start + die = wtf

[ProZach626]

It's been a while since my Lemon spec v has acted up, so I'm long over due for something big. Lately my car has been starting just barely rough. Doesn't happen everytime, just every so often. I will start it and the rpm's will start dropping and bouncing around until I wait a few seconds or tap the gas. After that everything usually comes to life. I related it to the cold weather. This morning I started my car up and it coughed badly and died after about 2 seconds. The second time I started it and tapped the gas like usual and it was fine. I can't tell if it is in my head or not, but lately I think I have lost a little power. It seems like I have to give it a little more gas from the start as opposed to the easy clutch and if I want to get going a little quick for whatever reason it seems like I have to damn neer floor it. Like I said, maybe it's just in my head. I also smelled some pretty strong exhaust smells when I started it this morning(not precat smells). I have smelled precat smells in the past even after I had it replaced by Nissan about 3-4K miles ago, but it usually only happens after WOT. I think I have smelled more non-cat exhaust smells to be more prevelant lately. Also, I didn't drive it all day yesturday. My old car used to die after not driving it for a day when my cat was going out... but that was a geo with a 1.6. My question is... is this expected of an 03 with 81k miles on it in the winter, or could it be something more? Could my new precat already be going out???

Sorry I wrote a novel, I just try to be as descriptive as possible. Who knows, maybe my engine chewed up one of those awesome butterfly valve screws that I have been too lazy to loctite...

[slideways...]

id try a couple things, not necessarily in any order
1. check for vacuum leaks
2. check fuel pressure at the rail, cold start and warm start. you should have roughly 35-40 psi iirc.
3. ohm your injectors. i believe they are high impedence injectors, which means they should be about 12 ohms, plus or minus 1 ohm.

you may want to double check all these specs im listing off, i dont know for sure all about the spec v, im just listing some generic specs nissans tend to follow.

[ProZach626]

Originally Posted by slideways...

id try a couple things, not necessarily in any order
1. check for vacuum leaks
2. check fuel pressure at the rail, cold start and warm start. you should have roughly 35-40 psi iirc.
3. ohm your injectors. i believe they are high impedence injectors, which means they should be about 12 ohms, plus or minus 1 ohm.

you may want to double check all these specs im listing off, i dont know for sure all about the spec v, im just listing some generic specs nissans tend to follow.

Thx, I'll look into this stuff, lol, but i'm not really sure how to do these things.

[slideways...]

1. surest way is to take it to a shop with a smoke machine. it pumps smoke thru the vacuum system in your car so you can tell where leaks are coming from. having a shop do it is the only reasonable option since smoke machines cost several thousand dollars.
2. fuel pressure guage. tee into your fuel line if you dont have a schraeder valve on your rail.
3. use a digital multimeter, and test between the two prongs on the injector with the harness off, car off. use your lowest ohm scale on the meter.

[slideways...]

oh. also to check for vacuum leaks you can spray starting fluid around areas of y our engine, and if theres a leak, your idle will change.

[ProZach626]

Since I'm pretty much unequiped for this stuff would a basic diagnostic test do the trick? The car has been running great all day since the weather warmed up, so I don't think it's in immediate need of attention... if there is even anything wrong with it. I hope all goes well, because I have to go in for emmisions testing this weekend... I hate that crap.

[slideways...]

basic diagnosis usually doesnt cover it unless you tell your mechanic what is wrong. he still may charge more than the base diagnosis cost just because its a driveability problem, not a maintanence problem. go to a shop you trust, get it fixed right the first time.

[ProZach626]

The other day it was very cold outside, but about 40 degrees in my garage... Went to start the car in the morning and it was turning over, but the engine would not fire. It bucked a few times and that was it. I didn't try to hard to get it started in fear or hurting something. Later that day it started fine, besides the usual new rpm dips at 1st. Today I was driving and listening to my car and noticed it sounded terrible. I got to my garage and reved it out to about 4k and when I let off I got a little cackle-back. Because of this and the usual sulfer smells, I'm suspecting the new cat is out already. Taking it in early next week to find out wtf is wrong. When my old cars cat was really bad it didn't start on me once. If it went out... AGAIN, I will just buy a header now instead of in early March as planned. Fuck pre-cats...

Any ?

[nismo_pilot]

precat = shitty...........might want to check your O2 sensors though, when cold they dont read anything so there is a little heater coil in the sensor itself to heat the sensor so it will read, if that isnt working your car will have a hell of a time in closed loop operation i.e anything under 3500rpm or so

[ProZach626]

Originally Posted by nismo_pilot

precat = shitty...........might want to check your O2 sensors though, when cold they dont read anything so there is a little heater coil in the sensor itself to heat the sensor so it will read, if that isnt working your car will have a hell of a time in closed loop operation i.e anything under 3500rpm or so

Very interesting. One thing I noticed IS a drop of power @ lower RPM's. I'm taking the car in early next week, but another fear that I have is that I might have swallowed a butterfly valve screw. I read it can lead to unsteady idle, and I have had that for quite a while. It has kind of bobbed around on me for about a year or so now. Damn my procrastination... If a butterfly valve screw did come loose, is the unsteady idle due to the interuption of air flow that it might have caused, or would it be cause by internal engine damage? I'm hoping that the air flow would just be messed up and that by a mirracle the screw went through the engine without hurting anything. This way I could remedy the problem by just replacing the screw. I don't think I did loose a screw, but at 82k miles it is very possible.

[nismo_pilot]

possible thats it, a maf sensor might cause weird idling also

[ProZach626]

Originally Posted by nismo_pilot

possible thats it, a maf sensor might cause weird idling also

I have also heard that can make your car smell bad because of the mixture as well.

[Chiquae07]

did you lockite your butterfly screws at all?

[ProZach626]

Originally Posted by Chiquae07

did you lockite your butterfly screws at all?

I'm the shittiest procrastinator of all... no. I planned on doing it when I use my balance shaft removal kit... which I am literally resting my foot on. No time lately, not that I haven't had time 6 months ago when I talked about it... but right now work and school have me bummin.

[nismo_pilot]

well you could always ship me the BSR if youre not going to use it.....lol