Cam spec causing rough idle?
Cam spec causing rough idle?
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Discussion

Planman350i

Original Poster:

599 posts

275 months

Tuesday 26th October 2004
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Why is my car always so rough on start up? I've always known its been fettled with (new 4.0 engine), but its a bit annoying to have to warm it 10 mins before I can drive off. I've assumed its because of the cam (a hybrid 200 according to the service history) but could it because of something else...?

jmorgan

36,010 posts

306 months

Tuesday 26th October 2004
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Mine sounds like a bag of spanners on 90 a day but drivable straight away. Never more than 2000 odd anyhow 'till hot.

pwd95

8,438 posts

260 months

Tuesday 26th October 2004
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Bought mine early September, the weather was still quite mild. On first start up it would miss a bit but settle down within 30 secs. This morning lowest temp so far and after a couple of days standing it was as rough as hell for about 2 miles, fine there after. It's gone in today to have stainless manifolds put on and hopefully a tune up at the end of the week, we'll see if they pick anything up there. Keep you posted.
Edited to say: Have a look at this
www.pistonheads.com/gassing/topic.asp?f=12&h=&t=126377

>> Edited by pwd95 on Tuesday 26th October 22:22

rev-erend

21,597 posts

306 months

Wednesday 27th October 2004
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Planman350i said:
Why is my car always so rough on start up? I've always known its been fettled with (new 4.0 engine), but its a bit annoying to have to warm it 10 mins before I can drive off. I've assumed its because of the cam (a hybrid 200 according to the service history) but could it because of something else...?


My car is also rough on start up .. my other wedge was too.

Bit like a bear with a sore tooth.

Personally - I don't think it's the cam as the 200 hybrid is a very mild cam. I had one of those in my 4.6 and have changed it for a 404 Mechanical.

I think the bad manners on startup is down to a poor design of fuel enrichment system.. it was early days of EFI aftewr all.

redcar

737 posts

268 months

Wednesday 27th October 2004
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rev-erend said:

Planman350i said:
Why is my car always so rough on start up? I've always known its been fettled with (new 4.0 engine), but its a bit annoying to have to warm it 10 mins before I can drive off. I've assumed its because of the cam (a hybrid 200 according to the service history) but could it because of something else...?



My car is also rough on start up .. my other wedge was too.

Bit like a bear with a sore tooth.

Personally - I don't think it's the cam as the 200 hybrid is a very mild cam. I had one of those in my 4.6 and have changed it for a 404 Mechanical.

I think the bad manners on startup is down to a poor design of fuel enrichment system.. it was early days of EFI aftewr all.


Alan.
You back on the road yet after car running rich.

Martin

rev-erend

21,597 posts

306 months

Wednesday 27th October 2004
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No car is at Austec awaiting new airflow unit ..
hopefully have it back soon...

v8 racing

2,064 posts

273 months

Friday 29th October 2004
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because alot of the wedgies were fitted with 234 cams in the early day's they need a lot of fuel in cold start conditions if the cam has been changed they will flood and run rough untill warm, imho i would send talk to mark adams give him the spec of your engine and send the ecu to him hope this helps.

GreenV8S

30,999 posts

306 months

Friday 29th October 2004
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I've no idea what that cam is, but taking the number at face value it does sound like a very mild cam. Assuming it is not original, has the ECU been mapped to suit that cam? I've had similar problems where the engine feels like it is about to cut out as soon as you touch the throttle, caused on one occasion by excessive fuel pressure (overfuelling) and on another by poor plug condition. It might also just be a symptom of a weak spark since hot plugs and reduced throttle both make it easier to get the thing to light. Changing the plugs can do no harm and might show that you have an ignition related problem.

Planman350i

Original Poster:

599 posts

275 months

Friday 29th October 2004
quotequote all
GreenV8S said:
I've no idea what that cam is, but taking the number at face value it does sound like a very mild cam. Assuming it is not original, has the ECU been mapped to suit that cam? I've had similar problems where the engine feels like it is about to cut out as soon as you touch the throttle, caused on one occasion by excessive fuel pressure (overfuelling) and on another by poor plug condition. It might also just be a symptom of a weak spark since hot plugs and reduced throttle both make it easier to get the thing to light. Changing the plugs can do no harm and might show that you have an ignition related problem.


Hello, Looking at the history it seems that it is a vizard 200 fast road cam. Its had a remapped 'e-drive?' ecu by Mark Adams. Plugs have been changed quite recently and I seem to remember that they were quite wet when I last changed them. Even when its warm it often feels as though it might cut out at junctions - any thoughts?

P.s. ignition amplifyer and distributor cap have also been changed recently so they should be ok.

pwd95

8,438 posts

260 months

Friday 29th October 2004
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Mine won't idle when fully warm sometimes, but only sometimes

As far as I know it's a standard 350 with a rising rate pressure regulator as the only mod.

>> Edited by pwd95 on Friday 29th October 23:21