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Errors with Link G4+ PNP MINI r53- unused digital input flickers on/off and car missfires

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While mapping my car we ran into one major issue that seems to be ecu related. When blipping throttle there is something strange happening with the ecu and the car does not enrich for some seconds and it misfires that can be also heard and felt well. We have been searching for the cause and found following strange happening that is definitely not map related but it seems to be ECU related, the fault can be replicated as follows:

Digital Input 1 flickers by itself between active and off (proof on video 1). Digital Input 1 is not used.

The number CL Lamda Fuel Corr. (%) is showing crazy numbers when blipping throttle. Video 2

Our issue is that the car does not take the enrichments as it should after blipping throttle or going on off throttle stronger and it can also be heard as a big missfire happening. This was well felt also on the street when opening the throttle faster and the car missfired badly with very lean afr readings for some seconds before it started to enrich, if adding throttle slowly it seemed to accelerate and enrich correctly.

What also happened was that the engine just went off on the dyno and it also has happened to myself on the road sometimes when going on and off throttle and then pressing clutch in.

I am looking for your help and your ideas because there looks to be some major problem with this ecu or my wiring that I just cant find myself and i am out of ideas because we have checked so many things already.

Attached Files


Misfiring, stumbling from temporary lean condition is very common until properly tuned. Before looking for a fault in the ECU, I suggest reviewing your acceleration fuel settings which likely just need work.

Also be sure all RPM/load areas traversed when you snap the throttle, are very well tuned in steady state, before attempting throttle transitions, as less than ideal main fuel table values will exacerbate this issue.

Make sure accel enrich is being used. Perhaps your thresholds aren't allowing it to occur.

Have you tried increasing sensitivity? For example if at 1, try at 3 and see if there's a significant change.

Potentially related, have you tuned the wall wetting value yet?

Hi Mike,

Thank you for your reply. Car was perfectly tuned in steady state on dyno etc. and also runs with perfect AFR and the map also looks as it should without spikes etc. Problem occurs when you open throttle fast then something is happening in the ecu what you can see in my 2 posted videos. Car does also audibly misfire and bogs for some seconds with very lean afr like there is a fuel cut happening for some seconds before the fuelling proceeds again and acceleration enrichment starts. It does not help increasing sensitivity etc for this event happening. After this goes by it runs and enriches but the problem is this major event when opening throttle for more than a % where it does this strange missfire and bogs as crazy like a fuel cut limiter was hit. This can be repeated without problem and at different rpm. If i accelerate with slow throttle opening and add throttle slowly it works as it should and afr is perfect and also accel enrichment works. Therefore we believe this definitely is not a tune related issue but something is happening with the ecu itself, you can see in my movies what bugs we found, there is something in the ecu doing some not understandable stuff for sure what my movies proove.

it is totally strange, also the engine goes off sometimes by itself when I press in clutch at around 3k rpm and it just shuts down like there is no ignition event happening anymore. This cant be. Engine other than that runs fine with no mechanical issues also it makes good power.

Any ideas?


I understand your frustration, but there are simple tune related causes to the behaviors you are describing so I would focus on them first. I don't see your video as proof of something other than the tune needing improvement, so I'm trying to help you resolve this.

How much accel enrichment is being applied during the lean condition, in ms. You can log this to find out.

Have you done basics like turn on async injection on accel, adjust wall wetting %?

When you decel and the car stalls, perhaps overrun fuel resume RPM is too low vs. idle target to give the engine a chance to recover

Perhaps moving idle offset isn't sufficient or base idle value isn't sufficient.

Perhaps you have a negative fuel trim in decel areas that causes a lean condition on idle re-entry, stalling the engine before the trim can update sufficiently.

There are many causes of what you're describing which simply require tuning adjustment.

If you'd like to post the tune and a datalog with all pertinent items logged, that would help narrow things down. Perhaps they will make it clear you do have a wiring issue or other issue.

Hello Mike,

To which email can I send the Map and Logs for you to check?

As mentioned before we believe that this is definitely not a tune related issue. As you can see in my 2 Videos the closed loop lambda Fuel correction is jumping to crazy high numbers of around 6437 % , a number that high is not possible to set. :) It happens every time and at all kind of rpm when the throttle is opened fast. When the throttle is opened slowly then the car is working fine and also enrichment works but as soon as the throttle is opened fast the ecu seems to "die" for some seconds, it feels like the fuel is cut and this would also confirm what we show on our video, that the CL correction is somehow making a 6437% correction. Closed loop correction should be limited to the set number of 10% also the ECU usually has not mapped the range of CL Lambda correction to go up to over 6000%, this does not make any sense and can not be set that wrong in the map... I believe. :)

We have this issue since this ecu was fitted but it became visible to us only now when we started finishing the map and driving the car more aggressive.

Also this Digital Input 1 should not be flickering constantly between on and off because this input is not in use and not set.

If you're confident there's a fault with the ECU itself, you should contact your Link dealer for support if you have not done so yet.

We are happy to try to help, but it's your dealer's responsibility to assist if there's an issue with the ECU.

You may be experiencing a communication issue so I do suggest verifying what an onboard ECU log shows vs. what you see on screen in real time, as well as confirming you're on the latest software, ECU is on the latest firmware. I also suggest logging the database error ID monitor to see if your tune file may be corrupted, or some other issue may be present which doesn't show up as an error code.

After that I'd reset the ECU settings, then load the base file from Link on the ECU, unchanged, and see if any behavior changes that's safe to test without tuning.

We have dig deeper and found following issue: on the Link website, they have the latest Firmware stated as of .3669 for download, but in the release notes the version .3671 is mentioned to be the latest one. Also in the release notes for this version .3671 this CLL Spike that we have found and proove with my video is mentioned to be corrected with version .3671. So Link has done quite a confusion here with stating a wrong Firmware version for Download on their official Website, we had thought to have the latest Firmware on the ECU with .3669 as stated on their website and also marked by their download .3669 but it was not the latest! We have lost at least 15 hours and 100 Liters of Fuel because of searching this issue to find out something like this.

I received from link support the download instructions to choose the download under the submenu legacy versions- and choose from there the .3669 version that has a small note .3671 by its side. lets hope this CLL spike will be corrected with this and we can finish our car.

I will let you know if this has solved our issue.

Thank you for assisting.

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