Problems running the SR20...help please.

[encasemyheart]

I am looking at a car here in TX, the problem is it doesn't run too well, supposedly it runs very very rich, to the point of bucking and stalling.

I want to buy the car, but could you all tell me what I would be getting into? I hear the problem could be related to a bad wiring job...if so, aren't there only a select few wires that would have anything to do with running like it is? (MAFS wires, ECU grounds etc.)

I guess the problem could also be an 02 sensor, is it the same o2 sensor as the 87 300zx turbo? Or do you have to special order it?

Another possibility is the MAFS itself, but that is supposed to be a NEW 300zx MAF, so I believe I can rule that out.

I think TOPS I am looking at a brand new wiring harness (LAST resort) and maybe a new o2 sensor, what do you think? I have heard there is a quick way to check for the o2 sensor by just unplugging it, is this true? Details?

The ECU is also a NEW #62 ECU, so I doubt it could be a problem with the ECU itself.

Would you buy this car knowing that it doesn't run well? The motor is perfect with perfect compression and a rebuilt transmission.

I appreciate the help and I'm looking forward to joining the SR20DET community.

[SpeedRacer1]

In order to run a Z32 MAFS on an SR20DET you need something to convert the voltage, the stock ECU (#62) cant figure out how to run the car with that MAFS.

If you dont have something to change that voltage (SAFC, HKS AFR, FCon, Power FC, standalones) then the car will not run worth crap. I would fix this issue then see if you still have issues.

[encasemyheart]

The car has an SAFC-2, so I assume this is being used for that purpose.

But how would I verify? Go into the SAFC settings and see what voltage it is set at?

I am familiar with those actually, I used to have one. What should the voltage type be?

[SpeedRacer1]

You dont check voltage, you check the sensor in and sensor out readings. On an SAFC2 the sensor in should be 2, the sensor out should be 6 (for an S13 SR20DET, 5 for an S14 and S15 SR).

I would guess that the SAFC is what is causing the problems, if it isnt programmed right it can make a car run horribly.

[encasemyheart]

Wow, that would be awesome. Just in case, any other educated guesses? I am going to get the car in a couple days.

[encasemyheart]

And if it is the wiring harness, would I be able to test it by just running a seperate wire in place of the offending wire to see what happens? I'm guessing I can tell if it's a wiring problem immediately by testing the voltage across the wires with my ohmmeter...

And the o2 sensor thing, will unplugging it relieve the symptoms of a bad o2 sensor?

[SpeedRacer1]

Perhaps the MAFS is not wired properly. You can try using alternate grounds or see if there are wires that dont connect to anything.

If you disconnect the O2 sensor, the car will just run really rich at anything above idle. You might want to check and see if the O2 sensor is getting power from its brown (usually) power wire. Also TPS setting is important and can effect engine performance.

[encasemyheart]

I appreciate the help alot. I did a search on everything you mentioned and also am going to check the timing on the motor just for grins.

If there is anything else, please let me know, but between this and the coorespondence from heavythrottle about this issue, I think I have the problem licked.

It seems lik at most I'm going to have to do a little bit of checking wiring voltages and maybe picking up an o2 sensor or something.

[encasemyheart]

Okay, I just found out that the car used to run fine until after he put in injectors/turbo/safc in, so that isolates the problem it seems.