My car is idling like crap. It'll start to idle then start dropping off and sometimes die. Other times it won't want to rev up at all. Also, when going at WOT once i get to about 5500 it just stops revving and actually starts to drop in rpm when i keep on the throttle. Could this be because I'm running my MAF on the charged side of the turbo system? I'm thinking I might also have a vacuum leak because my vacuum is a bit low at idle which might be causing my idling issue but I can't explain the revving issue. Any help would be awesome. Thanks in advance!

btw, this is on a 1990 maxima.

 

Give us some more details on the vacuum readings and other things.

Do you have an OBDII that you can hookup to read some data?

The MAF on the charged side shouldnt cause this, its going to be either gone or working. So if you reving past 2500rpm, then it sounds fine. Seems like there is a possible IACV issue since its happening when you start the car. Does the car idle fine after its warmed up? Or always rungs like crap?

Dixit

 

when i start the car after its been sitting a while it misses really badly until it warms up a bit. i'm not sure if it still will because someone said it might be the distributor so i changed the cap today and haven't been able to see if it still misses.

the car seems to always run like crapwhen idling unless the the high idle is on.

my car has obd1 so i'm limited on what can be read. it hasn't been throwing any codes at all though.

the vacuum will sometimes read about 17 inhg but when the idle gets crappy it will drop down to 10 inhg or so and will sit there and fluxuate a bit (idle drops down revs back up and repeates or will just plain shut off).

um... only other things i can think of is this has been going on for about a month probably. before that the idle was fine. i changed the ecu out once to test a reprogrammed chip but it was running terribly rich with the chip so i pulled it back out and put the stock ecu back and readjusted the s-afc to the same settings i had it on when the idle was working good. if i remember correctly, that was when it started acting up. i don't know what i could've done to make it do this so i'm totally baffled now.

another thing that is happening is sometimes when just driving it'll feel like the car is surging or cutting out for a split second a few times then it will totally stop. i'm just totally baffled at what could be going on.

thanks for your help!

 

Lets start with checking the plugs first, they could be fouled up from running rich.

Dixit

 

did that just a few days after it ran horribly rich. didn't fix the problem.

 

which injectors are you running?? the stock VGT ones?

 

yeah. i believe they are supposed to be 259's.

 

i think i found my problem (or at least for the inability to rev to redline). i think it is possibly running to rich up that high so i'll have to turn down the fuel flow on the s-afc. i was messing with it today turning it on and off and it definitely was screwing the car up. i'm now thinking that somehow this engine has 370 cc injectors. i have the s-afc turned down by 50% on the low throttle and it still seems to be running rich... wish i had the time to get the dang things flow tested.

 

I was looking at your pics and didn't see your maf sensor? is it before your bov? if so you need to recirc that bov. thats why it won't run right and why it seems to run rich.

 

its after the bov right now

 

why dont you go to a dyno and get your A/F readings

 

i need to but haven't had a chance yet but also, i'm waiting on someone to finish their car so i can get some better prices on a dyno when they go to dyno theirs.

 

well if you are running a s/c do you have the censor pluged in right before the intake manifold? whatever your answer is to that and if it does not work try just turning up the idle. right there on the intake manifold. just some input. just something simple to try

 

yes i am new on this site but i have been around here unspoken for along time. this site really answered alot of my ?s

 

he is turbo(VG30ET motor swap)...if I'm thinking of the sensor you are speaking of, the 3rd gens do not have that sensor