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Discussion Starter · #1 ·
question for you guys..i've got a 90 Sentra (GA16i) that is just kicking my ass.

the heater got lukewarm and the idle went up really high right before xmas. i was told by a shop that professionally flushed the cooling system, that they thought it had blown a head gasket. after i got back in town from xmas, got to scratching my head and decided to fiddle with it myself. so far i have replaced TWO thermostats, replaced all the cooling hoses and heater hoses *almost all originial hoses and nasty rust/corrosion*, put K&W Block Sealer *just in case there was a problemw with the head gasket*, back flushed the system so there is no more rust/corrosion but yet its still acting weird.

the idle is really high like its starting cold constantly, although i can hear for a few seconds when the thermostat opens, the idle drops and then back up to a high idle again. the gauge will go about halfway up, sometimes a bit more before it will go down again. we're a military family and we live on the base where the speed limit is 25 and lots of stop signs. i just replaced the coolant fan switch last week..the radiator fan DOES come on but not until the coolant has gotten so hot that it goes into the overflow bubbling. then i checked out the ECU and it popped up with 2 codes...23 and 25, idle switch and AAC valve respectively, which would explain the high idle. everyonce in awhile i can switch the heat on, and feel a blast of hot air for about 10/15 seconds, then it goes back to lukewarm. when i'm on the highway, the temp gauge never goes about 1/4 way or so, like it used to normally show, and i can get more hot air to flow in the car. when i was changing out the hoses, i was able to push water through the heater inlet and outlet holes...so the heater core is flowing...

not sure what to do!!!! any info/advice/help would be greatly appreciated...we just got our orders and will be moving to Ft. Lewis, WA in about a month, which we will be driving the 2100 miles from Texas, where we're currently stationed at....need this car in much better shape before then and we really can't afford to buy another car right now on a private first class's salary

bout ready to kill the car!!! :givebeer:
 

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First off, you're gonna like gettin outta Tejas. Unfortunatly you're moving close to Seattle. Traffic sucks and don't let the rain get you down. Summer is right around the corner.
I dunno much about the GA but here is a few common probs that I've ran into with my E. The heater started not working worth a dang til I added about 12 ounces of water. Granted the overflow resevoir is not connected. But that wasn't til after running it hard for over a year. Yes, a pop can full of water cured it.
Another problem I had sounds very similar to yours. Replaced thermostat, fan relay, temp sensor, even the radiator. I did all that cuz the car would start to warm up and the gage would go "boing" right up to the hot line. Turned out to be the voltage regulator on the instrument cluster. When that puppy goes, one of the symptoms is that your fuel and temp gages (may) start to act wierd. Others have had other symptoms from the same faulty part.

So next time the car is cold, pop the cap and see if you can squeeze just a few ounces of water in there.
Good luck and keep us posted.
 

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get that AIV valve off and clean it good ... that may help a lot on the idle ...

did you bleed the air in the system after you changed all the hoses ??? ... might help a lot too ... if you want to make sure the HG isnt blown, check into the radiator for constant bubbling.. if it is bubbling all the time, you got a cylinder pushing air into the cooling system (bad)..
 

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Discussion Starter · #4 ·
live in the Washington State area? yeah i'm down for getting the hell outta this part of Texas...i'm from Alabama. i miss mountains and valleys and pine trees..they block the wind well ;) everytime we move for the Army, i try to look at it as an adventure and new places to see!!! how's the fishing up there? i love to fish but of course i'm used to freshwater fishing and catching grouper, triggerfish, and tuna in the Gulf of Mexico.....

anyhoo....back to the car stuff. regarding the voltage regulator on the instrument cluster, would that affect my actual idle speed, if that regulator had crapped out?

thanks for the info!!
 

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Discussion Starter · #5 ·
Crazy Mart: after i replaced all the hoses, i literally stood there with the car running after i filled it with water letting the air bubbles out...of course i have yet to find any of these bleeder holes on the engine itself...could you point those out please?

the antifreeze in the radiator doesn't bubble all the time although sometimes it acts as though its vomiting a chunk o' something...but sometimes it does bubble....

i've found that if i turn the AC fan on as soon as the gauge starts moving, it doesn't bubble into the overflow.....i've been scratching my head on this car and this particular problem/s for a month. trying to decide on whether or not to just buy a used car and get rid of this one...gotta move in 27 days and 2100 miles is a long drive that needs to be done in something reliable.
 

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can use TB cleaner for the valve ...

use the trick i gived for bleeding the system, get the front of the car higher and make it go to temp from there ... i posted a complete how to somewhere whitin the section, but i just need to go now.. (work) just make a little search with bleeding in it. should come up :)
 

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kharmahappens said:
live in the Washington State area? yeah i'm down for getting the hell outta this part of Texas...i'm from Alabama. i miss mountains and valleys and pine trees..they block the wind well ;) everytime we move for the Army, i try to look at it as an adventure and new places to see!!! how's the fishing up there? i love to fish but of course i'm used to freshwater fishing and catching grouper, triggerfish, and tuna in the Gulf of Mexico.....

anyhoo....back to the car stuff. regarding the voltage regulator on the instrument cluster, would that affect my actual idle speed, if that regulator had crapped out?

thanks for the info!!
You're gonna love it here then. Big ass mountains. Salmon, sturgeon and dungeness crab. Lots of hiking and skiing. But this the wrong forum for all that.
No, the vreg only effects the gages. I replaced all that crap cuz my gage was lieing to me. Your prob kinda sounds like a head gasket. You mentioned spewing chunks. White milky colored chunks? Have looked under your oil cap for a white slug or milk?
 

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Discussion Starter · #9 ·
no white chunks..no milky substance in the oil or under the oil cap....no oil in the water/anti-freeze...only thing that has me worried that it might be the head gasket is the smoke that comes out of the tailpipe occassionally..but then again it has been in the 30's all week and every other car i've seen has the same thing coming out of their tailpipes..guess steam...but until it got cold here it wasn't doing the smoke thing.

found out that the two parts i need, idle switch and AAV valve, are dealer only parts..think i'm just going to break down and pay the Nissan service dept here to do a diagnostic on my car....i HATE having to pay a shop to work on my car. that's what happens when you have a mechanic as a husband for 7 years who does all the work on your car for free at his shop ;) now its just little ole me working on it since we're divorced and he's in Alabama and i'm in Texas ....dammit
 

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Discussion Starter · #11 ·
you know the water pump i was going to replace from the get go, but the guy that was "helping" me and who appears to know more about cars *in certain aspects* than i do, told me "there's no way it could be your water pump"....starting to wish that i had listened to to myself, and not him and gone ahead and put a new one in anyway,back when it was warmer outside to work in.....since i've replaced all the hoses and thermostat, it wouldn't hurt i don't think, just gonna freeze my fingers off in the process probably...thanks for the reminder though!!!
 

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Does the cooling system appear to be pressurizing when it gets hot ? I would maybe try to find a Radiator shop that can test to make sure the system is holding pressure, also have them check the flow rate on the radiator to make sure it is doing it's job, and for the little cost and arguments sake, I would replace the radiator cap as well to make sure it has not gone bad. :)
 

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astreamk1 said:
Does the cooling system appear to be pressurizing when it gets hot ? I would maybe try to find a Radiator shop that can test to make sure the system is holding pressure, also have them check the flow rate on the radiator to make sure it is doing it's job, and for the little cost and arguments sake, I would replace the radiator cap as well to make sure it has not gone bad. :)
My old Blazer overheated in the middle of winter cuz of the cap. I'd go for the thermostat before the PITA water pump. I've seen corroded impellers but the bearings seam to go out before they're gone to the point where it won't circulate coolant.
Note: DO NOT overtighten the goosneck. Just snug it down with 25-30 ft/lbs of torque. You can always come back and snug it sown some more if it leaks. Otherwise you risk cracking the gooseneck or stripping the bolts. I think 90% of DIY mechanics have learned this the hard way. But I just noticed you replaced the thermostat 2x.
Hmmmm, so you have 2 probs. 1 the idle and 2 the cooling. Beginning to wonder if your temp gage is lieing to you. When you sit at an idle for say 5 or 10 minutes, does the fan kick on? And what does the gage say?
 

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If you find the problem let me know. I had to get rid of mine 1990 Sentra, i put $2500 into to find out what it was. I will tell you you won't find the problem but still hope that you do. Didn't get much help here with it either, seems you're getting some help but again everything that is posted for you i have already been there done that. I traded mine for a 1994 Sentra and am very happy with it. I even have Air and Cruse now. I believe the problem is electrical and will never be fixed, i kept trying to fix it but $200 later it wasn't what was "fixed". Just give her up like i did, because you will screw the tranny up soon and it won't be pretty, that cost me $1400. I was told by a Nissan tech that once the Idle starts doing that it's time to put her down. Wish i would have listen to him $2000 ago, i'd have a real nice car right now.

Help 1800 rpm after it warms up (Check out this link)
 

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mjb92761 said:
If you find the problem let me know. I had to get rid of mine 1990 Sentra, i put $2500 into to find out what it was. I will tell you you won't find the problem but still hope that you do. Didn't get much help here with it either, seems you're getting some help but again everything that is posted for you i have already been there done that. I traded mine for a 1994 Sentra and am very happy with it. I even have Air and Cruse now. I believe the problem is electrical and will never be fixed, i kept trying to fix it but $200 later it wasn't what was "fixed". Just give her up like i did, because you will screw the tranny up soon and it won't be pretty, that cost me $1400. I was told by a Nissan tech that once the Idle starts doing that it's time to put her down. Wish i would have listen to him $2000 ago, i'd have a real nice car right now.

Help 1800 rpm after it warms up (Check out this link)

If everyone on this forum that has had some sort of problem that caused a rough idle had given up on their car, there would be nobody left. Anything can be fixed. Wait till you start having MAF problems with your GA16de. :thumbup:
 

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astreamk1 said:
If everyone on this forum that has had some sort of problem that caused a rough idle had given up on their car, there would be nobody left. Anything can be fixed. Wait till you start having MAF problems with your GA16de. :thumbup:
Bud please reread my post, i didn't have a ROUGH IDLE.
 

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mjb92761 said:
I believe the problem is electrical and will never be fixed, i kept trying to fix it but $200 later it wasn't what was "fixed". Just give her up like i did, because you will screw the tranny up soon and it won't be pretty, that cost me $1400. I was told by a Nissan tech that once the Idle starts doing that it's time to put her down. Wish i would have listen to him $2000 ago, i'd have a real nice car right now.
Actually I didn't read your original post because you didn't post the link properly. I was referring to your above statement. Unless I read it wrong, your suggesting the idle problem is incurable and as a result they should get rid of the car. :)
 

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astreamk1 said:
Actually I didn't read your original post because you didn't post the link properly. I was referring to your above statement. Unless I read it wrong, your suggesting the idle problem is incurable and as a result they should get rid of the car. :)
Never said that either. just said what i did, i guess you can figure out the rest since you already have. Don't ever assume...................... you know the rest.

http://www.nissanforums.com/showthread.php?t=81883
 

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mjb92761 said:
Never said that either. just said what i did, i guess you can figure out the rest since you already have. Don't ever assume...................... you know the rest.

http://www.nissanforums.com/showthread.php?t=81883
whatever man, I am not going to fight with you, it is a moot point anyways. I did read your thread, and it jogged my memory. 89-90 were the only years that the TBI used that wax pellet idle control module I believe. Basically utilizes heated water from the engine to melt the wax an this allows a cam or whatever to move and change the idle. I remember reading on here about this when I first joined. Basically what happens is when the cooling system sludges up (as hers did) those lines get blocked, the coolant never reaches the unit, and your idle never comes down. The cure was simple, remove the 2 little cooling lines on the back of the TB, blow compressed air through the tbi where you disconnected the hoses, and make sure you get all the shit out and air blows through freely. put your lines back on, bleed your cooling system, and your good to go. If anybody remembers any particulars about this, please chime in. It is a little late for you, but hopefully not for her. :)
 
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