Hey. Greeny really is a good guy. It pays to at least listen to him.

 

I believe it. Him and everybody else on here have been very helpful with my questions and I appreciate it. My dad made a point last night that I was unaware of. Cars were tuned from the factory with a certain plug and it should always be used. He said he's seen Honda's and Toyota's throw Misfire codes because they didn't put factory spark plugs in it. Which makes sense to me now.

 

I had the same problem and turned out to be the fuel pump was going bad replaced it then that problem went away. Could be that your having the same issues. Just a another thing to look at.

 

hey since the noob threadjacked already id figure id do it too

ive been having mysterious throttle problems ive run the ecu diagnostic i took it for a "proffesional" diagnostic and i pressed my ear up against every hose in that car and have not found a single thing

just so everbody knows ive had new injectors and plugs for less than 20k ive had the fuel system cleaned out "professionally"

the idle is just surging it goes up about 3-400rpm's randomly usually with the brakes depressed not when crawling in park nuetral or any other gear

 

hey, sleepy, it sounds like a little vacuum leak to me.
somewhere between the brake booster, and some other junction, maybe...

 

thats what i thought but shouldn't there be some kinda of hissing sound or signs of cracks or something it looks fine to me its not even dirty they all look fine so is there anyway to tell which one it is or should i just replace every single one

 

hows ur alternator's output? it could be cuz of heavy electrical load wen u push brakes it need more power and idle goes down....turn ur high beams and watevere u have to on and see wat happens to idle....it should go down a lil but NOT TOO DOWN...

 

alternator is 2 months old i doubt theres any problem with it also the idle surges when brakes are depressed but this could just be the fact that im idleing longer with the brakes on or that i just haven't noticed it when i was crawling also ive tried messing with the elecrtrical system the ac, the tranny switch, the headlights, and tried to see if changing gears did anything and i got no reaction from the car at all before it surges or after

ill try the hi beams but i doubt it will get different results....

 

then jus pinch the blow-by hose on the back of the engine beside EGR...wen u pinch it nothing should happen but if ur engines speed rises then u have a leak somewhere which u have to hunt down ur self....OR it could be ur IACV needs to be cleaned if u hadnt in past....


blow-by hose is a big hose on the back of the engine same size as brake booster hose...

 

Possibly, not totally sure though.
Open loop just ignores the O2 sensor and calculates fuel requirements from the remaining sensors, mainly the MAF and CTS (not sure about the VE, but on the VG the TPS is NOT used by the ECU). Your engine runs in open loop a lot more than most people realise, closed loop operation really only kicks in during constant RPM and load (cruise or idle) conditions as there is a significant lag between the ECU changing the mixture and the O2 sensor seeing the results. During acceleration, deceleration and gear shifting, closed loop operation is too slow to be useful, so your ECU is in open loop

 

where exactly is that hose ive never heard of it im thinking of replacing all the hoses but the closest diagram i can find is this: http://www.240edge.com/manuals/89-90_240sx/m_vacuum.pdf

i do need to clean my iacv as well as the throttle body and maf and my filter probably could use a regreasing but im starting to think its electrical now because when the idle surges i notice a dimming in the headlights also in the display actually all the little lights in and outside the car dim for some reason when the idle surges what would cause this

 

There are 2 hoses of similar size on the back of the upper intake manifold/plenum, one goes to the brake booster, the other goes to the rear rocker cover, try pinching off the one that goes to the rear rocker cover.
It is always a good idea to give the IACV and throttle body a clean if it hasn't been done for some time.
Lights dimming when the idle surges, seems a bit back to front.. It is normal to notice some dimming when the idle drops too low as the alternator is unable to maintain it's output at extra low RPM, but if it is dimming when the idle surges, then I don't really have any thoughts on causes.

 

shyt sorry dude i kept thinking u have VE lol and was telling u by that... and diagram u have is from 240sx wats up with dat? ......

get ur alternator rechecked if it was installed properly and check for the belt too i doubt if its lose or something.....and forget about blow-by hose but u can try pinching it as sonicii said.....i thought u had VE.....and what ur car idles at? should be around 790rpm or 800rpm...u need to clean it iacv as well

 

the idle shouldn't be that high most of the time.
my A/T idled at 750 in neutral and 525 in gear.

 

uh.. your iacv must have been messed up because it should idle like 50rpm lower in gear.. not 225rpm lower. my VGauto idled 50rpm different in or out of gear.

 

both my VEs that I drove regularly did that IIRC.

 

this is what mine idles at as well then it jumps from around 750 to 1000 -1250 and in gear it jumps from around 525-550 to 800-900

 

*update*
throttle is now gettin worse it now starts up at 1300rpms

 

I went through the same thing my problem was the MAF

 

depending on how cold it is, that may be normal

 

*update*

i cleaned out the MAF and reoiled my K&N filter and the throttle problem is gone

i started it up and the idle slowly climbed to almost 2000 rpm's in park

then it stopped and slowly fell back down to 900 and went down to 700 when in gear and its now rock solid in any gear if the problem continues ill clean out the TB and the intake manifold

thanks to all who helped!

 

I do recall a Nissan tech bulletin on idle problems with aftermarket air filters, I believe it had to do with the filter clogging unevenly, causing uneven air flow through the MAF tube and therefore mis-reading the correct air mass entering the engine.

 

the issue was that the aftermarket filters allegedly were not sealing to the airbox correctly.

 

great!!!......wat did u clean ur maf with? maf cleaner? and clean ur TB too as soon as possible, will be better for future...and ya wen i start my car in the morning or its very cold my rpm jumps to around 1800 too then its come down to 800 as car gets to its normal temp as u can see in my signature pic thats my normal rpm..

 

crc maf cleaner it made the car sound alot nicer at startup the bottle says it gaurantees 4-10hp but i didn't notice anything

and yeah i wanna get to that soon definetly within the next 10k ill replace the distributor wires plugs and scrape and clean the intake manifold and test the injectors while im down there then replace alot vac hoses and finally install the TB bypass

it'll definetly gimme a chance to get some spray paint under the hood...

 

sleepyvg - be aware that I had some problems with intermittent "missing" that turned out to be fuel injector related.

The culprit turned out to be corroded electrical injector prongs. I cleaned some of the ones I could easily reach without removing the intake manifold (by filing a tiny screwdriver and scraping the electrical spaces on the injector until they were bright and shiny copper color!) and then wrapped electrical tape over the torn electrical connector rubber "boots" on the back injectors, and also put in some dielectric silicone grease on the connectors before reassembling, and it made a world of difference.

Of course it took me replacing out all the injectors with problematic, crappy aftermarket ones, not being happy, then replacing them all out on a different set of used oem injectors that had the exact same problems, before I realized it was just the *corrosion* of the copper electrical spades on either set of the OEM injectors was the culprit and causing the intermitted misfire.

I never went back and scraped off the corrosion from the harder to access injectors, and every once in a while my idle RPMs and very occasionally engine miss occurs, but I've been intending to do that. However your finding with the MAF cleaning making an improvement will be something I am going to put on my list now to try out in addition! You might want to put cleaning and maintaining those old injector electrical connectors on your list as well.

This is just a word to the wise of other high-mileage VG motor owners... if you have stock injectors still and have never performed maintainenace (as I described above) on their electrical connectors, plan on doing so at some point. Also be on the lookout for the cracked rubber boots of the electrical connectors, (which may be what causes or at least really hastens the corrosion of the injector's copper electrical terminals in the first place.) Also consider as a preventive maintenance measure, to remove your injector's electrical connectors, dabbing some dielectric grease into them, and reassemble to slow or stop the corrosion.

Just doing the grease + adding electrical tape to any torn electrical injector connector boots would be a heck of a lot easier than having to the the scraping of the terminals, and a whole lot cheaper than buying a new set of the "good" (oem bosch, very expensive) injectors.