running rich

flinty

Hello All,

I've been doing some lockdown jobs on the old SP4 but now all back together and i'm having a big headache getting her up and running. I'm starting to get to appreciate that part of owning an 888 that isn't simply the untold joy of the riding!?

The problem is that she's running, but running very rich on both cylinders and after much testing and head scratching, I've found that by cranking over and looking into the vertical throttle body, both the injectors (IW031) are firing, which I'm thinking is the main reason for the rich running.

I'm visually checking the injector spray by disconnecting the vertical throttle butterfly from the linkage and looking into that throttle body, held open while cranking over, so the TPS is in the closed position on the horizontal cylinder. Not sure if the TPS position affects the control of the second injector anyway? My understanding is that only the inboard injector on each cylinder should be firing at low revs and with the throttle shut?

The TPS output at the ECU pins is checking out OK (~350mV to 4.7V). I've swapped out the P8 ECU for an old spare P7 and the same outcome, with both injectors/cylinder firing. I've checked the various sensors relating to the fuelling, like airbox temp, water temp etc. All are checking out OK. The resistance of the timing pick ups also checking out OK. If I disconnect the flywheel pick up and crank the motor, the injectors don't fire, if I reconnect, both fire. The flywheel and cam pick ups checked with respect to the connectors going to the right leads into the loom (i've not had the engine out, so these connectors weren't disconnected anyway, air gaps on pick ups not disturbed but flywheel gap checked anyway and all good)

If I disconnect the outboard injectors and fire her up, she barely runs any better, still very rich, so its like even with only one injector per cylinder, the duration of that injector pulse is too long or something else meaning still seems to be way too rich.

The fuelling wasn't giving me any problems previously, so the basic set up is OK.

Any ideas? Any mistakes I'm making in my assumptions? I'm trying to get out for a ride before I get locked back down again!!

Thanks
Gavin

hindsight

Have you checked your temperature sensors?

The air and water temperature can affect fuelling as the ECU tries to compensate for the temperature. If one of those sensors is giving inappropriate readings, then it might be affecting your fuelling.

You should see about 3750 Ohms on the sensors at 20C and 200 Ohms at 100C

Mike

Edit: Oops - you already said that the other sensors were checking out ok..Ignore me 😄

flinty

Thanks Mike,,

I though that the coolant sender was going to be the problem, specially as it starts fine but then quickly goes off and starts smoking. I bled the coolant system with the sender loosed off so I could be 100% that there was no air lock. Tested the sendervresistance at various temps in water on the cooker, all checked out OK. The voltage at the ECU also looked good, about 2 V at room temp, which seems to indicate no major fault at least. Same for airbox temp sender. This was all before I noticed that both injectors were running, so then I started to think it wasn't so much a trim type input that was wrong, more like ECU or rpm pick up or something electrical.

griff851

Is you reversion valve opening? Increase in fuel pressure will make it run rich.

hindsight

It occurs that if you're getting both injectors firing at low revs, then the ECU has definitely calculated a high duration. If it was an issue with the cam/crank sensors, then I'd imagine it would have trouble running at all, as it would knock out your spark timing.

Rather than the sensors, could it be a ground or loom issue?

flinty

griff851 wroteIs you reversion valve opening? Increase in fuel pressure will make it run rich.

Thanks Griff..

yes fuel over pressure seems like something I need to rule out. I'll need to rig up a pressure gauge into the fuel line. I have replaced the pump and filter, so I may have upset the pressure regulator.

flinty

hindsight wroteIt occurs that if you're getting both injectors firing at low revs, then the ECU has definitely calculated a high duration. If it was an issue with the cam/crank sensors, then I'd imagine it would have trouble running at all, as it would knock out your spark timing. Rather than the sensors, could it be a ground or loom issue?

Yes, mike, I fear this could be where i am headed. it seems like the injector side of things is timed OK but that the duration and number of injectors is not being controlled, just on at 100%.

Am I definitely right that at cold start, only one injector per cylinder should fire? there's no choke function that fires both injectors?

hindsight

flinty wrotethere's no choke function that fires both injectors?

I've not had the need to verify this on my SP5, but there is a warm-up-enrichment facility available in the ecu, and if the figures I see in the SP5 image are to be believed it could add 34% fuel: is that enough to go dual injector at cold-start? I'm not sure - I suspect Brad might be able to answer that.

flinty

griff851 wroteIs you reversion valve opening? Increase in fuel pressure will make it run rich.

Checks out at 3.4 bar, I'm thinking that's not so high as to cause the problem..

jakepeewee

3.4 bar will not be the cause of the problems you're having, I think. It does mean that someone messed with the Fuel pressure regulator though.

AFAIK the ECU triggers two injectors per cilinder based on an RPM setpoint, doesn't calculate the amount of fuel needed and then decides two injectors are needed.

Could it be sticking injectors?

dudlington

Just my 2 pennyworth. This is an easy job. Rig up a seperate earth to the ECU to the Engine or something steel and see if that makes a difference. SP4,s run Ali subframes. I had some weird stuff going on on my SP4 and did this and it came back to normal. I kept the extra earth cable attached.

flinty

dudlington wroteJust my 2 pennyworth. This is an easy job. Rig up a seperate earth to the ECU to the Engine or something steel and see if that makes a difference. SP4,s run Ali subframes. I had some weird stuff going on on my SP4 and did this and it came back to normal. I kept the extra earth cable attached.

OK, thanks for the tip dudlington. I'll give it a try. Run an earth from the ECU case?

Mr.R

dudlington wroteJust my 2 pennyworth. This is an easy job. Rig up a seperate earth to the ECU to the Engine or something steel and see if that makes a difference. SP4,s run Ali subframes. I had some weird stuff going on on my SP4 and did this and it came back to normal. I kept the extra earth cable attached.

I don't think your problem had anything to do with the alloy subframe, since the ECU isn't earthed to it?
The ECU earths through the loom to whatever earth point it uses, so your problem was probably in the loom.

Steve R

flinty

Mr.R wroteI don't think your problem had anything to do with the alloy subframe, since the ECU isn't earthed to it? The ECU earths through the loom to whatever earth point it uses, so your problem was probably in the loom. Steve R

Hi Steve, I see what you mean. The ECU pins that are to earth, 1 and 19? checked out ok from the back of the plug. But I'll try the bypass idea anyway., nothing to lose.

I'm having a week off banging my head against the wall next week with a trip to Cornwall. You still there? Maybe I can pop by and pick your brains? I'm staying up near newquay, where you based?

flinty

jakepeewee wrote3.4 bar will not be the cause of the problems you're having, I think. It does mean that someone messed with the Fuel pressure regulator though. AFAIK the ECU triggers two injectors per cilinder based on an RPM setpoint, doesn't calculate the amount of fuel needed and then decides two injectors are needed. Could it be sticking injectors?

I think the 3.4 bar was more just an offset error of the gauge. Injectors been given a service as part of the winter refresh! They're all visually firing fine, just too many of them firing. The manual says that to test the outer injectors you need to swap them with the inner ones, so that also implies that only inner ones fire at cranking over revs.

I tried the ecu earth strap suggestion, but no joy there. Now deep into multimeter world, it's not a great deal of fun..

Sparks are good and injector timing must be ok as it starts up no bother.

Anyone tried the manual fix if hooking up a live to pin 20 so as to bypass the inputs from the various temp/pressure sensors so as to rule these out as a possible fault?

griff851

I had the air pressure sensor break a wire on the plug which gave me rich running. I found it with the multimeter using the ecu plug and basic continuity check. You have to wiggle the leads going into the back of the sensor plugs with the plug disconnected. I pulled the plug apart, sure enough broken wire. Fitted a new pin and good as gold again.

ducati dad

Hi Flinty, did you resolve the problem yet, or any update on it ?

flinty

ducati dad wroteHi Flinty, did you resolve the problem yet, or any update on it ?

Still deep in the mire! Groan! I'm slowly counting things out, but generally I'm not really feeling like I'm getting any closer! If I had the parts, I'd ideally next try to swap out the fuel injection system part of the loom and see what happens, but I don't expect to be able to find a willing donor!! (any offers put there?)

I've been in touch with Brad who has offered some good advice. Main point being that the cold start condition does not lead to a 4 injector operation, 4 injectors is only a function of the engine speed. As the timing of the spark and injectors looks good, then I am thinking there is no issue with the pick ups.
Brad had suggested to try a 2 injector type chip for the P8 ECU and see where that leads, so I will be trying to find a suitable chip to try that setting.

I've got more continuity checks to do to keep myself busy in the meantime!

ducati dad

Thanks for the update...

outtacontrolla

Check the two fuel lines to the tank are not swapped over ....
Easy done .