rb20 bogs in high rpms

[nekoabandoned]

ill go through the list of other issues ive noticed , maybe someone will be able to connect all of them.

1. when decelerating in gear engine misses or pops "alot" (i know a little is normal)2. sometimes its hard to crank , cold hot doesnt matter3. around 4.2 - 6k the motor revs but falls flat on its face 4. i seem to be getting blow by in the upper rpms ,( although it also kinda looks like the smoke i saw when the charge pipe blew off..) 5. turbo,compression,injector seals,fuel pressure all good

*edit* also the idle is high (1.2k) with the iacv screw all the way down.

any ideas?
Modified by nekoabandoned at 3:52 AM 10/4/2009

[MRNA]

Double check your timing.

[MRNA]

*It sounds over-advanced.

[nos487]

Make sure TPS is set.

[maryjane]

timing.......

[nekoabandoned]

the tps is set correctly , i will double check the timing when it stops raining. any other ideas?

[Yellow4g63]

ill go through the list of other issues ive noticed , maybe someone will be able to connect all of them.

1. when decelerating in gear engine misses or pops "alot" (i know a little is normal)2. sometimes its hard to crank , cold hot doesnt matter3. around 4.2 - 6k the motor revs but falls flat on its face 4. i seem to be getting blow by in the upper rpms ,( although it also kinda looks like the smoke i saw when the charge pipe blew off..) 5. turbo,compression,injector seals,fuel pressure all good

*edit* also the idle is high (1.2k) with the iacv screw all the way down.

any ideas?

Modified by nekoabandoned at 3:52 AM 10/4/2009

how many inches of vacume do you pull at idle?

[nekoabandoned]

18-19 psi

[rb25det250sx]

boost leak would cause a studder...but i think it should be an even 20--. mine is at 15 so your fine. but timing and TPS might be bad to.

[Yellow4g63]

18-19 psi

Your making that much at idle!!!! OMG j/k I know u mean inches. It should be in the 20's may be a boost leak some place. What kind of boost gauge is it? Electric? mechanical? autp crapper?

[nekoabandoned]

auto meter and yeah sorry XDum it does seem a little low

[nekoabandoned]

ok so timing is perfect now... and now it runs like poo all the time haha*edit*seems my o2 went bad, think that might be the cause o.o

[Yellow4g63]

Ur ecu throwing any codes?

[nekoabandoned]

nope 55 o.o , ok so i volt tested the o2 . it has a good connection on all 3 wires but it doesnt get a 12v and the ecu doesnt send the ground signal...

[nekoabandoned]

i will seriously paypal money to the person that figures this out.

[rb25det250sx]

check the pins and the exposed wires... check and make sure your ECU is grounded correctly and not on paint, but bare metal. that will make a difference.

[nekoabandoned]

theres no exposed wires, the ecu grounds are grounded.. you can put the ecu out the window and its not going to make a difference.as of now i ran a new switched 12v to the o2 connector and a new ground (115) for the o2, low and behold im not getting a signal from "any" of the o2's i have laying around.gunna try to see if i can find one around town tomorrow

[rb25det250sx]

just invest in a wideband...your gonna need one anyway.. narrowbands are junk. even the stock one for the car.

[mello88]

How are your coilpacks/plugs? Many RBs have the issue with the packs shorting out at high rpm, sending the arc to the head instead of the plug. Check your plug boots to see if any are cracked. Does it randomly miss at idle?

I don't think the problem is related to your O2 sensor. Reason is at high RPMs the ECU runs in an open loop mode. It ignores the O2 sensor and runs only off it's internal maps and primary sensor input (maf, cas, etc). O2 is really only used at idle and cruise to fine tune the afr for clean burn. Anyway if you really want to test it out, you should measure continuity of the wire from the ECU connector back to the o2 sensor plug. I assume you know how to do this with a DMM, just measure the ohms of the wire from the ecu connector to the o2 plug with the ecu connector unhooked from ecu and the o2 connector unhooked from the o2 sensor....

Always a good idea to go back over the basics, check for boost/vac leaks, check your base timing, check plug electrodes, etc... GL

[nekoabandoned]

*update*i ran new wires from the ecu to the o2 ( just in case) and also bought a new o2, heres something to add to the list.when i rechecked the timing i have to put the cas almost all the way clockwise just to get to 15*. if i put the cas in the middle its no where near the marks...



ideas?btw yes im using spacers and no the tabs are not broken off
Modified by nekoabandoned at 2:13 AM 10/9/2009

[danman04x]

are you using the wire off the harness to check timing or a spark plug wire.. When i tried using the wire off the harness it was giving me incorrect numbers.. I too had the timing way off until i used a spark plug wire and checked timing that way..The car felt very sluggish but now its all good.. Hey mello88 i have a random miss at idle and cant figure it out.. the miss goes away once i touch the gas. I havent been able to figure it out..let me kno if you kno anything

[rb25det250sx]

should be a black and pink wire that you use right off the ignitor. it goes to the 1st coil pack. use that.

[danman04x]

thats what i originally used and it was giving me incorrect numbers..The best way i think is to use a spark plug wire..there are threads on how to do it

[nekoabandoned]

thanks guys but i know how to check timing XD i use a plug wire :Pany other ideas?

[dtowngoalie]

Timing looks very advanced, timing is supposed to be set at 650 rpm give or take 50. Not 1.2k, the ecu has more advanced timing for that.

[nekoabandoned]

oh yeah i figured out the timing issue.. the crank was advanced a tooth.. weird right XD but now thats fixed , its still doing it.

[WizardBlack]

If engine timing was off and you fixed it, you need to recheck your vacuum, etc.Having it idle high and the IACV is maxed in adjustment sounds like a vac leak.

[DustinZ]

Sell It and buy something more reliable like a rotary or a mitsubishi.

[Yellow4g63]

My RB also has this problem the idle is really high so I'm going to tackle it on Monday and see if get it to idle like normal so I can set the timing. It's been a while for me so it might take me the whole day to figure it out lol.

[nekoabandoned]

yeah there was a vacuum lean on the tps shaft XD