runaway motor b17 in del sol swap

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autotechhonda

New Member
I just finished dropping a b17 with a hydro ls tranny into a 93 del sol. the computer is a chipped p28, no knock sensor needed, only minor modification to wiring was needed because the car was an si with a sohc vtec. all vacuum lines and sensors are hooked up correctly as far as i can tell (though the MAP sensor is dangling by a vacuum tube) save for ONE unnamed connector of a green color in the back near the knock sensor. my manual makes no mention of it and i don't, as far as i know, have the right connector for it though several will fit. anyway, i start the car after the swap, it sputters, runs up to 3500 rpms and idles here. when i apply pedal, the motor coughs and rpms drop, and at wot pedal position the motor dies. it does this upon repetition, so i scratch my head, check all the tubes and connections, make sure the throttle cable is ok... anyway no change. i reset the ecu by pulling out the fuse, try it again... the engine runs up to 5000 rpms ( at idle throttle) before i get nervous and kill it. it does this every single time up to the last time i've tried it, and any pedal at all will nearly kill the engine. the strangest thing about it all is that the engine doesn't throw a code, and aside from trying to leap out of the engine bay and run down the street, it purrs like a kitty. so where am I at? any ideas? thanks...
 
check vaccume i had a similar problem with a 89 plrelude H22 swap, spray some carb cleaner all over the intake mani side and see if you get any flux in the idle if that doesnt work double check your wiring that you did, might be a crossed wire or someting ! good luck
 
thanks for the feedback, i will do a vacuum check for good measure. meantime i've tried disconnecting sensors and rechecking, and here's an interesting find: when i disconnect the idle air sensor/valve/thing, the car doesn't rev up like it did, but idles roughly, fluctuating between 1 and 2 k rpms (and of course it throws a cel). you can actually drive the car like this, but it isn't fun. the sensor on my old sohc is identical, so i'm just gonna go swap em out and see if it fixes the problem. if it doesn't, at least it eliminates a possibility. i'll post the results soon.
 
ok so i swaped the IAC from the old to the new, and NOW it wants to rev to 3, back to 1, up to 4, back to 1, and repeats. it does this every time, the cycle is constant... what in *&@*!!! unplug any other connector and it doesn't change. i haven't gone over the motor with a fine tooth comb for vacuum leaks, but it just doesn't seem like a vacuum leak would do that, or am i wrong? and if it's not leaking, then that certainly means that the engine is reving itself up on fuel, right? which means something PFI is responsible. would a computer compatability issue do this? i know the p28 ran my sohc vtec fine, and the moded parameters worked for it (early vtec, ect.) if it wasn't functional for the dohc like i was told, would this be the result? and if so, why would the engine's behavior change like this? i'll pick up some carb cleaner tomorrow and try that, but it seems like it would be hard to hear the engine rev when its reving up and down already. i might have to take it to a shop i guess...
 
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