Thread: Turbo gurus look; Stumped- help please

Heres the deal - been dealing with this problem for months now and i'm at the end of the line with my setup, it runs super rich and breaks up. Here is my setup and what I have tried to help fix the situation.

stock de
bc264
msd 75# topfeed
walboro 255
z32 maf
hahn 20g turbo
nismotronic ecu with a fresh map
Draw through- Yes, my BOV is recirculated.

On the first initial start up car runs and idles fine at 1k, but is pig rich. Black smoke from my side exit (exhaust). After trouble shooting and ruling out other possible issues, it was thought to be an issue with my harness (short somewhere maybe) causing my injectors to open wide and dump as much fuel as possible. (concluded this from checking injector clip wires, supposedly one wire will blink on current tester and the other wire gives a solid light. Blinking light means injectors are pulsing as they should. This is all correct information right?)

Anyways, just for the sake of troubleshooting we switched out z32 mafs and ecu's with a similar tune, no difference at all with either. I've tried different injectors, different resistors, pretty much everything except my external FPR as i don't know anyone with a spare i can borrow.

So I sourced a new clean uncut untouched harness, soldered my new JWT resistors and JWT injector clips to harness, (nice strong clean solders) all taped up appropriately. After wiring the maf we went ahead and put the harness in, car starts with the same issue. Still rich, not a clean rev (breaking up) not safe to drive. When I did bring it up the street, it obviously falls on its face at 4k.

After acquiring this new harness I had high hopes of that being the issue..well it wasn't and I'm back where I started.

Thats where you all come in. I want to see what you guys think, I ask for any thoughts, considerations, pointers. Anything because ripping everything out and re-doing everything again seems to be the only option I have. Kinda don't want to do that if i don't have too. This is my first build, i'm no pro, and i'm stumped.

Thank you.

Are you monitoring fuel pressure? Seems like you might be running too high of fuel pressure.

What fuel pressure are u running? Did u try leaning it out to see if it runs better? The diaphragm goes bad sometime. Did u also try a BN coolant temp sensor?

My apologies i forgot to add that piece of important information. I'm running 3bar.



CTS is OEM from nissan. Yes I did try to lean it out but no difference.


I'm going to start hunting for an external FPR to borrow.

Also check distributor. Could be not firing 100% sounds lime you've got the fuel down.

Easy enough, wouldnt hurt to try, ill do that tomorrow.

I would say revert back to side feeds and tweak the tune to accommodate. If your problem goes away then your injectors may be the problem.

On second thought, what are your a/f ratios at idle? Do you have a a/f gauge?

If not I would suggest taking your car to a smog station and get your exhaust numbers or take it to a dealer to have an exhaust analysis done as well as a diagnostics.

do the fans come on right away when you put the key in the ignition?
you sure the tune is for the correct setup?

Thought about it but side feeds are expensive..I like my top feed. These injectors are not the issue.

I have a Wideband but no bung for it yet. I don't need kne to tell me my car is running to rich to drive.

right but easier to diagnose when your troubleshooting like this and how will you know once you get it going correctly that you arent harming the motor?