Both AFR's Bad.
Discussion
markys said:
Where are the coil packs ?
Its a 4.2 by the way.
>> Edited by markys on Thursday 3rd February 14:40
They are in the V behind the alternator and under the fuel rail. Shine a torch down and you'll see all the plugs down there. Mark them carefully before you pull them out....
Mine's started doing that sort of thing. The computer shows both lambda sensors not working properly.
Mine won't tick over, its the driver's side bank that's the problem.
If I hold the revs up that side bangs and misfires excessively.
If I twist the throttle pot anti-clockwise, to simulate a throttle wide open position, it runs ok.
This leads me to suspect that there is a fuel shortage, possibly caused by the dodgy lambda sensor.
I'm going to take off the cats and see if they're knackered, and at the same time change the lambda sensors.
Unless anyone has any other ideas...
Mine won't tick over, its the driver's side bank that's the problem.
If I hold the revs up that side bangs and misfires excessively.
If I twist the throttle pot anti-clockwise, to simulate a throttle wide open position, it runs ok.
This leads me to suspect that there is a fuel shortage, possibly caused by the dodgy lambda sensor.
I'm going to take off the cats and see if they're knackered, and at the same time change the lambda sensors.
Unless anyone has any other ideas...
markys said:
Did a ECU reset and a fill up with Optimax and a good run both AFR's good but at 1450'ish rpm adaptive 1 is at 0% give or take 1% and adaptive 2 around -20% give or take a couple of % is this correct ?
Not correct in the slightest, they should be pretty much equal. Have you checked to see what condition the spark plugs are in?
markys said:
Did a ECU reset and a fill up with Optimax and a good run both AFR's good but at 1450'ish rpm adaptive 1 is at 0% give or take 1% and adaptive 2 around -20% give or take a couple of % is this correct ?
Is -20% the adaptive limit? It can't be far off. If the lambda reading is cycling rich/lean then the sensor is working as intended and there may be some other fault throwing the afr out - air leak or misfire for example. If it's cycling very slowly or not at all then it is non-responsive or faulty.
markys said:
Did a ECU reset and a fill up with Optimax and a good run both AFR's good but at 1450'ish rpm adaptive 1 is at 0% give or take 1% and adaptive 2 around -20% give or take a couple of % is this correct ?
your starter for 10, no conferring ..
if you don't have any obvious misfire you should be able to think about what's going on here and be able to work out the cause .. think .. one bank is having to reduce the fuelling by 20% to get it cat friendly .. what could be the cause ..?
joospeed said:
Did a ECU reset and a fill up with Optimax and a good run both AFR's good but at 1450'ish rpm adaptive 1 is at 0% give or take 1% and adaptive 2 around -20% give or take a couple of % is this correct ?
your starter for 10, no conferring ..
if you don't have any obvious misfire you should be able to think about what's going on here and be able to work out the cause .. think .. one bank is having to reduce the fuelling by 20% to get it cat friendly .. what could be the cause ..?
ok, joolz, no idea what i'm talking about here so will no doubt be completely wrong but I'm bored.
obvious answers then are too much fuel or too little air.
Going with too much fuel. Are the throttle pots set properly, IIRC fully closed (remove cable) is 15%, idle about 19% and fully open about 97%.
My theory is if one TP is set too high then for any given throttle position one bank will have more fuel than the other for equal air.
Too little air doesn't really work unless you have a blockage in your air intake or if the butterflies arent opening properly.
Like I said, no idea what I'm talking about so if it's completely off the mark tell me so I can delete all this bollox
joospeed said:
very good .. the sites move up the fuelling and ignition map as you advance the throttle pots .. so for any given airflow yuo get more fuel one bank with the higher pot reading .. but you should be aiming to have the pots about equal anyway .. so that leads you to ....
So.. assuming there is one fuel line from the tank (don't know this) which feeds the fuel rail.
Fuel rail is constant pressure system and injectors simply open/close.
Does that lead to a problem with the injectors or am I going too far. If one side had an injector problem resulting in it being open all the time then that would prob lead to overfueling.
Can't imagine it would be an air blockage because if it was at the filter it would affect both banks.
The throttle pot takes it's reading from butterfly position, yes/no?? So if the pots were set up correctly then the linkage should be ok.
Aaarrrgggghhh, I knew there was a reason I'm not a mechanic.
clue :
the throttle pots can be rotated relative to teh throttle spindle that carries the butterlies .. so you *can* have equal throttle pot readings and unequal airflows bank to bank ..
so ..
if you have equal throttle pot values you have equal fuelling to both banks, yet one bank is still trying to reduce the fuelling .. so that bank must be .....
flowing less air.
what you've got is an inbalance across the banks in airflow .. you need to adjust on the threaded link rod
It's the method I use to balance the engines .. I hardly ever use the air mass gauge, I just get it all equal off the laptop .. takes a quarter the time once you understand what's going on ..
the throttle pots can be rotated relative to teh throttle spindle that carries the butterlies .. so you *can* have equal throttle pot readings and unequal airflows bank to bank ..
so ..
if you have equal throttle pot values you have equal fuelling to both banks, yet one bank is still trying to reduce the fuelling .. so that bank must be .....
flowing less air.
what you've got is an inbalance across the banks in airflow .. you need to adjust on the threaded link rod
It's the method I use to balance the engines .. I hardly ever use the air mass gauge, I just get it all equal off the laptop .. takes a quarter the time once you understand what's going on ..
ok.... i was thinking butterflies if it was an air problem but I would have thought that if he had the pots set up recently then the linkage would be ok.
if it has been set for full closed, then set the idle, you can see if there is any opening delay between banks i would have thought.
i know my car has your mod from when you were up in harrogate but is it really that bad originally?
just curious in case i have the same thing myself someday.
if it has been set for full closed, then set the idle, you can see if there is any opening delay between banks i would have thought.
i know my car has your mod from when you were up in harrogate but is it really that bad originally?
just curious in case i have the same thing myself someday.
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