Running rich/idle at 2k

Evul9

New Member
So on the way to school yesterday my car started being weird. Running at 10/1 a/f ratio, very stable, it does not move more than .3 either way. The idle is also high, 1.7-2k rpm after driving for 30 minutes. Same thing happened on the way home, for the last 15 minutes... On the way today it did it the whole time. And it is definitely running rich, smells like petrol when I step out. Fuel pressure is normal 40-45psi. Only difference I can see between when it started is I filled up all the way for the first time for like 2 months. Will be able to look at the engine later today. Thanks for any help and tips.
 

Aussie

Zoom-Zoom
Sounds like a sensor went wacky. TPS, MAP, Temp Sensor, check the readings if you have a multimeter and see if they're in the appropriate range.
 

Evul9

New Member
ok did the same thing all the way home, I took the voltage of the TPS, its .98 just with key in and 5.5 at WOT. From my understanding that is not correct... Whats next?
 

cvcrcr99

New Member
What sensor and gauge are you running? What type of tuning system do you have? How old is the wideband o2 sensor?
 


Evul9

New Member
cvcrcr99 said:
What sensor and gauge are you running? What type of tuning system do you have? How old is the wideband o2 sensor?
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Do you mean the tps? It looks like a stock one... Its running on a AEM EMS not tuned by me, it was already there when i bought it. No idea on the age of the wideband but it has been fine and when the car is warming up its acting normal, just as it did before no matter what condition.
 
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Muckman

Not a M0derator
Jump in the AEM software and look at what the TPS is reading at idle. Im thinking your throttle is stuck open a little or you have a vac leak. If you had datalogs from before you could easily compare idle MAP to see if you had a leak but it sounds like you dont.
 


Evul9

New Member
Muckman said:
Jump in the AEM software and look at what the TPS is reading at idle. Im thinking your throttle is stuck open a little or you have a vac leak. If you had datalogs from before you could easily compare idle MAP to see if you had a leak but it sounds like you dont.
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Thanks, will do this weekend. I don't feel comfortable doing this by myself so will go over to a friends with more experience( me and computers do not get along). If I clean the TB up a bit that wouldent hurt anything huh? Might do that tomorrow.
 

Muckman

Not a M0derator
IF the throttle plate is sticking, then yes. Just try closing the throttle plate manually with your hand and see if that lowers the idle. That will help us narrow down the cause.
 

Evul9

New Member
Ok cleaned the tb really well, seems to be a little better but still goes to the 10A/F but only for a short time. Funny thing is now the idle is apparently 16+, at normal idle, most of the time is saying it's so lean that it dosent give a number :confused: so I have a feeling my o2 sensor might be going out, will try to figure out tomorrow. Also, considering that the aem ems does far too much stuff that i don't know/need, and it does have a but of a strange tune anyways, so I am thinking about selling it and getting probably a neptune rtp instead. Any idea what I could get for the aem? Unfortunately it's the series 1.
 

Aussie

Zoom-Zoom
There's just not much going on at idle, I've seen pro shops tune as much as 18:1 at idle: sometimes there's just nothing you can do about it.

If you're on a flat road and at full throttle and that's what's happening to your AF, yea you need a better tune, or something's outta wack.

edit; wait your just cruising at 65mph? that's not a big deal then. your car isn't under constant load when cruising. Your AF will constantly change because your manifold pressure is constantly changing.
 
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Muckman

Not a M0derator
Depending on the engine, it may or may not like to idle that lean. Bigger injectors, bigger cams wont like it lean. You can add lots of timing to help but I usually never go past 15.5~16 before I run into unstable idle.

You went from full rich to now full lean? Something changed - broke, dying, leaking etc to cause a drastic change like that.

Calibrate the wideband in free air according to the AEM documentation found on their website. That will tell you if the wideband is dying.

Also if you are at a steady load (throttle) your AFR should not jump wildly. It would be easy to blame the tune but I haven't seen it nor do I know how the engine reacted before.
 
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