god damn shunt is killing me

[PapaButch]

blitzracing said:

Who remapped it (assuming it still 14CUX ?) . If this has been done properly it should have picked up an major issues with the fuelling on the rolling road. Large amounts of shunting can mean the ECU is trying to sort the fuelling out with big corrections if something is wrong in the first place. Best bet on the 14CUX is to run it on the green tune as you can add more fuel at the shunting point.

How do I run it in green mode lol? I don’t know much about the electrics of cars at all or maps.

[Sardonicus]

PapaButch said:

But the car dies when that rubber hose is taken off that spaceship looking saucer next to the dizzy

Well it shouldn't its ported to a non vacuum side of the butterfly on idle or should be, when you pulling off the vac pipe your loosing lots of advance and hence the stall this is not correct and should only pull vacuum under very light throttle openings, dont go pissing abut with the green tune or changing things willy nilly like mentioned already speak to your mapper otherwise if you undo his work he is definitely not going to want to look at your motor/tune

Edited by Sardonicus on Sunday 7th January 22:53

[PapaButch]

so on that vacuum - there is 2 metal pipes, one on top one on bottom, which one should the rubber pipe go on? ill try this tomorrow and post an update! thanks for all your help...again!

[MPO]

Simon is correct in saying it’s a ported vacuum and under normal circumstances removing the pipe shouldn’t really cause it to stall.

It’s quite possible you may have a problem with the vacuum unit and/or dizzy by the sounds of things.

Best to get it diagnosed and checked by the mapper.

[blitzracing]

Umm-- It would be interesting to have a copy of your "remap". There are very few people who can really remap these ECU's and as already stated tuning for max power is a stupid statement- you would never tune for less than maximum power, plus its perfectly possible to get the map to work perfectly well over the whole RPM range as long as you know what you are doing.

[blitzracing]

PapaButch said:

How do I run it in green mode lol? I don’t know much about the electrics of cars at all or maps.

There is a resistor plugged into the loom called a tune resistor, and depending on its value it selects the different maps. Lucas put a plastic sleeve on the resistor wire to colour it- typically this is white on catalyst cars, and green on non catalyst cars, so they get referred to as the white or green tune. So to change maps, you change the resistor value, and then reset the ECU. I do have a switchable tune resistor laying around somewhere if you want to try a test.

its 470 ohms for the green tune and 3.9k ohms for the white tune.

[spitfire4v8]

If the op has rovergauge a quick screenshot will tell us if any remapping has taken place. But even so theres something more fundamentally wrong if disconnecting the vac advance causes a stall. Has it always been like this or just since the recent work?

[PapaButch]

There’s something very wrong. Drive it back from work today and it’s hesitating like mad! Not smooth drive at all! Spluttering all over the place. Is there anyone near Suffolk that can take a look?

I just got back now so will test the vac thing you guys said

[PapaButch]

It’s akways been a lil shunty over the 5 years I’ve owned it but it’s worse than ever now and like I just said it’s hesitating extremely bad on throttle and jurking the whole car when driving at normal speeds

[PapaButch]

Can’t really take it back as it’s far away in Kent where the work was done on it. Stuck here. I have Tvr Kerridges but they are far to expensive for me

[m4tti]

They’re a mobile business aren’t they. Make them come to you to sort it.

[blitzracing]

I've seen cowboys install a chip from the TVR 5ltr into the smaller engine thinking it would give more power as more fuel. All it does is screw up the low speed fueling as the air scaling is all wrong. You could remove the top of the ECU to see what was plugged into the chip socket- all the TVR ones are normally simply marked like 4 ltr cat.

[PapaButch]

I'll go look and take a photo - where is the ecu :/

[blitzracing]

Black metal unit behind the battery in the passenger foot well- its held together with star screws and the case splits apart to expose the circuit board. Its the chip here marked G33 if you look closely- but in your case it should have the TVR markings or something aftermarket.

[skiver.]

[quote=PapaButch]There’s something very wrong. Is there anyone near Suffolk that can take a look?


If you can get it to Mat Smith Sportscars in Downham Market I'm sure he will sort it for you. Not too far away and highly recommended by many on here.

[PapaButch]

Wow amazing thank you all so much for your help!!!!! I’ll take it down there as I do not want to trouble the good guys down Kent anymore as they done a cracking job with returbing most of it!

[black_potato]

If i didnt read all the ECU posts I would think you have a vacum or fueling issue. I have had to replace a blocked injector or find a manifold leak to fix something like this.
It also sounds like its getting worse which would also be a steer to something other than mapping to me.

Anyway... im no expert but thought id mention an alternative path.

[ukdj]

Chris,

we've just been pointed at this thread,

You were quite happy with your car when you picked it up & test drove it around 9 months ago, this is the first we've heard of your issue since then, not sure whats happened since you picked it up, but we obviously stand by our work and would be happy to take a look at if for you.

Please contact us to discuss.

[PapaButch]

I didn’t really explain the story well did I. I have had the car many many months with a very small shunt which is normal and absolutely fine to bear with. Your work has been fantastic you gave me updates all the time via photos and receipts and I couldn’t of asked for better work considering I was always on a tight budget and you even helped me out there!

For the rest of you Kent Tvr are very very good. They are not cowboys at all! They even go out on Xmas day to help people out who have broken down in there chimaeras

So I’m very sorry for giving the wrong impression about these guys.

I have indeed spoke with them and they will be checking the car out for me very shortly. Thanks guys!

Will update everyone what they found out was causing the issue!

[Blackpuddin]

I've just read this thread and didn't get the impression anywhere that you were bad-mouthing the tuner.