pigeonkiller22

hey i just got a 1999 honda accord ex.F23A4. i just rebiult the motor with everything brand new. the pistons, rods, crankshaft have been balanced ,hot tanked, and lightened, and media blasted the crankshaft has also been polished, radius oil holes, weel everything is brand new but those parts. the tranny just got rebiult also. so i started it up and everything was good until i reved it up to about 2500 and when it droped back to idle it turned off. i double checked the lines sensors grounds and everything so i dont know what is going on. PLEASE I NEED HELP.

locosiete

did it idle OK before you reved it up? and was it a smooth idle or ruff? also what was it idling at?

pigeonkiller22

it was very smooth. just like a normal car. it was idling at about 750-800. then after i reved it the car went down to 100 and stayed there for a bout 2 seconds and died after that.

locosiete

would it start back up? and have you tried to drive it yet? might just need to adjust the idle/throttle cable. could be when you reved it up it went to kick down the idle and if it was out too much thst why it went so low. when it is cold should idle around 1500 rpms and than kick down to about 7-800. worth a shot to look at.

pigeonkiller22

yeah it would start backup right after it turned off on me. the motort started at about 500rpm and worked its way up to 1200 and back at 800. i did try to drive it and the car wont turn off but its way slow.and i adjusted the cables before i turned the car on to touch the actual throttle spring plate. before they were way back and i had to press the gas pedal a little just to get the cables barely opening the throttle plate. and the car warms up good and when it goes down to normal idle(750-800) i rev it and it dies. but if i rev the car when it still hasnt warmed up yet the car revs fine and doesnt die.

locosiete

have you checked to see if here is any trouble codes. if i had to guess i would think it your timing is off or a clogged cat or intake is not getting enough air

pigeonkiller22

the mil light does come on but for some reason i cant access the ecu with an obd2 reader. it says error 1. i checked to see if the all the wires are attached and they are. so i cant really check that way. i bought the car with the tranny bad so i rebiult everything. i still cant find out why this is happenning. i checked the sensors and everything is good. i havent touched the cat, the guy that had it before me put a high flow cat in there. and a dryflow aem intake. before i rebiult everything the motor sounded hella good and it warmed up and everything worked good. i rebiult everything because the car had 144k miles. and i havent checked the timing but when i put everything together i made sure that the timing was right but like you said it might be the timing so i am going to buy a timing light to check the timing.

locosiete

well not that i have helped rebuild hundreds of engines but i know it has always been the small things that caused us the LARGEST problems. plus if you replaced the timing belt who is to say the old one wasn't stretched out a little so now that you have a fresh one on it threw of the timing off. check that and let me know.

pigeonkiller22

i did check the timing and it was right on, the belts where also not to tight. for some reason when i unpluged any vacume hose going into the intake manifold it wont die after i rev it. but when i put the hose back into place and i rev it up it dies. i checked all the sensors to see if they worked and they did the only thing i cant check is the egr. i also checked the canister purge valve to see if it opened and closed and it did. then when i bypassed it and the car ran normal again. i dont know if its opening in time or if thats even a problem. i changed out the map and the air temp sensor. i also reset the ecu to erase the mil light because a sensor wasent pluged in all the way so i double checked all the sensors and now no mil light but it still dies. i am stuck and dont know what to do next.

3zFree

You answered your own question...what happens when you unplug hoses going into the manifold, more air gets bypassed to the manifold right? Clean your throttle plate with some carb cleaner or look for another restriction in the intake. Ive seen accord with same engine even refuse to start over due to crap completely covering the space around the throttle plate.

AccordVT

Idle Air Control Valve (Wiring, dirty valve seat, incorrect polarity on the stepper motor?) ECU is having trouble maintaining and correcting idle. Throttle position input is a big part of that too; is the TPS adjusted correctly? Alot of pirated air from somewhere will throw the IAC system off too.

pigeonkiller22

see thats the problem all of the hose lines are not cloged i checked every one. the throtle plate was cleaned before i even fired up the car and looks good as new all the gunk was cleaned out from the holes and plate thats why i dont understand whats going on. the intake has no leak anywhere. i have checked the hoses both for leaks and for clogs. including all the gaskets on the manifold. as for adjusting the TPS i dont know how to do that i havent even messed with it, i cant even take it off the throtle body. as for the dirty valve seat, i did a 3 angle valve job and also laped the valves. as for the stepper motor i dont know what that is. but im going to take off the wiring harness today to see if there is a lose conection or messed up ground somewhere.

pigeonkiller22

i took all the wires off. cleaned all the sensor. and preatty much redid the whole wiring harness. i put everything back on and now the car doesnt turn off but when it gets warm the car starts surging from 1000-1800. i was told that it was the iacv. what do you guys think?

locosiete

well that seems to be a real common problem and although i can't guarantee it if you take off your iacv and tighten down the white plunger/screw that should fix it but since from the sounds of it you have put the $$ into it, i would replace it with new one. unless you want to determine if that's the problem than take off and tighten it. if it fixes it than get a new one if not than at least you didn't spend the money. this way if isn't the problem you are only out $5 for a new TB gasket

pigeonkiller22

i already ordered it from autozone and its coming in tomorrow. so ill see what is happeing. oh i bought a new throttle body gasket and put it on today and that made no difference so now the only things i havent bought or checked yet are the TPS and IACV so ill see if it is the iacv tomorrow. ill get back to you guys tomorrow in the afternoon.

pigeonkiller22

i finally found the peoblem. it was the iacv. THANKS alot i really apreciate the help.

locosiete

well glad to hear we could help lol and it wasn't anything major