Rb25 Swapped S13 Won't Start, Ran Previously.

[5150DSM]

Aloha from Hawaii.

I have a S1 RB25 swapped into a USDM 240SX(S-13). The car has been up and running (badly) for several months on a Z32 AFM. I recently purchased a S2 RB25 AFM hoping to return the car to stock and alleviate the tuning problems I've had.

I wired the sensor in as per Paul33's diagram, combining the 2 grounds and then proceeded to return the car to stock fuel pressure and timing. The car cranks and tries to start but will not, unplugging the AFM has no effect on this condition. I am 100% positive that the meter is wired correctly. I recieve output voltage of .4 with key on and .6-.7 during cranking... Are these normal voltage values or are they indicative of a specific problem? As I said the car ran off the Z32 AFM with elevated fuel pressure and advanced timing, however, boost is limited to 5psi (.3 bar) and AFR's are quite lean making driving the car no fun and potentially damaging. Any help would be much appreciated, as I've tested everything I can think of and have no solutions.

Thanks in advance.

[stricnynel0s]

Aloha from Hawaii.

I have a S1 RB25 swapped into a USDM 240SX(S-13). The car has been up and running (badly) for several months on a Z32 AFM. I recently purchased a S2 RB25 AFM hoping to return the car to stock and alleviate the tuning problems I've had.

I wired the sensor in as per Paul33's diagram, combining the 2 grounds and then proceeded to return the car to stock fuel pressure and timing. The car cranks and tries to start but will not, unplugging the AFM has no effect on this condition. I am 100% positive that the meter is wired correctly. I recieve output voltage of .4 with key on and .6-.7 during cranking... Are these normal voltage values or are they indicative of a specific problem? As I said the car ran off the Z32 AFM with elevated fuel pressure and advanced timing, however, boost is limited to 5psi (.3 bar) and AFR's are quite lean making driving the car no fun and potentially damaging. Any help would be much appreciated, as I've tested everything I can think of and have no solutions.

Thanks in advance.

out of curosity your running some sort of Air fuel controller with that maf ? the z32 maf will not work properly if u just wire it up, it needs voltage adjustment, thats where an air fuel controller comes into play

[5150DSM]

out of curosity your running some sort of Air fuel controller with that maf ? the z32 maf will not work properly if u just wire it up, it needs voltage adjustment, thats where an air fuel controller comes into play

Yes, I am running one of the old 5 knob AFC's. The z32 required a lot of adjustment to run even as badly as it did, hence the reason I switched back to a stock meter.

[James_03]

I don't think the AFM is causing this and by the look of those return voltages you have it wired up correctly. I would hazard a guess and say that the poor afr's have since fouled the plugs up hence why it has difficulty starting.

Change or clean up the existing plugs, then switch the ECU over into diags and see if it throws up any error codes re AFM or otherwise. Should start with some replacement plugs but.

Edited July 31, 2008 by James_03

[VB-]

yeah the AFM shouldnt stop it starting. check if you have spark/fuel first and work from there

[5150DSM]

AFM bench tested bad. I hooked up power and ground and then blew air across the wire, the voltage stayed fixed at .56v

The guy I bought it from offered to exchange it so I guess I will send it back and put the Z32 back in. It will run crappy, but it will run until the other meter gets here. Thanks for the help, it's appreciated.