Mello said:

I understand your frustration. From everything I've read, it's like everything is inside out. I don't think I agree with a restriction causing a lean condition due to less flow. Example, if you completely block the return & could go max IDC's your flow would eventually equal almost 6 liters. In your case the flow would stabilize at whatever pressure 4 x 1450cc would be. The only problem with no return is you can't control pressure making the throughput flow irradic.

Just a thought but I have seen software (tuning software actually) that when looking at the input setting, they look correct. But they were actually screwed up because of a software glitch. The fix was go back & re-enter the data & up load. I'd try it some of your fuel stuff like the injector dead times. Can't hurt.

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I have actually been loading up different tunes that my tuner has been sending me so the inputs have definitely been refreshed. It wont hurt to upgrade the fuel lines anyway even if it doesn't fix it. The fuel is not having any issues getting to the rail if I jack the settings way up, its just not within the range it should be.

Well my guess from everything you've checked, you have a bad fuel pump.

Mello said:

Well my guess from everything you've checked, you have a bad fuel pump.

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That is one of the last things on the list as it is brand new. Less than a year old on a car that is not a daily. Realistically it probably has like 7k miles on it at best.

So. Less than a year old. Does it work within design specs?

Mello said:

So. Less than a year old. Does it work within design specs?

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As far as flow capability I assume so. It gave me the fuel I needed at 30psi with the maf sensor still being in use. Maybe my car just hates speed density .

I have the necessary fittings to complete the fuel feed line and return line in the mail. Once that is all buttoned up next week ill report back with the results. God help me if that doesn't fix it. Because the entire fuel system minus the fuel rail will be brand spanking new. Im even replacing the sock on the pump for god sake.

jakk220 said:

Maybe my car just hates speed density

.

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You need an old school Al Blaha MAF.

Vegas smith said:

You need an old school Al Blaha MAF.

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No kidding. Well I heard back from ECMtuning and got a somewhat helpful response from Mr. Tomas Dorris. Here is what he said.

"Looks like some excellent research on your part. Thanks for that!!

Yeah, I would really have expected the -48% number to work out better for you. But if you find you need more fuel to make things work out right (and you're fairly sure your airflow numbers are right), then I would just adjust that global and be done with it. I wouldn't give it too much of a second thought because there are just so many unknown variables at work here."

I guess maybe I am just making it a bigger deal than it is? I didn't really think there were too many variables that went in to a "standard" fuel system. It's not like I'm running a fuel cell, surge tank, 2 fuel rails, or anything like that. I guess there could be airflow differences, but still.

I had a similiar problem with my fic 1650's being scaled down to 9xx (dont remember exact number) to keep my ve table under 100. My airflow numbers and deadtime scaling was correct. I had several wide known tuners look at it and they all said exactly what thomas said. If it works run it. Ive been watching your thread to see if you ever got an answer.

gsxeclipse102 said:

I had a similiar problem with my fic 1650's being scaled down to 9xx (dont remember exact number) to keep my ve table under 100. My airflow numbers and deadtime scaling was correct. I had several wide known tuners look at it and they all said exactly what thomas said. If it works run it. Ive been watching your thread to see if you ever got an answer.

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Personally, I usually don't accept a "Just go with it" if it doesn't seem right to me. I always want the scientific or mechanical explanation of why it is the way it is. Mainly because I have lost engines and other expensive parts in my 8 years of owning my car because of it. But in this case, the entire fuel system will be brand new minus the fuel pump which is only a year old.

I am however beginning to think that in this instance I just have to accept that the car is capable of getting the fuel there, and I just need to scale the injectors lower. Once the fuel pump hanger mod and the fuel lines are completed this week, I will see what happens. Assuming the result is the same, I'm just going to scale them down and go with it. I need to get this tune perfected asap as the Shootout is only about a month away and I have other things with the car I would like to tend to.

My entire fuel set up is new also. Brand new pumps lines rail and injectors. Meausred fuel pressure with mechanical and electronic gauges. I chased the answer forever also. I still dont think it makes sense but my afr is spot on and im getting no knock.

gsxeclipse102 said:

My entire fuel set up is new also. Brand new pumps lines rail and injectors. Meausred fuel pressure with mechanical and electronic gauges. I chased the answer forever also. I still dont think it makes sense but my afr is spot on and im getting no knock.

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Well I guess that I am not the only one then. I have a feeling the injectors will just end up being scaled low and ill never know why .

GST with PSI said:

1) Have you tested the ethanol content of your fuel? Is it actually E85 grade?

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Update on the E85 currently in the tank. It is indeed true E85 on the dot. Im actually impressed. Speedway FTW.

Update: after replacing the fuel pump sock, a new feed line, summit racing fuel filter, and converting the seding unit / fuel pump to a bulkhead -8AN, I know have a fuel pressure issue except this time it is too high at idle and I cant adjust it down. Its sitting at almost 60psi currently.

I believe this is because I am still on the stock return line. I'm waiting on a fitting to adapt the stock fuel feed line to be used as the return. So now I'm waiting on that.

It does however seem that something, somewhere that I replaced was indeed a restriction. At least thats what im gathering from the increased fuel pressure. Wont know for sure until I get the final fitting I need.

I may need to drill out the siphon hole to 1/8" which I'm still unsure of what exactly I am supposed to drill out. Does anyone know so that I dont mess it up?

jakk220 said:

Update: after replacing the fuel pump sock, a new feed line, summit racing fuel filter, and converting the seding unit / fuel pump to a bulkhead -8AN, I know have a fuel pressure issue except this time it is too high at idle and I cant adjust it down. Its sitting at almost 60psi currently.

I believe this is because I am still on the stock return line. I'm waiting on a fitting to adapt the stock fuel feed line to be used as the return. So now I'm waiting on that.

It does however seem that something, somewhere that I replaced was indeed a restriction. At least thats what im gathering from the increased fuel pressure. Wont know for sure until I get the final fitting I need.

I may need to drill out the siphon hole to 1/8" which I'm still unsure of what exactly I am supposed to drill out. Does anyone know so that I dont mess it up?

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Nevermind. I figured it out. It was pretty obvious. It has my fuel pressure back under control now. Just waiting on my tuner to go over the tune and see if everything is fixed.