Why Tuners Hate 60lb Siemens Deka's

[mic]

I'm sure he will cross reference but idle quality improved when an unsaid few worked on my car. Most noticable improvement was the lack of 'hunting' on decel.

Danny....much appreciated input.

hunting, sweet as I have 2 try this. cheers headsex.

[IH8TOADS]

mate can you define " hunting on decel " ?

Would say, specifically, the revs would hang when you lifted your foot at say, 50 - 60 kph?

Yes as you described and engine braking is delayed. As Danny mentioned fuel is added despite the pcm not knowing...root cause is scaling and why I noticed a difference between tuners.

[Headsex]

that decel hunting you so call can be address by disabling the Decel Tip-out.. setting it to 0

=)

Also guys, this isnt a Drilled injectors vs Deka injectors.

I just highlighted this fact that when shops scale injectors, they do not alter the Battery Offset table, which essentially is the open time. Deka's dont need as much "opening time" as Bosch injectors. This is why people say deka's suck because they have sh*t idles due to being so rich, or not having enough pcm resolution to adjust

Previously, Setting up this table would have been impossible without the specification sheet from FORD Racing. But the value file that sct provided was "close" to whats required, albiet for only 39.5psi, not 4bar. So it still required modification to the slopes as well as the Offset battery comp table.

Also keep in mind, the High slope and Low slope may need some alterations to suit your application. They are a GUIDE only. But it should be withing 10% of commanded AFR's.

My car, since I am running united 100, has 10% ethanol. Being that, I have also altered the "Stoich AFR ratio for lambda 1" under the Fuel scalars to 14.1 instead of 14.64. My High slope scaler is also around the 0.0192 mark (not 0.0203). As it ran a little leaner than commanded AFR.

[_Spin_]

Yes as you described and engine braking is delayed. As Danny mentioned fuel is added despite the pcm not knowing...root cause is scaling and why I noticed a difference between tuners.

My car has drilled injectors ( FWIW ) and does this. It really sh!t`s me..

[Headsex]

Wouldnt say its the drilled injectors doing it..

Under "Accelerator Pump"

Change the "Accelerator Pump Filter for Tip out" to 0.000000

[R-SPEC]

I remember when the scaling was changed on my car with my Dekas, we could all smell the difference in the exhaust as soon as the car was started. It was quite an incredible eye opener!

[_Spin_]

FWIW stand for = For whats its worth. I wasn`t suggesting it was the injectors, merely that my car has them.

I`ve read this thread with great interest,

Why, would a car ( lets say, oh.. mine? ) begin to exhibit this hunting - running on behaviour after a tune?

Okay, it`s in the scaling, acelerator pump settings or somewhere, but why does it need to be changed after the tune? What change cause this new unwanted aspect?

[RIPGMH]

Very interesting and infotmative write up , hope other tuners atleast read this post

[Mr Man]

very informative write-up Danny

for the record I have Deka's tuned by Danny and my idle is just as good as it was stock, and my cold starts are perfect as well...

[IH8TOADS]

Wouldnt say its the drilled injectors doing it..

Under "Accelerator Pump"

Change the "Accelerator Pump Filter for Tip out" to 0.000000

.....ahhhh so that's what it was