Make a V8 idle and run. Engine runs, but not perfect. Help!?

For discussing injector selection, manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
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abbamust
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Make a V8 idle and run. Engine runs, but not perfect. Help!?

Post by abbamust »

I have a 302 cid Ford V8 engine that I will run MS-II, v3 board, v2.36 code.

The engine will run with twinturbo soon, but now I do not have turbo instaled.
So I have bought 8 large low amp. injectors, 72lb/hr, that I am planning to use with the twinturbo setup for 7-800 hp.
But now I have about 400hp, so now I have eigth 42lb/hr injectors that I use.

I have tried to tune this, but cant make it idle, and after some startup hours, the car totally stopped, and never ran again.
I checked the plugs, and they where all dirty and still wet of gasoline.

What shall I do to tune it right for a trip on the road?
Last edited by abbamust on Wed Aug 30, 2006 12:31 pm, edited 2 times in total.
PSIG
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Post by PSIG »

Can you post copies of your .msq file and a datalog of the starting problem?

David
S.Bretz
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Post by S.Bretz »

LOL...72's. I have 96'er's on a 1.9l with set of cams that make about 10in vac at 900rpm. If I can get it to run, then 72's on a 5L should be pretty easy.

What I did was just estimated the base number...or about what I thought it would put out at what rpm and pressure. It doesn't matter if you are off 30or 50hp up top...it will be pig rich anyway.


Next, get it to idle...which you did. It will be super rich. go to the table transform pull down and start multipling it by .75-.8 at a time until you get close....WHen you get close, the rpms should shoot up and it should stop sputtering. Once you get it close, Select the "goto" feature in the fuel tuning window and just follow the rpm's around and adjust up or down depending on your A/F ratio's. Once you get a few spots that are good, you should be able to start to see a pattern of how the map will look in that area. Adjust the area and go from there.


Ok....this is just incase you are known to do brainless stuff every once and a while like myself...Did you plug the vac hose into the MS unti?


IF YOU DON'T HAVE A WIDE BAND THEN BUY ONE. YOU CAN'T TUNE BLIND.
S.Bretz
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Post by S.Bretz »

Oh yeah. Buy a few sets of cheap plugs, and change your oil alot until its not running stupid rich. Stupid rich will wash the rings out in a hurry.
abbamust
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Post by abbamust »

ok... my problem is this:

I changed to 42lb/hr injectors, and the engine started again. It went for a coupple of minutes, and then I turned it off.
After this the engine did not start again, because the the plugs where all wet of gasoline. Then I washed them, and tryed againg, but it never started...

So, the engine gets to much fuel. :D

How shall I set it up, so it don't gets to much fuel?

Can someone help me with a setup that will idle, and start after a stop?
The enigne is a 302ci V8 with about 400hp. I have 8x42lb/hr injectors, high imp. (16 ohm).

Please help... :lol: :lol:
Jack
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Post by Jack »

Once plugs get soaking wet, they sometimes don't fire again correctly. I'd swap them out with new ones or burn them clean with a propane torch.

I'll leave the running issues for others with more experience.

jack
Good judgment comes from experience.
And where does experience come from?
Experience comes from bad judgment.
. . . . . . . Mark Twain
S.Bretz
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Post by S.Bretz »

I just looked at your MSQ...it looks like you haven't even tryed to tune it. The req-fuel is wway off, and the ve's of 3x's seem a little high for 30kPa at 500 rpm.

Try chopping the ve table down until it runs right by using the table transform feature in the TABLE->VE1 screen.

Aghhh, here. try this. I dropped the VE at idle alot.
abbamust
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Post by abbamust »

Thanks. The engine started agian, but ran only for a minute or so, and then the plugs where wet again.

I just can't get the fuel amout down enough. What else can I do now?
Rolling_Thunder
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Post by Rolling_Thunder »

from what i know - the 42 lb/hr injectors are a pretty good injector - but possibly too large for your current application - this is why your plugs (and rings) are getting washed... 400hp you should need around a 32lb/hr injector...

Im new to the whole EFI thing - but its just a thought
abbamust
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Post by abbamust »

Rolling_Thunder wrote:from what i know - the 42 lb/hr injectors are a pretty good injector - but possibly too large for your current application - this is why your plugs (and rings) are getting washed... 400hp you should need around a 32lb/hr injector...

Im new to the whole EFI thing - but its just a thought
actually the injectors are 35 lb/hr... just checked it now. som they should be perfect!
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