power problem
Author
Discussion

smuudge

Original Poster:

190 posts

261 months

Sunday 10th October 2004
quotequote all
Hi all, seem to have a strange intermitant problem with my Noble GTO-3R.

When cruising at approx 100mph, then accelerating, i get a flatness in the power increase, its difficult to explain but it feels although the engine isnt engaging with full power....this has happened 2 or 3 times now, its been to MV but typically it didnt do it when they test drove the car.

Has anyone got any suggestions on what may be causing this?

Thanks.
Ben

DanH

12,287 posts

283 months

Sunday 10th October 2004
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Accelerating how hard? What does the boost gauge say?

smuudge

Original Poster:

190 posts

261 months

Sunday 10th October 2004
quotequote all
Im taking the car out this week to take some details down, when (and if) it happens...usually accelerating pretty hard from 100 +

robp

2,097 posts

264 months

Sunday 10th October 2004
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Ben - does this occur only when the engine has been driven hard and is hot? (Possibly why not picked up by MV -'cos it will pull fine during 'normal' road driving). Did MV check out the cats and lambda sensor?If they're OK give Bob Shape at Noble a ring. May need re-mapping (with a new map recently devised by Yellowshed I believe)

smuudge

Original Poster:

190 posts

261 months

Sunday 10th October 2004
quotequote all
Yes thinking about it the car is probably fairly warm by the time it has happened, will be speaking to MV about it this coming week so will mention your thoughts and see what they have to say...cheers.

LaurenceFrost

691 posts

275 months

Monday 11th October 2004
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Problems always hide when you need to demonstrate them, but then re-apear at the most undesirable times!

I spent 15 minutes showing a technician the rattle in my exhaust that would happen EVERY time I hit 4000rpm. Did it do it? NO!

In the end I just started driving how I usually did to make the problem apear. The poor guy wouldn't let go of the grab handle.

Anyway, I find the best thing to do is make sure the car is doing the problem right before you visit the dealer. Heat does sound like the most likely cause though, so have a blast before you get there, try and re-create the problem, then grab one of the MV guys and do it again.

Good luck.

capelink

15 posts

257 months

Monday 11th October 2004
quotequote all
What sort of fuel are you using - 98RON optimax ?

I've experienced this sort of thing in the past on other cars. At the 100mph sort of speeds, when you floor it the boost would come in damn hard (overboost city !) and the ignition timings would definitely be changing (advanced ?) to give you optimal power. This is the ideal time for the ECU to detect either pinking/pre-ignition or serious overboost and perhaps cut back the ignition advance and boost to save the engine (you feel the dip in power). I'm certainly no expert on the noble ECU's and am talking from a more general point of view, but perhaps when you turn-off the car the ECU resets the limits - until they are again exceeded and the safety limits kick in again. You get to the dealer - turn off the car - ECU resets - no problem until you're steaming down the M4 and give it some serious welly. I wonder if the ECU would keep a history of such pinking events ?

Probably something completely different though

ThatPhilBrettGuy

11,810 posts

263 months

Monday 11th October 2004
quotequote all
capelink said:
What sort of fuel are you using - 98RON optimax ?

I've experienced this sort of thing in the past on other cars. At the 100mph sort of speeds, when you floor it the boost would come in damn hard (overboost city !) and the ignition timings would definitely be changing (advanced ?) to give you optimal power. This is the ideal time for the ECU to detect either pinking/pre-ignition or serious overboost and perhaps cut back the ignition advance and boost to save the engine (you feel the dip in power). I'm certainly no expert on the noble ECU's and am talking from a more general point of view, but perhaps when you turn-off the car the ECU resets the limits - until they are again exceeded and the safety limits kick in again. You get to the dealer - turn off the car - ECU resets - no problem until you're steaming down the M4 and give it some serious welly. I wonder if the ECU would keep a history of such pinking events ?

Probably something completely different though

Don't think there's a knock sensor on the cars.

Q: When you feel the lack of power do you ease up, then try again? What happens then?

stuh

2,557 posts

296 months

Monday 11th October 2004
quotequote all
smuudge said:
Hi all, seem to have a strange intermitant problem with my Noble GTO-3R.

When cruising at approx 100mph, then accelerating, i get a flatness in the power increase, its difficult to explain but it feels although the engine isnt engaging with full power....this has happened 2 or 3 times now, its been to MV but typically it didnt do it when they test drove the car.

Has anyone got any suggestions on what may be causing this?

Thanks.
Ben


I had very similar symptoms to this. Problem was resolved by VegantuneRoush. I believe it was fueling problem and some ECU mods sorted it out..........

joust

14,622 posts

282 months

Monday 11th October 2004
quotequote all
Ben,

Just get the ECU checked to see if it's on the latest map - sounds like one of the normal map artifacts that some people have suffered from over the time that have been weedled out.

Apart from that, get the lamda sensor and any air leaks checked - they send the ECU a little bit "mad" if they have them.

J

YellowShed

587 posts

306 months

Monday 11th October 2004
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Ben,

Feel free to drop in to Roush - 5 miles from Jcn 28 of the M25 so a lot nearer than the factory for someone in Kent - and we'll give the ECU a once over FOC. If there's anything more involved, we can talk about it then.

YellowShed
01277 261400

m12_nathan

5,138 posts

282 months

Monday 11th October 2004
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That's great service []

joust

14,622 posts

282 months

Monday 11th October 2004
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Even after 2 years it amazes me how friendly the Noble service centres are!

J

ThatPhilBrettGuy

11,810 posts

263 months

Monday 11th October 2004
quotequote all
YellowShed said:
Feel free to drop in to Roush - 5 miles from Jcn 28 of the M25 so a lot nearer than the factory for someone in Kent - and we'll give the ECU a once over FOC. If there's anything more involved, we can talk about it then.

I really must try to drop by one day. I feel almost embarrassed that I live 3 miles down the road and I've never had the pleasure. I've been passed in the last couple of days as well. I'm sure that 30MPH zone runs out on purpose just before the railway bridge

Regards

Phil

Alfa Dave

967 posts

307 months

Thursday 14th October 2004
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Phil - you really ought to drop in. Ask for either Trevor or me (Dave Jones). We can show you the place and what we're able to do.

smuudge

Original Poster:

190 posts

261 months

Friday 15th October 2004
quotequote all
Hi Guys, many thanks for all the replies. For your info the ECU has allready been remapped only a few weeks ago, and MV or almost 100% certain that isnt the problem, although they will happilly look at it again if the problem persists.

The car was test driven over 25 miles and they couldnt spot any problems, in fact they were impressed how smooth the car was compared to some others that come in for a once over!

Basically im out in it over the weekend with a mate to hopefully take down some vital stats if we can get the problem to rear its ugly head.

In the meantime if anyone has any other thoughts on the problem then please let me know....this topic will be printed out and making its way to MV with me the next time im passing!

Cheers again
Ben