Just finished putting a b20 into my 98 hatch. Fixed all the check engine light and everything looks good. When i'm driving normal, I'll have a consistent amount of pressure of the gas pedal when im speeding up and the car hesitates/lags as if i took my foot of the gas and then kicks back in 2-5 seconds later. I have no idea what's going on with the car.

 

Have you checked your timing belt, to make sure it's not off by a tooth or two?

 

Check to make sure all your timing marks are lined up correctly.

 

Check your header.I had a small crack on the top portion and when I weld it back the lag is gone.But it could be something else.

 

it could be a few things... the crack in the header could throw off the O2 sensor and mess that up too... it sounds like a fuel problem so, there a a lot of things that can affect that. it should throw a code though.

 

yea no CEL. I'm gonna check out the timing belt tonight.

 

fuel pressure, ignition timing and timing belt...check it, good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rodrez &raquo;</TD></TR><TR><TD CLASS="quote">Have you checked your timing belt, to make sure it's not off by a tooth or two? </TD></TR></TABLE>

Uh if the belt was off by a tooth or two, he wouldn't have this lag problem because the engine wouldn't be runing.

Give a better description of the problem..
when does it happen most? when doesn't it happen? any certain rpm range? full throttle, partal, light,etc.....

 

Something like that happened to me today, but it was my sensor on top of the throttle body...check that and see if its connected...if its not it causes great hesitation.

 

i got this same problem. i just installed a y8 IM on my d15 and it laggs around 2-3k rpm. im thinkin it may be the fuel also because i had to use my old injectors. the y8 injectors didnt work for some reason.

 

It could also have something to do with you IACV. Make sure it's clean and relook everything over. Hope that helps, if any at all. Good Luck.

 

hey.. i had the SAME problem.. i did b20b in a del sol and it would lag like that.. do you have a stock cat back or an aftermarket.. i noticed when i put stock exhaust back on that it helpe a **** load.. i wasnt getting any back pressure.. let me know what you got on thier.!

 

maybe as simple as a fuel filter?

 

Checked the car out tonight. The timing belt was off by acouple of teeth. Fixed that problem and now the car runs like a champ Thanks for the help guys

 

Car was driving ok for like a day but now it lags again. Took out the timing light gun and tried adjusting the timing but car wont idle correctly. RPM keeps jumpping up and down. I'm gonna take a look at the belt again and see if I put the belt on wrong again.

 

Someone metioned something about fuel being my problem. Now that I think back to when I did the swap, the b20 fuel pressure regulator didn't fit on my golden eagle fuel rail so I ended up using a 1990 SOHC CRX si FPR that was laying around. Not sure if that makes a difference.

 

If your car is still idling weird check the IACV Idle Air Control Valve, like someone else said.

 

Just finished cleaning the IACV with carb cleaner. Still running the same. Maybe the valves need to be adjusted? My car doesnt have that lag until I drive the car for about 15-25mins. After that the lagging begins.

 

Does the car stall for a few seconds and then surge?

I had the same problem and it only happened when the motor was warmed up. Turns out some wires going to an O2 sensor got burned, but it did NOT throw up any CEL.

I have driven w/o the last O2 sensor with no problem, but when the wiring got messed up the car hesistated and surged like crazy right around 4K rpm. Check it out.

 

Maybe my o2 sensors has gone bad? Any way of checking them? During the swap they were sitting on the floor and coolant spilled on them.

 

Check the resistance on your plug wires.....

 

i have the same problem... i just swapped a B18C into my hatch and i get a hesitation around 2 - 3K rpms. it's almost as if the engine is "breaking up" or something.

i messed with the timing and solved the problem for a couple hours then it started again. it doesn't happen all the time... only when i'm accalerating under normal conditions.

if i figure it out, i'll let you know what it is... let me know if you figure it out first.

 

yea samething for me. only seems to lag when the engine is really warmed up and driving normal.

 

same here..........but is an old 89 civic with 140k

i replaced the water pump and the seal, and after that.......

the lag starts.......

still don't know......i think is my timing, but i set it to TDC

 

I'm starting to think it might be the throttle position sensor. When I start getting the lag, instead of pushing down on the gas more like I normally would do, I got off the gas and slowly pushed it again and the lag would go away for that moment. Then it would happen again seconds later. I would just keep having to get off the gas once I feel the lag.