Tiger running poorly - things to look for please

[Timbox2]

Just answered your post over on chat, but yeah looks like you may have a wonkey sensor.

I too have .465v cold, but my voltage rises as the engine warms to about .93 when warmed up.

[ChazzyB]

;-) And I just replied to you over there too!

Suspecting the O2 sensor, I made up a sensor eliminator, but it's made zero difference to the poor running. But as a replacement, seems to function OK, in that there was no DTC for sensor heater fail and sensor voltage reported by TuneECU sat at a constant 4.35v. That was using a 1 meg ohm resistor (all I could get) rather than 1.2m ohm, which is what a pal's pukka plug measures.

[Timbox2]

;-) And I just replied to you over there too!

Suspecting the O2 sensor, I made up a sensor eliminator, but it's made zero difference to the poor running. But as a replacement, seems to function OK, in that there was no DTC for sensor heater fail and sensor voltage reported by TuneECU sat at a constant 4.35v. That was using a 1 meg ohm resistor (all I could get) rather than 1.2m ohm, which is what a pal's pukka plug measures.

Im confused now as Ive just done a bit of reading and that led me to believe that the sensor itself generates the volts depending on mixture, so if you put a bypass in where is the voltage coming from? The heater circuit I presume.
But anyway, maybe the sensors fine and the voltage is low as its detecting a very weak mixture, so what do the plugs say?

[ChazzyB]

But anyway, maybe the sensors fine and the voltage is low as its detecting a very weak mixture, so what do the plugs say?

Plugs say weak. I wonder if I've got a fuel rail pressure problem.

[Timbox2]

But anyway, maybe the sensors fine and the voltage is low as its detecting a very weak mixture, so what do the plugs say?

Plugs say weak. I wonder if I've got a fuel rail pressure problem.

Didnt you say it was OK on full throttle? Have you tried reloading a map?

In view of chairheads recent discovery might even be worth unplugging the ECU connectors and having a looksee.

[Bixxer Bob]

What's expected usually from the O2 sensor? A bit of net trawling suggests typical O2 sensor output cycling between 0.8V and 0.2V, but I guess this depends on the sensor and the ECU? Oh, and when I changed the plugs last weekend, I thought they looked a bit on the weak side.

Aaargh!

The wid eband O2 sensor in the Tiger only reads around 0.1v for weak, 0.45v for normal and 0.9v for rich.  Any voltage in between is not related to how rich or lean, it's not that clever.

So to have a permanently lean reading you either have a duff sensor, or lean mix.  A duff sensor would not immediately affect the running, but would take the trims out of range.  Since you've reset the trims and the fault hasn't gone away, you need to look elsewhere.

Regarding the bypass resistor, the resistor is the same value as the internal resistance of the O2 sensor and is there only to fool the ECU into thinking the O2 sensor is connected otherwise it would log a fault and turn on the MIL light.  The bypass resistor adds nothing to the fueling function, that's the whole point of disconnecting the sensor.

If it's rough with the sensor disconnected (with or without the bypass resistor) something else is wrong.  A blocked injector maybe, or - as you say - fuel rail pressure down.  Either need specialist kit to check / rectify.  Or an air leak somewhere....

Have you read your trouble codes?  Is there anything relating to the injectors?

[ChazzyB]

Didnt you say it was OK on full throttle? Have you tried reloading a map?

I'd thought about that and have a note on my desk to remind me to try tomorrow.

In view of chairheads recent discovery might even be worth unplugging the ECU connectors and having a looksee.

Remind me of Chairheads problem (apart from having a chair   ) ???

[Bixxer Bob]

Didnt you say it was OK on full throttle? Have you tried reloading a map?
I'd thought about that and have a note on my desk to remind me to try tomorrow.

Make sure the battery is fully charged.  Remapping with a weak battery will look as though it's mapped ok, but the trims will be corrupt and it will run like crap.  I know this because that is what the dealer did to me on one occasion.  The reason for this is the signal to the ECU (which normally has an internal 5v power line) to allow the remap involves taking the Vff pin on the memory storage up 12.5v.  If the battery is not up to it, it can't sustain the 12.5v for the whole mapping period.

[Timbox2]

Didnt you say it was OK on full throttle? Have you tried reloading a map?

I'd thought about that and have a note on my desk to remind me to try tomorrow.

In view of chairheads recent discovery might even be worth unplugging the ECU connectors and having a looksee.

Remind me of Chairheads problem (apart from having a chair   ) ???

Its the thread below this one (Tiger comes home), he found a nasty surprise in one of the ECU plugs. His Tiger wasnt running at all mind.

[ChazzyB]

Its the thread below this one (Tiger comes home), he found a nasty surprise in one of the ECU plugs. His Tiger wasnt running at all mind.

Eeeugh! My ECU connectors are nice and clean inside - I checked.

[Bixxer Bob]

Please be sure to double back to my post on battery.  It was overtaken while I was writing it... :lol:

[Timbox2]

Please be sure to double back to my post on battery.  It was overtaken while I was writing it... :lol:

Funny you mention that BB, today when I was loading a new map a couple of times it "Timed Out", wouldnt load. I noticed it reported the Batt voltage at 12.6v. I ran the engine for a few minutes and got the voltage up to 13 odd, and then it went straight in :D

[ChazzyB]

Please be sure to double back to my post on battery.  It was overtaken while I was writing it... :lol:

Noted, will stick my meter on it before starting. Given the amount of starting and running at idle that's been going on, it could be weak. Could a weak battery that also cause a TPS reset to not 'take'? My guess is yes?

[ChazzyB]

Please be sure to double back to my post on battery.  It was overtaken while I was writing it... :lol:

Worryingly, battery at 13V (as reported by TuneECU, slightly higher on meter), reading current map has timed out twice now at 34%, TuneECU then appears to reconnect to the ECU (flashing red at bottom right, then amber, green). I have been having TuneECU loose connection quite frequently. Ideas? (Apart from "Burn it, it's a witch")

[Timbox2]

Please be sure to double back to my post on battery.  It was overtaken while I was writing it... :lol:

Worryingly, battery at 13V (as reported by TuneECU, slightly higher on meter), reading current map has timed out twice now at 34%, TuneECU then appears to reconnect to the ECU (flashing red at bottom right, then amber, green). I have been having TuneECU loose connection quite frequently. Ideas? (Apart from "Burn it, it's a witch")

Have you took the fuses out for the headlights? It drains the voltage pretty quick I have found if they are on.