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Discussion Starter #1
i am new to this forum, i have been looking around at stuff for about 2 weeks before registering, i have 2 sentras, but the one im currently driving:(1994 XE)

has a few problems, first off the speedo stopped working, so im assuming a speed sensor because i have checked all the fuzes and they are all good and thats the next thing so if someone could tell me the procedure on replacing that i would appreciate it, also the only other problem with it is when im accelerating through the gears it feels like there is a dead spot in the rpm's and i cant figure out what it is, i was thinking a throttle position sensor cause it seems like the dead spot is in the same range in the petal HELP!:confused:
 

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Discussion Starter #2
BUMP<HELP!>
 

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Others have removed the speed sensor then spun it to check the speedo head vs drive gear. apparently the drive gears can get damaged/stripped.
can you check the TPS with a resistance meter, if there is a dead spot you should be able to see it.
 

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Discussion Starter #4
would a voltage meter work, and how would u go about testing that?

and to take the speed sensor out, its the electrical thing on the top of the tranny under the intake, it has like one philips head bolt on it? i bet thats a pain in the ass no?
 

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Discussion Starter #5 (Edited)
ok well, i fixed the stalling problem, it started getting better the more i drove the car but now its not stalling at all, i cleaned the IACV with intake cleaner at work

i cant get the TPS off of either of the cars so idk what to do ( i think thats the problem)

and tomorrow im changing the fuel filter along with my free oil change, courtesy of work :woowoo::loser:

does anyone have any other ideas of what the problem is? as im driving (mostly in 1st + 2nd) it starts to spit and sputter and lose power

if i can get the TPS off i will take the effort to take the TB off and clean that out as well, and eventually get a sr20de TB

thanks for the help guys

oh yeah and on top of fixing all of this i have to buy 1 fender and paint one of the ones off of the other sentra, when i hit the guy i didnt realise i hit my fender, didnt feel a thing just the mirror flew off and landed on my seat and there was nothing wrong with the truck i hit


:( :'(
 

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you really want to know what to do?

first off, you're making a badass car, out of an old one.

what to do:
get an FSM
rip the engine
check every sensor for resistance/volt/amp via the FSM's instuctions and specs, replace if bad.
replace all hoses
repair all wires
run the codes via the ECU after you put it all back together...
and change any bad sensors that come up from a code, but make sure you have disconnected the battery for a while letting the ecu reboot and erase the old codes. run the engine for a while, and it'll bring up the remaining problems around the engine.

and by then... you'll have one badass stock car... it'll run like brand new... until the piston rings of the valve seals go out because you basically made the car run brand new without making sure the compression was locked up tight.

ha! i've done it before... didn't change a damn thing except hoses and fixed everythign electrical on a car... dropped it back in and it ran flawlessly... til i blew the motor from it running so good the rings and seals gave out, burned all the oil on the highway before i knew it was happening....damn thing hauled ass!! i had to play!

no more motor. ;]
ain't that a beach?
 

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Discussion Starter #7
hahaha nice, sounds like a plan, but i was thinking of selling the engine out of this white hunk of shit

and taking the money to buy a sr20de engine to build and fix the small amount of rust this car has, yes it is old but this is my 3rd car and im only 17 and i fell in love with the thing so i think its a good plan to me haha
 

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Discussion Starter #8
i got really bored sence nobody was talkin to me on here haha so i took the fender off the white sentra (as u see in pic) sanded down the rust, little bit of bondo and primer, then im like hmm, how good am i with spray paint, so i gave it a try, looks pretty good, i think the top coat is going to be a darker paint cause this paint is a little bright lol

 

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would a voltage meter work, and how would u go about testing that?

and to take the speed sensor out, its the electrical thing on the top of the tranny under the intake, it has like one philips head bolt on it? i bet thats a pain in the ass no?
As the reply above said download the FSM, has the specs for testing the TPS. You can test it on the Car.
When i had a TPS code I removed the connector and tested it, it was Ok, put the plug back, code went and problem never re-occurred. Just a bad connection I guess.
I have not taken the speed sensor out but I believe you have the right one.
Download the FSM for free at Phatg20.net
Good Luck...
 

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Discussion Starter #10
Download the FSM for free at Phatg20.net
Good Luck...
i downloaded that about 2 weeks ago, there is a shitload of files, i cant just search through it.......idk its a pain in the ass
 

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Discussion Starter #11
Download the FSM for free at Phatg20.net
Good Luck...
i downloaded that about 2 weeks ago, there is a shitload of files, i cant just search through it.......idk its a pain in the ass
 

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if you have all of them in one folder, one one, at the top it says "quick Reference Index"
Open this and you can see an iundex and description.
I will see if I get time at work to cut and post some info for you.

 

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Discussion Starter #13
ok i tested my TPS while i was hooking up some accent lights, im running:
Idle: 4.5V , constant
WOT: 1.8-2.8 (i only had one spike to 1.8 the whole time i was testing it)

seems normal to me, but thats the only other thing that would explain my power loss
 

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i downloaded that about 2 weeks ago, there is a shitload of files, i cant just search through it.......idk its a pain in the ass
that's not an acceptable answer.

if you want to pay the money for someone to have read and read and read and read on just everyone's car.. then find a mechanic. who in which is not going to give you the service a dealership will cuz they've got the toys to do it... which is why you pay so much.

you want to do it yourself and save a ton of cash..

read. til your brain hurts... read. til you're constantly fallin asleep on the book... read. when you wake up in the morning next to the book... read.

and you take shortcuts, be prepared to deal with it. no matter what you're talking about on a car..

ducktape does wonders.. till the part flies off and slams into someone's windshield.. ha j/k but you get the drift.



there are ways of testing sensors while driving too... you have to pretty much run wires from the sensor to the cab and do the same test while driving... but remember.. the sensor has to be connected.. so that means you have to do droplines on the wires.
 

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Discussion Starter #15
ok now i feel like a complete NOOB :newbie: and a total idiot, haha that FSM isnt difficult lmao

well idk, i just realised i was getting shit gas mileage, from what i read thats a o2 sensor....i went through almost half a friggin tank of gas in 2 days ( i live in the suburbs so i dont have to go very far)

but that wouldnt make a dead spot in my power band would it?
 

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Discussion Starter #16
also another idea of mine, could it be the cap and rotor? i put new wires and plugs in but i believe t has the original bosh just like the fuel filter i have yet to change (just lazy, have the filter)
 

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lol, ey man, i'm not tryin to be a dick.
i wrote that because that's what i had to say to myself when i was under the gun to save my 240.
i was literally cramming 240 info into my head for days on end.
sensor testing, vacuum diagrams, electrical circuit voltage needs, torque specs, component operations, ecu code checks
i'd wake up lying on the spread out books and pages only to read vacuum diagrams while eating cereal cuz i was sure i'd forgotten something. ;]
you wanna talk "pain in the ass", teach yourself how to read a wiring diagram. lol, i'm still no good with that.. as for knowing knowing what's all in one circuit... the fun part is modding a stereo system... when you do it professionally off the original battery.. you have to add up every resistor (pretty much anything that uses electricity, including the length of the wire) so you know that every resistor along that circuit has the amount of juice it needs by the time it reaches the end of the line.

there's more than one thing that robs a car of it's power.

there's a guy on here with a signature qoute...
"Your car's the sum of it's parts."

i'm bored, i'll make this a long, shootin tha sh!t, sorta reply, and i'll probably miss some things you asked.

k... power band lag... you feel power and then it lags at a certain point..

1ST QUESTION: is it completely congruent with your pedal position, or with the engine rpm? does it happen right before a shift when a certain gear might be getting too much torque for an old tranny? or just when you're applying throttle (air) to the car.

if it's the pedal position...
it could be TPS (that lovely picture, the guy was nice enough to find for ya),
because of this...
like it shows you in the diagram, the needle (connected to your throttle butterfly valve) sends an increasing amount of voltages to the ecu as you open the throttle... as the throttle is applied, the voltage increases, letting the ecu know exactly where the throttle is(ONE OF YOUR REASONS WHY FUEL INJECTION ENGINES ARE SO FINELY TUNED..this works along with the Crank Position on the distributor ~what fires the plugs~ so that the ecu knows when to spray the injectors... on old carb engines this is done by the fuel pump that has a rod running off the camshaft [MAKING EVERYTHING WORK IN UNISUN... AIR, FUEL, SPARK]). if the sensor is giving erroneous readings, it'll throw the computer off, things won't work right and it won't get enough fuel for the air coming in??? *thinking*
if your voltage output from the TPS drops at the same time the CPS is giving a reading of crank revs, then it's almost like the engine rpm is still the same but there isn't enough air, in turn it not needing the fuel, so it lessens the amount of...

damnit i'm doing it again... i'm in a spiral of thought.
the CPS is more for the spark than it is the fuel, but it still coexists with it.... the rotor cap is mechanically linked to the timing... allowing the spinning rotor to spark at the time it passes the cap's metal notches (this is how you play with spark timing a lil... rotate the cap... you're advancing or retarding the spark) but there's also a light diode in there that shines through slits.. when the light hits the other side... that's the degrees of timing... allowing the computer to also know the crank position for the fuel timing... but i think it also helps the computer adjust the spark timing.. no... i don't know... i need to read more! lol.
when i think about it... a fuel injector is operated by a small solenoid... it recieves a voltage output from the ecu... it opens the injector, and due to the pressure in the system from the fuel pump... it sprays fuel for as long as the solenoid is open... there's no in between, it opens, it closes. (this is how you test injector solenoids... apply current... it clicks... but you also have to test the spray... "if it's clogged") but the timing of how long it's open is all due to how long the ecu passes current to them. and of course, all off the CPS (crank position sensor) and TPS (i think.. i'm not sure which one tells the ecu to spray the injectors!!!!)

if the TPS is sending a small voltage when it should be sending a higher voltage... the ecu thinks you're letting off the gas pedal. (the Air Pedal)

basically... your computer thinks you're letting off the pedal, but you've obviously got the throttle open... the engine is getting air, but it's not giving fuel...

but here's where i get confused...
the TPS says "Hey, i'm trying to go faster. There's plenty of air."
the CPS says "Hey, this is where the pistons are. This is when you need to give me fuel and spark."

if your tps is going out.. it's like your telling the ECU, "Your not getting enough air for how fast you're going. Slow down, and Stop giving so much fuel so you're not running rich or flooding the engine."
but your engine IS getting the air. so it's like you're really running lean.. your engine stops asking for fuel and wants more air. in turn, making the engine run more lean for a second, then when you press the pedal harder, it gets to a point to where the TPS inside the sensor is fine... and then your ECU realizes you're gettin the air all of a sudden and it start giving the correct amount of fuel again.

damn... i need a drink.

that's right, right? someone, anyone?
damnit, WHO KNOWS IF IT'S THE tps OR THE cps THAT TELLS THE ecu TO OPEN THE INJECTOR SOLENOIDS?
i'm confused now.

when you droptest that sensor your just trying to get the reading of the increasing voltage; you don't get the readings your FSM tells you (or close readings) then it's not working properly. thing is though, it's pretty obvious on your car when the full throttle position isn't working... when you push the pedal to the floor you don't get the feeling of the car downshifting if it's at the right rpm, or steadily increasing in speed.

if you've got an auto tranny it can be a point to where the rpms aren't high enough for shifting, but low enough to not have that last bit of torque just before shifting. but that's more of just regular engineered gearing... it would act the same way the first day off the dealership lot.

or... like that one guy said, a slightly mushroom gear could keep it from catching quite right...
but that mostly happens when ppl jam the gas pedal down during midshift... reving up the engine before it's in gear is bad on any kind of car...
that's how you blow a tranny.
 

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Discussion Starter #18
ok well i think i found the problem, i replaced the fuel filter, something that simple i will let you know what i find when i put gas in the car, but yes it did seem like the TPS cause it was in the same range of the pedal:lame: thanks for the help guys
 

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lol, yeah, a clogged fuel filter would cause lack of power when you press the gas.
a clogged injector would do the same..

but if you end up using that injector cleaner crap, you need to make sure you use enough of it for it to trully eat all the crap out of the lines...

when you use that stuff there's high chances of all that crap just going down to the injectors and clogging them
 

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Discussion Starter #20
the fuel filter did help, alot! but it is still sluggish and slow unlike my old sentra was =(
 
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