almost everytime i push the clutch in and let off the gas the rpms drop down to damn near 400rpms or so, then slowly raises back to 750rpms. the battery volts drop to 12.4-12.6 when it boggs out also. the car has a slightly rough idle. the fuel pressure is also about 8lbs too low.
ive checked all grounds, cleaned the IACV, bypassed the FITV, ground the motor and battery with 2g cables, replaced battery, fuel pump, pressure reg., fuel filter, air filter, plugs, wires, dizzy cap, rotor button, 02 sensor, throttle body gasket, and all vacuum hoses.
cant find any vacuum leaks or anything at all wrong for that matter.
anyone know why this is happening? maybe the alt. is going out?

thanks in advance guys.

 

Bumpy McBumperson!

 

i had this problem in my eg with a ls swap i had the timeing 1 off would always fall on its face and then be find when i drive

 

timing is spot on. i checked it a couple days ago. it is advanced about 1 degree though. but that shouldnt change anything.

 

so anyone think it might be an alternator? i dont want to spend $150 for a new one till i narrow it down...

 

voltage is dropping because the rpms are dropping so low (ie, the alternator isnt putting out any current because its spinning so slowly, so the voltage drops to battery v.). Whats your base idle set to? Chipped ECU or anything like that? Sounds like either the base idle is set too low, the IACV needs to be replaced (cleaning isnt always the magic charm...they do go bad, might be time to replace) or there is some abnormal friction with the clutch where its binding up when you push it in. Also could be a bad tune (running too rich usually) if you have any non-stock components. How did you measure fuel pressure? Vacuum hooked or unhooked? That 8psi could also be the problem.

 

well it is running rich. horribly rich as a matter of fact. (like 14mpg rich) the base idle is at 750. it bounces around there. sometimes it idles fine and other times this problem occurs. its not a constant thing. its a virgin ECU. the only things aftermarket on her are a b18b intake mani., short ram, header, exhaust, ect. nothing internal. i have a fuel pressure gauge on the filter. i measured the fuel pres. with the vacuum unhooked. i did find that the ground on the battery is a wee bit loose. but wiggling it didnt change the idle at all. im going to replace the terminal clamp anyways.
one thing that doesnt make sense to me though is that im running rich but fuel pressure is low. kind of ironic isnt it?

 

bumper cars!

 

bumpy bumpy!

 

so i was told obdo doesnt always throw a CEL untill a part completely fails. and that i might have a TPS peoblem. does that sound legit or was i told wrong?

 

oh yea. also when i turn the headlights on my rpms dorp by about 100. then go back up when i turn them off.

 

so...this is getting really annoying. and i feel like im talking to myself.

 

did you check your speed sensor's...sometimes that can effect for the bogg! thats what happend to my friends LS!

 

yup...speed sensor is fine. im going to change my IACV as soon as i find one that doesnt cost and arm and a leg. and im putting a b18b throttle body with a FITV back on as soon as i buy a new throttle body gasket.

 

well i changed the TB and gasket. and rewired the map sensor. (the TB i used has the map on the TB itself.) it got rid of the loud annoying vacuum sound. but the rpms still dip down when i let off the gas. the idle is a bit smoother though.
any ideas on the rpm dip?

 

at OP temp, when i plug the whole for the IACV, the car drops rpms and wants to stall. IACV bad? or is this normal?

 

well i thought i had it all figured out. the idle smoothed out. (sometimes it would idle a touch low and rough though). but on the way to hang out lastnight, a CEL popped on. code 43...ugh! anyone know whats going on? its really getting on my last nerves. theres no power diff when the CEL is on.

 

As per HONDA service manual, if you plug the large hole in the throttle body the RPMs shouldn't budge from where they are. You sir have a bad IAC, plain and simple. You should also check your voltage at the TPS sensor and see is you have .45v closed and 4.45v wot if you do, then go to the ecu and back probe the appropriate pins and see if you have lost any voltage. It is possible to have poor pin fit at the ecu which acts as higher than normal resistance. If you don't have the proper voltage at the TPS then you can adjust as nescessary. Either way you still have a bad IAC, as stated before cleaning isn't always the trick! If that was the case every parts store in America wouldn't have one in stock! lol
Hope that helps!

 

Also make sure that your idle screw hasn't been F**ked with! Screw all the way and and 1.5 turns out, that will get you to "factory setting" GL

 

i would go with what this guys says

 

yea im replacing the IACV with another one tomorow. hope it helps. and ill check the tps while im at it i guess...

 

Not saying trrbl1bmx is wrong by any means but I had very similar symptoms in my DA and all it turned out to be was a weak battery and corroded terminal ends. The idle would drop real low and stay there and eventually it just wouldn't stay running without giving it some throttle. New battery and terminal ends and it runs great.

 

Did you reset the ecu? Does it idle funny when the engine is cold or warm or both? Did you let the IACV relearn? Also are the bolts down tight enough, gaskets on correctly for your manifold and other? Also if you put your hand over the TB does the car shut off? Any check engine light? It could be your ecu going out too.

 

i need to replace the ground terminal on the battery to. i just havent yet. the car idles fine while its cold. (at about 1600rpms) as soon as it heats up it starts idling funny. yes when i cover the TB it dies. ive unhooked the battery a couple times so i know thats straight. i just took off the IACV and everything was tight, gasket was fine. im going to try a new ECU as soon as i find a friend to let me use one. i just cleaned the IACV again just to make sure. if it doesnt help im going to try the terminal, and ECU. if those dont change it, im just going to shell out the money for a new IACV i guess. im about ready to sell the damn thing.

 

so yea....after clening the IACV again. it still dies when i plug the whole for the IACV. so a bad IACV for sure? the car does whoever idle pretty damn smooth when i take off the intake. when i put the filter back on, it idled rough. a sign to clean my K&N filter i guess. so on to the ECU and terminal replacement.