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Evo IX Link plugin - acceleration lean issue

Link G4 Plus Software Tutorial

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This is a 2.2ltr with BW EFR7163 turbo and Link G4+ plugin and I am using the traditional fueling model.

I am trying to figure out a lean issue which is mostly apparent when I am cruising and let of the gas without cluthing and I let the rpms fall down to 2500rpm or so.

This same issue does appear in normal driving but just milder.

Then when I go back on the throttle there is a hesitation with a few seconds where AFR is lean.

What I have tried is

increasing fuel in the mpg -50 to 0 @ rpm 1500-3000

increased accel fuel by increasing Accel sens , accel hold , accel decay , Clamp and wake up , this made it a bit better but the issue didnt go away and sometimes in light driving it would go pig rich.

attached are map and log

Played with 4d and 5d tables but couldnt find a method which would not affect normal driving

any help would be greatly appreciated :)





I found out that there were high impedance injectors in the car and it still had the resistor

Deleted the resistor and after that I needed to start from scratch with fueling.

This lean issue is still there , to depict it a bit the blue lines drawn on the fuel table shows the path the active cell takes when I step on throttle again.

If rpm is 2500 or 3000 it rises directly up the map scale and while that is happening AFR's are lean and engine looses power untill it regains power and AFRs get back to normal.

I have done some driving where the target cells are a few of these cells and I cant see that they are to lean or way to rich

I changed the acceleration fuel back to the base Evo IX map , I tried increasing acceleration fuel and I tried decreasing acceleration fuel but without any luck

Fuel table picture

What is your ignition timing before and during the hesitation?

The area which is selected is the area where I feel this issue the most

ign table

That's a pretty big range -- (60-160 kpa and 1500-3000 RPM). Have you tuned the Ignition timing in the 2000 RPM column at steady state on the dyno? I suspect that with a leaner mixture is could probably handle some more advance from 80 - 120 kpa)

You have some pretty big timing changes from cell-to-cell -- more than 10 degrees around 2000 RPM, 40-60 kpa, I can't believe that 80 kpa wouldn't want at least or 6 deg more than you currently have.

I've only had a very breif look at your log, but the first thing I notice is you have the over-run ignition trim pulling timing out for 2 seconds after you open throttle. Can you set the overrun fuel cut retard to zero and see if that helps.

Also, your VVT is not working at all, the cam is sitting at 0deg all the time. I think this is possibly because the pull-up on DI1 is turned off, can you turn that on and check if VVT works.


Thanks for the reply , I didnt notice that it was as well the introduction time.

I tried turning it to 0 sec , tried turning overrun fuel off at all , zeroed out 4d and 5d tables , but I still have this issue.

Will post another log later.

I also turned the resistor pullup on , but this is the way it was set in the base map so I thought that was correct

This is BTW an USDM Evo IX

Another test I did was to use 4d tps/rpm based map where I added 30-40 of fuel in the problem areas and that made the issue better.

I then made the map quite a bit richer from -40 and up to 120 aprox , but this makes normal driving really rich

In the end I found out that fuel pressure regulator had been Teed into manifold pressure source for the ecu

and it was working as a damper for manifold pressure seen



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