Random engine stumble and mil

[BenP]

I have been having an issue with a hard engine stumble at light throttle and mil is set with many dtc's for a very brief moment
Also there have been a few times where it keeps wanting a firmware update when uploading changes to the ecu.
Any thoughts to what may be happening?

Attached is the datalog and calibration - just over the 4 second mark is where it has happened.

Thanks

[Spunkster]

What is the serial number that is on the s300 board inside the ECU?

From Help, About, what is the version of software you are using?

[BenP]

The serial # is 22305

The software version is 2.7.8.0

[Spunkster]

Have the capacitors been replaced on the ECU?

[BenP]

The capacitors have never been changed.

I see no signs of leaking or swelling of the of the original capacitors on the ECU board.

[DaX]

I see no signs of leaking or swelling of the of the original capacitors on the ECU board.

By the time you see them swell or leak, they have gone bad a long time ago. You need to replace them before they get to this state. If you have never replaced them, do it now, as even in the best case scenarios the original capacitors in these OBD1 ECUs are reaching the end of their life.

[BenP]

Thanks for the info on the ecu capacitors.

I would have never thought they could caused ecu glitches because of there age.

[BenP]

I have changed the capacitors in the ecu - no diference made

The problem seems to be getting much worse

Attached is a datalog that is just a complete mess of everything going on.

Has anyone ever seen this before?

[Spunkster]

Post a picture of the soldering on the bottom of the ECU for the s300 pins.

[BenP]

I have narrowed this problem down to the switch control datalogging. Every time when the switch is turned on to datalog everything starts to go crazy all the numbers start maxing out for sensors on and off also error codes start to flag up to 16 error codes.
I have tried another switch and wiring just to rule that out- there was no change still chaos and errors
I tried moving the pin from B5 to B8 on the ecu connector and there was no change.
There could also be 2 to 15 or so datalog files saved in the few seconds when the switch is on for datalogging. Also other times it will not save anything.
I have also seen for a split second very random and not very often at times all the sensors going crazy even with the switch not pressed.
It all shows in the datalog I posted in the previous post.

Attached is the photo of the soldering

Has this s300 gone bad ?

[Spunkster]

One of the 14 pin connectors looks like it may have a problem with the soldering and may actually have a damage through hole via.

Also make sure that J12 has been cut on the ECU.

[BenP]

I see in the picture of the pins how you mentioned that one looks damaged and have a through hole. I inspected that pin and there is no damage or solder cracked or broken. I resoldered that pin just to do so and made sure j12 was cut and not contacting.
There was no difference made. All the sensors still going crazy maxed out on and off when switched datalog.
When using the laptop datalog record button it seems to work perfect.
I have been using the switch for datalog for years with no troubles till now.
If I didn’t mention already when uploading a calibration it will also have a random upload failed error and I have to try again to upload, and random firmware updates when clicking the upload button.

[Spunkster]

Send an email to support <at> hondata.com with the following and I will issue an RMA and give you further
instructions:

Name:
Address:
Phone:
Email:
Serial#:
Description of problem:

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