bamboosted

I tryed searching but i found a few thing simular and tryed checking those items but nothing like it! There is two problem they might relate to one bad item but not sure so i figure id turn to H-T

Ok here it goes. It a ls/vtec turbo with stock ls block 210 compression all acroos the board, gsr head with skunk2 intakemani and type r cams rest of the head is stock. Rc440 currently stock fuel pump.

tryed street tunning but is wierd about 4500ish up to 5500ish area the car sputters if you get on it (over 50-60% on tps) but on the datalog everything looks good 12.0 af, tps working , map sensor reading, and iat work properly

and if i sit the at a dead stop rev it up a few time and let of the pedal the rpm comes down and it like a surge or something for a few seconds about 100 or 200 rpms higher than set where it goes super lean and goes back to where it was set at 14.6-15.0 af and 950-1000 rpms

all wiring is stock was never touch before just ran the two wires for vtec by the way its a obd2b ( its a CRV )
I tryed new Spark plugs ,new cap and rotor, new wires ngk ones. and it still does it.
I changed out the map to another good map sensor i had kicking around and iat just in case was sure if the other ones might of been on its way out. I also checked timing its dead on 16degress on the pully and on the hondata. Oh yea iand i try plugging in another s300 i had kick around was sure if the sockets might of been coming aprt inside but still did it.

I cant figure out what it is. there are no check engine light nothing. So please any idea
h-t.
I tryed explaing my issue the best as possible if u can't understand something I will try to explain it better.

Bailhatch

Needs to be tuned more betterer

kranky81

i feel you need a 255hp fuel pump and bigger injectors, atleast 550cc. my car did the same when i had 440s on there , then i put 650s on and no problem. it seems like your injectors are maxed out and not wanting to give you more. unless i read your post wrong.

HiProfile

Any idea how much boost you're running? What spark plug gap, and P# for the plugs? If they are basicly stock heat/gap, you're just breaking up once you hit moderate boost.

I'd also change the fuel pump ASAP, as only the dohc vtec cars came with decent stock pumps. Everything else used the weak 79lph pumps; you're lucky if you get 200hp out of them.

Besides that, you need to be very careful with tuning. That head can help do a lot of damage, as it will allow lots of HP per PSI. It won't take much to break the stock ringlands with that head.

bamboosted

Running 10psi plugs are 7's heat range 1095ngk part number gapped to .30 Well im not the actual one doing the tunning a friend that tunes is doing we are street tunning he has done a ton of other cars. and also the crv was once b20 with the same turbo kit ran great no issues street tuned also then the timing belt went took of the b20 head and ended up dropping the left overs of the motor out, a friend had a ls/vtec sitting in his basement which he offered it to me for a great deal and it was all togehter so i figure why not just throw it in i need my car back on the road asap.

bamboosted

Thanks but the tune has been worked on over and over it will look good for a cruise up the street and next min the car runs like crap at the same time datalogging , then looking at the datalog it looks the same as when its running good. The map doesn't change but it almost like the motor it self changes like it a different motor and run like it un tuned!

HiProfile

I would start to look at the wideband in this case. If a car stutters, something is happening that usually involves unburned gas, which actually shows a lean condition. If the sensor is bad, it can do a wide variety of things, including very slow reaction, and not reading anything but a narrow range. And don't forget sometimes the controller itself can take a crap.

Do a pull the best you can, shut off before you close the throttle, and check the plugs. That will give you an idea of the real AFR per cylinder.

narfdanarf

I agree with checking the wideband. Also I had a similar problem with my car going rich randomly and it was due to some capacitor went out on the main board of the ecu. So maybe it could be a problem with the actual ecu and not the s300 unit itself.

bamboosted

The actual O2 sensor to the wideband has just been replace with a brand new sensor a week and half ago. And I would think it might of been the ecu board but i try another ecu that i had with s300 for my integra which was 100% working order before i parked it.

Man this suck Ive tryed so many thing and nothing yet. Well thanks guy i appreciate ur input on all this so far

Also Hiprofile i will try making a run the best i can tomorrow (due to snow on the roads) and pull the plugs

Bailhatch

Try closing the plug gap to .025" and see what it does. Generally, you should be able to run 30 with that kind of setup, but maybe heat is changing how your ignition functions. I would do a visual on your position sensors in the distributor as well. Clean em up if needed. The surging could be a timing issue around those rpms or even a crappy FITV.

bamboosted

today i will try to close the gap on the plugs and also iam going to check both map and tps wires all the way to the computer just for the hell of it and hope i will get down to the bottom of this issue!

bamboosted

Okay well today First I try testing Map, tps, iat wires to make sure there was good connections through out the harness to Ecu which every thing was good there, decided to change the TB, So I fixed one problem the slight surging after reving and partcial throttle When changed out the TB with a good tps and another map sensor, when changing it I notice the gasket had a slight rip in it and it look like the guy that actually had the motor in a car copper sprayed the old gasket to try to seal/glue the rip together instead of buying a new one. What an idot!

I also had another jumper harness in my tool box so i figure try that also and not sure what fixed it but im thinking more of the new gasket. But i was just wired because it showed such great vac and was idle high or anything, It must of been such a little leak of air that was getting in that messed with the partial and even 4500-5000ish issue is gone.

But now i can get it up to 5500 with no issue but after that it breakes up we have try to street tune really quick but no luck on that so far. Any inputs?

Bailhatch

Idle surging is a classic vac leak symptom, so that's probably what fixed it.

Did you change the plug gap yet? Does it just go pig rich or something?

GTibunny16v

Im going to say new plugs with a .023-.025" gap. Sounds like you're blowing the spark out at peak torque.

bamboosted

no have had the chance to change the gap Im going to get some fresh plugs today or tomorrow and try a tighter gap. Hoping that will fix the last issue other than that it runs good.