TouringBubble

iTrader: (2)

Car

'03 VIII
stock turbo
HKS 272s @ -4, -1
Stock bottom end and head
1200cc PTEs
Perrin MBC
E85
Tephra V7 (throttle map switch)
MAF
BR7ES @ .024

The Issue

We just installed the injectors and I tuned it for 93 oct with no issues. 23 psi and solid 11.2:1 with a little taper up top. Cams were at the settings mentioned above. This tune was done using BPR7ES @ .029.

I move to the E85 tune, set up the injectors and bump up the boost. I set the boost at 28 psi and start tuning. I see some lean readings and get some misfires, so I switched to the BR8ES and gapped them properly. At WOT from about 2500, it continues to dip down to maybe 11.8:1, then keeps climbing to the high 13's around 5500 RPM. This mix was verified via the on-board AEM UEGO and my LM-1 in the tailpipe.

Notes

IDC%s are in the high 80s, so it's sending plenty of fuel. I've richened the fuel map all the way to the 7s (down from the mid 10s where it should be) and verified that it's on the correct map. Fuel trims are around -7 low, -4 mid currently.

I'm going to try setting the cams back to 0 tomorrow and try again.

The car does seem to have a boost leak currently. We tried to test it originally and it would hold no boost. we found the upper IC pipe had been damaged and was way out of round. That has been fixed, but load levels are still in the 330 range, which seems high to me. I'll be testing it again tomorrow.

The MAF screen has been removed. It was like that when the guy got the car.

I do not see or hear any exhaust leaks that would definitely be causing a false reading.

I've bypassed the FPR solenoid to test, no change. We're working on verifying and testing the rest of the fuel system components.

The plugs read lean as well, so it seems this is an accurate reading.

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We're racking our brains on this one. Any help would be awesome. I have no idea what could be causing this kind of issue. Thanks guys.

Ceddy

What fuel pump(s) do you have?

Could be running out of pump.

TouringBubble

iTrader: (2)

I'm considering that. The owner is unsure and we're planning to take a look tomorrow.

When I originally tuned the car, the fuel pump did just fine on 23 psi and 93 on stock injectors, so I assumed it had a 255. I may have been wrong.

Fast_Freddie

iTrader: (50)

Check your fuel pump, and double check for boost leaks.

TouringBubble

iTrader: (2)

Given the load, I'm pretty sure the boost leaks are there. I just need to find them.

And I think just typing this all out made me really think clearly about it, as it seemed very clear that it's likely the fuel pump once I finished typing. Thanks for the input guys.

jrohner

I would rig something up to watch fuel pressure as you do a pull. Pull the fuel pump first though to see if it actually has a 255hp in it, if not that's your problem.

SoCalRedLine

iTrader: (2)

Yea, the injectors are way too big for the stock fuel pump to flow past 80% IDC. IIRC the stocker was a 225lph, which is only able to support up to 937cc/min injectors running 100%IDC.
80% IDC of a 1200cc is ~960cc/min at 40psi.

fostytou

iTrader: (15)

Even still you should be able to compensate for the drop in fuel pressure with injector on times, especially with an '03 turbo.

Bryan had a problem where shortly after going to E85 he cleaned all the crap out of his lines and clogged the filters (both on the pump and the return assembly which requires a whole new return assembly).

SoCalRedLine

iTrader: (2)

You can't compensate for a pressure drop and increase fuel output at that idc. Once the fuel pump reaches it's full flow capacity, it won't matter what you compensate because the motor won't get more fuel.
Increasing the fuel rail pressure only cuts overall flow of the pump.
1200cc injectors are even too large for a 255lph pump, which can only handle ~1000cc Injectors max.
This has nothing to do with turbo size. I'm basing all this off his idc values.
If he has a clogged return line that too will cause it to run lean like you said, cause the increase in fuel line pressure will choke out the fuel pump.

TouringBubble

iTrader: (2)

We pulled the pump assembly yesterday and it does have the stock pump. That seems to be the issue. A 255 has been ordered. Thanks for the input guys.

Strangely, we also found lots of crap on top of the tank under the pump cover. Acorns and stuff ... weird. There is some trash in the tank too.

And, I was able to control the fuel slightly after it leaned out, but adding in a full 2 points of fuel to the map, only got me a change of about .2 AFR.