Strange SR idle resurfaces

[s13sr20chris]

i love spare parts. i have tons of spares. my biggest two droors in my toolbox are full of spares and then i have boxes stuffed everywhere with them too.

[180fan]

ha ha ha yeah. I've got spares for the entire fuel system, and ignition system now. Just gotta start hoarding all the other spare parts for the sr I can get my grubby mits on. lol

[180fan]

Alright guys, here's the current situation. I've taken the replacement IACV and given it a thorough hosing with carb cleaner and a tooth brush. Installed it, and I've still got the bad idle. I don't know what it is.

recap:I've already changed the coolant temp sensor, switched the mafs, replaced the IACV

stuff I've noted:the car still starts up like poop. When it warms up, it's a bit better but when the idle screw's set for lower rpms the idle oscillates rapidly, and the vac pressure runs between 5-15 in/Hg. When I've got the idle screw up so the idle is around 1200-1300 rpm at warm up, to get the vac pressure stable at 18 in/Hg. When the idle is stable, the car runs moderatly rich and also has very little exhaust fumes that sting the eyes and sinuses. When the rpm's are fluctuating, the stinging stuff from the exhaust fumes increases.

Any ideas as to what else I could look for?

[180fan]

bump

[NISTECH]

it sounds like you have a vaccum leak. The stinging indicates a high content of HC's and NOx emissions. which would also indicate a lean condition.

[180fan]

yeah I guessed it'd be a vac leak still somewhere. This thing's really pissing me off. I think I'm just gonna order some new gaskets for the intake manifold to block, runners to collector, and throttle plate and be done with it already. This thing's taken way too long and it's way frustrating. *shakes fist*

[180fan]

You know, there's something I overlooked yesterday. I noticed that when I took off the fuel rail, the injector seals were very easily removed. Is it possible that there's an air leak through there and asking me "how do you like the size b****"?

[NISTECH]

oh yea that is possible. carb clean the chit out of it and see if it effects the idle.

[Gladius]

Ohh the suspense!! LOL.

Anyways, my sr was idling fine when I first got it and now it has a low idle(approx 600-650) when cold, but idles great when warm (approx 900). Only thing i touched was a bump in timing and the problem didnt even surface at that time. The low idle reared its ugly head about 2 weeks later. Dirty IACV?

[180fan]

Ohh the suspense!! LOL.

Anyways, my sr was idling fine when I first got it and now it has a low idle(approx 600-650) when cold, but idles great when warm (approx 900). Only thing i touched was a bump in timing and the problem didnt even surface at that time. The low idle reared its ugly head about 2 weeks later. Dirty IACV?

Possibly. It couldn't hurt to give it the hosing of a lifetime with some carb cleaner.

Oh here's an update. Not really willing to take chances, I've ordered some new o-rings for my injectors. They didn't fit snugly around the injectors and could be pulled from the intake manifold with ease and by ease I mean just pull it without any effort from the manifold. Me thinks the o-rings are a pretty good possibility. I know they're supposed to be a bit more snug than pulling easily by hand. I'm gonna give the injector o-rings a shot of carb cleaner when I get them hopefully tomorrow so I can slide in the injectors without the risk of tearing that some get with their injectors.

also it looks like alot of people are checking out this thread for their idle issues too. hopefully this thread's helping some of you out.

[180fan]

Alrighty, update time again. The plot thickens...

I found that when I pulled the hose running from the intake manifold to the PCV on top of the valve cover and plugged the hose with my thumb, the idle would stabilize. So with this in mind, I decided to plug up the hoses that run up to the pcv and put a breather on the pcv itself. I couldn't find a fitting in my boxes of parts so I just cut the spring and valve out of the PCV so it's now just a fitting with a breather filter on it. It did help the vac pressure from bouncing to 5 in/Hg so that's a good thing.

However, it didn't solve everything. I am certain I do have a vac leak now. Absolutely certain since when I was fiddling with the IACV screw, I heard a rushing sound of air around the throttle/coldpipe/rubber hose to IACV section. I'm certain the leak's coming from there now and messing up my day.

The vac numbers today were a bit better after the PCV thing. It would go as low as 10 in/Hg (cold range from 10 - 18 or 19 in/Hg) but is pretty stable once warm, ranging from 15 in/Hg to 19 in/Hg. Not too shabby considering it'd stabilze at 18 in/Hg previous to the PCV modification. Also I figure the PCV thing is mainly for emissions isn't it? It's also not likely that my SR's gonna pass smog in CA so I figured why not.

I did however still commit myself to taking the intake manifold apart again, because when I hosed down the small rubber hose that I put in place of the metal pipe that runs to the PCV, the idle stabilized where the intake manifold meets the head. So this time I got some aircraft gasket maker slapped that on the gaskets and sealed it back up. I mean everything got sealed on the intake manifold with that stuff. This time I'm not taking any chances. However, one thing though is that rush of air, I'm not too clear as to where exactly it's coming from, but I know the proximity. So now it's pretty close to figuring out where this effing vac leak is but yeah, if it's making that big a rush sound, I figure it's pretty big.

[s13sr20chris]

not coming from the breather filter right?

[NISTECH]

The rushing air sound you hear could be eminating from within the air inlet tube to the IACV. the smaller the gap in the IACV the more audiable the air passing by it will become. if making slight adjustments to the valve change the pitch of the noise that is likely what you are hearing. try pinching off the 1" hose leading to it from the breather hose and see if the car will stil idle.[if you havent done that already] this will determine weather or not you have a air supply other then whats going through the IACV.

[180fan]

I've pinched the 1" hose for the IACV before, and I saw the vac pressure slowly drop from the 18 in/Hg (I tested that when it was warm) slowly until it was near death.

The sound could be a change in the sound from the IACV but the screw was up pretty high. Not totally sure though. It would make sense though considering that I had all the hoses up there clamped down. The sound wasn't coming from the breather that's for sure. Looks like today I'm going to have to test the IACV part again by capping it with my thumb like last time.

[180fan]

Alrighty, with the PCV seperate from the vac system, I started up the motor and it still idled like crap. It gets better alot faster than before though. So I popped the IACV hose off and plugged up the hose with my thumb. The motor died instantly. I guess I don't have a vac leak...but I still have the poo for idle.

Checked the resistances across my coilpacks and they all read 0.7 - 0.8 ohms...but is this the right way to test them?

Only other thing I could think of that could be causing my issue was my ecu since I don't have a vac leak before or after the throttle, I've replaced my coolant temp sensor, checked over and switched my mafs, cleaned and replaced my IACV, only other thing that I can possibly think of is my ecu. Could that be the culprit? I'm gonna put my ecu in my buddy's car tomorrow to see if it is the ecu. If not then I guess I need to double check the harness again as that'd be the only other thing that could be wrong.

Any other ideas before I take the plunge and possibly tear apart my harness again?

Oh here's a movie clip (1.29Mb) of the idle.http://youngpark.home.mindspring.com/idle.MPG

[NISTECH]

I was like cool a movie:D After I clicked it and waited a few seconds It said this needs addition software to play the quicktime movie:(

I dont like quicktime its a memory hog on my computer and slows it down.therefore I did not get to see the movie:( and I already made popcorn..lol

EDIT: nevermind learned something new was able to open it w/ WM by directly using link COOL.

Sounds like something is opening up then closeing back off,like the IACV keeps compensating for something,the lifter noise is also pretty loud, you say you set your TPS contacts to closed contact???.[continuity exists at idle] If its off idle it will keep trying to open the evap and egr vaccum signal.

Are you going to formula D this weekend at infinion? I will be there. Also I know I asked before but where exactly are you in the bay area was it concord?

[180fan]

Yeah I was hoping to go to formula d but this car problem's sucking the money out and got me pretty worried. I'm in San Francisco and was going to go up that way to visit my woman since she lives in Napa that day but that was if I could get my car to run properly.

Yeah the lifter noise is pretty loud since I forgot to bleed the lash adjusters since they were dry for a while lol. I was gonna get around to doing it sometime but was too lazy to do it...unless it's causing the rockers to stick in a position for a second and keep the valves open a little longer...dammit ok I'll try that today.

The TPS contacts, how would I check for closure on those? the voltage reading is 0.4v when the car's off. I'll double check that for when the motor's running.

I don't have the AC hooked up and never had an egr on the motor. One thing I'm going to investigate for sure though, is that on the IACV unit, there is one component that's got a contact for the ground missing. I'm looking into if other people have that wire going somewhere important.

Yeah I figured the movie clip would give a better idea of the problem than words could describe. lol so hopefully there won't be more I'm gonna have to take but there might be if the problem persists.

[NISTECH]

I dont think your lifters are your problem I was mearly commenting they were loud. on your TPS you have 2 connectors one is your liner throttle position[the one you take voltage measurements off of] the other is the hard idle contacts and wide open throttle contacts. when your engine is warmed up and off you unplug the other connector and look for continuity between the center terminal and one of the outside terminals in the switch[one is WOT the other is hard idle. use your ohm meter to check for continuity at idle. once you have the right terminal crack your throttle slightly and see if it goes open. you should have about.012" before it goes open circuit. if you check both those terminals and niether has contact you need to adjust it so it does. shouldnt take to much movement to aquire that. the measure ment would be taken at the throttle stop screw.

[180fan]

oh ok. Yeah the lifters are pretty irritating though, makes it sound like a train chugging along. lol.

I'll give the TPS a shot today, that and finally bleed the damn lash adjusters too. lol I've been meaning to get to it but...too damn lazy like I said. It's a pain taking off the cams and all that other stuff that's holding down the lifters...*cries for laziness*

but yeah the TPS thing is a will do! *salutes*

[180fan]

Nistech, I couldn't find the second plug you were referring to. Here are pics of my throttle.



I did a search for the throttle compatabilities and apparently they're compatable with the sentra se-r's with the SR. I'm not sure if the TPS is the same though but it's worth at least a shot on my end.

[NISTECH]

that is odd usually if they only have one plug they are just a hard idle switch and not a linear switch. I was expecting to see a pig tail coming off of it with another connector on it. I am at a loss I dont know where you should go now as it appears the engine is set up differently then the KA as far as tps. just by the way its acting its got a problem where it opens vaccum to something and its leakint so then it compensates and closes it. What that something is is beyond me.

[NISTECH]

whats that loose bolt in picture 2?

[180fan]

That's for one of the alternator bolts that tightens down the tensioner lol I forgot to tighten it down when I pulled the AC compressor off. I'll get to that when I get back up to my car. I did spray my throttle plate with carb cleaner, noticed that when I sprayed it, there was a little bubble that would pop up from the throttle plate about once a second. Could that also attribute to where the air is coming/going from?

[180fan]

just an afterthought, perhaps the throttle plate is letting slight amounts of air seep through? If that's the case I'll pop the throttle off and check it against my KA one and see if that'll alleviate the problem. The only other lead I can think of now is the one wire missing for the IACV on the plug. I've still yet to get someone's car that has the sr in it to check around for that one wire. There are a few things I noticed on that part though, the IACV unit has an FICD, AAC and the IACV all built into it according to the FSM. Just wondering what each of these do? I'll take pictures of the other unit I pulled when I get back to the car tonight. Maybe that'll bring about some more ideas. I'm stumped on this thing and it'd probably be better for me if I knew exactly what everything does that I don't know enough about.

Oh yeah Nistech and Chris, thanks again for all the help with this problem. I'd Get ya both beers one of these days but it'd be hard with Chris on the east coast. lol. But Nistech for sure, I'd be able to swing over at least a few.

[180fan]

nm found out what everything there does. I just wasn't sure what the FICD did. But I'm still not too sure as to which part exactly it is. I'm assuming the FICD is the hexagonal part of the unit and the IACV is the circular part.

[NISTECH]

this is what the FICD looks like on a KA

[180fan]

So any thoughts on the throttle plate issue I've noticed? Or should I make another movie? ha ha ha. I'll probably capture another bubble that way or two in the next clip if that helps.

thanks again

[s13sr20chris]

just noticed in pic two that your vacuum lines at the top of throttle body were off. thats not how you are running it when it runs bad right? i think you already told us about it and i just forgot. now i want to make sure.

[s13sr20chris]

please confirm this all as i am having to recap. vac sucks as the movie shows, compression good(right?), ign timing 15btdc(you prob already mentioned it but i dont have time to read the whole thread, im going to work), no known vac leaks, swapped out like every component, etc. heres a strech, could your converter be clogged? i have never seen a clogged cat idle like that, but anything is possible. maybe pull the exhaust loose from the downpipe and try if you want to. do you want to know what that idle sounds like? i used to work at a cadillac/old/gmc/saab dealer and i put a few injection pumps on 6.5 diesels(i hate non-nissans). an improperly timed injection pump or one without the resistor will idle just like that. solution? you dont have an injection pump but your ecm may be injecting fuel at the wrong time. i think you should try to swap out the ecm. i have one sr buddy who has swapped with me before just to clear things up. it can help a lot.

ok, off to work. im gonna pray for you and your car bro!

[NISTECH]

Also I cant hear in the movie but when the engine is dropping down do you hear a hiss when it gets to the low point then it goes away and the idle jumps back up? That would be a definite tall tail sign. If you can also snap a shot of your intake set up and of your intake manifold. something is seriously sucking air and the IACV keeps compensating for it.

Chris does your SR not have a hard idle switch in the TPS either?That doesnt seem right to me