Leaning out high RPM

[LZeppelin513]

Fuel pressure is set at 57 psi. When the return was clamped, and pump primes, only the fuel pump ability will limit pressure. Thats why it pegged. The key is that it didn't fall back to zero when fuel pump turned off (like it would do without clamp on return line). This shows that FPR is leaking, not injectors or pump check valve.

edit: 3400-95-Modified, you beat me to it.

[3400-95-Modified]

Why is the FPR set that high? That's almost double what mine is at key-on.

It's probably not set that high, its just the fact that he crimped the return line completely so no fuel returned to the tank... pretty much like jacking up the setting on the FPR to as high as the pump can push... And I guess thats 100PSI.

[AleroB888]

Why is the FPR set that high? That's almost double what mine is at key-on.

[LZeppelin513]

Just got done testing FPR by clamping off return line at fuel tank. Primed pump and then pulled out key. Went back and checked fuel pressure, it was pegged at 100 psi and held rock solid for a few minutes until i un-clamped return line. Then, instant drop to zero. So fuel is definitely leaking past FPR down return line. Also, injectors and check valve at fuel pump must not be leaking.

At this point I am not sure if I should take apart the FPR to see if I can fix it, or just scrap it for a different FPR (and not Aeromotive).

[LZeppelin513]

dude,
I'd just get rid of those 3500 injectors and drop in some stock 3400 injectors with a regular rail. They seem to be causing you all kinds of problems, 3400 injectors are more than enough for your engine.
Hope that helps!

I have some money invested in braided lines and their routing. I would have to throw away the braided lines and start over with new lines to make 3400 rail fit. I would really like to make my set up work, it should work fine as long as the parts are good. If I cant, Ill be going to a 3400 rail.

Im leaning towards a bad FPR, hopefully I can find a problem with it and fix the leaning out.

[3400-95-Modified]

I've tested that table on many dyno sessions as well as hundreds of of track runs, it has never made any noticeable changes.


personally I just set it to what i want the AFR's to be, then compare it to the wideband readings and do all the fueling adjustments through the VE tables.

Correct, that's what I do, I match the command value to the wideband readings by scaling other tables so they are correct. Then after that if I want to richen the setup I will use either the base PE table, or the PE vs RPM vs Time table to make my adjustments.

[Superdave]

I've tested that table on many dyno sessions as well as hundreds of of track runs, it has never made any noticeable changes.


personally I just set it to what i want the AFR's to be, then compare it to the wideband readings and do all the fueling adjustments through the VE tables.

[3400-95-Modified]

huh?

it does noticably change BPW and the commanded AFR.

I was gonna say the same... Thats how I adjust my afr's at WOT in OBDII... I did not like the previous methods suggested back in the day if just scaling the maf higher, or screwing with the injector constant... It's a constant for a reason.

The only issue with using the commanded AFR tables is you have to have all the constants scaled properly... the injector and ve table for OBDI... if they are not right your commanded wont match your actual.

[robertisaar]

The PE commanded AFR table does nothing useful at all. Ignore it.

huh?

it does noticably change BPW and the commanded AFR.

[Superdave]

dude, no offense but you really need to start over with a fresh binary file. There just is no way you'll ever have a good running car with how that file looks. Forget it even exists.

Attached is a clean BFUZ file, it's the latest 3.1 5 speed from GM. If you follow the next bit of advice, all you need to do is change the BPC to 150 and you'll already be in the ballpark. Just clean up the WOT advance, use the adder table to add some more fuel in the upper RPM's and then the rest is just fine tuning.

Also, don't forget to disable the EGR and CCP, just max out their enable temps in the constants.


I'd just get rid of those 3500 injectors and drop in some stock 3400 injectors with a regular rail. They seem to be causing you all kinds of problems, 3400 injectors are more than enough for your engine.





here are some quick pointers;

IMO, The PE commanded AFR table should be set to your real target AFR, then tune your VE tables to get you there. Others may have a differing opinion on the matter but this is how i personally tune WOT fueling. It's never failed me.

your main VE table + VE adder cannot ever equal more than 99 (@ 4K RPM you're at 99.6, after that you're well over 100).

The smoother the cell to cell transitions are, the better.

Rule of thumb is that the values in those tables should never exceed 50


Hope that helps!

[LZeppelin513]

doesn't seem to be calibration limited, more along the lines of not being able to supply enough fuel to the injectors or not enough injector for the engine.

Cool thanks.

I have stock 3500 injectors so I assume they supply enough.

[LZeppelin513]

click the "go advanced" button at the bottom right, once in the new window there is a "Manage attachments" button. Click that, at the upper right of the new window is where you can upload files.

It'll show you the files you've uploaded in the middle and also at the bottom is how you know which ones will be added to your reply.

Thanks!

AZKX 92 J-L car 3.1MPFI 5 speed.1.176.1new spark.bin

[LZeppelin513]

I am still leaning towards FPR. I have had this FPR on through two fuel pumps and I THINK it has been letting pressure drop immediately after prime the whole time. This makes me think its not the check valve.

I also found this page: http://forums.evolutionm.net/evo-eng...regulator.html
His aereomotive FPR was leaking where the ball fits against the seat. Poor quality control. When I get a chance, I am going to clamp off my return line to see if pressure still drops. Will this cause pressure to go to high and cause any damage anywhere?

[robertisaar]

i setup my ADX's to do the calculation for me, but here is a quick link:

http://www.stealth316.com/2-calc-idc.htm

note, that is meant for a "single-fire" injection system, while A1 is setup to normally use double-fire(1 injector pulse per revolution, so 2 pulses per 4-stroke cycle), so the DC calculated by that is actually half of reality.

doesn't seem to be calibration limited, more along the lines of not being able to supply enough fuel to the injectors or not enough injector for the engine.

[Superdave]

click the "go advanced" button at the bottom right, once in the new window there is a "Manage attachments" button. Click that, at the upper right of the new window is where you can upload files.

It'll show you the files you've uploaded in the middle and also at the bottom is how you know which ones will be added to your reply.