88 Z28 Guy

iTrader: (1)

I am about to dive in head first. I am very close to buying a APU1 Autoprom, and get after it. I have two questions i would like answered first before spending $350.

1. When i buy the Autoprom, will it be able to read the tune thats already on my car. From what i understand from the previous owner that it was tuned for the setup it has, cam, runners, heads, etc. Since then ive upgraded/replaced to 24lb injectors and its cause a idle problem. I wanted to start with the tune done my whoever because before it ran the car great and dont want to mess up by having to start with a stock tune because i have no idea what kinda cam the car has.

2. Ive been playing around in Tunerpro RT before i buy the autoprom, but i cant find the Fuel Injector Constant Flow parameter. Anybody know what its called?

Six_Shooter

iTrader: (2)

1. Yes, but you may need an HDR1, if the EPROM is not removable from the MEMCAL, or adapter.

2. Depending on the code that you are running there may not be a constant as such. Also it may not be defined in the XDF that you are using.

88 Z28 Guy

iTrader: (1)

I figured as much by reading on moates, it's just that they say it will let u read the stock tune and my tune is not stock. Also as far as my second question, I'm using the stock files for my car off the tuner pro website. So you are saying that my tune may or may not have a injector flow constant?

Six_Shooter

iTrader: (2)

Moates says the stock tune, for peopl just getting into tuning to know they can read their EPROM. Stock or modified binary, reading it is the same.

That is correct, there may or may not be a specific injector flow constant. Some codes use a table for a base scaler, usualy modified by EGR percentage.

88 Z28 Guy

iTrader: (1)

Ok ty but for one more ques. If my tune doesnt have the constant value. Will i have to modify the whole fuel table to compensate for the 2lb extra.

EagleMark

So what XDF are you using?

88 Z28 Guy

iTrader: (1)

I'm using the $6e.xdf off of tunerpro's website. I haven't downloaded the one from my ecu yet cuz I don't have the hardware yet.

gbayfisher

No, your xdf will have it. In the scalars under:
Single fire FI size @40psig
Double fire FI size @40psig

Set both values to your injector size.

hellz_wings

iTrader: (2)

That's amazingly simple! Definitely going to upgrade my injectors now thanks!

RBob

iTrader: (1)

Be sure to also change the injector compensation tables. They make a big difference in the tune, more so on a MAF set up versus SD.

And the "@ 40 psig", is really "@ 43.5 psig", assuming you are running stock fuel pressure.

RBob.

hellz_wings

iTrader: (2)

Which tables are you referring to? The "Accel enrich %BPW factor vs. async pulse" and "Injector pulse width correction vs batt voltage" tables?

RBob

iTrader: (1)

The second one: "Injector pulse width correction vs batt voltage", and the other being the short PW compensation.

RBob.

hellz_wings

iTrader: (2)

So, if by increasing the injectors from, say, 19 to 22 for example, this table "Injector pulse width correction vs batt voltage" will require an increase or a decrease in the "usec added" column? And I'm assuming it should be adjusted in between 10 and 15 VDC (I don't see the voltage going below or above that range), correct me if i'm wrong though..

RBob

iTrader: (1)

It has to do with the injector characteristics not the flow rate. Best bet is to get injectors that the compensation values are available for. Today that is the only way I would buy injectors. As many have this data available.

RBob.

hellz_wings

iTrader: (2)

I was thinking Southbay or Injectors Plus since they are on these boards.. Off the top of your head, do either of these vendors have this information available?

RBob

iTrader: (1)

I don't know. I do know that Ford has on their web site the specs for the injectors they currently sell (Ford Motorsports).

RBob.

hellz_wings

iTrader: (2)

Cool i'll find out. Thanks!