1-4,000 rpm's not running smoothly??

[l.jonez.civic]

About a 3 weeks ago my engine swap was complete from a stock engine in my 1990 honda civic hatch to the b16a. Since then i have been having problems getting from 1,000 rpm- 4,000 rpm's. I am getting a lot of stutter and hesitation in that rpm range. Once the car reaches 4,000-4,500 rpm's it takes off and works fine?? It seems to me that i have some type of fuel management problem, but i'm not sure.
When i drive it seems like the car lets off a certain amount of fuel, then realizes to much fuel has been released so it lays off the fuel, next the engine realizes not enough fuel is being released and releases to much, then cuts back and continues this process until 4500rpm???

Can someone give me some ideas on how i may solve this problem???
p.s. i added a new header & exhaust with 2 1/2 inch down, so i don't think it is back pressure from exhaust.

[crxlvr]

check your O2 sensor, it seems as if your only running in VTEC mode.

[1990civicdxhb]

you might wanna check your ecu & see if its throwing codes & if you know someone with another ecu you might wanna try that,
also when you installed the swap,make shore all your wires was properly connected to the right ones,I swapped my motor & the rpm's was shity up to 2,000 rpms,so you might wanna re-check that,
if all thats good,you might wanna do a compression check,fuel pressure check & a vacuum check with pressure gauges make shore everythings working properly.

[EF You]

where are your o2 sensors mounted on your exhaust? the non-OBD b16a uses 2 sensors. one reads cylinders 1+2 the other 3+4. if you have one sensor mounted to your header, and dont have the other one mounted at all, that could be it. or if you did like i did on my first swap, and mount one before the cat and one after the cat (like OBD2) that will definitely be the problem, because that second sensor is always reading lean.

does this problem occur throughout the throttle range, or only at partial throttle?

[91civichatch2571]

timing too advanced?

[icE_x]

sounds like something is throwing the fuel regulator wack signals

check the ecu and sensors, and check the camshaft as well just in case

[l.jonez.civic]

Thanks for the info,
I bought a new hasport header which is supposed to be equipped for this swap. On the header itself are two holes where the oxygen sensors screw into. I'll check on some of the other recommandations, however it seems as though my check engine light is only coming on during warm/hot tempetures?

[Expando1]

IceX, that's a good looking civic; i have the same year model but mine looks like crap, suspension is shot, but still hanging in there.

[EF_CaSe]

ok i have the same problem its cuz my senor is broke.. u need to plug up the tps.. maybe u got the map n tps senors crossed or dunt even have the tps hooked up it gose on the back of ur TB.. u didnt say nuttin bout this but dose ur car shut off or even sound like its gunna shut off it u gun the gas real fast??? if so theres ur problem.. or even if u have n after market fuel pressure regulator get rid of it my brother almost just blew his motor cuz he wasnt gettin enuff gas...

[l.jonez.civic]

Originally Posted by EF_CaSe

ok i have the same problem its cuz my senor is broke.. u need to plug up the tps.. maybe u got the map n tps senors crossed or dunt even have the tps hooked up it gose on the back of ur TB.. u didnt say nuttin bout this but dose ur car shut off or even sound like its gunna shut off it u gun the gas real fast??? if so theres ur problem.. or even if u have n after market fuel pressure regulator get rid of it my brother almost just blew his motor cuz he wasnt gettin enuff gas...

My car does not feel like it's gonna cut off at all. Sometimes the idle jumps from 1500 to 800 and back and forth, but no sign of cut off. What exactly is the tps sensors. I know of the two oxygen sensors attached to my header, but i don't know what the tps sensors are??

[EF_CaSe]

tps means Throttle Position Sensor.it tells the computer how much ur hittin the gas n lets it know how much gas 2 pump in2 the motor. its located at the back of ur throttle body n then u got the map sensor that means: Manifold Absolute Pressure sensor.. thats located at the top of ur throttle body the plugs that go in2 each of them r the exact same just try switchin them around if not that maybe ur timing is to advanced.. or do u have some kinda Vtec controller those r the top things i know of that can be ur problem.. but like i asked dose ur car bogg if u gun it?? it dosent always have 2 shut off.. open ur hood n gun the gas real fast try it acouple times n let me know what it sounds like maybe that can help us know whats wrong here

[l.jonez.civic]

Originally Posted by EF_CaSe

tps means Throttle Position Sensor.it tells the computer how much ur hittin the gas n lets it know how much gas 2 pump in2 the motor. its located at the back of ur throttle body n then u got the map sensor that means: Manifold Absolute Pressure sensor.. thats located at the top of ur throttle body the plugs that go in2 each of them r the exact same just try switchin them around if not that maybe ur timing is to advanced.. or do u have some kinda Vtec controller those r the top things i know of that can be ur problem.. but like i asked dose ur car bogg if u gun it?? it dosent always have 2 shut off.. open ur hood n gun the gas real fast try it acouple times n let me know what it sounds like maybe that can help us know whats wrong here

I'm gonna check that out, thanks. The car doesn't bogg when i gun it. The higher range rpms are ok, it just seems to be in the 2-4000 range. Also my ecu was showing a code for a knock sensor. When the mechanic did my swap I got a brand new knock sensor, so we sent the ecu back and are awaiting a new one. Hopefully the new ecu will correct my problem