car hesitates when cold, fine when warms up

Post by **ca18detpowered** » Wed Oct 04, 2006 5:56 pm

Like the title says. when my ca18det is cold, it idles ok, but if i give it any gas it tries to die until after it warms up a bit, after the gauge moves a bit, i can give it gas and it only hesitates if i floor it, but if i try to drive it bucks and backfires until 3000 rpm, then after then, pulls fine, no hesitation.

once it warms up, the hesitation is vague to nonexistant

it sounds to me like it could be my engine temperature sending unit to the ecu......anybody second that?

ive tryed a few different mafs and the problem is always same.

Post by **splintercell** » Wed Oct 04, 2006 6:06 pm

mine does the same thing. it has to do with iacv and air regulator not bunged into my intercooler pipe. at least that is my problem. just waiting on answer to my post.

Post by **eliterit** » Wed Oct 04, 2006 6:16 pm

i too am also having this same exact problem.

please post back in here if you find the solution.

thanks

Post by **float_6969** » Thu Oct 05, 2006 3:06 am

First things first, always pull the codes from the ECU when you've got a problem. Then we're not chasing our tails.

The first things I would check would be the coolant temp sensor, and to make sure that all of the extreneous idle crap is all functioning properly. This is discussed in the FSM.

If you're stuff isn't connected to your intercooler piping, you've basically got a big vac leak and the car is going to run like crap because you're pulling in air that the MAFS didn't count.

Post by **r34 gtr** » Thu Oct 05, 2006 7:46 am

mine has done exactly that for about a year. i know my iacv is bad, and ive checked everything else and its all working fine. i would suspect that first as they are notorious for going bad. if it was the coolant temp sensor i would think it would it would just run like crap when it got warm or something.

Post by **biosehnsucht** » Thu Oct 05, 2006 10:18 am

Bad CTS can make it run rich (run like crap) at any time, not just when warmed up.

If you've not tried changing the CTS yet, do the FSM diagnostic thing I think it specifies an ohm range for a test 'normal' temperature ..

Post by **driftin8ez** » Thu Oct 05, 2006 12:23 pm

I have the same problem. I changed my cts didn't help. I'm in class now so i dont have any time to chase this one around. Just let your car warm up before you drive it. It seems that A LOT of people have this preoblem and have no idea how to fix it.

Post by **fitch9014** » Thu Oct 05, 2006 4:56 pm

isn't this just what they do? i mean the motors...i have mine near stock and it's always been a slug when it's cold, when it warms up it's fine. point of fact, i didn't have a problem all summer, and now that's it's chilly in the morning, it's a slug yet again...

this slug's going to get some salt tommorrow!!

Post by **ca18detpowered** » Thu Oct 05, 2006 4:56 pm

Just changed coolant temp sensor, checked the old one. was totally fine

tomoro gonna check for intercooler leaks, cuz the motor just started idling like *** once the iacv kicks in.

then im gonna check iacv like you said. thanks for the input

my friend has the exact same problem with his ca18 swap as well.

i did a swap for another friend, and his is totally fine, no hesitations whatsoever

btw i checked for codes, 55

everything is fine as far as the computer knows

Post by **float_6969** » Thu Oct 05, 2006 5:13 pm

Problems with the IACV won't show a code. I wonder if they get gunked up maybe? Has anyone tried just cleaning theirs out? I don't have any of that idle crap anymore so I can't try it.

Post by **biosehnsucht** » Thu Oct 05, 2006 9:12 pm

I took mine apart when rebuilding my motor.

They manage to get gunked up, even tho they should not be getting any PCV blow by lovin'.. I guess oil from the turbo getting past turbo seals and/or sucked out of the breather pre-turbo? It's easy for just a tiny amount over 15-17 years to gunk it up..

if you're going to take it apart, get new gaskets for its component parts first..Section 148, 23785P between IACV/AAC and the intake mani, 23785N between the IACV/AAC halves..

too lazy to look up the part#'s right now, those are just part codes (and from JDM too)..

Post by **float_6969** » Sat Oct 07, 2006 9:29 pm

You're not going to be able to get those stateside are you?

Post by **biosehnsucht** » Sat Oct 07, 2006 10:48 pm

I did.. someplace I probably still have the part #'s

took alot of FAST cross referencing tho

edit:

nah, I'm thinking of something else hard to track down. different partcode but same part#'s stateside.

from the KN13 pulsar with CA18DE:

jp-partcode .. us-partcode .. part# ............... desc23785P ........ 16253M ......... 16253-D5710 .. IACV-IAA UNIT GASKET23785N ........ 23785N ......... 23785-D5720 .. IACV-AAC VALVE GASKET
Modified by biosehnsucht at 4:10 AM 10/8/2006

Post by **ca18detpowered** » Sun Oct 08, 2006 6:50 am

well i took apart that iacv valve apart, it was gummed up, cleaned it, checked its resistance, its 1 ohm away from factory service manual specs

put it back together....still hesitating.

any other input? LOL

this is SUCH a pain in the ***. Im the kinda guy where if theres one thing terribly wrong with my car, or one hindrance, such as having to warm it up before i drive it, it drives me completely nuts.

heh, anyways.

Post by **ca18detpowered** » Thu Oct 12, 2006 2:01 pm

UPDATE!!!

Just changed engine temp sensor to a BRAND NEW one. still hesitating. All fingers point to that, like this morning, it was collld out, wouldnt stay running for the first lil bit without some throttle......the rest of the day, started no prob, it was warm.

Post by **driftin8ez** » Thu Oct 12, 2006 3:53 pm

I'm pretty sure unless you have every vacuum line and solenoid ran like stock your sol until the car warms up. But keep us updated if you find anything else out.

Post by **float_6969** » Thu Oct 12, 2006 6:11 pm

Does the car fast idle (approx 1500-1900RPM) when you first start it?

Post by **Not_a_sr** » Thu Oct 12, 2006 8:30 pm

welcome to owning a ca18det, and its stock electronics! they dont like being cold... none of the ones i have ever seen have not hesitated while cold.

Post by **dvd** » Thu Oct 12, 2006 10:16 pm

my motor does this too. I changed the coolant temp sensor TWICE. Because 3 months down the road it poped up on the ecu. I cleaned my IAV. My car has fast idle when its cold. But only revs to 1.2 1.3?

Post by **rico05** » Fri Oct 13, 2006 3:09 am

Yeah, I get fast idle, then it idles fine, but won't take any throttle that gets the motor above 10in/Hg until the car is full warm. Oh well...I can drive it cold just not very fast, lol.

Post by **float_6969** » Fri Oct 13, 2006 3:40 am

Ok, to you guys that have this problem. Do you have a wideband A/F gauge to see what the fuel is doing when you give it throttle and it tries to die?

Post by **rico05** » Fri Oct 13, 2006 5:31 am

HA! $300+ for a sensor that I can't even utilize yet is kinda out of my league.

Post by **biosehnsucht** » Fri Oct 13, 2006 10:13 pm

myself kinda like rico, with fast idle, then normal idle but boggy. mine doesn't die tho.. just jerks. if I manage to get it over 1.5-2k or so (guessing) tho it'll suddenly pick up and move.. which I'm thinking is some kind of rogue vacuum leak someplace, and once I hit boost instead of running horribly lean and not having enough fuel it's running somehwat rich (boost leak) but has enough fuel.

thing is, I don't know where my supposed leak might be from, I've checked everything before more than once..

also, I suspect that having DSM injectors on a ghetto tuned (i.e., scale pulse width and correction maps by % based on bigger injectors, no real tuning) doesn't help.. and I err'd on the side of richness.

Post by **ca18detpowered** » Sat Oct 14, 2006 3:09 am

my car DOES NOT fast idle......what could that prob be. The highest it idles cold is 1100 rpm....

Post by **float_6969** » Sat Oct 14, 2006 4:36 am

Two things, have you guys tried cleaning the MAFS? Perhapse there is some buildup on it that is making it slow to heat up properly when it's cold?

If it's not fast idling, there is another little gadget below the TB with a 2 wire plug on it. It has a hose coming in the bottom, and then another hose coming out of the top that goes into the intake mani right behind the TB. It's a pretty decent diameter.

It often gums up and fails. You can try cleaning it, but I've never had it work. You can get another from an SE-R Sentra. Auto or Manual will both work, but the Auto will make it idle even higher.

Bio, I'm sure you could find us some PN's????

Thanks buddy....

Post by **ca18detpowered** » Sat Oct 14, 2006 1:11 pm

thats the air regulator valve i believe....hmmm.......ill have to get one.

i just hooked up safc, i can lean it, or richen it in that range....still nothing

Post by **rico05** » Sat Oct 14, 2006 2:26 pm

http://www.thepartsbin.com/rep....html

I bought a brand new one, and mine still does this. I think I need to check and make sure that the wiring to it is good. The wiring to my ECU temp sensor was bad, and I had to rewire it directly to the ECU (Bypassed the wiring harness)

If I just hop in drive, the car is good to go withon 2-3 minutes of driving, so this is more of an annoyance than a real issue for me any more. Used to be BAD. Like 5-7 minutes of warm up or my car would barely even drive.

Post by **ca18detdrift** » Sat Oct 14, 2006 5:16 pm

Mines does the exact same thing! Every morning its kind of embarassing having your car act like a slug and die when you give it gas. And its only in the winter when its cold outside that this happens. After a few min of driving it warms up and idles/drives perfect again. As long as I've known most if not all ca's just have this in common.

Post by **biosehnsucht** » Sun Oct 15, 2006 12:31 am

heh I already have a minty new air regulator

I'm pretty sure this is the one I'm using:

22660-93L00 B14U 1194- SR20DE.AT B14X 0798- SR20DE.AT B13 0890- U/SR20DE.U/AT.F4 B13 1190- J/SR20DE.J/AT.F4

There's other applications as well, and you can even get them for some SR20DE Infiniti's..

That part# is what is used on automatic CA18DET's.. as well as 22660-72L01, and for manuals 22660-35F01 and 22660-35F10 .. however only the one I listed above is available in the US, the rest aren't directly available under those part #'s..

Presumably an automatic's would be slightly bigger and generate a bit higher cold idle since the autotragic would have more rotational and other mass to push around..

Post by **ca18detpowered** » Sun Oct 15, 2006 1:44 pm

well....figured it out....for my car anyways. I dont know if the rest of you are using ka24e mafs, but i am. I hooked up my safc....tryed leaning, richening. NOTHING.

so i went to where you set up for what kind of afm you have, after you go to hotwire, theres another setting

in:01 out:01 or whatever

i set mine as in:02 and out:01 as it was

HESITATION IS GONE, without a trace

perhaps try this, maybe itll work for some of you guys. Strange solution but hey...what the hell

car hesitates when cold, fine when warms up

car hesitates when cold, fine when warms up

Re: car hesitates when cold, fine when warms up (ca18detpowered)

Re: car hesitates when cold, fine when warms up (splintercell)

Re: (driftin8nez)

Re: car hesitates when cold, fine when warms up (ca18detpowered)

Re: car hesitates when cold, fine when warms up (ca18detpowered)

Re: car hesitates when cold, fine when warms up (ca18detpowered)

Re: (float_6969)

Re: (biosehnsucht)

Re: (float_6969)

Re: (rico05)

Re: (biosehnsucht)

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