FAST, VE??@idle?

[Superskwrl]

I'm using a FAST b2b on my 100% stock (for now) 5.0 mustang, in preperation for the turbo i changed from 24lb to 36lb injectors, with the 24's the VE #'s @ idle were about 64-67, now i changed to 36's and to get the car to run good VE#'s are 85-87, and at higher rpm VE is over 100?

Does this sound right??,doesn't make sense to me although whatever is happening the car is running good

Still learning,thanks for lookin

 

[bobc455]

Does not sound right.

Did you remember to change the injector size in Calcom? Also, do you have other settings (i.e. # of cylinders) right?

-Bob Cunningham
bobc@gnttype.org

 

[Superskwrl]

Yes,too both

 

[bobc455]

Have you verified correct fuel pressure?

You can't really have a VE over 100 on any NA car, you should be idling with your VE around 40-45 on a stock application like that.

What is your target A/F ratio at idle?

Are there any other symptoms (i.e. smells rich, poor fuel economy, etc.)?

-Bob Cunningham
bobc@gnttype.org

 

[Craig Smith]

VE can exceed 100 on an NA engine, but you typically won't see it on anything other than a very expensive all-out racing engine.

Where is your air temp sensor?

Does the timing light match what the ECU tells you the timing should be?

Are you doing your calibrations with the engine fully warmed up?

Also make sure that the ATS and CTS correction factors are at 0% at operating temp.

Keep in mind the purpose of the VE table is to get the ACTUAL air/fuel ratio to match the TARGET air/fuel ratio, not just to get the car to run right. Is this how you are going about this?

Keep us posted... good luck!

 

[Superskwrl]

Originally posted by Craig Smith
VE can exceed 100 on an NA engine, but you typically won't see it on anything other than a very expensive all-out racing engine.

Where is your air temp sensor?

Does the timing light match what the ECU tells you the timing should be?

Are you doing your calibrations with the engine fully warmed up?

Also make sure that the ATS and CTS correction factors are at 0% at operating temp.

Keep in mind the purpose of the VE table is to get the ACTUAL air/fuel ratio to match the TARGET air/fuel ratio, not just to get the car to run right. Is this how you are going about this?

Keep us posted... good luck!

Air Temp sensor is in stock location which is in the lower intake manifold, i suspect it's ok @ idle because it reads very close to ambient temp +1/2*

Timing light does match, which brings up another question? It seems as if any more than 30*timing it will detonate, with stock electronics i was running 14*base and comp adds 18=34, and i've run as much as 19 base in the past

Engine is fully warmed up,I also have a 180 t stat, car runs no higher than 185, i was thinking of puttin in a 160, is there any negative affect in doin so?

I'm not sure on the correction of the ATS/CTS, i'll have to check

The actual A/F is within 2%, and is as close as aprx .9% Car idle's best @ 12.5:1, any leaner and it starts to surge

Craig, since i've got your attention, I was wondering is it possible to make a car with FAST start up like stock, every car i've ever seen with DFI or FAST always seems to take noticably longer to start than a stock car. I've asked a few people and they all say "thats the way it is". My company truck 84 E150 van with 284k starts so quicky i dont think the starter even turns 1/4 revolution.

Another point, is that i still have the stock converters on the car, is that a problem?

Is it possible to make a car pass emissions with this setup, I initially though it could be done by leaning it out alot but it surges like crazy when i do that

What parts/vechile are they from to use a knock sensor? I've called around and most places steer me away from the idea?

I'm also thinkin of tryin a 1 bar map, what vechile can i get 1 from @ the local parts store?

Thanks For the replies, this is the sole reason I bought instead of Gen 7

 

[bobc455]

>>Engine is fully warmed up,I also have a 180 t stat, car runs no higher than 185, i was thinking of puttin in a 160, is there any negative affect in doin so?

Not from a performance standpoint. However, generally hotter engines will get more complete combustion giving better emmisions, better gas mileage, and the engine will last longer.

>>The actual A/F is within 2%, and is as close as aprx .9% Car idle's best @ 12.5:1, any leaner and it starts to surge

Sounds like your VE table is well calibrated. However, I've never heard of a stock car that has to idle so rich, most cars that are factory stock should be able to idle at 14:1 easily.

>>Craig, since i've got your attention, I was wondering is it possible to make a car with FAST start up like stock, every car i've ever seen with DFI or FAST always seems to take noticably longer to start than a stock car. I've asked a few people and they all say "thats the way it is". My company truck 84 E150 van with 284k starts so quicky i dont think the starter even turns 1/4 revolution.

My $0.02: In order for an engine to fire, there has to be fuel in the cylinders. If the engine is shut off dry, you have to go through an engine cycle before the intake valve will open, etc., so that fuel gets in the cylinder. Maybe Craig will have some more insight on how this functions, but even on most of the cars that I drive, you can practially count the engine go through 6 cylinder compressions and have it fire up on the 7th (assuming a 6 cylinder engine).

>>Another point, is that i still have the stock converters on the car, is that a problem?

Only if a lockup convertor was controlled by the previous ECM. If you don't have a lockup convertor, or the tranny has it's own controller, you'll be fine.

>>Is it possible to make a car pass emissions with this setup, I initially though it could be done by leaning it out alot but it surges like crazy when i do that

The engine should idle at the same A/F ratio and timing as when you had the OEM ECM, once properly tuned. If you can get the same amount of fuel into the engine, and the same timing as stock, then you'll get identical emmissions results no matter what ECM you have.

 

[Superskwrl]

I checked both ATS/CTS are @ 0% correction

 

[Ricky Trussell]

Did you have to make changes in the other cells for the engine to run right?
Is your voltage okay?
Is your AIC active at idle?

 

[nightdiver]

The car can start better than stock. In fact my truck can start without depressing the gas pedal , something that never happend with the stock chip or with KB chips i had
All you have to do is tune, and search the forum for details that helped other guys
Thats what i did and i broke the flexplate with the torque monster and thats with a baby T68
Not to mention the increased MPG

 

[Superskwrl]

Originally posted by Ricky Trussell
Did you have to make changes in the other cells for the engine to run right?
Is your voltage okay?
Is your AIC active at idle?

Yes
voltage is between 13.7-12.9, but steady @ idle about 13.5/6

Yes, i've got the throttle blade closed almost all the way and am relying on the AIC


nightdiver, do you have sequential system or B2B?



Anyone think that having the stock cats on the car affect anything ie wb02, the sensor is before them


Thanks

 

[Ricky Trussell]

There are many on this site more qualifiied to answer but, I don't think you should have your IAC active at idle. I have been working with the shop that I bought my system from and was having the same problem as you.

He told me to:
Open throttle blades until my IAC was not active at idle. Once I did that my throttle follower would drop to around 10.

 

[TurboTR]

If your IAC is not active at idle then it's no longer an idle air controller, and not much point in having it then.

The stock cats may not like having the engine run away from stoich a/f ratio for long periods, and not cycling rich-lean-rich-lean while crusing...

TurboTR

 

[nightdiver]

Well, its a B2B WB system with an adapter harness that i got from Mike Lee
I got the Fast the same time that a friend got an other unit from england.
I did all the tuning with only help from this forum and i got an 500 hp engine that has 60000 race miles from 1991
The other guy has MELTED (4) FOUR engines
and thats a cosworth
I just got the pontiac top end with 320 cfm heads and im on my way to low 10s

 

[Ricky Trussell]

If your IAC is not active at idle then it's no longer an idle air controller, and not much point in having it then.

TurboTR,
My understanding of what he said was that the IAC would open and close according to engine and A/F ratio, but not at idle with no load. FYI, I said not active but there is a small amount at idle. Again, not trying to mess anyone up, just relaying info from FAST qualified installer.

If you have time could you explain why you would need a throttle blade adjustment if IAC was the way to set idle air needs?

 

[Craig Smith]

The IAC motor should be open at idle, but only a little bit. This way, if it needs to open WAY up, it can. If the IAC is already maxed out and it's the only thing keeping the car idling, if any load is placed on the engine that could drop the idle speed, the IAC won't be able to compensate. I like to have the IAC open around 20-30 counts at idle. Adjust the throttle blades until this is the case.

Above idle, IAC position is determined by the throttle follower graph. A/F ratio actually has nothing to do with where the IAC will go. IAC position is determined by the ECU and is based on engine speed at idle and by the throttle follower everywhere else.

Hope this helps clear a couple things up... back to work!

 

[NoSlix]

Superskwrl: What is your injector opening opening time set at? That can effect what your VE at idle is, although it's effect as the rpm increases is far less.

 

[Superskwrl]

Originally posted by NoSlix
Superskwrl: What is your injector opening opening time set at?

it's 1.0

Thanks for the replies guy's