i cant see how fast im going, or my rmp at night) Seems like when the engine warms up they turn on, so if i turn off my car and come back in 5 mins, they will work. Yes i checked the dimmer, and fuses. I dont wanna open up the dash and not know what im looking for. I dont think its a bad connection...since it is predictable when it will turn on (on a hot day while racing = 5mins, on a cold day of normal driving = 20 mins) Some old man told me theres a crack in a chip, and when the engine gets warm, it expands and the crack is filled in (like a really really tiny crack). 
Could this be true? I have no clue, i saw someone ask this question before on a different forum, but it wasn’t answered. Got any ideas? 

**3** Ok, Lets say im driving at night, and i have my headlights on, my back lights will be on too. But the second i brake, my lights completely shut down in the back (excluding the little light in the back window). During the day, my brake lights work fine. Could there be a ground problem? (this is probly my most important problem, since its winter now, and if its a blizard, no one will see me ) Any ideas? 

**4** If i have my headlights flipped up, and i push the button to close them, they will. But if im holding the brake and i push the botton, nothing will happen until i release the brake. I dont even need to touch the botton again, just release the brake and it will close. This isnt really a problem, or anything im worried about fixing, just to show you that my brake is in the middle of all my problems. Also when i push the brake my clock turns off, (but keeps its memory) 

Well if anyone could help me with any of these problems, that would be great. Im really young and i know that. I know im a noob, but i cant help it, i have to learn first. Also, please say what number you are explaining, thank you.


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## 240sxstud (Sep 20, 2005)

raboyto2 said:


> Hello, ok well heres my situation, im 16 and i just got my license and i was forced to buy my own car with my own money because my parents suck. I dont know much about cars, so what i learn is from the Internet or my own experience. So, i went to the auto auction, and bought myself a 1990 240sx. ya, ya i know....**sports car + new driver + rwd = bad things**... but i couldn’t help myself, the car is so sexy. Anyway, im on a small budget and i have some problems with my car (what do you expect from an auction) The car has 214,000 kms on it and was driven hard by the previous owner. (really hard) Here are my problems, hope you can help!
> 
> Engine Problems:
> 
> **1** My engine vibrates at a low rpm, around 1000rpm. So when its idling at a red light, it will start vibrating. Well i figured that since its a 4 banger, one cylinder must be miss firing, and making it go out of balance (i know it is the 3rd cylinder), . So i changed the spark plugs, nothing. Checked the wires for the spark plugs, nothing. Changed the fuel injectors (11$ for 4 of them off ebay, i have to brag because there $240 each at Canadian tire.) But i still have the same problem. It is on and off, some days, even runs like a dream, some times it feels like someone is bouncing on the car. (when it gets really bad i keep the revs up... at like 2000, cause the vibration stops, im sure it cant be good for my motor mounts) I got the compression checked, turns out the 3rd cylinder has a compression of 105 and the rest have 135. Now what could cause that? (my guess, valves, valve relays, cams) Now, would those cost alot? im guessing yes. But could it be anything else?


Have you looked at your injector orings? You still may have a bad injector, start the car and pull the cord from the injector one at a time, if it get worse put it back on, if there's no change that's your bad injector. The coil could have been bad so the electrical part doesn't work...unless the injector were brand new, there's no gurantee they work...


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## raboyto2 (Nov 8, 2005)

*...*



240sxstud said:


> Have you looked at your injector orings? You still may have a bad injector, start the car and pull the cord from the injector one at a time, if it get worse put it back on, if there's no change that's your bad injector. The coil could have been bad so the electrical part doesn't work...unless the injector were brand new, there's no gurantee they work...


Thanks for the reply, but i thought of that, and i changed the fuel injectors around... 3rd injector to 1st, 2nd to 4th . Started her again, still 3rd cylinder. So i switched the injectors again, didnt another combination, still 3rd cylinder. I checked all the seals and o-rings for the injectors, they all look good, and none are leaking when she is running (iv been driving on them for about a week now, no leaks or wet spots), so i dont think its the injectors.


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## Riceman240 (Nov 7, 2005)

i was having a similar problem with my hyundai that i finally got rid of...anyways the problem with your engine vibration is probly a valve but im not sure on this one so dont take my word for it...so once i fixed the valves no more vibrations and ran better than i first had the car...the repair cost me roughly $800 US. 
oh and your head lights and clock problem is probly a bad ground wire somewhere im not sure


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## rogoman (Dec 16, 2004)

raboyto2 said:


> I got the compression checked, turns out the 3rd cylinder has a compression of 105 and the rest have 135. Now what could cause that?


The rings may be bad in cyl#3. Remove the spark plug and pour one tablespoon of oil into the cylinder. Spin the motor a few times, then take another compression reading; if the compression comes up appreciably, then the rings are worn.

As for your electrical problems, check all your grounds first.


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## raboyto2 (Nov 8, 2005)

What if i just changed the hole dash cluster? I have looked around and some people have mentioned that. No one has really given a straigh forward answer. Is this a common problem with nissans? What about that little box by your left foot, right above the fuse box? Some people have mentioned that. Please me me.....


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## rogoman (Dec 16, 2004)

raboyto2 said:


> What if i just changed the hole dash cluster? I have looked around and some people have mentioned that. No one has really given a straigh forward answer. Is this a common problem with nissans? What about that little box by your left foot, right above the fuse box? Some people have mentioned that. Please me me.....


Trouble shooting electrical problems can very frustrating. Like I mentioned previously, check all the ground connections; replug all the harness connectors under the dash area and around the fuse panel, in particular the dash cluster.

You should have an FSM and a multimeter to trouble shoot your electrical problems.

The previous owner may have made some mods to the wiring and screwed something up; check for this.


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## raboyto2 (Nov 8, 2005)

*PROBLEMS SOLVED*

Hello, well i found out all my electrical problems. turns out that i needed to replace one little capacitor in my digital dash cluster and all my problems were solved. if u are having the same problems i was, take a look at this site. it gave a perfect description of what to do, and how to do it. it helped me so much. 
click here  

or here

http://multi-index.myonlinesite.com/240sx/240sx_speedo.htm


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