I"ll make this as short as possible . . . . a few weeks ago we took my stock d16z6 motor out that had 145k on it, and I slapped in a fresh y8 block that had like 30k on it, but I still kept my z6 head. Before we pulled the motor everything was good . . . at WOT I was running rich, and while cruising I would run stoich . . . .
Now that we got my car running with the y8 block I was watching the gauge lastnight (I know it's not 100% accurate) and it was barely reading Lean. I got DSM 450's still in my car as I will be boosting as soon as I get this LEAN problem fixed. At -34 on my vafc I use to run stoich, but now it runs way wicked lean.

If I add fuel and take it down to -22 I can sort of get it into the orange, but what could be causing my car to lean out so bad? After we start it and let it sit for a bit it just eventually dies out like it's not getting enough fuel, but why would this all of a sudden just happen out of no place?

Any and all help is welcome . . . I would like to get bosoted tonight! I got everything ready for boost . . . I just need to isntall my turbo manifold, and intercooler and that's all.

I do currently have the walboro 255lph just so I don't leave anything out that might factor in with the Lean problem.

AIM:vtec92civic

Thanks Everyone!

 

I'm assuming you've got one of the a/f gauges that flips back and forth. It's not going to tell you anything. The only true way to tell if you're running rich or lean is by using a wideband o2 sensor. Until you get everything together and running for boost, I'd suggest putting everything back to "0" and wait until you can get dyno tuned. Just my $.02.

 

Well I wasn't even planning on getting it dyno tuned since the only place that has a dyno here is shady and rips people off. I self tuned my last setup and it ran perfectly fine.

If I zero everything off (if that is what you are saying) since I have dsm 450's I will run really really super rich! I think someone said I am running way rich as it is right now which might be why my car is acting weird.

 

You raised your compression ratio slightly higher with the y8 block. That's probably why your engine is running a bit leaner.

 

did I really raise my compression? It should be effected that much though should it?

just picked up some new spark plugs in hopes that they would help, but they didn't. Is there a way for me to tell if I am running to rich or lean? I am dying to get boosted, and I have all the stuff to boost, just trying to solve this fuel related issue before I boost.

Just noticed that the lights on the autometer gauge don't even come on at all only when you first start the car for like maybe 20 seconds or so, and then it drops off, and I can't even get them to liht up at all . . . .

Apex'i Turbo Timer reads 20.0 and is flashing which means i'm lean off the chart but they are both run off the o2 sensor so they are getting the same reading.

Someone Help me Get Boosted!

 

Maybe you need a new O2 sensor?

 

BINGO! I think you hit the money . . . . what we did lastnight was . . .

Took my friends 1 wire o2 sensor off his CRX, took my o2 sensor out of my stock exhaust manifold, we left it plugged into the wiring harness on the car, but we put his CRX o2 sensor into the manifold and hooked the 1 wire up to my a/f gauge and turbo timer, and that shit was running hella rich . . . . it was all over the place but for the majority of the time it was running really rich . . . . . the car was idling kinda rouch though even when I tried to lean it out or turn up the fuel . . . . . I think it was because at idle the car takes the readings off the o2 sensor to determine the fuel, but at WOT it reads off the base map in your ECU so I think it just might be the o2 sensor.

 

No check engine light???

 

The ECU runs in open loop (i.e. no fuel trim adjustments via the oxygen sensor) most of the time. This is because the stock oxygen sensor is a narrow band unit. It's only effective through a very limited range of operation--most of the time the signal it sends is worthless which is why most of the time the ECU doesn't pay any attention to it.

Assuming you're tuning with a V-AFC the general starting point for adjustment with injectors in the 450 cc/min range is -40%, but you really should hook it up to a dyno with a wide band oxygen sensor to get more precise readings.