soccermike

Hi, so my brother and i just did an auto to manual swap in my 2000 civic ex (d16y8 with a z6 tranny) and it ran pretty well up until a couple of days ago...you see, ive always noticed that it idled a bit low in neutral, but thought nothing of it until the other day when i reved the engine in 1st and then pushed in the clutch and let it come all the way back down and it died on me. its done this many times while actually driving and originally it did this when the ac was on or off. yesterday i fiddled with the idle air screw and cleaned out the iacv with throttle body cleaner and now it seems to run decent with the ac off. yet, as soon as i turn on the ac and rev the engine high and let it fall (even at a stand still) it either flickers the oil and battery light and barely stays on or just dies completely. the thing that sucks is that i cant trace it down to anything...i have some theories though....possibly the light weight flywheel means that i should up the fuel pressure? throttle position sensor needs to be adjusted? distributor timing is fully advanced at the moment and should possibly be tuned down? throttle screw should be advanced a little as to not let the throttle drop so low? im running out of ideas and time saying as i leave for college in a week/ any and all help will be greatly appreciated! thank you.

mike

724chris

my car does this too. i messed with the idle screw and it just went back to mormal after a few days. im pretty sure its the tps

Former User

Any CEL codes?

Check the plugs, wires, cap, and rotor. If those are fine, set the ignition timing to spec and then adjust the idle speed.

soccermike

well i had an o2 sensor code because i didnt put my secondary in the cat anymore...i put it in the aftermarket header and it wasnt reading correctly but now that i gapped that out today i dont have any codes anymore...i adjusted the timing back to normal and then tried to fiddle with the air screw. i went up in rpm and down and neither helped also, i cant truly be precise with the idle screw because my tach doesnt work (auto to manual and i havent had the chance to get a new cluster yet). also tried fiddling wiht the fuel pressure and that didnt do anything either...so all this gives me the feeling that its not a simple tuning problem...any ideas?

soccermike

oh and i checked my sparkplugs and they looked decent although number 4 looked pretty bad so im going to advanced to grab some new ones...ill let u know how it goes

soccermike

new spark plugs didnt help...my dad thinks my ac might be over compressed which might cause more stress on the engine... and he is checking it now...

soccermike

not the ac, i feel like the ac just exagerates the problem, if you know what i mean. before, my car would stall regardless of whether the ac was on or off, but now with some tuning, it can stay on with the ac off. but tuning jus tdoesnt fit because that wouldnt explain why my car all of a sudden started doing this oh and if it helps, u might be interested to know that the car has header and muffler, cold air intake, fuel pressure reg, throttle body has been bored by my bro(which may or may not be the cause of the problem). not sure if that helps

freydaddy

are you using the auto ECU?

soccermike

no the ecu is from a 98 manual, and my bro rewired the whole thing to work with the car...i considered taking apart the ecu cover and checking for dangling/shorting wires

The Survivor

What about the IAVC? Do you trust your brothers wiring?

soccermike

well it was good enough for the car to run perfectly for a couple weeks, but he did mention that something might have come loose or undone, or that the resistance in the wires might be higher than normal due to lack of insulation, but wouldnt the symptoms be much worse if the iacv wasnt operating? and as for checking it i opened up the iacv and it wasnt very dirty at all because he cleaned it before putting it on a couple weeks ago. i cleaned it yesterday again and it didnt seem to make a difference, but perhaps something electrical is going on there...i think ill go check the ecu wiring really quick while i still have daylight

soccermike

checked the ecu and any loose wires that we had were still insulated to prevent shorts and no wires had come undone from the plugs...

soccermike

i tried checking some fuses as well as checking vacuum hoses and didnt find anything...any other ideas?

soccermike

UPDATE got two new codes...if im right i think theyre for the iacv... p0505 and p0505pd which im pretty sure means it just repeated...any thoughts?

slvrlude

im having the same issues with the same code....keep the updates coming...

soccermike

well i woke up today at 11 and started working on the car (something that's become routine for the last couple of days) and i started out by plugging the throttle body with my hand...car stalled means that no vacuum leaks. then i plugged that little hole in the throttle body just to make sure and it stalled again...then run the car with the iacv unplugged...runs like crap but i rev the engine and the little throttle jump still didnt go away...so this all gives me the feeling that it was not the iacv's fault for all of this...so it must be somehting else related to it. i looked around on hondatech and found a couple of other people with the same problem, but each time it seems like someone mentions a bunch of things that could be the problem, and then all of a sudden the posts stop and no one says what the fix was! and this is true for other websites as well! im taking my car to my brothers today and hopefully he'll just do his little "mechanical engineer" thing that he always does and somehow magically fixes my car lol but ill let u know what happens...also im planning on replacing the iacv gasket saying as i got the iacv used from the junkyard and the gasket looks awfully flat to actually be sealing anything...

soccermike

so my brother and i are working on my car today after i had just gone to honda and ordered an iacv gasket and he is looking at the throttle body and says to me "oh yeahhhh so i just remembered that when i put your engine back together i forgot to replace that broken throttle position sensor gasket..." apparantly it broke as he was taking apart the engine in the first place and now he tells me after five days that he forgot to replace it...im hoping this will be the fix and when i go tohonda to get my part tomorrow ill order one...as for now he and i duck taped the contact point of tps to the throttle body and the dip in my rpms has cut out a little bit and i havent gotten any codes...fingers crossed that this will be the fix...ill update in a few days once ive gotten that other gasket