Forum

[LOTUS7]

Hi,
I have a 2014 500 EFI B5 that has an issue with the fuel injector.

The bike will start and run , but on opening the throttle under load the engine cuts out and dies.

I have checked the MIL readout and the ECU reports that the throttle circuit and the injector circuit are bad.

the throttle pot has 5v to it and reads .8V closed and 4.8V open.
the cable back to the ECU is ok on continuity. and the .8v/ 4.8V is being fed back to ECU plug.

I have checked the injector and it has continuity to pin 16 on ECU and 5V available to + pin on injector.

With the injector out of the throttle body, but connected to fuel and ECU it has a good spray pattern and atomisation BUT anything more than 1/3 throttle the injector cuts out and wont spray.

Im thinking that their is a fault with the ECU preventing the injector working at anything more that minimal openings,.... any one else have any imputs on this fault....?

All other sensors appear to be ok and connected to ECU, injector has been cleaned and pump is new.

thanks in advance.

RIK

[Rattlebattle]

An interesting one. When I had the EFI on my 2015 C5 (I've put a carb on it now) I had a similar problem. The engine would start and tickover but misfire and die on opening the throttle. In my case it turned out to be a bad tps connection. If I understand you correctly though, you've eliminated this as a cause by verifying the voltages at the ECU on closed and at WOT and anyway you are getting different fault codes. I doubt that the ECU is faulty; it's usually a sensor connection that plays up. I wonder whether it could be the side stand switch cutting out as the engine is revved. Most (or at least many) of us disconnect that switch as it is a known PITA as the contacts get dirty. The other usual culprit is the negative battery cable that can cause intermittent connection issues. Apart from the side stand switch (and of course the kill switch) the rollover sensor would also cut off the fuel supply. I can't really see that this would be the cause here though. Could it be a dodgy fuel pump connection? Sorry I don't have a definitive answer; I would double check all the sensor connections, the battery leads including the small cable to the negative terminal, and if you haven't already disconnected it the side stand cut out switch.
Hope that helps.

[Tim NZ]

You apparently have access to a manual of sorts?


But without a DOL tool one is only second guessing, the alternative is to check by substitution of the alleged offending sensors; tps and or hook up a jumper power feed to the injector...


Make and break all connector blocks again, and pay close attention to the MAP and TPS ones. The side-stand switch is really only a PITA to the staring circuit, but it would not hurt to bypass it for the time being?


You could also by-pass both the neutral and clutch switchs for good measure?

[jefrs]

i would have to check the throttle volts on my C5's PCV, those volts do not sound right. The electrical connections/connectors are a known poor area so break and re-make all connections in sight including the fuses. The injector is working which shows the fault is not there, more likely at the TPS or the air flow sensor and the connectors are a tight squeeze besides the throttle body. Do check for corroded fuses as these can throw up some weird issues. Also check battery connectios and electrolyle level, there is a thin wire from battery to ecu that can come adrift.

[jefrs]

The DOL Tool provides little more information than the MIL blink. Showing faults on throttle and injector probably means little more than bad electrical connections.

[nigelphoto]

Lotus sounds like fuel pump and/or filter (in the tank) to me - even with a faulty relay it will still run in 'limp' mode which is what its doing according to your description.

[LOTUS7]

Thanks for the responses.

I have checked the ECU to -Ve terminal cable and it is connected and continuous.
I have disconnected the side stand sw.
I have re-checked the TPS voltages and 0volt line.
power feed to TPS is 5.2 V
the output is .6v throttle closed and 4.1 V opened.(the works manual only states .6V (+/- .2v) at throttle shut.)

I have also rechecked the pump (which is brand new)this runs when engine is cranked and also when running.

The injector is also getting a continuous supply @battery and regulator voltages during cranking /running and importantly has its supply present when the injector
stops injecting when the fault is apparent eg on opening the throttle.

This leads me to believe that the injector fault is being caused by the ECU which may be in "limp home " mode or otherwise faulty.

I do not have access to a spare ECU or a DOL tool as suggested by TIM NZ

Im hoping to get the ECU checked by a local dealer before comitting it to re flashing.

Again, thanks for the responses and I will post any updates as this may help some other poor soul in future.

RIK

[jefrs]

My C5's Dynojet PCV does report the throttle volts and also calibrates on it. Unfortunately I'm nowhere near my bike this week but seem to rember 0.5 & 3.85V, however I do not trust my memory with numbers. I need to check my numbers! The MAF also regulates the injector so there may be something amiss there. Not forgetting the O2/Lambda sensor which only starts to play when hot, and has litte effact near idle, unlike the wide-band Bosch O2 sensor on the Dynojet Autotune AT-200 which shows and regulates mix in real time. I.E. having had both, and that the PCV/AT200 data-logs can see that a dodgy O2 sensor could shut the injector off (I use this capability to shut off the injector to prevent/reduce popping). I was not aware that the EPROM in the ECU could be flashed, it is however possible to do a reset on the ECU (which I don't have with me,workshop manual?). I still strogly suspect electrical connection fault.

[LOTUS7]

Problem solved....!!

Cutting to the chase...

The in tank fuel filter was collapsing on to the inlet port cutting off the fuel feed during extended throttle openings.

I have now removed the in tank filter from the equation and am running an external filter in the air filter side panel.

I did have to clean and remake all the sensor connections as they were causing intermittent faults on the system.

Also cleaned the injector and MAP sensor and its port.

I now believe that the blocked filter caused the demise of the original fuel pump, which is what started this whole pantomime off in the first place.

For any one who wants to know, the pump is replaceable as a stand alone unit, from http://fuelperformance.co.uk (search keihin) .. but it wont come with a suitable filter .

[Boxerman]

I went to the page you linked to and searched for Keihin. The pumps shown were all the same, code HFP397 and looked nothing like the pump module shown in the parts book.
Am I correct in thinking that you dismantled the module and fitted an HFP 397 pump into it?
If so, that would be a tremendous saving for anyone needing a new fuel pump, £60 compared to £550.

Frank