y33 idle jerk / hesitation discussion (lets fix this!!)

[beancan]

Seeing this as an unsolvable problem.. My car started doing it.. Didn't do it when I bought it.. Had it about a month.. Figures id have the problem.. Which is good, because I want to fix it.. and will stop at nothing to do so..

My 99 Q45t .. 124k I love it to death. Black on black .. seriously good lookinGreat fun to drive - especially when you turn off the stupid traction control..BUT - its makin me angry!! I take good care of it - only run GOOD premium, and keep the regular fluid changes / filters and flushes

Sometimes it just.. missfires.. Only in gear, and only when im stopped. Randomly. Once or twice.. Its like a quick JERK.. then its gone.. Tach never moves. It doesnt do it at all some days.. Other days its bad. If I put my foot on the gas just a bit, (750rpm) it NEVER does it.. I Cleaned the maf - the throttle body, ran a can of bg44k through it.It runs better.. But it still does it.. It hesitates sometimes.. feels like its dragging something, then around 4800 or so it rips ***.. When you drive medium throttle, It hesitates when it changes gear randomly as well.. I know its not the transmission.. Cuz it dosen't do it often. And at full throttle its just right. I know the ECU retards timing and fuel to soften the shifts.. If the knock sensors are out, the timing is already retarded... That would make it do that!

SO - to cure that im going to bite it and tackle the knock sensors.. I hear you can do this without pulling the plenum.. I don't want to get my hopes up, but I don't want to pull it..

I'm also going to throw a set of plugs at it first..I did search - but no one has resolved this issue fully.. I will, I assure you The car needs to run how it looks.. Period..

Any thoughts are apreciated - its just a discussion

-Bean

[Mopar]

well, my car does this as well, i have changed my coils and plugs, cleaned the MAF, changed all the fluids, transmission flash and all. Still it has those "jerks"..... My Q has seen numerous mechanics no one can fix it, since it doesn't light up the check engine..... such a mystery I feel sorry for not being able to help my Q

[bullittandy]

This is an excellent place to start in resolving this problem.

I also had this problem briefly at one point but it has not appeared in approximately 20K miles. I did all the normal tune up stuff etc etc. I also replaced the K/S around the same time-I think. I cannot say for certain that the new K/S fixed the problem because I wasn't trying to fix the stumble problem.

So, you guys replace your K/S and nothing else and let's see what happens. Replace the K/S harness as well.

You DO NOT have to take off the plenum (on a 97+) I know this from first hand expereince. They (K/S) are not that hard to replace but you will have to cut off a coolant hose that gets in the way, so buy that hose when you buy the parts. You'll have to get a look at a parts diagram to see the hose-I can't remember what its called.

If you guys replace the K/S and nothing else we will have an excellent baseline to find an actual answer. As opposed to "read the FSM, bad gas, dirty intake, spend $3000 on maintainence items etc etc etc"

[dodiho]

hey Guys...I FINALLY fixed my herky/jerky misfire problem...after cleaning TB and MAF...remember I was the one that met a senior Infiniti mech in line at a BBQ place and bought his meal if he'd tell me a few things...his best technique was to tap on the side of the MAF plug and cover with his pocket knife with the motor idling-IF tapping caused it to rev up,stumble or die-the culprit was the sensor board INSIDE the MAF body...he said road vibrations over time sepaerate the solder joints.....I put a rebiult one from Cardone in it last Saturday morning in about 15 minutes..went on a 300 mile trip that afternoon...not one misfire or glitch.....I did do all the suggested maintenance too: changed trans fluid,changed oil/filter, air filter, injector rails cleaned out,etc....but this was before I changed the new MAF....hope this helps.....I saved tons of money by doing it myself and have sent the old one back to recover my core charge.....dodiho in central Texas

[Qproject]

glad we are making progress.

with the help of Audiovisiony33 (who has a wealth of knowledge with the y33), my car drives a lot better and the slight hesitation looks to be gone.

My symptoms are not as big as most of you, my symptoms usually consist of a intermittent slight stumble while driving. It is not a "constant" occurrence, it happens once and will trigger my TCS and SLIP lights to go off. It happens on freeway or city streets. It will then reset itself when I shut off engine and start back on.

Audiovisiony33 checked my voltage on all the sensors, readjusted a few things and readjusted the idle one full turn up. It drives a lot more nimble with less lag from start.

[Qproject]

when you replaced your MAF, did u have to remove all the sensors and re-install them ?

it could have been just dirty connectors no ? just a thought.

hey Guys...I FINALLY fixed my herky/jerky misfire problem...after cleaning TB and MAF...remember I was the one that met a senior Infiniti mech in line at a BBQ place and bought his meal if he'd tell me a few things...his best technique was to tap on the side of the MAF plug and cover with his pocket knife with the motor idling-IF tapping caused it to rev up,stumble or die-the culprit was the sensor board INSIDE the MAF body...he said road vibrations over time sepaerate the solder joints.....I put a rebiult one from Cardone in it last Saturday morning in about 15 minutes..went on a 300 mile trip that afternoon...not one misfire or glitch.....I did do all the suggested maintenance too: changed trans fluid,changed oil/filter, air filter, injector rails cleaned out,etc....but this was before I changed the new MAF....hope this helps.....I saved tons of money by doing it myself and have sent the old one back to recover my core charge.....dodiho in central Texas

[96Qowner]

when you replaced your MAF, did u have to remove all the sensors and re-install them ?

it could have been just dirty connectors no ? just a thought.

G50 owners have taken their MAFs apart and also found these same breaks in the circuit board. It could very well be the gremlin Y33 owners are being plagued by.

[dodiho]

I had already cleaned all the sensors involved in fuel/air flow loop....nothing helped...it got so bad that it would idle and die when I turned ac on...I didn't really want to spend the $ on a new MAF..but glad I did now..it runs like it was meant to ... I think the culprit with most of our "stutter" problems IS the connector/circuit board under the raised square part of the MAF....I have more trouble with the ABS SLIP lights staying on ...for no reason...

[bullittandy]

I had already cleaned all the sensors involved in fuel/air flow loop....nothing helped...it got so bad that it would idle and die when I turned ac on...I didn't really want to spend the $ on a new MAF..but glad I did now..it runs like it was meant to ... I think the culprit with most of our "stutter" problems IS the connector/circuit board under the raised square part of the MAF....I have more trouble with the ABS SLIP lights staying on ...for no reason...

Have you replaced the ABS relay yet?

[maxnix]

Seeing this as an unsolvable problem..

Any thoughts are appreciated - its just a discussion

-Bean

It's not as you will see if you read the previous thread on this subject. Well discussed in that thread also, even by people looking for a magic bullet, which dosen't exist.

[beancan]

I should of worded that differently..A problem with no exact firm solution..I love Q's.. such a challenge Ill report my findings as I get er dun

[Q_SHIP]

My god guys!! ks and harness. Just bite the bullet and do it.

[Qproject]

I don't think it is that simple because every one of us are having similar problems, but some of us are having similar but slightly different problems.

some of us are getting a constant stumble, some of us are getting a light stumble, some of us only have the TCS and SLIP lights on, some of us have all TCS, SLIP, AND ABS lights on.

so far the possible solutions are idle adjustment, connection cleaning, knock sensor, MAF unit, ABS-TCS sensor.

but for sure we know it is not the throttle body cleaning, it is not fuel injector related.

My god guys!! ks and harness. Just bite the bullet and do it.

[Qproject]

good looking out bro.

looks like some infiniti tech's are actually working on cars, rather than sitting around in NICO forums being a useless smart aass.

hey Guys...I FINALLY fixed my herky/jerky misfire problem...after cleaning TB and MAF...remember I was the one that met a senior Infiniti mech in line at a BBQ place and bought his meal if he'd tell me a few things...his best technique was to tap on the side of the MAF plug and cover with his pocket knife with the motor idling-IF tapping caused it to rev up,stumble or die-the culprit was the sensor board INSIDE the MAF body...he said road vibrations over time sepaerate the solder joints.....I put a rebiult one from Cardone in it last Saturday morning in about 15 minutes..went on a 300 mile trip that afternoon...not one misfire or glitch.....I did do all the suggested maintenance too: changed trans fluid,changed oil/filter, air filter, injector rails cleaned out,etc....but this was before I changed the new MAF....hope this helps.....I saved tons of money by doing it myself and have sent the old one back to recover my core charge.....dodiho in central Texas

[Q_SHIP]

just do them. If any of you have 80k on the car or more, it's time for them anyways. I have done all my own work to my Q thank you very much.

[beancan]

OK - knock sensors AND harness it is.. Now, if some one would name this hose ill have to destroy, and god knows what else ill need while in there.. Ill purchase parts in advance so the replacement will be completed in a weekend.. I don't like driving the Z to work, its ride is HORRID.. Handles good though Me and my poly bushings and stiff springs and high dampend shocks

I did turn up the idle a bit and it quit stumbling.. For today... ODD..

What SHOULD the q idle at in drive with the AC on.. mines usually around 650 +- when it does it..

[miata007]

Bean,I had the stumbling problem at idle and sometimes driving (hi and low speed). It would also trigger my TCS light.

Anyway, I don't think it is the KS. My KS wire was chewed by rodents so go ahead and replaced the KS at that time. No improvement to the situation at all. If you do a search on knock sensor, you should find links with good pics on them.

My car's MAF was replaced new 3-4 years ago so I doubt that is the problem. I will try to tap it with a pocket knife/screwdriver to see if it is still ok.

Hose name? Get a FSM and will show. I had to removed the following: fan, various belts, drain coolant(not sure?), alternator, engine cover. If still don't have access, you will have to start removing things on the passenger side and rear of the engine. Good luck.

007

[gotgarth]

91m30 137k. only 10mpg since owning 2 years. my 2cents: my hesitation started after hard driving. symptoms: 1-hesitated at slight throttle to 1500rpms and when trany upshifted (bringing the rpms back under 2000 because of the higher gear shift). 2- intake backfire on uphill driving. after tune-up she drove better but went right back to hesitate. timing was my biggest help. clean maf helped little. injector cleaner helped little. thought giving 2 co-workers a ride one day was serious trouble because of hesi and backfire, but the added weight seemed to make the car run fine to my surprise. finally throttle posistion sensor changed from .4v to .42 helped then hesitate again. then to .48 and runs ok. but i raced hard again this weekend and it hesitated again for about 3 minutes and then corrected itself and ran fine again.(for my total fix i'm thinking of replacing all 6 injectors. but before that i'll try bg44 and/or strauss auto "run-rite" cleaning service.) my driving is all start/stop city. no highway. (race hard = flooring it because the car next to me wants to see an infiniti do what and infiniti do)

[UM97Q4.1]

miata, that kind of sucks cause I thought the MAF was going to be the issue here. This is getting ricoculous, to the point we are going to have to start a "Save The Infiniti" fund. It got soo bad the other day I wanted to drive it into a bridge embankment and be done with it, but today it drove beautifully and I remembered why I love this car.

It is kind of strange to see a 91 M30 has the same problems. Could this be some kind of clue? Do these cars share some components that could be causing this?

[bdijanni]

Ok, BeanI have been having the exact same problem, I have done everything thinkable, I even did the KS' didn't fix the problem, did do it without removing the plenum driverside KS is the pain to get bolted back in. I've also done a full tune up, changed out the front two o2 sensors... checked the coils (they seem fine) but my car doesnt do the TCS light thing, it does give a p0303 code like some of the other people on here. We've had major talks about this before check out the p0303 thread on here somewhere it's on page 2 i think of this forum. The only thing that seems to help temp, is either a can of bg44k or recently I ran a can of seafoam through the plenum seemed to get better for a couple of days then back to the normal issues today. My thoughts were that it might be some kind of carbon build up issue maybe on the back pistons or something like that. Beacause again the only relief I've found was bg44k or the recent can of seafoam that i ran through there, so this only leads me to believe that its got to be some kind of carbon build up issue. I didnt get any relief from the KS' or the o2 sensors, which is what the ECU is reading when I get the engine light checked

[beancan]

I changed the PCV valves , and replaced a couple marginal looking vacumn lines.. I even checked the EGR and everything else.. Im not going to waste the money on the KS(s) but I did order some spark plugs.. It jerked ONCE after the pcv change. Just ever so slightly...Before I worked on it,. it was so bad in traffic for about 20 minutes I was ready to scream.. Then it stopped.. And didnt do it again.... I did my work anyway

I'm not stupid and know what "usually" causes this on ALL OTHER CARS..When my altima did it, the IAC valve and maf were dirty and it needed a seafoaming.. I did this to the Q and it ran good.. for a day.. Maybe Ill do it some more.. I don't understand this car..Its had its BG44k .. no result.. ****..

[beancan]

Well, I changed the plugs. Still does it It had densos in it so im glad I did!!! I'm thinking it has ONE coil pack thats dying slowly. Everything else is spotless..

[beancan]

ps - i think im going to do the ghetto coil pack testresults later

[UM97Q4.1]

I am still thinking MAF. I am going to pick up a used 1 this weekend for $50. If it works I am a champ if not I am beat for 50, seems worth it to me.

[beancan]

ok - you do that and ill play musical coil ..

the car didnt want to miss when I wanted to do the ghetto coil test...SO - I turned EVERYTHING on, set the parking brake - put it in drive and stood behind the car with a sheet of phone book paper on the exhaust pipe for 10 minutes... Nothing but perfect, flawless flow..

[bdijanni]

I was reading in ealier posts that both things where tried, But I have not tried either of them myself. So I am bitting my nails waiting on the outcome with the coil and MAF tests. But I am pretty sure about the coil test, I have read about many people trying that one with no results. More curious to see the MAF results. Oh yeah I know what you mean when your trying to make it stumble, it never wants to act up when you need it to. But will almost always do it at the worst times. For example: when your just getting off work from a hard day and you might even be just a little pissed off and your sitting in hot, stop and go traffic and it starts stumbling so much that you think its going to die right there!!! I hate that!! I actually turn off the AC and bake in the hot FL sun waiting for it to run correctly. Or it will do it when your trying to show off. Like when you've got someone in the car with you trying to show off the Q and BAM cant get it to accelerate like an Infiniti is supposed to!! WE HAVE GOT TO FIX THIS PROBLEM!!!! SOMEONE PLEASE HELP Also I did two can of seafoam the weekend before last. I put one through the brake booster vac line, and one in the gas tank. Car has been running worse lately. IE more stumbling doing more with or without the AC on, doing it when its blazing hot or cool. Didn't alway do this much, its been on and off . Just didnt get the results that I wanted from the two can's of seafoam. Let us know if you guys figure something out.
Modified by bdijanni at 8:21 PM 9/18/2007

[gjh20]

guys i played "musical coils" for about two months to no avail. i did that because my problems started after a major tune up (belts, plugs, etc) and i thought it could have triggerd a coil that was on the brink to go totally bad. i replaced two of the coilsthen gave up as no more codes were thrown but i still had the miss. i use bg44k frequently, and also recently replaced my fuel pump so i dont think the stumble comes from that area. i believe its MAF, O2, or Knock sensor related. those are next up on my list.

[Qproject]

hey guys, Audiovisiony33 helped me out and my problems are gone.

try simply cleaning out all connector sockets (the little plastic clips that connect your sensors) and raising up your idle a bit.

also my problem was not as extreme as most of yours.

[beancan]

Ok - For the people with the TCS / SLIP lights on.. I have GOOD reason to believe maf failure.. UNLESS the lights only come on when the car miss fires bad enought for the rpms to drop really low (below the rpm the alternator can charge at)

Reason : I took my maf out and cleaned it.. AGAIN.. And didn't plug it in well.. When I started the car, the check engine light was on, along with theTCS and SLIP lights... Funny huh?

Another interesting tid bit of information ... I got in my Q friday after work to a dead battery.. Batteries fail..Usually a reason (Cough *ALTERNATOR* Cough) BUT - no symptomsother than the jerk at idle.. This battery went with NO warning, after replacement the car dosen't do the missfire as much.. Matter of fact, it barely does it..

What im thinking is, if there is a diode bad, it can spike AC voltage back through the system totally freaking out the electronics.. Wish I had a scope to check it out, but think about it.. When do all of our cars mess up? When the alternator is under alot of load (below 2k) at higher rpms, you wouldnt notice....

If I find a scope, ill let you guys know.. Worth a shot to solve the mystery?I think so.. Considering my car may be giving me clues with the surpise dead battery

[Q45tech]

The ecu via Consult or OBD2 data scanner shows the actual voltage provided to ecu in real time.

As to AC ripple riding on DC alternator, VOM contains an AC position that allows this ripple to be accurately measured. Sure it is an average ripple not a peak as observed via an oscilloscope, however this can be estimated accurately.

If 13.8 volts is produced then 1.38 volts ac superimposed ~-20db and 138 millivolts ~ -40db ripple

http://www.labscopes.com/pg09.htm

"Typical AC ripple on a healthy alternator/battery system is about 10-20 mV as read on a DVM. A single open diode can produce in the “Y” diode matrix, anywhere from 200 mV to 800 mV ripple depending on the age of the battery. A shorted diode will produce much higher ripple until the shorted diode is blown open by excessive current draw.

Also the age of your battery is a factor in Alternator whine. Alan had mentioned that your battery is a large capacitor and this is true. The frequency reactance of a battery to alternator whine changes with age. The battery impedance increases with age and your battery will become less of a filter as the years pile up. Buying a new batter will reduce the effects of alternator whine but that is masking the problem for a properly working alternator should produce very little AC output ripple. ........."