Delicious Tuning Flex Fuel issue : Ethanol content sudden drops

[nkobns]

Hi everyone !

I have a Delicious FFK for 12’ models modded for my EUDM ‘17 (details on this below)

I am encountering problems with the ethanol content value : it suddenly drops to zero for an unknown reason, and I can’t use a flex fuel tune since it would mess up the injection and might run the engine leaner than it should.

An important detail is that those drops seems to be directly linked to road bumps. Lots of bumps, lots of drops, no bumps, no drops.

Green is the ethanol content :



Any clue on what’s happening ?

Thank you !!

Here is a bit of the background story for those of you that would be interested :

Long story short, after some mixup with a group buy, i ended up with a 2012 model FFK for my EUDM 2017 GT86.
On 17’, there is no ground in the O2 sensor plug, so it had to be added by making a T connection out of the black wire of the O2 sensor to link it to a ground spot.

Delicious suggested that I could add the ground myself. Of course, they offered to make the mod in house, but since it would have cost a 2way trip from US to FR, it does not look like a reasonable solution for such a simple mod.

I used the ground spot that’s just below the fuse box. I made a weld for the T. Here’s my T that I stripped out from its heat shrinking protection to check it :

[steve99]

check if the gounds\earth good also check volts connection


check if the drops shown in ecutek logging correspond to drops in ethanol content logged in blutooth app

[Mr_Eyo]

I had these symptoms.
https://www.ft86club.com/forums/show...&postcount=243

My cause was the flex fuel kit's feed pressure sensor was reading low, which triggers a "safety" feature of the kit to zero out the E%. The cause of the low feed pressure was the in-tank fuel sender pump not being fully seated. If your kit has Bluetooth and the pressure sensor, try downloading the DT app and reading the feed pressure.

[nkobns]

Originally Posted by steve99

character ck the gounds and earth

check if the drops shown in ecutek logging correspond to drops in ethanol content logged in blutooth app

With the DT app, the ethanol content is perfecly steady, but I doubt refresh rate would capture the drops.

I checked my ground (between the black wire and my battery negative, it looks solid with a nice and steady 0 Ohm)

Originally Posted by Mr_Eyo

I had these symptoms.
https://www.ft86club.com/forums/show...&postcount=243

My cause was the flex fuel kit's feed pressure sensor was reading low, which triggers a "safety" feature of the kit to zero out the E%. The cause of the low feed pressure was the in-tank fuel sender pump not being fully seated. If your kit has Bluetooth and the pressure sensor, try downloading the DT app and reading the feed pressure.

That is an interesting lead, I didn’t expect such a « safety » feature. I will check your topic.

My FFK could be ordered with a fuel pressure sensor option but I did not take it. Would that mean there’s no ‘feed pressure sensor’ at all ?

[Mr_Eyo]

Originally Posted by nkobns

With the DT app, the ethanol content is perfecly steady, but I doubt refresh rate would capture the drops.

I checked my ground (between the black wire and my battery negative, it looks solid with a nice and steady 0 Ohm)



That is an interesting lead, I didn’t expect such a « safety » feature. I will check your topic.

My FFK could be ordered with a fuel pressure sensor option but I did not take it. Would that mean there’s no ‘feed pressure sensor’ at all ?

I did not see the drops on the app either. The only indication was the low feed pressure. If you do not have the pressure sensor, then this feature shouldn't be the cause of your issue. One other potential cause could be a bad wire crimp on the E% sensor connector.

[nkobns]

I’d have to open the Delicious box to check that... I also contacted Delicious, I hope they will provide some advice. I will wait a bit for them to answer before opening the box.

Thank you !

[DeliciousTuning]

Originally Posted by nkobns

I’d have to open the Delicious box to check that... I also contacted Delicious, I hope they will provide some advice. I will wait a bit for them to answer before opening the box.

Thank you !

If it happens when you hit bumps. Try turning the car on and watch the logs as you move different parts of the harness around. Might just be a bad connection at the O2 sensor or maybe the ground is not secure. Even wiggle the wires coming out of the box.

You can also check out our facebook page for more immediate help, as we check this far more often.

https://www.facebook.com/groups/tunedbydelicious/

Regards,
William

[nkobns]

Originally Posted by DeliciousTuning

If it happens when you hit bumps. Try turning the car on and watch the logs as you move different parts of the harness around. Might just be a bad connection at the O2 sensor or maybe the ground is not secure. Even wiggle the wires coming out of the box.

You can also check out our facebook page for more immediate help, as we check this far more often.

https://www.facebook.com/groups/tunedbydelicious/

Regards,
William

Thank you for your reply, William.

I will try this and post afterwards here and on your FB page (My application has just been approved)

Regards,
Nicolas.

[nkobns]

Car idling, I monitored the ethanol content while moving and hitting bits of my FF kit. I could see some drops (around 1 or 2 drops per 2 min window), but I could not find any relation between what I was moving/hitting and the drops.

I went on for a drive and it seems that it occurs more often with bumps, while being on a bit of gaz. If I’m idling on neutral while rolling, there is less drops. Hence I’m considering something with the ethanol content sensor and the fuel feed... Bubbles ? or a similar problem to Mr_Eyo’s ?

In my case the car accelerates pretty well, consistently and smoothly.

Originally Posted by Mr_Eyo

The cause of the low feed pressure was the in-tank fuel sender pump not being fully seated.

Can you tell me more about the sender pump not being fully seated ?
Could you feel anything with the throttle/acceleration ?

Anyone knows whether the Delicious Tuning E content sensor signal sent to the D-Box is analog or digital ?

[Mr_Eyo]

Originally Posted by nkobns

Car idling, I monitored the ethanol content while moving and hitting bits of my FF kit. I could see some drops (around 1 or 2 drops per 2 min window), but I could not find any relation between what I was moving/hitting and the drops.

I went on for a drive and it seems that it occurs more often with bumps, while being on a bit of gaz. If I’m idling on neutral while rolling, there is less drops. Hence I’m considering something with the ethanol content sensor and the fuel feed... Bubbles ? or a similar problem to Mr_Eyo’s ?

In my case the car accelerates pretty well, consistently and smoothly.



Can you tell me more about the sender pump not being fully seated ?
Could you feel anything with the throttle/acceleration ?

Anyone knows whether the Delicious Tuning E content sensor signal sent to the D-Box is analog or digital ?

The DW pump installation required stacking 3 o-rings on each other to seat into the basket. When I pulled mine, the o-rings were deformed and not co-axial and thus did not perform the sealing function they needed to, hence the pressure drop. I could feel the effect of the ECU being lied to about the E% content: with E85 in the rails, low pressure caused the DT box to 0 out the reported E% content to the ECU. It then thinks it has 91 octane and reduces the injection amount. This then leads to a very lean sensed AFR after combustion, which then leads to pegging fuel trims and pulled ignition timing. I could feel this as a stutter when idling, but I couldn't really feel it during acceleration.

[nkobns]

Thank you for the details !
In my case I still run the stock fuel pump (NA setup, E85).

Does anyone know if the ethanol content sensor signal sent to the D-Box is analog or digital ?
If the signal is analog I could try adding a bespoke filter to smoothen the value and see if it removes the drops.

[nkobns]

UPDATE :
At the grey wire going from the D-box to the O2 sensor plug :
Multimeter reads 3,143 V very steady most of the time. Some drops could be noticed, very sudden ones (I’d say a tenth of a second long) :
- Once in a while (every 30s to 1min), drops to around 3,050 V. Usually nothing shows on the E% monitoring, and sometimes there’s a drop (small -40%- or big -0%-)
- And a bit less often (every 1 or 2 min), drops to around 2,950 V. Then, but not each time, there is an E% drop (half the time drops to around 40%, other half drops to 0%)

[nkobns]

UPDATE :

Could it be some kind of interference messing with the signal ?

I inserted a 0,5MΩ resistor between the Dbox output and the O2 plug to measure receiver’s impedance, and noticed something strange :
During the 10 min that I left it that way, I haven’t had a single drop ! (Sent signal was lowered to 2,2V giving a 44% ethanol content)

What’s mind bugging is that during the whole time, no drops while the connections looked like this :

(do not try to figure out color coding ^^)


Next step is to add a capacitor to smoothen the signal...

Any idea ??

[Mr_Eyo]

I think you physically manipulating the connector caused something intermittent to make contact. Tear it down, manipulate it a bunch, then re-instrument it like you have it and see if the drops come back. If so, it's likely an intermittent open on one of the conductors. Don't add a capacitor, it would not address root cause and would only add phase lag to the signal going to the ECU.