Help: Cold Start Problems

[PBfrEAk]

I made this same post in the Maxima forums but I figured I'd get a better response here...can someone delete the one in the Maxima forums for me??

Thanks...now on to the problem:

I recently put on a "custom" intake. (two elbows and a straight piece from AutoZone, a spectra rubber piece, and a Older K&N filter...which I'm replacing soon.)

It sorta looks like this (I posted this pic a while back when I was installing it...so don't mind the arrows and other ****.)



Ever since then, when its cold its hard to start. I have to run the throttle and keep it around 1,000 rpm's for a minute or two to sorta warm it up. Other wise it just starts up and dies.

Its acting the same way as it did when I was having trouble with installing the intake. It turned out I forgot to hook the IACV back into my intake (it apparently HAS to be pulling in metered air). When I had the IACV unhooked. I'd start the car and it would fire up and immediately die. If I ran the throttle it would stay running.

Now its doing the same thing except only when its cold. I know my intake doesn't have any leaks (I wrapped my hand around every seam one at a time and revved the engine and the only place I feel air is right at the filter where it sucks it in).

I thought maybe if the hose running from my IACV into my intake was a little old it may have leaks in it. But it doesn't seem to.

Could this be the culprit??

What do you guys think??

[mtcookson]

Hmm... one thing I can think of off hand is the valve inside the IACV. You may try cleaning the IACV itself and see if that helps.

To check for leaks in that area I recommend the keyboard cleaner. Its simply CO2 in a spray can and you just spray it around the hoses and such. If you hear the engine stumble, it sucked the CO2 in somewhere, which means there a leak. Good, safe way to hunt down those hard to find leaks.

[PBfrEAk]

I've got a couple bottles of that lying around...I'll give it a shot!!

As for the IACV...how do I go about cleaning that?? (how do I take it apart.)

[mtcookson]

If I remember correctly there are 4 bolts holding it on the intake manifold. There are two gaskets, one for the IACV to the valve I mentioned above and the other for the valve to the intake manifold. I'm pretty sure when you take the bolts out the valve and IACV come out in one piece (I can't remember for absolute sure though... its been forever since I've messed with the Maxima). If you're careful not to break the gasket you can usually get lucky and reuse it... though that isn't really recommended so you may want to order the gasket (or both) first just to be on the safe side.

You can get them from Courtesy here:Up to 4/1991 - http://www.courtesyparts.com/b...=1610&4/1991+ (probably means 5/1991 up but you make ask someone at Courtesy if you just so happen to have a 4/91) - http://www.courtesyparts.com/b...=1610&89-94 Gasket - http://www.courtesyparts.com/b...=1610&

[PBfrEAk]

I found this link here ...and this guy was putting a new cone filter on his Pathy and at the end he says something about reseting the ECU.

I never thought about it but would I have to do that since I an introducing more air quicker or would the ECU adjust accordingly on its own??

EDIT: Oh and can you delete this same thread over in the Maxima Forum...Idk why I posted it over there 1st but yea...thanks lol
Modified by PBfrEAk at 11:50 AM 2/13/2008

[mtcookson]

I don't think our ECU's can really learn anything. They simply have a fuel and ignition table and it bases how much fuel and ignition it gives to the engine on RPM and essential load (which is based off of other inputs, I believe being, the MAF, TPS, and possibly a few others... maybe speed sensor and something else).

The ECU can't change the maps itself so it simply sees X amount of air coming in at X rpm and injects the correct amount of fuel based on where those two essentially meet on the table.

All resetting the ECU will do is remove any error codes that are stored in it, if there are any.

As for the thread in the Maxima section, I actually just left it and locked it for future searching reason. In case any other 3rd gen guy goes through the Maxima section looking to solve the same problem, he'll have the link to potential answers in here.

Its always hard for me to figure out whether to put a thread like this in the car section or engine section so since there was one in both I figured I'd leave them just in case.

[PBfrEAk]

I don't think our ECU's can really learn anything. They simply have a fuel and ignition table and it bases how much fuel and ignition it gives to the engine on RPM and essential load (which is based off of other inputs, I believe being, the MAF, TPS, and possibly a few others... maybe speed sensor and something else).

The ECU can't change the maps itself so it simply sees X amount of air coming in at X rpm and injects the correct amount of fuel based on where those two essentially meet on the table.

All resetting the ECU will do is remove any error codes that are stored in it, if there are any.

Thats what I figured...I think I'm gonna check the ECU for codes though...I don't think its EVER been checked lol.

Thanks...and thanks for fixing the link in the Maxima forums as well...good idea!!

[bcarr]

Hi all,new to this forum, but the reason i am here sounds very similar to this problem..let me explaini have 2000 i30t bought used about 5 years ago. Last spring (about 72k miles) it started having horrible cold starting problems (below 50 degrees!) and would set off check engine light etc.i brought in to mechanic and he charged me $1200 to replace all the coils (engine had code p1320) and air filter; of course this didnt help. He then relaced the air flow meter. this helped, but within a week the problem returned and has gotten progressivey worse. i now need to have enging warm (10 min) or it will stall when in drive, and i need to give gas if idling more that 2min (eg at stop light) for first 10 min or so of driving.

i have heard many suggestions about what this could be (fuel pump, EGR, intake manifold gasket) but am a little hesitant to bring in without some idea of the problem...still stinging from the waste of $1200 last time i guess

any all comments appreciated!

thanks

brian

[mtcookson]

Brian, you car actually has the VQ30 so most of the electronics are going to be different than what the VG's have.

I'd look around and ask in the Maxima/I30 section and see if they have some ideas for you in there.zeroforum?id=83

[bcarr]

Thanks..I'll check out the VQ30 forum-brian

[PBfrEAk]

Well I know this thread is old...but for the sake of people searching...I figured I'd update this just so they know what happened.

I ended up taking of the intake and putting the stock one back on...problem solved.

I just had a leak somewhere along the intake that wasn't sealing correctly.

I did however do a MINOR tweak to my stock box.

The lower part of the box that the filter sits in is now swiss cheese!!! I took a power drill and a whole saw and cut holes in it to let it breath more air.

I've noticed a slightly quicker rev but thats about it.

Just thought I'd let everyone know!!

[MinisterofDOOM]

To check for leaks in that area I recommend the keyboard cleaner. Its simply CO2 in a spray can and you just spray it around the hoses and such. If you hear the engine stumble, it sucked the CO2 in somewhere, which means there a leak. Good, safe way to hunt down those hard to find leaks.

I know it's a little late for this, but:Not all keyboard cleaner/canned air is CO2. In fact a lot of them are HIGHLY flammable these days, which doesn't serve this purpose at all. Check the ingredients and warning labels to make sure you aren't buying one that's got flammable propellants. I bought some 3M stuff the other day that uses some environmentally friendly propellant (which is oddly also a refrigerant) that happens to be extremely flammable according to the can. I've bought other 3M canned air that says it's 100% non-flammable, though, so just check the can before you buy it.

[mtcookson]

Interesting... maybe I can find some flammable ones and have some fun with 'em!