Lean at high rpm

[XfireZ51]

I would agree w Hans. Dyno ing the car makes no sense until u have the fuel issue resolved. The shop should be able to email u the run file.

[ALLTHECAMS]

Originally Posted by XfireZ51

I would agree w Hans. Dyno ing the car makes no sense until u have the fuel issue resolved. The shop should be able to email u the run file.

Dynoing the car is how I found out it was lean.

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[XfireZ51]

Originally Posted by ALLTHECAMS

Dynoing the car is how I found out it was lean.

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Yes I understand that altho checking FP ahead of the dyno would have also made u aware of it. What I meant is that going forward dyno would not make sense.

[ALLTHECAMS]

Originally Posted by XfireZ51

Yes I understand that altho checking FP ahead of the dyno would have also made u aware of it. What I meant is that going forward dyno would not make sense.

Yes you are right.

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[ALLTHECAMS]

Tested the pumps at the test plug by the ECM. Read 7 amps.IMG_20190507_180202169.jpg

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[Ccmano]

Originally Posted by ALLTHECAMS

Tested the pumps at the test plug by the ECM. Read 7 amps.Attachment 9512

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That’s too low. 8amps is minimum for both pumps. Now pull the FP1 fuse (in the fuel box) and test it again. It will give you the draw on the secondary pump, FP2. Subtract that from the 7.1 you just got and you have the reading for the primary pump FP1. I would replace both pumps.
H

[ALLTHECAMS]

Originally Posted by Ccmano

That’s too low. 8amps is minimum for both pumps. Now pull the FP1 fuse (in the fuel box) and test it again. It will give you the draw on the secondary pump, FP2. Subtract that from the 7.1 you just got and you have the reading for the primary pump FP1. I would replace both pumps.
H

Did that test and got 3.8 on the secondary and 3.3 on primary. Given that I have a few mods, should I get high flow pumps?

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[Ccmano]

Originally Posted by ALLTHECAMS

Did that test and got 3.8 on the secondary and 3.3 on primary. Given that I have a few mods, should I get high flow pumps?

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Thought so... for the mods you have standard pumps are more than enough. You have to go to a larger cubic inch engine before you need high capacity pumps. Don’t waste your money. Glad you found your issue.
H

[ALLTHECAMS]

Originally Posted by Ccmano

Thought so... for the mods you have standard pumps are more than enough. You have to go to a larger cubic inch engine before you need high capacity pumps. Don’t waste your money. Glad you found your issue.
H

Thank you for the help!
Matt

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[Paul Workman]

After blowing up the AF graph, I noticed it looks a little like my initial dyno pulls, i.e., trends up with RPM, and looks like the operator cut it off just shy of 7000 rpm - prolly cuz AF was going lean?

Here are the graphs of my stock 90 Z, taken back in 2007. The leaning you see was due to deteriorating OEM injectors in the presence of alcohol doped fuel; a fact born out by reading the resistance across each injector, AFTER the motor was fully warmed up.

(I'll post the procedure for measuring the injectors w/ o removing the plenum...if/when I can find the diagram I made!)

My 1990 LT5 base case with defective OEM injectors