Wierd fuelling issue
Discussion
Right, my problems appear to be back, confirmed by some spirited driving to and around north wales over the weekend.
Driving along happily I lose one bank (the near side) which is very dangerous, particularly in an overtaking manoeuvre. The idle is very rough, there is no power at all and even won;t maintain a constant speed, and it kicks what smells like neat fuel out the n/s exhaust - the o/s side smells of pure pre cat carbon so convinced its the n/s bank going and would appear that fule is still getting through just not being ignited, but why one bank only??? If I turn off and/or disconnect the ECU it is fine for a while but then just goes without warning. It is also has a spate of stalling when you dip the clutch but seems to sort itself out (eventually) so not sure if they are related but more than likely.
It pulls like a train when its on song, but the nature of the problem inspires no confidence.
I've replaced the dizzy and attached ignition amp, swapped ECU and fuel pump relays, swappped the ECU, checked leads, plugs etc, and had a lot of refreshed wiring done in the under bonnet area. Got a spare coil I can try and an AFM which I'll also try.
I thought this had been cured towards the back end of the year but I haven't been out in it much, in fact after the Growl it went in. I've done one day at Shakespeare Raceway 1/4 mile strip (about 8 runs), and took it for an MoT so this was its first real test.
Not heard of this one before so it could be straightforward, but as its not fixed, maybe not.
Do I need an ECU Mate to check, and does anyone near Redditch have one I could borrow and knows how to use it?
FFG
Driving along happily I lose one bank (the near side) which is very dangerous, particularly in an overtaking manoeuvre. The idle is very rough, there is no power at all and even won;t maintain a constant speed, and it kicks what smells like neat fuel out the n/s exhaust - the o/s side smells of pure pre cat carbon so convinced its the n/s bank going and would appear that fule is still getting through just not being ignited, but why one bank only??? If I turn off and/or disconnect the ECU it is fine for a while but then just goes without warning. It is also has a spate of stalling when you dip the clutch but seems to sort itself out (eventually) so not sure if they are related but more than likely.
It pulls like a train when its on song, but the nature of the problem inspires no confidence.
I've replaced the dizzy and attached ignition amp, swapped ECU and fuel pump relays, swappped the ECU, checked leads, plugs etc, and had a lot of refreshed wiring done in the under bonnet area. Got a spare coil I can try and an AFM which I'll also try.
I thought this had been cured towards the back end of the year but I haven't been out in it much, in fact after the Growl it went in. I've done one day at Shakespeare Raceway 1/4 mile strip (about 8 runs), and took it for an MoT so this was its first real test.
Not heard of this one before so it could be straightforward, but as its not fixed, maybe not.
Do I need an ECU Mate to check, and does anyone near Redditch have one I could borrow and knows how to use it?
FFG
SSPPGG said:
thinking about it, i once had a similar issue with an air leak in an exhaust, before the o2 sensors, would send the ECU fuel map off the charts trying to compensate for it.
Pre cat so no lambda sensors.No visible leaks and fairly new S/S ACT system. Only does it randomly and did a couple of hours driving before it goes so suspect a dodgy wire somewhere but why one bank only??? Goes very well before the bank drops out.
FFG
so if its one bank... what could be the problem
The dizzy / plugs / Coil etc must be okay.. they can't pull a bank down
The sensors in the exhaust Y must be okay as they will run off 1 (or so I understand)although this would be a place to look if thats not true.
Can't be the MAF if its one side...
But your still getting fuel... so it's like 1 bank starts to over fuel and flood?
My guess would be the ECU or injector wires... but they would have to be getting a supply to hold the injectors open longer... so ECU?
Is there any way you can check to see if it is being over fueled when it goes?? (wet plugs for example)...
The dizzy / plugs / Coil etc must be okay.. they can't pull a bank down
The sensors in the exhaust Y must be okay as they will run off 1 (or so I understand)although this would be a place to look if thats not true.
Can't be the MAF if its one side...
But your still getting fuel... so it's like 1 bank starts to over fuel and flood?
My guess would be the ECU or injector wires... but they would have to be getting a supply to hold the injectors open longer... so ECU?
Is there any way you can check to see if it is being over fueled when it goes?? (wet plugs for example)...
FlipFlopGriff said:
Swapped the ECU so what are the chances of 2 ECU's having the same fault.FFG
Unlikely, Sounds more like a connection or wiring problem. Each bank of 4 injectors is connected to one driver in the ecu, ie all the injectors on the drivers side are connected together and go to one driver and all the ones on the passenger side are connected together and go to another driver. So if you have a dodgy connection in the ecu plug then that would affect 1 side only. TVR Beaver said:
so if its one bank... what could be the problem
The dizzy / plugs / Coil etc must be okay.. they can't pull a bank down
The sensors in the exhaust Y must be okay as they will run off 1 (or so I understand)although this would be a place to look if thats not true.
Can't be the MAF if its one side...
But your still getting fuel... so it's like 1 bank starts to over fuel and flood?
My guess would be the ECU or injector wires... but they would have to be getting a supply to hold the injectors open longer... so ECU?
Is there any way you can check to see if it is being over fueled when it goes?? (wet plugs for example)...
No lambdas as its a pre cat so rules that out.The dizzy / plugs / Coil etc must be okay.. they can't pull a bank down
The sensors in the exhaust Y must be okay as they will run off 1 (or so I understand)although this would be a place to look if thats not true.
Can't be the MAF if its one side...
But your still getting fuel... so it's like 1 bank starts to over fuel and flood?
My guess would be the ECU or injector wires... but they would have to be getting a supply to hold the injectors open longer... so ECU?
Is there any way you can check to see if it is being over fueled when it goes?? (wet plugs for example)...
If it was over fuelling and flooded, then presumably I wouldn't be able to start it straight away?
FFG
Pink_Floyd said:
Unlikely, Sounds more like a connection or wiring problem. Each bank of 4 injectors is connected to one driver in the ecu, ie all the injectors on the drivers side are connected together and go to one driver and all the ones on the passenger side are connected together and go to another driver. So if you have a dodgy connection in the ecu plug then that would affect 1 side only.
That sounds probable. I've changed the ECU but not the plug or associated wiring. Any idea which wire controls the n/s bank? If I could replace that wire then see what happens. I'm getting pretty fed up with it as you may gather as it takes all the enjoyment away from the driving experience as there is no warning and it could go at any time.FFG
yes.. they don't work as the valve opens or anything... they just pulse away against the RPM and fuel is drawn in as the valve opens (much simplified).... So in theory you could swap the banks over.....
If its not ECU it must be the wires to one back... But didn't you say you'd had some re-wiring done?.. what did they do??....
If it's going open circuit why would you get the fuel smell?... it would cut a bank out... the other bank would still run okay... so no un-burnt fuel??.. Thats why I thought it could be over fueling and killing the bank a bit... It may re-start okay.. but would have to give the injectors a supply to do this?... Not sure...
May be Blitz can comment...
If its not ECU it must be the wires to one back... But didn't you say you'd had some re-wiring done?.. what did they do??....
If it's going open circuit why would you get the fuel smell?... it would cut a bank out... the other bank would still run okay... so no un-burnt fuel??.. Thats why I thought it could be over fueling and killing the bank a bit... It may re-start okay.. but would have to give the injectors a supply to do this?... Not sure...
May be Blitz can comment...
I had an identical problem a while back after fiddling with the passenger well wiring. It turned out to be the connections in the ECU plug. A wire had severed, Pin 11 I think. Pin 13 controls the other bank. The problem arises as there is little play in the ECU cable so any serious movement can easily break a connection. I was changing the heater hoses at the time so wanted the ECU cable out of the way. The main relay feeds both banks so that will be OK. It could be the wiring though from the relay to your faulty bank, not sure how that is routed.
Smells exactly like fuel as confirmed by 2 seperate people following me saying it was overpowering. Wiring work was more related to the coil area but some rewiring on injectors. Need to maybe check if all injector wiring has been done.
Agree on the bank and exhaust issue but one side stank of fuel the other was fine - odd??
FFG
Agree on the bank and exhaust issue but one side stank of fuel the other was fine - odd??
FFG
Hi Paul,just dug out my old RV8 build diagram to check wiring for you.All eight injectors have a brown/orange cable which from memory shares the same feed as the AFM.The other side of injectors 1 to 7 have yellow/blue cables which go to a splice in the engine harness then to cavity 13 in the main ECU plug.Injectors 2 to 8 have yellow/white cables which also go to a splice then to cavity 11 in the main ECU plug.Plenty to check there for starters.Splice in engine harness breaking down? Dodgy terminals in cavities 11 or 13? Good luck.Regards,Dave. If you need to know where the splices are in the engine harness give me a shout.
Edited by DVR V8 on Monday 14th May 20:05
You cant rely on what each tail pipe smells like, as they are joined on a common down tube...
But if you want diagnosis you could treat yourself to a set of 8 of the Neon type plug caps to keep an eye on the HT (assuming there is enough space and they wont melt(?)or if you think its injectors you really need some live monitoring on each injector bank- like a noid light that is just an LED that fits across an injectors and shows when its firing- You can buy kits for not a lot, you just need to get the right connector but you will need the fault to occur with the bonnet up. Personally id run a pair if wires back from an injector on each side to the cabin, and use it to fire an LED in series with a resistor (or a noid light) so you can keep an eye on the injector pulses inside the car when it fails. The ECU mate wont help much as you dont have Lambda feedback, and it does not monitor the injector pulses directly. Otherwise the AFM is a good thing to swap and check the connections, as failure will often lead to severe over fueling.
But if you want diagnosis you could treat yourself to a set of 8 of the Neon type plug caps to keep an eye on the HT (assuming there is enough space and they wont melt(?)or if you think its injectors you really need some live monitoring on each injector bank- like a noid light that is just an LED that fits across an injectors and shows when its firing- You can buy kits for not a lot, you just need to get the right connector but you will need the fault to occur with the bonnet up. Personally id run a pair if wires back from an injector on each side to the cabin, and use it to fire an LED in series with a resistor (or a noid light) so you can keep an eye on the injector pulses inside the car when it fails. The ECU mate wont help much as you dont have Lambda feedback, and it does not monitor the injector pulses directly. Otherwise the AFM is a good thing to swap and check the connections, as failure will often lead to severe over fueling.
Edited by blitzracing on Monday 14th May 20:32
Edited by blitzracing on Monday 14th May 20:38
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