sr20det rough idle and smoking

[josho]

I've been driving my s13 Blacktop with a built head, gt2871r turbo, walbro 255, ect..., stock injectors, maf and a stock Blacktop ecu for a few weeks. It honestly runs very good for running off the stock ecu. I can drive it around as long as I want and it never gives me a problem, besides running a little rich(not bad enough to smoke out of the exhaust).

But, of course, I wanted to get my car tuned and running properly. I bought an enthalpy tuned ecu that reguired 850cc injectors. So to finish and have it tuned right I needed 850cc injectors and a z32 maf. I bought new injectors and a used maf. With the maf, injectors and tuned ecu installed the car cranks up just fine but runs very rough. I swapped my maf with a known good maf and replaced the spark plugs with NGK BKR7E-11 gapped @ .30. Im not sure what the problem is but I know its getting too much fuel.

Heres a video:

[josho]

bump. please help

[asoomal]

Got a wide band?

[josho]

..no.. :/

Its the next part on my list.

[asoomal]

Too much fuel is probably your problem...

Take the plugs out and see if they're black and smell like fuel.

[turbotc]

this is a hard one with out haveing the car what color is the smoke and how old is your turbo your turbo could be bad your rings could be bad could be a bad maf or tune or injecter could be lots of things man start checking everything i just said and check for oil in the intake pipe or down pipe and do a compression check

[josho]

The motor and turbo are fine. The car only acts up when I replace the stock injectors, ecu and maf with the aftermarket injectors, ecu and maf. I could throw the stock stuff back on right now and drive it to all day with no problems on 12psi. It just runs a little rich. I really need to invest in a wide band before I start messin with the new stuff.. Not sure why it took me this long to realize that. Its my first build and Im doin it pretty much by my self so Im just learnin as I go. But Ill get a wide band and start from there.

[compactfean]

What is your fuel pressure at? When I swapped in my 740's my fuel pressure was a Tad high....but on stock injectors was not that big of a deal. With the bigger injectors it became a big deal.I got a tomei type l fpr and dropped it to 32 at idle, from 37 and made a world of difference

[josho]

What is your fuel pressure at? When I swapped in my 740's my fuel pressure was a Tad high....but on stock injectors was not that big of a deal. With the bigger injectors it became a big deal.I got a tomei type l fpr and dropped it to 32 at idle, from 37 and made a world of difference

Im not sure. I have the stock fpr on now. Ill get a fp gauge as well. Thanks for the help!

[josho]

I'm finally able to geet back started on my project car. I now have an aem wideband installed and a Nismo adjustable fpr. I'm going to install it and see what's going on now. Ill record the fp and a/f readings.
Any further advice would be appreciated!

[compactfean]

Also if it was running pretty rich before, look into your coolant temp sensor. It can reak havok on a tuned setup if it is bad. Update with some afrs and fuel pressure info when you get the chance.

[josho]

Nothing is wrong with any of my sensors. Like I said before, it runs great with stock injectors, stock maf and stock ecu. It only acts up when I install the 850 injectors, z32 maf and tuned ecu. I actually sold my last tuned ecu and sent a good e5 ecu to Enthalpy. I received it a few days ago so I know the ecu is not the problem.
My fuel pressure was set at 37psi. I cranked the car and it was still sputtering, a/f was at 14.9. I noticed that the a/f ratio was slowly going to the rich side so I turned my fpr down to 32. By then my a/f was ready 10-10.2. I turned the fpr down to about 24psi and the wideband still read 10. By then it was smoking out of the exhaust(smelled like fuel). I then unplugged the maf and the car ran the same. I could still rev it up, with some hesitation. So I plugged the maf back in, revved it up a little and shut the car off. Pulled the plugs and all of them are black, they were not wet or anything. And that's where I am so far.

[josho]

I had a z32 maf wiring write-up and it had one wire going to a chassis ground. Another write-up said to connect it to the maf ground wire, which would make 2 z32 wires going to one sr harness wire. My first way was, ground to chassis. I switch the chassis ground to the harness and now my car is in limp mode. Bad maf?

[compactfean]

No. bad ground. I have talked to jwt about this very issue and actually you can combine the 2 grounds as long as the ground is a clean solid ground. If I remember correctly, the maf ground goes to the grounds on the intake manifold, so you could run a new ground directly to there. (don't ask why, long story short, it does make a difference where it is grounded and it is best to keep your sensors grounded in the same area)

[josho]

I just tried that, no luck sir. It still has the 2500rpm revlimiter, wheather the maf is plugged up or not. I have a feeling its a bad maf. Can anybody confirm that, with the given information?

[compactfean]

Next thing I would check is if the maf has power. If so than id say its toast.

[josho]

This praly is a dumb question but... how do I check for power?

[compactfean]

Turn the ign on and check the black wire with white stripe for voltage with a multimeter. You can also check the behavior is the maf with a multi meter. I have cams and my motor is bored to 87mm and my z32 maf is at 1.08 volts on the signal wire (white wire). Depending on your mods, maf signal could be anywhere from .8-.9 v to 1.2 volts during idle.

[josho]

With ignition on my black/white wire reads 11.02 volts. Would it be possible for me to wire in my factory maf just to see if it will idle fine with that? Or will it be out of wack because my ecu is tuned for the z32 maf?

[josho]

I borrowed a known good z32 maf and that did not fix the problem. Its acting the exact same. Does anybody know where a really good wiring diagram is for wiring a z32 maf into an s13 sr? I have seen multiple write-ups and some are different then others.

[compactfean]

You can rather find the diagram on here our just give me the wire colors on both side and I'll tell you how to wire it.

[josho]

I don't know the exact order off the top of my head but these are the colors.-sr harness- black, white, black/whit. -z32 pigtail- white, black, orange, black/white

[compactfean]

”There are 4 wires coming from the MAF unit its self, 2 power the MAF,2 are the signal and sig ground. The dotted outline represents the shielding around the MAF SIG and SIG ground. The MAF gets is power from the ECCS relay and grounds though the chassis. B,C,D,E are these wires. ECU PIN 27 is B on the MAF, ECU pin 26 is D on the MAF. D/pin 26 is MAF sig ground. B/pin 27 MAF sig. There are two ground wires here please don’t get them confused, MAF sig ground and MAF ground.

B, MAF Signal (ecu input from maf) C, MAF Ground D, MAF Sig ground (runs in shield with maf signal) E, MAF Power”
Disregaurd the pin locations because those pins are for a 300zx ecu but this is off of another website and is specifically how that maf is wired in stock form in the z32's.

[josho]

Thanks for the info! Well I tried re-wiring it and I also installed another z32 maf that is said to be good. Its still doing the same thing. Is there anything else that would make my car have that revlimiter and run that way?

[compactfean]

No, that's pretty much the only thing that will cause that. The maf is pretty simple to test. Power-make sure the maf is getting power, ground-make sure there is continuity from ground wire to chassis and also continuity from ground signal wire to maf ground signal wire pin on ecu (look at ecu pinout) and last thing is signal. Check for continuity from maf signal wire at the maf to the maf signal pin at the ecu. If all of these tests come out good, then back probe the maf signal pin on the ecu and see what voltage you have coming in. if it is out of spec than you are safe to day the problem is not in the wiring and both mafs are bad.