HELP WITH MY RB25!!!!

hey, im new on this forum. ive been in love with nissan's for years. when i was 15 i saved put for months to by my first project car, a 1982 datsun 280zx. just turned 18 and figured i would but another nissan. i bought an 1990 240sx with a rb25det. when i bought the car it ran beautiful besides being a little rich from the tune. 2 weeks ago itjust desided it didnt want to stay running. ill turn the key, fuel pump primes, turn it over, it running okay for like 3-5 seconds then dies. but if i turn it over and give it gas it dies right away. people keep telling me maf's, fuel pressure, and plugs. idk what to do or where to start with this car. anyone having the same problem or can point me towards someone who is near milwaukee that can help me. willing to throw some cash at someone to help me get this thing going again.

Thank you very much
Ian

sounds like a big air leak maybe. check all your intercooler pipes

Post an introduction please.

did you but this off some guy named carlos from delavan?

I agree with the vacuum/boost leak theory. Also check that all the sensors are plugged in.

Ill check all my ic piping tomorrow. And yes I did by if from at carlos dude from delavan. Is there some back ground information I should know about the car? When I bought it, it ran amazing. Quick as hell, just ran rich and now all of a sudden I can't even get it to run. Is there any other things it could be? I'm getting spark from all coils, fuel pressure is pretty steady. I cannot figure it out.

maybe try new plugs too. never hurts since you dont know when they were changed last.

Series 1 or series 2 rb25? Why is it tuned? Who tuned it? How long have you had it/been abusing it?

Did you ever check to see if the IACV is working correctly? The way you are stating your problem, it sounds like its dieing while idling. If you know someone with another MAF try using theirs and see if the issue goes away. Also, check the basics, compression, spark, and fuel. Bad compression will kill it, and so will a leaky/stuck injector. Could also be a vaccuum leak. Check all the vaccuum lines, and the intake mani for open holes. How long ago was the car running "amazing"?

oh, and one final thing. How much did you get it for?

The car should idle even if the iacv is dead. Sounds like when you open the throttle it dies too. Put a vac gauge on it and tell me what it reads at idle.

Unplug the Maf and see if it will idle.

ONEwideS13 wrote:

Ill check all my ic piping tomorrow. And yes I did by if from at carlos dude from delavan. Is there some back ground information I should know about the car? When I bought it, it ran amazing. Quick as hell, just ran rich and now all of a sudden I can't even get it to run. Is there any other things it could be? I'm getting spark from all coils, fuel pressure is pretty steady. I cannot figure it out.

did you or anybody else messed around with the settings on the ecu or anything like that?

The factory RB ecu can't be "tuned". FWIW.

from what i heard the car was tuned with an APEXi computer and the previous owner removed the battery out of the car when it was sold, after that the car ran bad. so i would assuming when the battery was removed it lost the tune on the computer.

my .02

If it has a power FC installed to replace the factory ECU it won't lose any settings. If it has some piggyback shit installed, it's very possible.

Who originally built this car?

It has the apexi power fc but he also had an safc connected which isn't needed with a full stand alone. I had one of my buddys look at tuning it once the safc was out and he can't figure out the powerr fc because its such old softwear, And that carlo's dude said he built it when he went to uti or whatever in like new jersey, I don't believe him at all. Its a series 1 rb25. I've had it for like a month now, and I haven't really beat on it to much. Unplugging the maf doesn't do anything different. And ill hook up a vac gauge and check and do plugs if they are bad and check vac lines and compression. asap. My fuel pressure is solid. I have a gauge right after my fuel filter. On start up it goes to like 45-46 and at idle it is like 35-36.

Do you have any mods on the car? If you don't just take that safc out and do a hard reset on the PFC to put it back to stock parameters.

why would you buy a power fc then use an safc? anyways still kinda sounds like an air leak. but it could just be the settings on the safc if your guy was messing with them. verify that your in and out numbers are correct on the safc.

The safc is no longer in the car.

Is there anyone who is good with rb's that is close to milwaukee that can come and look at the car in person and try to help me figure this out?!

Was the SAFC in the car when it was running right?

It was in there while it was running good and like shit.

That sucks. Google the part number on your MAF sensor and make sure it is the correct one for the car. I wonder if they used something else and tuned around it with the SAFC then added the PFC later.

They are the z32 maf's. I've read other shit on forums where people say they are garbage. Ik someone who has extra's so ima try those and see if they work out.

If the PFC isn't set up for a Z32 sensor it's not going to run FYI.

Yeah Carlos never did build it. He got it like that from some guy over at uti. Did you check compression changed plugs vacuum leaks. Double check the wiring they might. Check to see if your sensors are getting power.. I hope you didn't pay 7k for it.