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Old 04-04-2005, 11:02 AM   #1
buzz313th
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Default Injector Duty Cycles Maxing out (Street Tuner/Ecutek)

I'm in the middle of tuning on ST....

Delta Dash is reporting Injector duty cycles of 103% at high loads and high RPM's Does that mean that I am running out of fuel at those load sites?

Possible solutions:

1. Lean out mixture at those sites?
2. Lower boost at those load sites?
3. Higher pressure fuel pump?
A. Would I need to rescale injectors for more fuel pressure?
4. Larger Injectors?

Thanks
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Old 04-04-2005, 11:17 AM   #2
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We need a hell of a lot more info.

You may not be running out of fuel, you are most likely just WAY too rich at that point. Do you have a wideband? I am betting on you are WAY richer than you need to be.

A bigger pump will do nothing. You need more pressure to lower the duty cycles (which you dont need to do, just re-tune the map, you shouldnt need more at your level if thats an STX legal car)
A rising rate fuel pressure reg should do the trick.
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Old 04-04-2005, 11:18 AM   #3
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you need a wideband.

asking what your solution should be is like taking a gun, shooting into a dark alley with a target at the end, and then asking us on this board if you've hit it or not--and if not, which way to correct so that you do.



get my drift?

ken
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Old 04-04-2005, 11:39 AM   #4
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Quote:
Originally Posted by Davenow
We need a hell of a lot more info.

You may not be running out of fuel, you are most likely just WAY too rich at that point. Do you have a wideband? I am betting on you are WAY richer than you need to be.

A bigger pump will do nothing. You need more pressure to lower the duty cycles (which you dont need to do, just re-tune the map, you shouldnt need more at your level if thats an STX legal car)
A rising rate fuel pressure reg should do the trick.

Ok heres my deal... I don't have a wideband yet... But I'm in socal and crappy 91 oct is my diet. I have been comparing the KC maps on ST with the amount of KC I'm seeing on my logs. If DD reported KC is pulling timing, then I add just a hair of fuel at those load sites. Results have been positive. By richening up a hair at those sites that are pulling timing I am getting more advance from the KC map thus getting more torque. Load values are also going up with torque. I am making very small adjustments at the top end. As small as I can, then I log. So it seems to me that by richenining the cobb st 93 oct maps for 91 cal gas is working.... only problem I can see is that Injector duty cycle is 103% at highest....

Please answer this question..... Is it correct to assume that if DD reports over 100% injector duty cycle, that the injectors are maxed out?


Thanks for the replies
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Old 04-04-2005, 11:57 AM   #5
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well what do you think 100% idc means?

as has been stated in the past, for more accurate IDC calculations from DD, log fewer parameters.
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Old 04-04-2005, 11:57 AM   #6
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Yes, if you are seeing 103% your injectors are maxed out. Whether that means you are running richer than necessary and you actually would be fine if you monitored and tweaked your AFRs... is another story.

Q&A:
1. Lean out mixture at those sites?

Get a WB setup.

2. Lower boost at those load sites?

Get a WB setup.

3. Higher pressure fuel pump?

Sure.

A. Would I need to rescale injectors for more fuel pressure?

Yes.
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Old 04-04-2005, 12:08 PM   #7
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Quote:
Originally Posted by ride5000
well what do you think 100% idc means?

as has been stated in the past, for more accurate IDC calculations from DD, log fewer parameters.

Considering that IDC goes past 100%, I think it was a valid question.

Didn't know that IDC values might be inacurate from low log rates... Thanks for that info...
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Old 04-04-2005, 12:10 PM   #8
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Quote:
Originally Posted by jblaine
Yes, if you are seeing 103% your injectors are maxed out. Whether that means you are running richer than necessary and you actually would be fine if you monitored and tweaked your AFRs... is another story.

Q&A:
1. Lean out mixture at those sites?

Get a WB setup.

2. Lower boost at those load sites?

Get a WB setup.

3. Higher pressure fuel pump?

Sure.

A. Would I need to rescale injectors for more fuel pressure?

Yes.

Sounds good.. Only reason I haven't gotten a WB yet is because $.... The WB I am looking for is the LM-1.... Any way to find one chaeper than 359.00?


What do U mean by this: "and you actually would be fine if you monitored and tweaked your AFRs... is another story." Can U elaborate?
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Old 04-04-2005, 12:19 PM   #9
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BTW, when I said "Sure" to the pump, I assume you are planning to do the stock FPR "dent" mod to increase your static fuel pressure (which will require a fuel pressure gauge to be installed during the work).

If not, you'll need to get an adjustable fuel pressure regulator.

And you should be looking for a higher flow pump, not a higher pressure pump

$320 - $360 is about as cheap as WB02 setups come.
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Old 04-04-2005, 12:22 PM   #10
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Quote:
Originally Posted by buzz313th
What do U mean by this: "and you actually would be fine if you monitored and tweaked your AFRs... is another story." Can U elaborate?
I mean exactly what other people above have said.

Just because your injectors are maxed out doesn't mean they need to be. For all you know they're maxed because you're running way too rich. Who knows. You could find out that with a proper tune and properly adjusted AFRs you are only hitting 95% duty cycle at most.
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Old 04-04-2005, 12:29 PM   #11
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Thanks.....

Jblaine... would U mind if We got intouch over the phone... PM me if you wouldn't m ind...
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Old 04-04-2005, 02:37 PM   #12
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This topic has been covered ad nauseum for all other EM systems, what is new here. You can either cool the air so that you can run higher AFR and dump less fuel or get larger injectors. End of story.
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Old 04-04-2005, 02:42 PM   #13
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(Bite My Tongue)

Ok thanks for the help...
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Old 04-04-2005, 02:45 PM   #14
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By all means, continue to ask questions about anything you don't understand in the above responses. Don't back away.
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Old 04-04-2005, 02:57 PM   #15
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Quote:
Originally Posted by jblaine
By all means, continue to ask questions about anything you don't understand in the above responses. Don't back away.
I won't.. I'm happy to see that I'm not the only one to see that reply as a being a little..... Rough...


I'm looking into getting a Wideband right now... But I will have many questions later...

Thanks
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Old 04-04-2005, 03:05 PM   #16
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Don't take it personal. My sentiment is the same as bboy's in general, I'm just not in a pissy mood today like he appears to be You do sound in over your head a bit and a lot of us have spent gobs of self-study time learning basics, so things get a little testy when people ask what, on the surface, appear to be very basic questions. There is definitely only so much effort all of us are willing to put in because tuning principles are spelled out incredibly well in several books and it makes zero sense to rehash that information.

I will always at least try to point you toward something to read (book, whatever) that has the answers you need.
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Old 04-04-2005, 03:06 PM   #17
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That said, I am by NO MEANS someone to be taking "past basic" tuning ideas/advice from
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Old 04-04-2005, 03:38 PM   #18
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how about "how to make your car run?"

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Old 04-04-2005, 03:41 PM   #19
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How about "shut up"

Got the ISBN? I'll walk to Borders right now. Then again, I'm thinking the book someone else needs is "How to make a sturdy wiring harness."
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Old 04-04-2005, 03:44 PM   #20
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Quote:
Originally Posted by buzz313th
I won't.. I'm happy to see that I'm not the only one to see that reply as a being a little..... Rough...


Thanks

I didnt think it was rough, but hell look at some of my replies.

I did find it useless and douchebaggy if that counts for anything
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Old 04-04-2005, 03:47 PM   #21
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Quote:
Originally Posted by jblaine
Don't take it personal. My sentiment is the same as bboy's in general, I'm just not in a pissy mood today like he appears to be You do sound in over your head a bit and a lot of us have spent gobs of self-study time learning basics, so things get a little testy when people ask what, on the surface, appear to be very basic questions. There is definitely only so much effort all of us are willing to put in because tuning principles are spelled out incredibly well in several books and it makes zero sense to rehash that information.

I will always at least try to point you toward something to read (book, whatever) that has the answers you need.
Well don't worry too much bout that. I'm not in over my head as much as it appears. UPS just delivered two books... The engine management book by Hartman and "Maximum Boost"... I'm gonna read Hartmans book first.

But I do appreciate...
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Old 04-04-2005, 03:49 PM   #22
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Right on.
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