94 J30 Rough Idle...IM lost and new...just got my J30

[Adam240sx]

Ok I just got me a 94 j30 feb 2nd. Im not quite sure whats wrong with it. the guy that had it listed said that it needed a timing adjustment. Well I brought it home, to have my gf's dad check it out. He's pretty good at fixing cars. He thought it was misfiring on one or two cylinders. Thats what I was thinking the problem was. I went and bought 6 new spark plugs, changed those, and checked the coil packs to see if one of those are bad. Those all seem to be fine, and all saprk plugs are getting fire. Next thing, was to check the computer for codes. I found the sticky on here that tells me how to do it. Im looking at the ecu and it has no lights on it nor a screw to turn. I called the closest Nissan dealer and they said it might have a newer ecu in it, and that I would have to bring it to them to scan. Im just curious if anyone on here has any pointers as to what might be my problem. What else could I look at? The car really has no get up power at all. It drives but is real rough, with shaking. It did manage to drive all the way from 25 mins south of St Louis to Effingham Illinois over a hour and a half away. Im very lost on what to check next besides mabey the timing belt, and the like. Anyone have any ideas??? I really appriciate all the help you could give.

Thanks Adam

[StevieRaySTL]

-- Knock Sensor? Fuel Injectors? Just a couple of guesses, but they are both common issues w/ the J30 that might be causing you're problems. GL and keep us posted.

[misfit6794]

Having just taken apart my engine after experiencing the same issues. Clean the IAC with carb cleaner, don't get any into the sensor, and its a ***** to get to. Have the fuel injectors cleaned and tested. My problem ended up being clogged egr tubes, also a ***** to get to. The timing belt cover isn't that hard to remove (compared to the intake manifold) and check the belt.

[gr8scott72]

Ok I just got me a 94 j30 feb 2nd. Im not quite sure whats wrong with it. the guy that had it listed said that it needed a timing adjustment. Well I brought it home, to have my gf's dad check it out. He's pretty good at fixing cars. He thought it was misfiring on one or two cylinders. Thats what I was thinking the problem was. I went and bought 6 new spark plugs, changed those, and checked the coil packs to see if one of those are bad. Those all seem to be fine, and all saprk plugs are getting fire. Next thing, was to check the computer for codes. I found the sticky on here that tells me how to do it. Im looking at the ecu and it has no lights on it nor a screw to turn. I called the closest Nissan dealer and they said it might have a newer ecu in it, and that I would have to bring it to them to scan. Im just curious if anyone on here has any pointers as to what might be my problem. What else could I look at? The car really has no get up power at all. It drives but is real rough, with shaking. It did manage to drive all the way from 25 mins south of St Louis to Effingham Illinois over a hour and a half away. Im very lost on what to check next besides mabey the timing belt, and the like. Anyone have any ideas??? I really appriciate all the help you could give.

Thanks Adam

You have to pull the ecu out and swing it around backwards to see the screw and light.

[Adam240sx]

The guy at the nissan dealership told me that it should be right there in sight. If I cant see the screw or the lights, that its a newer ecu and they would just have to scan it themselves. Really that makes no sense to me, cause the car was manufactured at the end of 93. I asked him if I had to remove it to see the screw and he told me no. ???

So do I actually have to remove the ecu from the bracket holding it in place? With my idle being as rough as it is, im assuming I would have some codes show up.

How would I clean the IAC? and what is a IAC? Where would I get my injectors tested at? and cleaned? Where is the knock sensor and how would I tell if it was good or bad/ my problem?

Thanks for everyones help, and I will keep all of you posted on my progress. Soon as I get a chance I will get my digi out and snap some good pics. Shes nothing to fancy, sat for a year, needs to be cleaned up. No major body damage, minor dings and scratches. Has the typical wear on the top of the door panels. Has some 15in. chrome rims on it. I also got the factory Infiniti rims from the guy.

Where could I find the kit to install my aftermarket cd player? Walmart dont sell one that says it fits my car.

[Adam240sx]

heres a pic of her that I took earlier with my cellphone. I also think theres something wrong with the front shock on the left side. Its really low to the tire, like it was a lowered car. All the other shocks seem to be fine.


Modified by Adam240sx at 6:03 PM 2/5/2008

[gr8scott72]

The guy at the nissan dealership told me that it should be right there in sight. If I cant see the screw or the lights, that its a newer ecu and they would just have to scan it themselves. Really that makes no sense to me, cause the car was manufactured at the end of 93. I asked him if I had to remove it to see the screw and he told me no. ???

So do I actually have to remove the ecu from the bracket holding it in place? With my idle being as rough as it is, im assuming I would have some codes show up.

How would I clean the IAC? and what is a IAC? Where would I get my injectors tested at? and cleaned? Where is the knock sensor and how would I tell if it was good or bad/ my problem?

You have to pull the ecu out and swing it around backwards to see the screw and light.

[Adam240sx]

ok, i guess i'll do that tomorrow. thanks scott. if i run into any problems, i'll be on here posting my ?'s

i was reading about the knock sensor in another thread,and im thinking thats gonna be B**** to get to. If the ecu dont show the knock sensor code, would I still need to check it? and how would I know if I need to replace my ks?

[gr8scott72]

ok, i guess i'll do that tomorrow. thanks scott. if i run into any problems, i'll be on here posting my ?'s

i was reading about the knock sensor in another thread,and im thinking thats gonna be B**** to get to. If the ecu dont show the knock sensor code, would I still need to check it? and how would I know if I need to replace my ks?

About half the time, you'll have a knock sensor code in the ecu. Another symptom is lack of power at any throttle position except WOT.

[Adam240sx]

WOT? sorry im new to the lingo. btw the car has no power pretty much what so ever. very slow to get up to speed, and its loud when doing so.

[gr8scott72]

WOT? sorry im new to the lingo. btw the car has no power pretty much what so ever. very slow to get up to speed, and its loud when doing so.

WOT - wide open throttle

Loud from engine bay?

Common problem on these cars is leaking exhaust manifolds. If your leaks, that seems to rob power as well.

[gotspeed]

Knock Sensor, for sure.

[gr8scott72]

Knock Sensor, for sure.

For the lack-of-power problem, yes. It's probably the knock sensor. Some have had the same symptoms when they had a clogged radiator. The car is running a little too hot and it pulls time.

For the running-rough-at-idle problem, that is not the knock sensor.

You need to see if there are any codes before doing anything else.

[misfit6794]

It definetly sounds like you've got more than one problem possibly. If your ecu comes up with nothing, start with the iac (idle air control). It is on the driver side of the motor, all the way in the back, at the top of the engine. Its held in with 4 10mm bolts, 1 of them you cant really see. Spray some carb/throttle body cleaner into the part where the spring is, don't let any drip into the actual sensor. OR take it to a mechanic, and have them test each injector and coil pack, it sounds like one might be bad. OR put some fuel injector cleaner in see if that helps, i only use techron. OR swap out the spark plugs, its actually reallly really easy if you have a wobble extension. Other things that may help a little, clean the throttle bodies, check for vacuum leaks, clean the mass air flow sensor (with maf cleaner), clean the battery terminals. Or get drunk and forget about it.

[misfit6794]

It definetly sounds like you've got more than one problem possibly. If your ecu comes up with nothing, start with the iac (idle air control). It is on the driver side of the motor, all the way in the back, at the top of the engine. Its held in with 4 10mm bolts, 1 of them you cant really see. Spray some carb/throttle body cleaner into the part where the spring is, don't let any drip into the actual sensor. OR take it to a mechanic, and have them test each injector and coil pack, it sounds like one might be bad. OR put some fuel injector cleaner in see if that helps, i only use techron. OR swap out the spark plugs, its actually reallly really easy if you have a wobble extension. Other things that may help a little, clean the throttle bodies, check for vacuum leaks, clean the mass air flow sensor (with maf cleaner), clean the battery terminals. Or get drunk and forget about it. Oh and if it turns out to be coil packs or fuel injectors, I have them for sale, cheap.

[Adam240sx]

you have 6 of both? injectors and coil packs? i havent been able to do anything today as it has been raining. i noticed today though that the one shock that i thought something was wrong with seems to have fixed itself? it was really low to the tire, now its normal.

[misfit6794]

6 coil packs all tested all good, 4 injectors that work perfectly, 2 that are a little iffy, all 6 are clean.

[Adam240sx]

how much would you sell it all for? tomorrow im taking the car to a auto shop to have the computer scanned., and see if any codes are showing up. then im gonna go from there. i wasnt able to do much today with the car, besides get it legal and fill the tank up with premium 91 octane gas. i bought a bottle of the good gumout fuel cleaner for the injectors. i drove the car around town to try and run some of that good gas through the injectors. i know i got a exhaust leak by the catalytic, i can hear it pretty good and i know thats having a effect on it aswell.

[misfit6794]

60 for the coil packs(all 6), 80 for the injectors (for all), definetly won't find them any cheaper. email me if you want them, [email protected] Hopefully its not a bad injector, thats a pretty big job to pull the intake manifold to access them, about 800 in labor.

[gr8scott72]

60 for the coil packs(all 6), 80 for the injectors (for all), definetly won't find them any cheaper. email me if you want them, [email protected] Hopefully its not a bad injector, thats a pretty big job to pull the intake manifold to access them, about 800 in labor.

Better find someone that knows what they're doing if you are going to pull the intake manifold.

Ironically, someone that knows what they are doing, is likely to NOT want to pull the intake manifold. The local Infiniti dealership told me that they would not do it. Too much trouble.

[gr8scott72]

how much would you sell it all for? tomorrow im taking the car to a auto shop to have the computer scanned., and see if any codes are showing up. then im gonna go from there. i wasnt able to do much today with the car, besides get it legal and fill the tank up with premium 91 octane gas. i bought a bottle of the good gumout fuel cleaner for the injectors. i drove the car around town to try and run some of that good gas through the injectors. i know i got a exhaust leak by the catalytic, i can hear it pretty good and i know thats having a effect on it aswell.

Your car is OBD1 which means that places like Auto Zone that will scan your car for you can't do it as they will only scan OBD2 cars.

[Adam240sx]

yeah ive already taken it there to find out they cant scan it. so im taking it to a place that actually works on cars and fixes them, as they would have a obd1 scanner just like a nissan dealership. im really hoping its not any injectors, but if i have to pull the intake manifold, i will. might be a bit** but if it has to be done it has to be done. i'll keep you all posted

[gr8scott72]

yeah ive already taken it there to find out they cant scan it. so im taking it to a place that actually works on cars and fixes them, as they would have a obd1 scanner just like a nissan dealership. im really hoping its not any injectors, but if i have to pull the intake manifold, i will. might be a bit** but if it has to be done it has to be done. i'll keep you all posted

I still don't think you realize the scope of that repair. Let me put it like this: I would sell my car before I attempted to take the manifold off again. (Yes, I have done it before.)

Injectors can be replaced without the manifold off. Hard but possible.

Why not just read the codes yourself? Just yank the ecu out and it's easy to see the code.

[misfit6794]

Depending out which injector is bad, you can shave the manifold a little bit to access the screws. The hardest part of removing the manifold is the egr tubes, and hoses that run under the manifold.

[StevieRaySTL]

Ironically, someone that knows what they are doing, is likely to NOT want to pull the intake manifold. The local Infiniti dealership told me that they would not do it. Too much trouble.

^^ Bad Business. ^^ I stay away from the local 'stealerships' anyways.

-- Adam, I notice that you aren't far from me. My pal owns and operates a performance garage just south of STL county. He is the brother of the previous owner of my J30 and his prices are better than anyone else in town. I'd be happy to get a quote from him for you if you aren't going to do it yourself. If you are interested email me with the info, Good Luck.

[yodawill2000]

all 6 injectors can be pulled without removing the manifold.

fuzzycats.com

[Adam240sx]

ok just got back from having my ecu scanned and they pulled up two codes 12 and 51. the mass air flow code and the injector codes. the guy had a tool that he put by the injectors to see wich were working and wich wernt. the only one that didnt seem to be working right was the very front one on the right side of the engine. is there a way i can clean my mass air flow sensor, or do i have to replace it? how do i know if its bad or not? the guy also said it sounds like a rod knocking in the engine, wich is deff not good. im so bummed out....

[misfit6794]

Buy MAF cleaner, but make sure it is a NO RESIDUE formula, clean it, it may work. I've got one that has a torn screen after the sensor, but it works fine, 20 bucks if you want it. Also if you want an injector 25 bucks (they are usually around 100). Not good about the rod knock though.

[Adam240sx]

i went to the auto store and picked up some maf cleaner. im gonna clean the maf tomorrow if the weathers ok. do you know if i could use that maf cleaner to clean my throttle bodys, and how would i clean those?

[Adam240sx]

my gf's dad said he dont think a rod is knocking. he's pretty damn good with cars, so im just gonna leave that at that. im praying its nothing in the engine itself, but i do think one or more of my injectors are bad. come on tomorrow...im ready to get my j rolling smooth.