Yesterday i decided to port my tb and raise my injector pod. anyway, after reinstalling it, it was running extremely rich and rough. found out the map sensor vac line wasnt hooked back up. after hooking it up and unhooking the batt for a minute, she runs better. idles great, but still smells rich. should this mod have changed my fuel curves or anything? whats the deal? im gonna auto x-raying it and see if anythings weird.

 

WHEN I DID THE TBI MODS I ALSO DID THE ADJUSTABLE FUEL PRESSURE REGULATOR IF YOU DID NOT DO THIS IT IS PROBABLY THE PROBLEM ,YOU NEED TO ADJUST THE FUEL PRESSURE!

 

Did you put in a new base gasket under the TBI? The gaskets typically deteriorate and are not reusable. The TBI base gasket will give a vacuum leak, straight into the MAP sensor fitting, this will make it run rich.

 

jsut as a quick visual to check, see if the return line got tweaked a little when you raised the injector pod. if it is pinched the restriction coudl raise teh fuel pressure on you.

 

 

my fuel lines are good, and i didnt replace the gasket because its pretty new and in good shape. i could always try a new one though. i never would have thought of a vac leak there. thanks.

 

my car runs better now and not as rich-smelling, but i still went ahead with a new gasket(this didnt help or hinder). had my buddy auto x-ray it yesterday. i dont know a lot about 'good' numbers... suprisingly i was a little lean, he saw something that didnt look right... my o2 reading was around 440xx (not sure how its measured) at idle. he said on both his LT1 and 350TBI the o2 reading always fluctuates a few 100xx. the highest reading i saw was still under 600xx at about 3/4 throttle. is this weird at all??

 

whats the negatives about your car running rich? Someone told me my car was running rich right after i got my edelbrock intake installed

 

well for one the smell of the exhaust, lol. other than that, im pretty sure it wastes gas, making my wallet empty even quicker. it may foul plugs sooner too i heard.

what you guys think about my o2 readings not fluctuating?

 

When my o2's stayed at one value(around 440) the sensor itself had come lose from the bung. Check how tight your's is and see if the o2 sensor wire is still intact and not burnt or has any insulation rubbed off anywhere.

 

If it's not fluctuating a lot back and forth it's pretty much either bad or not hooked up/ in the pipe like gta383 said.

They read from like 100 mv to 900mv 900 being richest and 100 being leanest if i remember correctly..... In other words you'd like for it to jump around in the 350-700 sections a lot. Mine tends to run a little rich even with a new 02 and a buncha other parts. My opinion is try to live with it or custom tune it (this is a generality though).
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All that iac sensor realy is is a controlled vacuum leak so yes most definetly you need it plugged in or it's going to run terrible and idle high of course.

 

i have a feeling that r0nin89 is calling his AIT sensor an IAC sensor. because the iac valve isnt a sensor its a 'valve' of sorts. the iac valve has nothing to do with an open element. im not sure my car would even start without the iac valve.

anyway, should i just search the boards on how to inspect and replace the o2 sensor?

 

just a few more details about my problem: the car hesitates and sputters(almost die) horribly when cold; she revs unsmoothly and sputters a little while under ~130*. it has a 170* tstat (recommended with my chip). the spray pattern from my injectors isnt a smooth/clean conical shape. fuel comes out in cone shape of clumps, almost droplets; o-rings are new.

 

have you tested the fuel pressure at the rail? Probably would be a good idea. If you don't have the money or equipment to test the pressure i'd reccomend replacing the fuel filter and removing the return line and blowing it out in case it's plugged up. Run a good injector cleaner through it if you feel that the injectors may be dirty.

If you're still having problems and are a do it yourselfer i'd just reccomend replacing the fuel pump considering it's you most likely prospect. The kind of injectors found on these tbi cars seldom/ practically never fail so i doubt they are in bad enough shape to perform as it sounds they do just due to being plugged up.

 

no, ive never checked the fuel psi, but i replaced my filter about 10,000mi ago. corect me if im wrong but if the return line is clogged then the fuel stays in the tb/injectors, so thats another reason for excess fuel. and i occationally use lucas... sum moron at school said lucas fried his dads o2 sensor and cat... what u think?

im replacing my 02 sensor in a few minutes. ill auto xray it afterward and see if i get some fluctuation from the new one. i hope this works!

 

after a new o2 sensor, the auto xray was reading from 4mV up to 848mV so i think its working right, i only drove her home so about a mile, ill update more on the drivability tomorrow.

btw: o2 sensor for a tpi is different from a tbi car lol. my buddy picked up the wrong 1, we had to make another trip...

 

Chiming in kind of late, but, did you happen to spray any silicone spray around the TBI or the intake when you were taking it off? That will kill an O2 sensor quick if it gets down there on it. Could be the reason why it went bad.