2 rb20 issues i cant figure out

[91ka24]

Alright guys, i can't figure this one out. So about a year and a half ago i purchased a rb20 from a local guy, no harness or ecu. Got a wiring specialties harness and a good ecu. The engine came with adjustable cam gears, i also installed new splitfire coil packs, z32 fuel filter, and walbro 255. The issues that I'm having is if the engine is at operating temp and at 20 deg timing, with cas in the middle, the car idles great, but the second u start to boost its like its hitting ign cut, but if i advance the timing it will boost just fine, but have a miss at idle. Now I thought maybe the previous owner may have had the timing off, well about 6 months ago I blew the hg, so I purchased a tomei hg, as well as had a 3 angle valve job, new guides and seals and a few other misc things. Put the adj cam gears on the 0 center mark, timed, and it still does the same thing. Now i know when installing different cams u have to degree them in, do u need to do that with cam gears also?

Problem 2. For some reason I am gettin alot of crank case pressure. The way i have the pcv system hooked up is a hose from that check valve on the intake to the intake side valve cover, then a hose from intake vc to exhauste vc, then to turbo inlet tube. But if I pull my cold pipe off there is oil all in there, in the intake and.all in the throttle body. I was thinkin pcv but when i called raw brokerage shawn said that the pcv valves on the rb20 or more of a breather then a valve. Did a compression test yesterday with the engine cold and they were all around 120-130. Any ideas???
Thanks

[91ka24]

Damn 75 views and nothin?? Lol alright just got done doin a compression test at operating temp and these are the numbers

135, 120, 125, 115, 135, 130

So I'm pretty sure it needs a rebuild and this could be the cause of the excessive blow by. But could that cause the ign problem as well?

[91ka24]

alright, few more things. ecu is throwing no codes, with the cas in the middle, timing at 15deg, idle is great. get into WOT and it just cuts out thru the whole power band. i tried adjusting the tps, no change. plugs are gapped down to .25. im running out of ideas. could ignitor cause this, or maf possibly? i found a thread on gtrcanada where a guy had the same issue, and his ended up being the knock sensors, but his ecu was throwing a knock sensor code.

[Yellow4g63]

Spedo hooked up? Check your grounds? Do u have nissan data scan? check the tps voltage and see if your with in range. Check for vacuum leaks, did you hold the throttle open when you bumped the motor? Change coolant temp sensor if it's bad (You would check the sensor in nissan data scan). The oil in the system is normal if your have it hooked up like the factory with the breather hose going to the intake side of the turbo.

[91ka24]

Speedo is hooked up, I have Tripple checked my grounds. I do not have any scan tools, wish I did though. Now if I start the car I have to pump the gas a few times to get it to start, but if i un hook the cts it fires right up. I know if the cts isn't hooked up it will pull timing, but would it still pull Timing even if its not at the correct voltage? I was gonna check voltage on tps next, as nothing changed with the car when i adjusted it. And yea the.comp test was done with wot.

[datsunnazi]

welcome to the RB20. Mine did the same thing. I just lived with the CAS turned all the way over and the little miss at idle. I made 250 whp with a VG30 turbo on 16 lbs. and a Mines ECU. Never had any issues.

[91ka24]

tried another ignitor chip, didnt fix the problem. i noticed if i give 50% throttle it does not cut out, but as soon as i go WOT it cuts out. gonna check tps friday

[Yellow4g63]

Speedo is hooked up, I have Tripple checked my grounds. I do not have any scan tools, wish I did though. Now if I start the car I have to pump the gas a few times to get it to start, but if i un hook the cts it fires right up. I know if the cts isn't hooked up it will pull timing, but would it still pull Timing even if its not at the correct voltage? I was gonna check voltage on tps next, as nothing changed with the car when i adjusted it. And yea the.comp test was done with wot.

Did you hook up the cranking signal from the dash plug to the ecu? I think it's the orange wire in the S13 dash plug. Do you have your OEM coil packs? maybe those splitfires crapped out already (seen it happen before). you can use the 300zx CTS. Do you know if u have a Auto ecu or 5speed ecu? if it's a auto ECU the timming needs to be set @ 20 deg. My swap came with a auto ecu and would run like crap when I set it to 15 deg.

[91ka24]

well its got a wiring specialties wiring harness so it should all be correct. i have been having this problem even when the splitfires were new, and they are only about 6 mths old. a z32 cts doesnt work, i have already tried that. the rb20 CTS is yellow where as the z32 is blue. i purchased one at auto zone and the plug on the harness wouldnt fit on the sensor. the ecu number is 00, i will google that and see if thats a 5sp ecu. but even if i advance the timing to 20 it misses at idle, where as when its at 15deg it idles perfect.

[91ka24]

just looked thru the part numbers and the ecu is a r32 rb20det mt 4wd ecu. so i dont think thats the problem

[Yellow4g63]

I got mine from the dealer and it is a Z32 CTS bolted right in and plug and play. http://i137.photobucket.com/albums/q211/Bluerb240/240%20stuff/07-12-08_2140.jpg

[91ka24]

ya that one looks different then mine. your has one raised part on it, where as mine has 2 (if that makes sense)

http://i263.photobucket.com/albums/ii138/91ka24/IMAG0538.jpg

[91ka24]

here is a closer view of the hump things im talkin about. the 2 raised things in the middle of the sensor. this is a oem CTS from raw brokerage

http://i263.photobucket.com/albums/ii138/91ka24/rb.jpg

[Yellow4g63]

Did your RB20 front cover say RB20 on it? If I remember right the last years didn't have it so might be why the plug is different.

[fliprayzin240sx]

Do you know what fuel pump you have? Maybe its a stock pump and not keeping up at WOT. Also, when you changed the HG, you sure you didnt stick a tooth somewhere when you intalled the timing belt? Might be off somewhere.

[91ka24]

The motor didn't come with a front cover :( and I know the timing is dead on, it did this even before I did the hg. And i installed a walbro 255. I can tell its an ign issue not a fuel. It still goes to red line just cuts out the whole time.

[Yellow4g63]

Do you know someone with a RB25? try and swap coils with them and see if the problem goes away. If your RB20 is the older plug style it might not fit tho.

[91ka24]

It's not a r31 rb20 which have diff plugs. I really don't think its the coils though

[Yellow4g63]

Damn If I were at home I'd send you some coils, I had a set from a Redtop RB20 that couldn't fit my silvertop because the plug was different but I could fit my friends RB25 coil packs.

[91ka24]

It just hit me to try the maf. I was thinkin since I was having so much blow by that maybe the maf sensor is covered in oil. I'm narrowing it down to tps, maf, cts, or knock sensors. Grrrr

[Yellow4g63]

Might not be the knock sensor, I know when my friends 25 didn't have them plugged in the car just ran slow all the time time.

[91ka24]

Well I was reading on skyline australia that a guy had a similar problem as mine and it was his knock sensors. But his ecu was throwing a knock sensor code. As soon as he would start to build boost the ecu would just pull timing.

[Yellow4g63]

did you post over on nico in the RB section yet?

[speedfreak90]

hey close your spark plug gap up i have a rb20 with a similar set up i run my plug gap at 18 to 20 thousands, but when i had my gap at 25 it did something to what you are describing.

[91ka24]

Man that's a really small gap for stock boost, I would rather find the problem then cover it up, ya know. And no I havent posted on nico yet, I need to though

[91ka24]

Just checked tps. With throttle closed its at .6 volts at WOT its 4.4 volts

[Yellow4g63]

It's close I think it's supposed to be ..45 - .50 closed and 4.1 open.

[91ka24]

Tried my friends tps and maf. Still no fix :(

[Yellow4g63]

Did you try his ecu too? if it's a rb20.

[P-Funk alot]

the difference in compression between cylinder 1 and 4 could be causing you a miss at idle. i have a rb25 that is stumbling at idle and ive narrowed it down to the rings on cyl 1. do a leak down test with compressed air across the board and see if you get air out the crank case, intake mani, or exhast mani.

[91ka24]

I'm gonna try my friends cts and ecu today, and if that doesnt fix it the car is gettin pushed off a cliff. I even gapped the plugs down even more to .020 which is rediculous.

[two40guy]

Any luck dude? My car is doing the same fucking thing and I'm about ready to set it ablaze

[garetth]

Any luck dude? My car is doing the same fucking thing and I'm about ready to set it ablaze

Only read through half the posts so sorry if i repost some information. Get some BCPR6ES-11 and if your not going over 12 psi then keep the stock 1.1 gap if running more gap to 0.8. Check the resistance of the coils and they should be between 0.6-0.8 Oms I believe. Make sure your coil packs are getting a solid connection, Here is a link for a factory fix HERE (http://forums.nicoclub.com/factory-coil-pack-fix-t503235.html)
Try disconnecting the o2 sensor and see if it makes a difference, Make sure your maf is wired right and spray it with some maf cleaner, Would be a good time to change afm filter also. See if the ecu is also pulling any codes to and if you have an afr gauge monitor it while getting the break up.

[91ka24]

Well i replaced the stock rubber turbo inlet tube, I made an aluminum one, and that helped some. Also bought some ngk's, but it still does it a little. I'm really thinkin cts, but raw brokerage, Fr sport, and jgy don't have any. I'm really not thinkin coils cause there new, and ecu isn't throwin any codes. I'm gonna try and try a friends cts and see if that works. Will keep yall updated.

[garetth]

Well i replaced the stock rubber turbo inlet tube, I made an aluminum one, and that helped some. Also bought some ngk's, but it still does it a little. I'm really thinkin cts, but raw brokerage, Fr sport, and jgy don't have any. I'm really not thinkin coils cause there new, and ecu isn't throwin any codes. I'm gonna try and try a friends cts and see if that works. Will keep yall updated.

The turbo is probably on it's way out the door :bash: Last year i had the stock rb20 turbo on and it would studder soon as i tried giving it gas and boost came on and i thought it was the coil packs but then i just tried going through the studder and the exhaust fans just blew off and went through the exhaust and the studdering went away and i just put a new turbo on and it was fine.

[two40guy]

god who invited garetth.. lol thank god rb turbos are a dime a dozen. i kinda thought about it i havent checked my turbo for shaft play in quite some time, and i was driving the piss out of it when it started. shit.

[Lethal240SX93]

Still positive the cutting out isn't fuel related? Have any kind of AFPR? I know some people that had a 255 pump and stock FPR with similar issues. The pressure from the pump is too high and basically the fuel blows by the injectors, mostly noticeable at WOT where fuel demand is high.

Check this thread out http://www.240sxforums.com/forums/rb-tech/35902-why-you-should-get-adjustable-fpr.html

[91ka24]

I have an aeromotive afpr