Ariel.Club Forum

Evening knowledgeable people,

My Ariel Atom (2011 supercharged) has developed a weird issue. I was at a track day yesterday and all was well. Parked up in a pit garage and put some fuel in and then switched ignition on just to get a reading off the dash fuel gauge. The fuel pump normally primes and then cuts out after 3 seconds or so, but for some reason it kept priming. Having investigated a bit further today, it primes 17 times and then stops. It does it 17 times every time you put the ignition on and repeat. If you try and start the car whilst it is doing this fuel pump priming/cycling it will start but idle very rough. After the 17 cycles of priming the engine dies. The engine will not start at all after this (the fuel pump is not running)

Here is a video I took today whilst investigating:



There is a relay at the front of the car that clicks/energises when the fuel pump activates; I swapped that out today and it makes no difference. At the back of the car near the ECU there is this thing which also clicks every time the fuel pump runs/cycles:





Googling the part number at trackside yesterday reveals its a "fuel pump module relay" and is from (amongst other vehicles) a Freelander. I found a localish Freelander breakers/specialist and they took one off a vehicle they had there. I got them to connect up the module from my Atom. Although I didn't see them start the Freelander, they said it ran but didn't sound "right". I was hoping it would make the Freelander cycle the fuel pump like my Atom and confirm this was the faulty part but no joy. However, they kindly let me borrow the unit they took off their Freelander so I took it back to the track and fitted it, it didn't make any difference. Today I also resoldered all the pads on the printed circuit board inside my original fuel pump module relay and again no difference. I'm fairly confident it has eliminated this part from being the cause.

If I turn the ignition on without deactivating the immobiliser, both the relay at the front of the car and the fuel pump module relay click 17 times but the fuel pump does not run. I don't think the immobiliser is causing the issue.

There is a quick release connection on the fuel line feeding the fuel rail. I disconnected this and aimed it into a bucket. When the ignition is on and the fuel pump starts cycling/priming fuel pisses out.

I've googled to see if the Honda K20 engine has a fuel pressure sensor incase that is the problem but it doesn't appear to have one.

I don't know if there is a fuel pressure regulator (maybe that red thing visible in the video?) or if a faulty one could even cause this issue?

I am at a complete loss now. I hate electrickery faults on cars. Can anyone help or point me in the right direction?

Many thanks

Sounds very wierd. Maybe attachments will help isolate

smokin wrote: ↑Wed Sep 19, 2018 5:46 pm Sounds very wierd. Maybe attachments will help isolate

Cheers for the pin outs etc smokin, that's a big help

This is indeed very strange and I suspect it's going to be a bastard to resolve, I hate elecktrickery type car faults

smokin, do you (or anyone else) happen to have a fuse/relay diagram listing what does what on the Atom?

Cheers

Just found it in my Owners Manual!

This is strange, the relay that clicks with the fuel pump is actually the "Throttle Pedal Relay." I assumed it must be a relay for the fuel pump due to clickin/energising in sync 17 times with the fuel pump.

I wonder if this is linked to my issue somehow?

Maybe the ECU is having an issue and rebooting/retrying 17 times before giving up. Do you have an OBD port? or an LED for check engine light? Might be worth checking to see if ECU is bitching about anything.

Also, the ECU just primes the pump for a set period of time rather than continuosly until pressure or some other signal is received

smokin wrote: ↑Wed Sep 19, 2018 7:17 pm Maybe the ECU is having an issue and rebooting/retrying 17 times before giving up. Do you have an OBD port? or an LED for check engine light? Might be worth checking to see if ECU is bitching about anything.

I only have a crappy £15 OBD blue tooth adapter, but I will give it a go. No other LED's etc

smokin wrote: ↑Wed Sep 19, 2018 7:30 pm Also, the ECU just primes the pump for a set period of time rather than continuosly until pressure or some other signal is received

I take it thats from your own kpro software? Is that freely available for diagnosis/checking ECU, or only available if you purchase an upgrade or get the ECU mapped etc?

Also, something I've just discovered, whilst the fuel pump is dancing on/off, when I press the throttle pedal you can hear it actuating the drive by wire butterfly in the throttle body. Once the fuel pump has primed 17 times and shuts down, the throttle pedal no longer operates the butterfly, it goes dead. I'm starting to think that this is an ECU issue....

Toilet Duck wrote: ↑Wed Sep 19, 2018 7:51 pm I take it thats from your own kpro software? Is that freely available for diagnosis/checking ECU, or only available if you purchase an upgrade or get the ECU mapped etc?

Software is freely available but only of use if you have the kpro board in the ECU instead of the factory K100. Had CPL fit the board and TDi North send me the file from when they mapped my car.

Toilet Duck wrote: ↑Wed Sep 19, 2018 7:51 pm Also, something I've just discovered, whilst the fuel pump is dancing on/off, when I press the throttle pedal you can hear it actuating the drive by wire butterfly in the throttle body. Once the fuel pump has primed 17 times and shuts down, the throttle pedal no longer operates the butterfly, it goes dead. I'm starting to think that this is an ECU issue....

I concur. If it's throwing a code then your £15 dongle plus an app like TorquePro should show it

If OBD doesn't give any clues and if you haven't already tried, might be worth powering off/on the ECU. Using master cut-off if you have one or disconnecting earth strap from battery, leave it off for 10 mins or so, reconnect and try it.

Just tried two blue tooth dongles and TorquePro on my tablet and unfortunately the tablet can't connect to the blue tooth reader. I've previously used this set up on numerous everday type cars and it's always worked, so I don't know if the Atom uses some unique protocol or if my set up just isn't compatible.

smokin wrote: ↑Wed Sep 19, 2018 8:55 pmSoftware is freely available but only of use if you have the kpro board in the ECU instead of the factory K100. Had CPL fit the board and TDi North send me the file from when they mapped my car.

Ironically my Atom is booked into CPL in a couple of months for some major work, including a FlashPro. I think I have exhausted my DIY skills so I think I'll get in touch with them as they are Hondata experts and try and get this looked at beforehand. My suspicions is that this is an ECU related problem.

Cheers

Toilet Duck wrote: ↑Thu Sep 20, 2018 3:10 pm ... so I don't know if the Atom uses some unique protocol or if my set up just isn't compatible.

I didn't have any problem with my obd setup, it works the same on the Atom as other cars I've hooked up to. I suspect it's a symptom of the fault. My dongle has lights so you can see it's connected sucessfully to the ECU, do yours?

Toilet Duck wrote: ↑Thu Sep 20, 2018 3:10 pm Ironically my Atom is booked into CPL in a couple of months for some major work, including a FlashPro. I think I have exhausted my DIY skills so I think I'll get in touch with them as they are Hondata experts and try and get this looked at beforehand. My suspicions is that this is an ECU related problem.

CPL will have ECUs will full diags to swap in to narrow down the problem. Experts in Hondata with plenty of Atom experience, probably better placed to sort your problem than the factory in this instance.

Here is a pic of my dongle:



Only the first light (POWER) illuminates when plugged into the Atom. I have two of these adaptors and they both do the same.

Cheers

That make/model supports all OBD II protocols so no green light suggests ECU isn't able to establish comms. I suspect the ECU is rebooting every few seconds (given the almost continuous attempts to prime the pump) and so is not getting far enough in its startup procedure to do comms. Could be something as simple as a bad ECU ground or, sadly, could be a knackered ECU. Please let me know what CPL discover