rb20 revving issues

[cashed240]

ok here goes. . i have a 90 coupe w an rb20 that i just installed, thanks to this site and others i wired it and it starts. . . and runs, but it idles a little rough and the exhaust smells like raw fuel. i put new ngk plugs in. i am using the z32 maf because wonderful OSAKA didnt send me one with the swap, anyway it wont rev past 2500 and is slow getting there. while it was running i unplugged the maf and it had no change. . . i tried the ka maf (rerwired accordingly) and still no change, idles fine, smells rich and still revs sloooooow to 2500. i HAVE searched and still cant find an answer. please gimme some direction to look and what to ck and how.

[Big Bronze Rim]

Well, the 2500 rpm limit sounds like a maf issue. Are you sure its wired correctly, as the KA MAF and z32 have different wiring. Also, there is no way to actually get the car to run right with the z32 MAF w/o some form of correction.

[slider2828]

Like he said.... Gotta get the right mafs for the right ecu. Input voltage for mafs signals are different for every ecu.

[slideways2004]

get a rb20 maf or get your ecu tuned for a z32 maf. after that, make sure you have it wired in correctly

p.s. i wish my car problems were this easy to solve

[cashed240]

i am sure it would run a little weird for the z32, but i mean this thing revs slooooooooow. . . . my sr would still rev fast to like 4000 with the maf plugged in and sittin on the valve cover. im not disagreeing with you guys but it seems as if its something else, it acts like its not running on all cylinders, how do i ck the coils and what resistance should they be? or i have also heard it could be the temp sensor. . . any way to ck that?

[slider2828]

Check the coils. You need to find the FSM though, it will tell you the specs of the coils. try www.zeryon.com I think they might have the RB manual, but I think they are all the same if stock 370cc? Not sure.

[onepuff]

What have you done to your fuel system?

[((sr)) kelly]

ill sell you a vafcII ... its the same thing as a SAFCII just with a vtec option ( ignore it) i used it on my dads Rb20det and it was fine...


install it and enter in the correct in/out settings and the z32 maf will work fine


PM for a price

[johngriff]

What part number plugs did you use?

BKRE Fits, but is wrong because it is ISO
BCPRE is Required because it is JIS.

http://www.rpsportengineering.com/nucleus/johngriff.php?itemid=19

[((sr)) kelly]

if you have not altered your in/out settings, then that is the issue...


you need to change them for the z32 maf to send compatable signals to the ecu

[cashed240]

Check the coils. You need to find the FSM though, it will tell you the specs of the coils. try www.zeryon.com (http://www.zeryon.com) I think they might have the RB manual, but I think they are all the same if stock 370cc? Not sure.
370cc COILS ??????? wtf. . um no other mods to fuel system besides the walbro, i now have picked up 2 different maf but havent tried them yet . .a E60 off a 95 dohc maxima and a N60 off a 92 sohc maxima, which one will be better?

[Big Bronze Rim]

Does lifting one coil at a time while revving make any difference? If you have one dead coil, it will rev the same as before. The 2500 rpm cieling though still screams MAF. Was any wiring done on the MAF circuit? If so are you positive of your wiring?

[Z U L8R]

common rb20 issue = leaky injector o rings. rb20's come with 270's and they are the same/interchangeable as sohc ka's. therefore if they are leaking, you can get the o rings for the top and o rings for the bottom from a parts store/dealership for a 89-90 240sx just get 6 upper and 6 lower instead of 4.

that may not be your issue, but check to see if you have any wet spots, fuel smell in that area.

other possibilities besides maf, are the coolant temp sensor, arching coil packs and incorrect plugs/gap

i recommend ngk3330's bcpr7es. they come at .030 gap which is fine if you're running stock boost. if you turn the boost up just gap em down to .028.

it also may not be a bad maf at all, you may have a vacuum/boost leak. check your intercooler piping/couplers/clamps

gl,
Dave =]

[cashed240]

i do realize that it is the maf sensor so i got the e60 and the n60, which is better? also i am using the bkr6e NGK's because they were listed on this site when i searched, should i get the BCPR's instead? not boost leaks or vaccuum leaks either.

[slider2828]

I think n60 is better? Isn't that what the skyline uses? I don't know the plug stuff of hand. Search for threads about the plus.

[cashed240]

it wires up the same right? blk to blk and wt to wt? cylinders 3 and 6 are wet with fuel so i assume they're not firing??? any way to ck coils?

[clark]

it wires up the same right? blk to blk and wt to wt? cylinders 3 and 6 are wet with fuel so i assume they're not firing??? any way to ck coils?

the way you check a coil is to pull the coil, slip an extra spark plug in there, hold it ~1 inch from your valve cover, have someone crank the engine, and see if it sparks and creates an arc to the valve cover. if you have a pussy weak as spark and it doesn't make like a ZAP sound, then your coil is shot.

if you have no one to help, you can kind of just rest the coil on your VC, crank the engine, and look through the little gap between your hood and windshield, that's what i did lol.

if you find THAT coil to be bad, swap in another KNOWN working coil (perhaps one from one of the other cylinders) and test again. this is to isolate the problem to be either a coil problem, or an ignitor/wiring problem.

sounds like you're almost there!

[cashed240]

replaced the 2 coils and rewired the maf. runs great except it now backfires at the higher rpms. i am runnig the purple label n60.