Ok so i just got a 1995 civic EX, knew there was an overheating problem, had water/pump timing belt replaced, immediately diagnosed as blown head gasket.

so.

took big hit and engine replaced completely from LKQ online, (identical engine except it originally was mated to an automatic mine's a manual new engine has 63k miles,felt this was a big deal , no core charge)

after swap, check engine light was coming on.
also low idle (~200rpm) , I should mention that previous engine did -same thing- and had NO ecu codes (just overheating due to blown head gasket)

was driving fine for about a day , but then on highway began get clunky at highspeed, then bam limpmode

i can restart it but limp mode comes back after 2-5 minutes (2200rpm max)

so i jump the ecu plug, and get the following codes:

7 Throttle Angle (TPS)
10 Intake Air Temperature (IAT)
14 Idle Air Control (IAC) valve

these -all- point to throttle / idle sorta problems ALSO seems like i have no Vtec but not pulling any codes for that. (previous engine did engage vtec perfectly fine)

the guy who swapped my engine still has the old engine (which was in fairly good shape -the head gasket), and will likely let me have the parts off of it, if i need them.

so the big question is: old engine had low idle problem but no ecu codes , vtec working fine.

new engine has low idle problem WITH ecu codes, vtec not working fine (at least that i can tell)

how should I approach this.

 

TPS and IAT are both just small sensors attached to the intake mani, should be easy to check. make sure they are plugged into the correct plugs. make sure that your TPS and MAP plug arent reversed, as they are the same style plug and are right next to each other. the idle air control valve is on the back of the throttle body, make sure that is plugged in as well. the IACV might also be dirty so taking it off and cleaning it with some carb cleaner wouldnt hurt.

are you even sure that all of these are plugged into the wire harness? seems weird that the sensors themselves wouldnt work if they worked on your last motor.

 

wouldnt it be throwing a MAP code and/or having more problems if this were the case?

 

most likely, yes, but it doesnt hurt to check. like i said it is wierd that your sensors just plain WOULDNT work if they did previously and the guy who did the swap just swapped them over.

 

update:
pulled battery cable just for kicks
-now only codes 10 + 14
-no limp mode but i suspect its based on driving xx miles with CEL condition, so i know its coming back
- attempting to hold throttle @1500 rpm bogs/hesitates/acts like its limpmoded at that speed, more gas and it throttles up fine.
-drove around block about 3 miles no limping. but definitely 1500rpm something is fishy.

 

The IACV plug and IAT plug are the same type, check to make sure they're not reversed. The IAT is usually red/green and the IACV generally has one yellow/black stripe or black/yellow stripe

 

update: so the plugs -were- reversed. we checked the iac before and after the plugs were put on right, the iac now engages properly (it wasnt engaging) unfortunately its still throwing the same codes and idle is still low.