04RedGTO

So I went to the dyno tonight to get a few baseline runs and spray runs with a wideband.

After a little tweaking by the guy tuning it, I put down 306 torque and 292 hp ON A MUSTANG DYNO. I have a basically stock 04 6 speed car. Ok cool, a/f is a nice level 12.9 at the tail with a wideband. Timing is still set to stock level. Onto the spray.

So I am spraying a 100 shot dry through the nitro dave halo bar. I de screened my maf. Bottle pressure was good...in the 900 area. Window set to 3000 to 5900.

For the first run we are really watching it. Start at 2000 rpm in 4th gear...all is well. Hit 3000, the spray kicks on, and the wideband at the tail instantly reads lean...like 15. I IMMEDIATELY shut it down.

We check a few things, everything seems well. We run it again. This time bottle hits nice, but same thing, it shoots up lean so we shut it down.

Pretty frustrated at this point IDK what to do. The guy who is tuning it lets me borrow his handheld scan tool...one of the nice expensive ones that can monitor all kinds of things.

We take the car out on the street and make a few baseline runs on the motor and log the results. A/F is reading good....in the mid to high 800's (860 area) on the voltage scale. It says that the actual a/f is in the 11.5-11.8 area. Not pulling any timing...all is well.

We arm the system, and monitor the same things. We start off at 2000 rpm in 3rd. At 3000 it kicks well. I shut it down at 4000 just to review the logs with the guy. Everything looks good. We try a few more runs each time adding a little more rpm to the amount of time I am in it. No timing is being pulled, the iat gets real cold showing the spray, the a/f stays in the high 800- low 900 (903 range) range. After we get pretty comfortable we make a few 2nd gear to 4th gear pulls. Everything feels good.

Ended up going through the whole bottle.

Now, any ideas what could have been causing the issues on the dyno, but not on the streets?

So confused and lost...don't know where to go now.

Also, on the motor runs on the dyno it was picking up some false knock at around 4500 to 5000 and pulling timing. On the street it was not.

Also on the motor and spray runs on the street. The timing would start in the 16 deg range at 2000 rpm, and slowly taper up to a high of 22 at around 5000 rpm, then would fall back to 18 to 16 by redline.

Z284U2TRY

iTrader: (5)

using the voltage from the o2 is not the a/f you think it is.
I use to tune by voltage 10 years ago i am thinking 940-950 was the target area.
The maf is not getting the n20 correctly.
You may want to try nozzle placement.

04RedGTO

I agree with you on using the 02 voltage is not the most accurate way of doing things BUT if I was doing on the street what I did on the dyno the voltage would have shown it. The voltage actually increased when the spray hit on the road...that tells me that the maf knows it is there and is trying to compensate.

IDK how skewed my thinking is here, but I know that 850-860 is what I was running na, and on the dyno this equated to 12.9 or so at the end of the tail pipe. This should have been 12.5 or so pre cat. So I figure if I spray and it goes up to 900-910 I should at least be 12.0 or so pre cat.

I cannot adjust nozzle placement...I have the halo kit that fits inside of the stock air box.

After talking with Chris at nitrous outlet today I am going to make a run and immediately shut the car down and pull a plug on each side to read it. I am also ordered a wideband 02 sensor which I am going to install before I spray again.

Z284U2TRY

iTrader: (5)

Does your car have cats?
Do a search on nozzle placement for dry kits.

Nitro Dave's Nitrous Outlet

iTrader: (25)

With the halo design the intire airbox should be seeing a heavy fog. How do you have the halo bar mounted in the aibox?
Dave

04RedGTO

Ok did some diagnosis and figured some more out.

To start things I bought an aem ugo wideband and installed it right before the cat on the drivers side.

They we went out and did some na logging.

When running na the a/f is a constant 12.5 to 12.9 under full throtle. All is good there. Timing peaks at like 22 at around 3500 I believe then backs off to around 17 at redline. Do not seem to be getting any knock retard.

Then we did a spray run. floored it at 1000 rpm in second. Once the spray hit it went instantly lean. Made sure it was not a spike, then I let off.

We thought maybe the maf was bad. All the wires are in good shape and intact, but to be sure we swapped maf's. Tried the spray again. Same deal.

Is there any way that the tuning could have tuned the maf out or caused it not to read properly? At this point, that is all I got. The car runs good na...real good.

Is there anything that we could have done that would cause the maf not to compensate? If not, at this point all I know to do is load the factory tune back in, spray it, and see what happens.

04RedGTO