Thoughts on these graphs please (pic heavy)
Discussion
Evening all!
Hoping to have a bit of a sense check on what is most likely going on here before I start replacing bits. Firstly a quick thank you to Calvin at Wilton Morgan engineering in Berks for letting me borrow the laptop and record a few traces!
A quick summary of the car.. it's a Tuscan 2S, with a 4.3 rebuild, and mapped around a year ago by Joolz. At the time there was a little play in the throttle linkages but this hasn't worsened over time. Recent 12k service by Calvin so generally all in good health.
So, the symptoms have only happened on around 3 recent drives, and consist of:
- Difficult to start when hot... needs a lot of throttle, and produces excess smoke as it finally turns over.
- Exhaust note changed to be very deep and boomy (very noticeable)
- Generally feeling a little sluggish although it is the exhaust note that I notice most!
I've taken a lot of screenshots with various times and of the adaptives. Once I'd done this, I reset the adaptives and took the car for a drive and it felt much much better, however a trip on Saturday showed the symptoms have returned.
My current thoughts are the lambdas as they appear sluggish and not switching consistently but if someone can spot anything else that would be great!
GX54AZZ Bank456 Before Reset by DH Photographic, on Flickr
GX54AZZ Bank123 Before Reset by DH Photographic, on Flickr
GX54AZZ Ignition Part Throttle by DH Photographic, on Flickr
GX54AZZ Ignition No Throttle by DH Photographic, on Flickr
GX54AZZ Ignition Full Throttle by DH Photographic, on Flickr
GX54AZZ Engine Running Part Throttle by DH Photographic, on Flickr
GX54AZZ Engine Running Part Throttle 2 by DH Photographic, on Flickr
GX54AZZ Engine Running No Throttle by DH Photographic, on Flickr
GX54AZZ Engine Running No Throttle 2 by DH Photographic, on Flickr
GX54AZZ Engine Running No Throttle then Part Throttle after adaptive reset by DH Photographic, on Flickr
Post Reset Ignition No Throttle
Post Reset Ignition Full Throttle by DH Photographic, on Flickr
Post Reset Engine running PartThrottle lo by DH Photographic, on Flickr
Post Reset Engine running part Throttle by DH Photographic, on Flickr
Post Reset Engine running no Throttle by DH Photographic, on Flickr
Post Reset Engine running No Throttle lo by DH Photographic, on Flickr
Post Reset Engine adaptive 123 by DH Photographic, on Flickr
Post Reset Engine adaptive 456 by DH Photographic, on Flickr
I'm starting, just starting to get too fed up with some of the little niggles and whilst most of them don't stop me using the car.. this is one I need to get sorted pronto!
Internet beer for your thoughts
Hoping to have a bit of a sense check on what is most likely going on here before I start replacing bits. Firstly a quick thank you to Calvin at Wilton Morgan engineering in Berks for letting me borrow the laptop and record a few traces!
A quick summary of the car.. it's a Tuscan 2S, with a 4.3 rebuild, and mapped around a year ago by Joolz. At the time there was a little play in the throttle linkages but this hasn't worsened over time. Recent 12k service by Calvin so generally all in good health.
So, the symptoms have only happened on around 3 recent drives, and consist of:
- Difficult to start when hot... needs a lot of throttle, and produces excess smoke as it finally turns over.
- Exhaust note changed to be very deep and boomy (very noticeable)
- Generally feeling a little sluggish although it is the exhaust note that I notice most!
I've taken a lot of screenshots with various times and of the adaptives. Once I'd done this, I reset the adaptives and took the car for a drive and it felt much much better, however a trip on Saturday showed the symptoms have returned.
My current thoughts are the lambdas as they appear sluggish and not switching consistently but if someone can spot anything else that would be great!
GX54AZZ Bank456 Before Reset by DH Photographic, on Flickr
GX54AZZ Bank123 Before Reset by DH Photographic, on Flickr
GX54AZZ Ignition Part Throttle by DH Photographic, on Flickr
GX54AZZ Ignition No Throttle by DH Photographic, on Flickr
GX54AZZ Ignition Full Throttle by DH Photographic, on Flickr
GX54AZZ Engine Running Part Throttle by DH Photographic, on Flickr
GX54AZZ Engine Running Part Throttle 2 by DH Photographic, on Flickr
GX54AZZ Engine Running No Throttle by DH Photographic, on Flickr
GX54AZZ Engine Running No Throttle 2 by DH Photographic, on Flickr
GX54AZZ Engine Running No Throttle then Part Throttle after adaptive reset by DH Photographic, on Flickr
Post Reset Ignition No ThrottlePost Reset Ignition Full Throttle by DH Photographic, on Flickr
Post Reset Engine running PartThrottle lo by DH Photographic, on Flickr
Post Reset Engine running part Throttle by DH Photographic, on Flickr
Post Reset Engine running no Throttle by DH Photographic, on Flickr
Post Reset Engine running No Throttle lo by DH Photographic, on Flickr
Post Reset Engine adaptive 123 by DH Photographic, on Flickr
Post Reset Engine adaptive 456 by DH Photographic, on Flickr
I'm starting, just starting to get too fed up with some of the little niggles and whilst most of them don't stop me using the car.. this is one I need to get sorted pronto!
Internet beer for your thoughts
Edited by MrChips on Monday 23 June 22:57
for a start your idle speed and hence idle aiflow is too low hence the negative adaptives around that point, you have 15 to 20 percent inbalance in adaptives between banks at idle, and big positive adaption at 2500rpm on closed throttle so maybe a butterfly resonance at that point and so I would be getting that throttle spindle mod done and the throttles set up properly, then get the fuel map re-trimmed at light throttles to account for the new airflows.
however there's nothing in those pics to account for your symptoms that I can see at first glance.
Have you done the basics? valve clearances, compression test, blocked cats / exhausts,
however there's nothing in those pics to account for your symptoms that I can see at first glance.
Have you done the basics? valve clearances, compression test, blocked cats / exhausts,
Cheers joolz and s6boy,
Valve clearances all done 200 miles ago, and it's decatted so no blocked cats to worry about. Not done a compression test so will try that but as it felt fine after resetting the adaptives then I would hope that the basic stuff is all ok!
Not checked the earth strap.. Aren't there more than one? If so..whereabouts are they located?
Valve clearances all done 200 miles ago, and it's decatted so no blocked cats to worry about. Not done a compression test so will try that but as it felt fine after resetting the adaptives then I would hope that the basic stuff is all ok!
Not checked the earth strap.. Aren't there more than one? If so..whereabouts are they located?
It was the hot start issues that made me think of the earth strap. I can't link to any pages but a quick search for hot start issues should help, or possibly Graham Varley's bible. As a quick fix try connecting a jump lead from the chassis to the engine block and see if that helps.
I would hazard a guess that the smoke on hot start was a by product of the car over fuelling due to the length of time it's being cranked rather than a separate issue. That is of course if the smoking stops?
Exhaust note is a strange one unless all the soot from the smoke has partly clogged the pipes but that is pure speculation.
Good luck finding the cause.
I would hazard a guess that the smoke on hot start was a by product of the car over fuelling due to the length of time it's being cranked rather than a separate issue. That is of course if the smoking stops?
Exhaust note is a strange one unless all the soot from the smoke has partly clogged the pipes but that is pure speculation.
Good luck finding the cause.
s6boy said:
It was the hot start issues that made me think of the earth strap. I can't link to any pages but a quick search for hot start issues should help, or possibly Graham Varley's bible. As a quick fix try connecting a jump lead from the chassis to the engine block and see if that helps.
I would hazard a guess that the smoke on hot start was a by product of the car over fuelling due to the length of time it's being cranked rather than a separate issue. That is of course if the smoking stops?
Exhaust note is a strange one unless all the soot from the smoke has partly clogged the pipes but that is pure speculation.
Good luck finding the cause.
Cheers.I would hazard a guess that the smoke on hot start was a by product of the car over fuelling due to the length of time it's being cranked rather than a separate issue. That is of course if the smoking stops?
Exhaust note is a strange one unless all the soot from the smoke has partly clogged the pipes but that is pure speculation.
Good luck finding the cause.
The smoking is just a puff as it finally turns over so yep pretty sure that it's fine, but something is definitely not quite right, and the exhaust note is noticeably different than normal so I cant think its just suddenly got coked up.
The car is now with Calvin at Wilton Morgan who is the local TVR guru. We're going to take the throttle bodies out and send them off to get machined/bearings sorted. Then the current plan is to check the basics as per Joolz advice and go from there. We're already using Powers' throttle gaskets so hopefully they're still doing a good job.
One thing which I don't quite understand is the lambda 2 on this graph appears just not to be switching for ages. Presuming that this the same one which is then pushing the adaptive2 to be +8.2?
Is the turquoise line ok for a lambda or is it actually showing that it's thinking it's lean, hence the positive adaptive, but maybe the reality is its not running lean so therefore the car is now overfuelling?
I did have one of the exhaust hangers break recently and had to drive for a couple of miles with it hanging down so we'll check that out in case the seal at the decat pipes is loose, as I'm guessing the lambda could then read it as being lean?
I'm not averse to just changing the lambdas anyway as I thought they had a lower shelf life having now run the car decatted for a couple of years, but not sure how to tell the difference between a lazy lambda, and one that's not switching as it's constantly reading a high O2 levels?
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