Really weird problem with an Infiniti G20..

[dj215]

Hey, thanks for not giving up on me, I'll try to answer the best I can.

1. Still no codes
2. Not sure how big the tear was because I taped over the duct tape, but I made sure to wrap it real tight and secure.
3. The problem occurs less often now that i've taped up the hose and even when the problem happens, it is less harsh.
4. I haven't checked for corroded hose yet, the last time I changed a hose was the brake line hose, because that literally cracked opened. (7 months ago)
5. Everything else hooked up to the air tube should be in good order as i've tried to clean everything I could.
6. It was running pretty smooth, after the taping and grounding of the MAF sensor, but that was only for like the first day. lol...

7. Throttle body... I think I just cleaned that part half a year ago without really taking it out, I believe I just sprayed carb cleaner in it.. maybe I should remove it and clean it..

Thanks for not giving up on me, I think i'll give things a few more shots.

 

[Brandon]

I had similar symptoms on my 98 Jeep. It was the Crank Position Sensor (CPS). It was replaced (original 110K miles) and all is good. I don't know if your car has this sensor but if it does I would look into that. By the way, a bad CPS does not always throw a code. Nuetral Safety switch is another possibility. Good luck.

 

[g20ooh]

Hello dj215 ,
OK ! Good to know .
One thing just to be sure . When you start up , the MIL/CEL light - lights up ok , correct ? In other words you know this " system " is good .
When you check for codes are you using CONSULT or OBD2 ? Last time you did this ?

Pretty much irrespective of above , " sounds like " vacuum/ vacuum leak related and because of your answers when taken as a whole , and number #6 in particular , best WAG = you still have an airtube leak , and if so , its better , but not good enough .

And on the vacuum hose thing , what you 're really looking for are hoses that may have been switched around or left disconnected or both . Also of course , any that are leaking . There are a few that could have been pulled on before you replaced the mounts . DON'T go pulling them off to inspect , just do a solid visual inspection for now .
Dj215 , I admire your energy ( wait till you get older and you will know what I mean

) and I'm not saying there isn't a tme and place to remove the throttlebody , but you really don't have to do that normally . There are reasons to use TB cleaner over Carb cleaner for this , and the weight of that depends on which two you are comparing , but it is always in favor of the TB cleaner .
BTW , how long have you been running with the knocksensor out ?
Do you also happen to know how bad/how long the mounts were ..... ?

Well , there I go again , an all over the place with what I'd be thinking about here post .

Most likely by far , is your airtube , followed by vacuum hose issues as listed above/TB simple cleaning with TB cleaner on car .
As I've said before , never have seen the tape solution work very well . I should have said , esp duct tape .
On all my old iron , esp certain English cars that was part of your STD. road kit , but for many reasons that won't cut it on your G20 with this problem .
There are a lot of more advanced tapes on the market , but I'm not real optimistic that they would work past 2/3 weeks if the tube leak is past a certain point .
I'm guessing here , but you probably did have it work , and work for awhile . Problem with that , is things change , including airtube leaks , so if you will remove that tube and all the tape from it , I " think " you might be surprised at how large your " split " really is . ( Flex the tube gently off the car )

SO , theres more , really a lot more little things to consider , but lets start with this .

 

[dj215]

Knock sensor been bad for like 9-10 months already i believe.. (still not fixed)

and motor mount was bad for months.. like 4+? fixed

yeah i regret not taking care of the problems sooner..

could a knock sensor cause this?

btw when i had CEL, it was brought up knock sensor, and 4th gear ratio error.

 

[g20ooh]

" could a knock sensor cause this? "

Short answer : No . Could running W/O function contribute to some other undesirable things that matter ? Yes , and depending on some other variables only a question of when and how .Does that mean here and now ?

I'm pretty much stuck at my prevous post and my other unanswered questions .

" btw when i had CEL, it was brought up knock sensor, and 4th gear ratio error. "?????

DJ215 , there are some things that are not adding up here , so what is happening is I'm getting confused .

Lets look at the one that matters most .

If your G20 currently and physically has a " failed knocksensor circuit " and is then driven at least 2 trips in a row in that condition , then on a functioning CEL SYSTEM you will have a CEL light on . Period .

So is it something like this ,
9 months ago my CEL came on . So&So using Consult/generic scan tester/CEL " blink " method determined two dctcode#/problems ........................

3/4 weeks ago I had my motor mounts replaced , and my CEL " reset " ........................................
......currently , on a working CEL SYSTEM , I no longer/still have occasionally a CEL LIGHT on and I do have this driveability problem ................

 

[g20ooh]

Quote:

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- So far so good! I will drive this car all week to see if it comes up again.

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Dj215 , If at this point , it was running right with no CEL , a reasonable assumption is that you " fixed " your problem .

 

[g20ooh]

Quote:

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Ah, so the problem persists, when it happens, it is not as rough as usual.

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So then roughly 2 days later the problem comes back in milder form .
If my post above is correct ,and at this point in time you still had no CEL , then a good WAG would be this is when the tape loosened up , which is what I would expect with your weather etc .

 

[g20ooh]

Quote:

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1. Still no codes ( and no CEL ) ?

3. The problem occurs less often now that i've taped up the hose and even when the problem happens, it is less harsh.

6. It was running pretty smooth, after the taping and grounding of the MAF sensor, but that was only for like the first day.



This again , assuming no light or code makes " loose tape " real likely .



Now here is the funny part . Your motor mount problem " may " have caused/contributed to your CEL light coming on .......... if its been no CEL LIGHT since your mounts were replaced ........
for both codes .

 

[dj215]

It is a WEIRD WEIRD situation, this is what happens...

CEL comes on, I go to autozone to get it checked.

Lights for knock sensor and 4th gear ratio error comes on..

I tell autozone to not clear the code..

code goes away after a few days... and no CEL would come up... then MONTHS AND MONTHS later CEL again for the same problems..

 

[g20ooh]

Well , thats definitely intermittent in a sense .
One thing , if you segment time , since everything started up are there any distinct break points in how ;
the vehicle has performed as the CEL has gone on and off .
etc.
Do you currently have the CEL on ?
What kind of fuel are you using ? ( OCTANE/BRAND )
How many miles ?
Do you have a tap/die set and a VOM , and if so , do you have a service manual ?
On most recent posts from here , can you remember what the CEL was doing ? ( Those were also meant as questions )
How much difference did cleaning the MAF sensor ground make ? And how corroded was it ?
Do you have access to a vacuum gauge ?
Have you checked the vacuum hoses and routing ?
Have/can you clean the T/B . ?
How do all the other easy to see grounds look ?

You " probably " have 3/5 little things going on right now , again no biggie .
If since the mounts were replaced , there has been no change in how the vehicle runs as the CEL comes and goes , go back to the airtube/vacuum stuff and then clean up all your grounds .
Final thing , did the rough /funny running start after you replaced the mounts ?
Are all the splash shields on the vehicle and serviceable ?
( 2 front and 1 per wheel well side = total of 4 ? )

 

[dj215]

I don't see a difference in performance with the CEL on/off. I use either Sunoco 89oct or Shell 89oct. Car has 130k miles... funny thing is I did all the tune up, dis rotor/cap, spark plugs, fuel filter, air filter.. and with all that done.. my last fill up for 7.5 gallons only netted me 73 MILES!! @#!@! My sis only gets 25~ with 90% highway driving..

I don't know what a "tap/die set and a VOM" is but I do have the factory service manual..

When I first had the CEL the car still ran perfect, always. Just poor gas mileage..

MAF was reading at .012v ground, after reground, .001..

I don't have a vacuum gauge... and I've checked all the hoses and routing..

I will retry cleaning the TB with a TB cleaner instead, i'll head to Pepboys tomorrow to grab one..

The grounds look fine.. just a bit dirty as with age..

This random problem was happening once in a blue moon before replacing the mounts, after the mounts was when i've started experiencing it more frequently.. and that's also when i noticed the duct tape on tube.. actually i don't have any splash shields on the front anymore.. a shop cut it off -_- to access fixing a rub from my wheels.. but the random problems happen even on a sunny dry day...

I tried to answer as best as I could.. thanks again..

 

[g20ooh]

Allthis is good to know .

Quote:

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I don't see a difference in performance with the CEL on/off. I use either Sunoco 89oct or Shell 89oct. Car has 130k miles... funny thing is I did all the tune up, dis rotor/cap, spark plugs, fuel filter, air filter.. and with all that done.. my last fill up for 7.5 gallons only netted me 73 MILES!! @#!@! My sis only gets 25~ with 90% highway driving..



OK . lets just say we have another 2/4 things to consider/or to deal with .

So far , no matter what else , and with about a 70% confidence factor ( not good , but good enough ) your airtube is still leaking .


Effective immediately , I would suggest you switch over to a tier one fuel (Shell ) or( stay with Sunoco ) as close to 93.5 (R+M/2 )octane as possible . Plan on doing this for at least the next 5 full tanks of fuel . I would like you to purchase at AZ one bottle of RX-7 Gas Kicker - its the little orange one . ( There are other ways to go here , but because its better if you do this fast just buy and get it in the tank . ) Follow directions sorta ,use a small funnel , and put all of it in ( first ) , then fill the tank . AFTER you run this tank thru 7/8s but no more , refill .
If at all possible , AFTER the first 3 gallons or so are burned , get it on the highway fully warmed up , running at at least 60 MPH for at least 20/30 minutes .
Consider this something like first aid , I'll explain later .



I don't know what a "tap/die set and a VOM" is but I do have the factory service manual..
OK , no biggie . I, m running short on time so i'm going to type worse than normal and skip some stuff for a little while . VOM IS JUST A VOLT , OHM , METER .



When I first had the CEL the car still ran perfect, always. Just poor gas mileage..

To the best of your ability I want you to trace your grd path from the AT to the battery and clean them up .
If you have time , do any other ground you see the same way .

MAF was reading at .012v ground, after reground, .001..
gOOD TO KNOW .

I don't have a vacuum gauge... and I've checked all the hoses and routing..
OK . Later .


I will retry cleaning the TB with a TB cleaner instead, i'll head to Pepboys tomorrow to grab one..

The grounds look fine.. just a bit dirty as with age..

This random problem was happening once in a blue moon before replacing the mounts, after the mounts was when i've started experiencing it more frequently.. and that's also when i noticed the duct tape on tube.. actually i don't have any splash shields on the front anymore.. a shop cut it off -_- to access fixing a rub from my wheels.. but the random problems happen even on a sunny dry day...




I tried to answer as best as I could.. thanks again..

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You did fine .
If possible , locate the knock sensor , and checkout the connection to it .Also , if possible , remove and reinstall the connector .
Do something for the grounds by the abs .
The overall idea here , working with what we can do , is airleaks , grounds , and fuel .
Just ahint about part of the picture here .No shields + lots of things being tugged when the mounts were bad .....
plus buying the minimum octane which may or may not have been 89 OCTANE and in any case is being diluted by normal tank pollution/condensation .your knocksensor is being effected by all the above , one way or another . Very overworked under tough conditions .Your G20 has a very wide range of " octane adjustability (89-94.5 , R+M/2 .Not much point going above 93.5 but the closer you get .........

Now , the above isn't so much about lights and codes , its about the rough running .
The next is about your fuel mileage - primarily .
Is your Auto trans , torque converter , and your mode switch working properly ? Have you checked fluid level and composition lately ? Same with coolant - radiator and bottle ?Gotta go - back tonight - i think .
Tell me about brake system /servicing , including fluid and parking brake operation . When is the last time you spun the rear wheels by hand and confirmed no brake drag ?
And what which brake hose replaced ?

 

[dj215]

Sorry, been stressing out about school.. i printed out what you said and i'm gonna check on it soon, so far the problem hasnt come up yet.. seems to come up if i had the car running too long..

 

[g20ooh]

I really understand that - school first .

If you can't do anything else short term , focus on knowing your fluids are good to go .
This includes fuel . So..... best fuel/octane thats practical , if the the budget allows it RX-7 ,all as per previous .After running the first tank down (7/8s - no more ) , keep the tank fuller than normal , something like refueling 2x a week .

OK , now I think you know by now how I feel about tape on the airtube . Lets look at how we could make that work short term /cheap/quick .

If possible , take the airtube off and take it inside the house . Get it good and warm .Clean the effected area , including the walls of the split itself .

Take an RTV sealer ( low - middle grade is best ) and neatly build an even " low" " gently tapered side " patch over the split extending one inch past both ends of the split .Use as little as possible of the RTV/sealer . When the rtv is 1/2 dry ,retape the tube - hopefully with something better than regular duct tape . The key here is to use relatively narrow , long ( full circumference +4/5 inch ) strips that don't grab both the flat/raised sections of the tube at the same time .

The over riding concept is this ; your RTV patch is going to be your seal . This patch is going to " float " - its not going to bond to the tube material . your tape is going to limit the amount of " patch float " , and in this way you will have an effective seal .

Two cases ;
1) Split is located in a flat valley section of tube . this is the best case . If this is so ,the idea is to make your strips of tape so that they are slightly narrower than the valley - flat area but wider than than your patch . The key concept is you don't want your first piece of tape on the raised accordion ridges and the flats at the same time .
2) This unfortunately is the more commom case . This involves part of or all of the split located on one of the ridges .To accurately describe proceedure here is too complicated , but the concepts are still the same . The most important of which is long narrow strips vs anything else .In this case do the flats the same as previous , and then add other narrow full circumference strips around the accordion raised sections ie multi strip approach .
If your split is too difficult to deal with this way , use a tire/tire tube repair kit with the same concepts .

 

[g20ooh]

dj215 ,
Long term , I would suggest you start thinking about how to best replace shields ( 4 ) and the airtube .

There are on any vehicle a few does/donts and common dissatisfaction pathways .On your G20 , a partial list would include ,

Power steering hose maintenance/neglect/wrong fluid .
Motor/trans mounts "............ "
Consistent use of less than 91 octane/always running around on an empty tank .
Removing and running without your shields - yea , I know , may you know who bless all the amateur reverse engineer/techs. in the service arena .
Not bleeding the cooling system properly at service/using a copper/brass replacement radiator with the wrong coolant .

Now , believe or not , this group will interact with each other in a way that multiplies dissatisfaction and can cost you big bucks .

This is not a complete list , nor is this meant with a critical spirit .These are but some of the keys to longterm high satisfaction/low cost motoring with these vehicles .