rb25det probelms cant find answers

[jdms13VA]

ok so recently i bought a s14 with a rb25det with a built bottom end and head along wiht greddy intake manifold and fmic and full exhoust. drawbacks are..... stock injectors ( only run car on factory boost with boost controller turned off , on 5psi) my oil pressure is at 50psi normal driving and 75psi in boost and my afr is 14.9 driving normal and 11.2 in boost..... i have checked for boost leaks. checked all vacume lines, checked timing and i have replaced knock sensors along wiht harness. know my car when i drive it it drives perfectly fine if i shift before 2500rpm but if i mat the pedal to the floor it feels like it hits a barier and doesnt want to rev fast nor does it want to move its just a slug in boost. idk why its doing that nor can i find a problem. then for a while it was cutting off at stoplights or whatnot unless i held the throttle down enough to sit around 1200rpm or so. but i replaced spark plugs also thinking it would help and went to a colder plug (bkr7e over the ones in the car that were bkr6e) and it idles a little better and drives smoother but still doesnt drive right. it still hits a barrier when entering boost and its not everytime sometimes it has some pull but still not alot. please help idk what else could be wrong i was thinking maf sensor but im not 100% sure.


FORGOT TO MENTION CAR IS A SERIES 1 RB25DET. AND IS RUNNING A SERIES 1 MINES ECU ( DOESNT HAVE A LED LIGHT IN ECU TO RUN CODES NOR DOES IT HAVE THE DIAGNOSTICS SCREW.) AND I DONT HAVE A CONSULT READER TO CHECK CODES AND THE FACT NISSAN WANTS $100 TO RUNA DIAGNOSTIC AND TELL ME WHAT THE CODE IS. NAD ID RATHER SPEND $100 ON WHATEVER IT IS TO FIX IT.

what im trying to figure out is what you all think could eb wrong wiht it based off expeierience becouse i am a sr guy by nature and rb's are all new to me so i dont know to much about them or the probelms people encounter with them but i have been searching and searching and searching for answer but have come to nothing solving the prob
i know for a fact im trying to buy 550cc injectors and a 300zx maf and get my car tuned ona r32 rb20det chipped ecu but im trying to findout what the probelm is first. any opionn or help is greatly needed thanks

[l0nestar]

Check for codes.

[jdms13VA]

forgot to mention..... im running a series 1 mines ecu on a series 1 motor and the sad thing is. i dont have a consult reader. and my ecu doesnt have the led light to blink the codes so tis kinda hard thats why im asking on here. alsop the fact noone in my area has a rb25 in a 240 and the only person i know that has one has a series 2 in a s13. so i dont think it would do any good asking to use his ecu

[jdms13VA]

ok so i checked for vacume leaks and found a whole in the tube running into my cold side chargeipe, the line that goes right into the chargepipe before the throttle body. ran better but then maf went out completely maybe replacing the maf will fix all my problems

[RustspecS13]

I had a problem with my rb20 where the smoother you were with the throttle the higher rpms you could go. You could drive around nicely and be ok but if you got agressive with the throttle it would just buck and backfire. It ended up being the ignitor was going bad.

~Alex

[dazarooney]

I had a problem with my rb20 where the smoother you were with the throttle the higher rpms you could go. You could drive around nicely and be ok but if you got agressive with the throttle it would just buck and backfire. It ended up being the ignitor was going bad.

~Alex

Same here. Luckily I have a friend who looks after any problems with my car and he fixed it.

[l0nestar]

Pick up a stock ECU from the Classifieds thread. Toss the Mines ECU.

[jdms13VA]

yes that is exactly what mines did! smooth under normal driving and easy into the throttle but if i floored it . it would hit a barrier it would buck sometimes but not often and yes im bout to ditch the rb25 ecu in general and get tuned ona rb20 ecu thats chipped cuz then i can atleast have it tuned this time around but the mines ecu is junk.... def dont like it. but thankyou for the advice and help ima replace my ignitor next if im still running into problems

[l0nestar]

The Mines ECU is not 'bad' per say, unless you know the exact engine configuration that the rom was built for, and you can run the equivalent of Japanese 'Premium' petrol. I think the closest is 101LL AvGas. I would love to get a copy of the rom dump though.

[jdms13VA]

i see what ur saying becoue when its cold outside my car hauls a** but once it gets to opt temp it starts pulling timing and s*** i think becouse it cant keep up with the fuel map on 93 oct

[jdms13VA]

ok so i replaced all knock sensors and t he maf sensor ! and still am having problems! the car still doesnt hold idle on its own..... and in 90 degree weather when it hits 0psi vac it starts to pull timing and the egt's shooot through the roof to around 1350-1400 when at like 4k rpm...... wierd thing is when i first start it up in the morning on my way to work i can put it on 14psi and it pulls like a bat out of hell wiht zero problems and doesnt show a single sign of something going wrong but then once weather picks up all the problems occer. also wanted ot add. car wont hold idle on its own i have to hold the gas around 1200k rpm all the itme so it doesnt cut off at lights and such
WHAT COULD BE WRONG!! Ahhhhh

[jey_253]

Ever verify timing with timing light?

[jdms13VA]

that i have not done yet but would it drive extremely well when first started if the timing was off? like car runs top dollar once started up and drivn but after about 10min the problems start to happen. im going to check timing 2morrow morning and make sure tis at 15 degress btdc. and if it isnt im going to set it at 15 degress and hope it fixes my problems

[RustspecS13]

Check your coolant temp sensor. Its the only sensor that tells the ecu the engines temp and could be your problem.

~Alex

[flatrate]

does the car have a Cat?

Exhaust plugged? calasped flex pipe plugged cat etc

[jdms13VA]

cat is deleted its like a simulator pipe on there so it apears to have a cat but in reality its a straight test pipe. but im leaning towards the temp sensor being bad so im going ot replace that know and see if it solves my probl;em cuz the past week everytime i start the car and just take off its a pure rocket but after 10-15min of driving it starts to pull timing and have problems when in boost and high egt's . even though my temp gauge doesnt go above 1/4 the way up!

[jdms13VA]

also checked timign and it is at 15degress like it should be so like i said im leaning towards coolant tewmp sensor as well! thanx for all the help will be sure to keep everyone posted!