1994SEV6 Posted January 30, 2012 Share Posted January 30, 2012 Every since I did my trans swap, my idle was been high. I haven't been able to get the idle below ~900rpm no matter what. It hasn't been too bad around here this winter, but the idle still jumps up to about 1800rpm when I start it up first in the morning. I would say that it has been a moist 35F in the mornings. I have also noticed that my idle will 'stick'. If I turn the key and do nothing else, it will stay at 1800 and eventually drop to 900. It takes about 5 mins. If I drive it while it's still high, sometimes when I push the clutch in, the idle will jump up to 2000 and stick there. If I give it some gas and let it go, it will drop down to 1800 but then just go back to 2000. My dad suggested it might be a sticky choke mechanism(don't take offence to this, he is used to working on old cars with carbs) So I adjusted the idle screw on the ECU. Somehow it has gotten up to 10% away from diagnostic mode. I turned it down to around the 40% area. It did nothing to change the idle. I just read a post from Sewebster saying his Pathy is the slowest out of his vehicles to warm up and he thinks it is because of a broken thermostat. I have been told that my thermostat is also faulty. This makes sense to me, but my heat is amazing and puts out fast. So, is my idle still high because it's in that loop mode where the ECU thinks it's still warming up? Link to comment Share on other sites More sharing options...
silverton Posted January 30, 2012 Share Posted January 30, 2012 both of my wd21's have had stuck open thermostat's, neither vehicle had problems with idle. Make sure the butterfly in your throttle body isn't sticking, and double/triple check your mechanical and ignition timing, I'm going to bet that's your issue. your ECU diag screw should be fully counter clock-wise. 1 Link to comment Share on other sites More sharing options...
krmiller07 Posted January 30, 2012 Share Posted January 30, 2012 I'd also check or replace the wiring (especially the pig tail to the Head temp sensor for broken connectors), connections and Head Temp Sensor. Throttle position sensor, clean the Mass Air Sensor on the throttle body. I live in a cold climate (for the winter) and when I warm up my 89 which has a throttle body, I turn the temperature control all the way over to cold (in the cabin) as so all the engine coolant is circulating through the engine (instead of going through the heater core) until the temp gauger is at least 1/4 way off the cold position. Then move it over to the hotter position to provide interior heat. This helps warm the engine faster, however all the pathy's I've owned seem to be cold blooded. There may be different heat ranges available for the engine thermostat, but I'd perform a thorough diagnostic on the throttle body and associated components before changing the thermostat. BTW...when was the last time you flushed the coolant and replaced it with the right mixture of coolant to water and properly bleed the air out of the system? This can throw it off too. Air can get trapped in the cooling system causing problems as well. Get a FSM or a Haynes manual and check the adjustments of all the Throttle body and emissions related components while your in there. 2 Link to comment Share on other sites More sharing options...
Tungsten Posted January 30, 2012 Share Posted January 30, 2012 A high idle at startup is NORMAL. I don't know about 1800 rpm but mine will definitely idle at 1200 rpm until warm up. You might want to check out the idle air control valve and the throttle cable for sticking. If your engine is carboned up inside, you will also get a ridiculous idle. Did you ever try seafoam through the brake booster line? 2 Link to comment Share on other sites More sharing options...
krmiller07 Posted January 30, 2012 Share Posted January 30, 2012 (edited) If your thermostat is 'stuck' open, then all the coolant circulates through the block and possibly the heater core(If the temp switch is on 'hot'). All the cold coolant will trigger the ECM indicating a cold environment, thus longer warm up and High Idle. After the temp gauge comes up to normal operating temperature, the idle should come down to normal. which is around 800-900 rpm's. Depending on whether it's been adjusted higher. If you have alot of miles on the engine, carbon build up might contribute to this as well(however it would be odd)Carbon build up usually brings on detonation or 'pinging' if you don't have a knock sensor, poor mileage (worse than the average Pathy!)and overall poor performance. It's worth a try, using the Sea Foam. I'd run it through the fuel system, via adding it to your gas. Then run about 1/3 of the bottle through the brake or PCV vacuum line, as per the instructions on the bottle. Theres also several YOU TUBE videos you can reference to choose which method you feel comfortable with. If you choose to add it to the oil, I'd plan on replacing it along with the filter after no more than 200 miles.It is a solvent and will break down the viscosity of the oil, and possibly cause any debris or sludge to get trapped in the oil filter. Edited January 30, 2012 by krmiller07 1 Link to comment Share on other sites More sharing options...
tmoore4512 Posted January 30, 2012 Share Posted January 30, 2012 A high idle at startup is NORMAL. I don't know about 1800 rpm but mine will definitely idle at 1200 rpm until warm up. You might want to check out the idle air control valve and the throttle cable for sticking. If your engine is carboned up inside, you will also get a ridiculous idle. Did you ever try seafoam through the brake booster line? X2 on the high idle. Every Nissan I have owned even the wife's 06 Altima does that... Come to think of it every vehicle I have owned has idled high at start up if from a cold start... Maybe not 1800 rpm, but it certainly idles up until it warms up As for Sea-foam... That stuff is wicked good. I run it every oil change, through the brake booster line... I went to the local Lowes and purchased a ice maker water line connection kit, (was like 10 bucks) and use the valve and some of the line along with an adapter to fit the booster line... That way you don't have to sit there and babysit it while it does its magic... Just start the truck, and slowly open the valve to where it draws the clear nectar of the gods out of the can and into the intake system via the booster lines vacuum... Sit back and let the white smoke billow... 1 Link to comment Share on other sites More sharing options...
sewebster Posted January 30, 2012 Share Posted January 30, 2012 Vacuum leak would be my first guess as to the cause. Normal idle should be 750 rpm. But yes, of course it idles higher until warmed up. 1 Link to comment Share on other sites More sharing options...
adamzan Posted January 30, 2012 Share Posted January 30, 2012 Screw the seafoam stuff, it has to be something you messed with during the tranny swap. Did you check to make sure the throttle cable isn't snagged or anything is rubbing on it. Check the pedal and the cruise one. Also check all your vacuum hoses. Actually, just replace them. It will cost you like 3 dollars in hose. 2 Link to comment Share on other sites More sharing options...
Tungsten Posted January 31, 2012 Share Posted January 31, 2012 Yes, vacuum hoses is another big one that will screw up the idle, unless your entire intake plenum gasket is leaking. The FSM has a really good diagnostic procedure for vacuum leaks. What's wrong with seafoam? That EGR valve sucks in a lot of carbon through the exhaust. Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 31, 2012 Author Share Posted January 31, 2012 Make sure the butterfly in your throttle body isn't sticking, and double/triple check your mechanical and ignition timing, I'm going to bet that's your issue. your ECU diag screw should be fully counter clock-wise. Thanks for the advice. I'll reset my ECU screw and check out my throttle body. I guess I just take the rubber tube off and manually move the cable? With the engine off of course. "double/triple check my mechanical and ignition timing"? Boy, I guess I should single-check it first. I haven't touched a single thing on my engine...ever. Changed oil, messed with my idler pulley once, took my air box out and that's all I've ever done to my engine. I'd also check or replace the wiring (especially the pig tail to the Head temp sensor for broken connectors), connections and Head Temp Sensor. Throttle position sensor, clean the Mass Air Sensor on the throttle body. BTW...when was the last time you flushed the coolant and replaced it with the right mixture of coolant to water and properly bleed the air out of the system? This can throw it off too. Air can get trapped in the cooling system causing problems as well. ouuu. Lots of good ideas here. Thanks. Yeah...I have personally never flushed the coolant and replaced it. Actually, I take that back. I stupidly removed the upper rad hose and lost a bunch of coolant. When I topped it off, it took a gallon. I know it's not the same, but it's better than nothing. Flushing the cooling system was at the top of my list. I guess I'll be doing that sooner than I thought. A high idle at startup is NORMAL. You might want to check out the idle air control valve and the throttle cable for sticking. If your engine is carboned up inside, you will also get a ridiculous idle. Did you ever try seafoam through the brake booster line? Of course... I know high idle at startup is normal. Of course. That's like "Duh Engines for Dummies 101". The engine has to idle higher to reach operating temperatures. I did use some Seafoam a while back. I put it in the gas tank and the crank case. I was a bit scared to do it through the vacuum hose, but I guess I'll be doing that. the idle should come down to normal. which is around 800-900 rpm's. Depending on whether it's been adjusted higher. If you have alot of miles on the engine, carbon build up might contribute to this as well(however it would be odd) I don't think 800-900 RPM idle at proper operating temp. is normal. Mine used to be around 500rpm in the summer. I guess "in the summer" is the operative phrase. My dad's truck idles precisely at 500rpm all day. It's not a Nissan, but I've taken note of gauges and things on cars since I was a little kid. I'm probably remembering wrong, but when I see the idle floating at 900, it just feels...wrong. As for Sea-foam... That stuff is wicked good. I run it every oil change, through the brake booster line... I went to the local Lowes and purchased a ice maker water line connection kit, (was like 10 bucks) and use the valve and some of the line along with an adapter to fit the booster line... That way you don't have to sit there and babysit it while it does its magic... Just start the truck, and slowly open the valve to where it draws the clear nectar of the gods out of the can and into the intake system via the booster lines vacuum... Sit back and let the white smoke billow... Some good words. I'll definitely be using this procedure. As I said earlier, I was a bit scared about using it through the vacuum lines because the last thing I would want to do is hydrolock my engine. I'm also a bit scared of the white smoke. I don't know if the cops will have a problem with that or what. Screw the seafoam stuff, it has to be something you messed with during the tranny swap. Did you check to make sure the throttle cable isn't snagged or anything is rubbing on it. Check the pedal and the cruise one. Also check all your vacuum hoses. Actually, just replace them. It will cost you like 3 dollars in hose. I'll check again. All I did was remove the airbox, carbon canister, and wiper fluid reservoir (don't ask why) when I did the trans swap. I didn't touch the engine at all. I didn't mess with any sensors or wires. The only wires I touched were the 02 sensor and I took out the A/T power wires. It could still be something I suppose. How do I go about buying vacuum hoses by the way? Does Nissan have a kit or something? ^^^^^^^LOL. NVM I can't believe I just typed that part about the vacuum hoses. I'll leave it for your own laughs. Sorry for the lengthy response. I wanted to respond to each one of you individually because they all have good advice. Thanks for all the input guys, I really appreciate it. Link to comment Share on other sites More sharing options...
NextToAlaska Posted January 31, 2012 Share Posted January 31, 2012 Check the distributor aswell! if its loose it can make your vehicle idle real high, or real crappy, Worth a check if your under the hood. my pathfinders came loose when i was messing with the harmonic balancer this summer n it was idling at about 1800 when ever i turned it on! Worth a look anyway haha Link to comment Share on other sites More sharing options...
adamzan Posted January 31, 2012 Share Posted January 31, 2012 I'm saying screw the seafoam stuff because if it happened after the tranny swap, it was something you may have knocked loose, not that it just happened it needed seafoam. Link to comment Share on other sites More sharing options...
krmiller07 Posted January 31, 2012 Share Posted January 31, 2012 When, and if you use Sea Foam through the brake booster vacuum line. Pour it directly down the booster hose very slowly (partially covering the top of the bottle with your finger). The natural vacuum will suck the liquid out of the can as you're pouring. This alone will prevent Hydro-lock. Your engine will actually want to stall as you pour this in, so turn the idle adjustment up when doing this. That is after you figure out what causing the High idle in the first place. Vacuum leaks can cause high idle, however it will also cause rough idle as well. As for the location of vacuum line. I wouldn't bother going to a dealer. There is no 'kit' available that I know of. You can go to any auto parts store and buy it by the spool. Or by the foot. Look at the lines you want to replace, and get an approx. idea of how much you need and buy a couple feet extra is a safe way to go. Spraying carb cleaner on and around the intake manifold and throttle body is a great way of locating vacuum leaks, as the idle speed will change if a leak is present. Link to comment Share on other sites More sharing options...
Trogdor636 Posted January 31, 2012 Share Posted January 31, 2012 How do I go about buying vacuum hoses by the way? Does Nissan have a kit or something? ^^^^^^^LOL. NVM I can't believe I just typed that part about the vacuum hoses. I'll leave it for your own laughs. I just bought 8 feet of the smaller vacuum line, that covered it with about a foot or more left over, and I was a little extra generous when cutting. Dont forget to replace the tiny length at the back on the intake manifold to the fuel pressure regulator. Link to comment Share on other sites More sharing options...
silverton Posted January 31, 2012 Share Posted January 31, 2012 Since you did recently replace your transmission, it is possible you also messed up a vacuum line. Link to comment Share on other sites More sharing options...
Hamz Posted October 31, 2013 Share Posted October 31, 2013 did this high idle get fixed? Link to comment Share on other sites More sharing options...
Alkorahil Posted November 1, 2013 Share Posted November 1, 2013 (edited) Bring it over to my house this weekend and we will figure it out and fix it. Seriously I would do as many others have noted. Nissans do idle high at start. Check the vacuum lines first. I always recomend just replacing them all given the age of the vehicle. It is just bulk hose you can get at any auto parts store and will cost you about $20 to replace them all. Replace the Engine Temp Sensor and PCV valve they can/will effect idle and probably need replacing. Get an old skool timing light and check your engine timing per the FSM proceedure. Edited November 1, 2013 by Alkorahil Link to comment Share on other sites More sharing options...
Hamz Posted November 2, 2013 Share Posted November 2, 2013 sorry man, the last post was almost 18 months ago Link to comment Share on other sites More sharing options...
Alkorahil Posted November 4, 2013 Share Posted November 4, 2013 ACK Zombie thread! Link to comment Share on other sites More sharing options...
Precise1 Posted November 4, 2013 Share Posted November 4, 2013 Rob got Zombied... B Link to comment Share on other sites More sharing options...
Alkorahil Posted November 5, 2013 Share Posted November 5, 2013 I need this for those Zombie threads! http://www.thisiswhyimbroke.com/ak-47-rifle-with-chainsaw Link to comment Share on other sites More sharing options...
Precise1 Posted November 5, 2013 Share Posted November 5, 2013 That'll work!! Still, your input is good and someone will come across it when they are searching for answers, so it wasn't futile, it just wasn't timely. B Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now