hi,

when i start my car it idles for around 2 minutes relatively good. then the rpms begin to bounce up and down. they go up to like 1200 rpm then it goes down to 300-400 then the ecm catches it and so on.... but it doesnt die.

checked for vacuum leaks today but havent found one. i plugged all vacuum lines except for the map but that didnt helped anything.

its running a bit rich. sparkplugs are all black. i lowered the fuel pressure again today. its way lower now than the original setting...

i also get the rich and forced to open loop flag in winaldl (?). got a chip from pcmforless. so i think that isnt the problem.
when the car reaches about 150°F the O2 volts are constantly at 1V. i thought the volts should bounce up and down?
winaldl sais i have around 50 kpa at idle.

and theres some smoke coming out of my oil dipstick tube when i shut of the car.
theres also a ticking noise coming from the passenger side head. the valve lash should be fine. its done with an idiot-safe method

many questions. hope someone can help me.

Nebu.

 

My geuss is that you need more tuning. I see you have 350 injectors. They will run rich unless you get them dialed in with the prom. Try using your stock injectors and see what happens. I normally suggest putting the stock chip back in but since you have so many mods your stock chip is worthless.

 

i've got that problem with my car too. i went from a 305 to 350.. but mine is opposite. my idles high then drops for about 2 minutes then it idles normal. my rpms go to about 1,000 then drop to 500. i tried a different iac and that didn't fix my problem. my chip is going back to get tuned so it stays in open loop mode so i'll see if that will do anything for me.

 

you are both in the same boat, it is in the computer.

Nebu --

the o2 will only swing in closed loop, in open loop, o2 volts in the 1v range mean you are RICH, very rich. what really needs to be done is tuning, the BPW needs to be set to match those injectors, and the fuel table needs to be adjusted to match. 50kpa at ilde means you are going to need quite a bit fueling changes to get it optimal. the only time i have experianced a really bad surge like that at idle, was when i was so far off in the idle tune, that i was really lean (emmisions time ) my o2 volts were in the .01 range, it was LEAN, and running 50/50 alchy/gas. I can only figure that being that rich will have the same effect, the IAC is cannot open/close enough to make up for it.

A couple of suggestions, 1) disconnect your IAC, and try to adjust the idle screw so that it idles without the IAC, then plug it back in. 2) start learning now so you can tune it yourself.

 

@dewey: wheres an idle screw at the tbi?

so should i try and move the 30 kpa to the 50 kpa row? maybe that helps? what do i do with the spark advance then?

i played around with the open loop vs. coolant/vacuum but that didnt help. maybe im doint it wrong

what do you think about this knocking sound and the smoke from the dipstick?

thanks,
nebu

 

you need to get it to idle first, try triming fuel from the cell that you are idling in. once you get it to idle, and somewhat drive, you can do the standard tuning based on the BLM data.

the idle screw is on the front side of the TBI unit, it is coverd on a stock TBI unit, you may been to punch through to get to it.

 

ok ill try that. only got 2 eproms left and i have no eraser

Nebu.

 

i think someone needs a moates adptor for eeproms

(i only own 4 chips, and i just cycle through them, and keep 1 known good configuration burned, and in the car.)

 

hmmm yeah that is a good idea just ordered the tbi adaptor with 2x29c256 chips.
good that i can use them with the pocket programmer without an adaptor for it.

Nebu.

 

Just a little tech tip here- Don't just unplug the IAC if you intend to adjust the base idle. The proper (recommended) procedure is to bottom out the IAC first. That way you're only adjusting what's getting through the throttle blades, and not the IAC passage. To zero the IAC, short the 2 terminals on the ALDL that you use to get codes, then turn the key on. Wait 30 secs to a minute to make sure it's zeroed, THEN unplug the IAC. Remove the paperclip/cotterpin from the ALDL, start engine and set base idle. The screw is usually under a metal plug on the driver's side, facing front. You can remove the plug by driving a drywall screw into it, or using a thin punch, nail, or something similar to pry the plug out. If I recall, the usual base idle setting is 500rpm. Shut it off, plug in the IAC, and that's that. If the idle's been played with at all, it usually idles much smoother and more consistantly when the base idle is properly set. This is also done on a warm engine, of course. Might be of some help?

Drew