4.0 running/ revving question.
4.0 running/ revving question.
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Garlick

Original Poster:

40,601 posts

269 months

Wednesday 24th August 2011
quotequote all
After my glowing praise earlier the car was a bit unusual tonight. All was well, engine was good and exhaust was popping and banging away....more than usual and a bit louder too, but it didn't bother me. Anyway, I reach a stretch where I can rev it properly (the first time in approx 25 mins) after a bout of town driving where most was under 3500 rpm.

It spluttered at just over 4, almost as if it was hitting a limiter. At first I thought I must have revved harder than I intended so I repeated while watching the revs. Sure enough it didn't want to go over 4500?

Oil pressure fine, engine sounds fine, all seems to be in order. Earlier today I refuelled, could it be related, or is it something else? Under 4.5 it runs as normal but did pop more as I said earlier.

I can't go to check anything right now as it's at the garage 10 mins from home, but all suggestions will be investigated tomorrow.

Thanks in advance

Simon says

19,440 posts

250 months

Wednesday 24th August 2011
quotequote all
Check for collapsed intake pipe from air filter to AFM scratchchin unless you have the ACT/smoothbore then just ignore that remark frown do you know the history of the fuel filter change interval?

Garlick

Original Poster:

40,601 posts

269 months

Thursday 25th August 2011
quotequote all
The car has a FSH with TVR garages, a trait that I maintain in my ownership. Perhaps it's due a replacement sooner this year? Worth checking.

Simon says

19,440 posts

250 months

Thursday 25th August 2011
quotequote all
Garlick said:
The car has a FSH with TVR garages, a trait that I maintain in my ownership. Perhaps it's due a replacement sooner this year? Worth checking.
I would still check the intake pipe if its the corrugated original though scratchchin

Garlick

Original Poster:

40,601 posts

269 months

Thursday 25th August 2011
quotequote all
Yep, will do biggrin

angry jock

1,005 posts

228 months

Thursday 25th August 2011
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Dont know if its any help Paul but my Griff 4.3 does this if I have left it for a couple of weeks then taken it out switched off when engine is at temperature then restart. It then feels like yours until I've properly warmed it up.
I have always put it down to the plugs slightly fouling then burning the crap off up to temp.
I never had the problem last year when I was using the car everyday.

EggsBenedict

1,795 posts

203 months

Thursday 25th August 2011
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Does sound like an ignition thing. Check condition of leads/plugs/dizzy cap/rotor arm. Dizzy cap can crack minutely and cause all kinds of problems. Start at dizzy end, obviously smile

Chim Chim Cheree

49 posts

225 months

Thursday 25th August 2011
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I had exactly that when I replaced the coil. New black and red one, from big name TVR parts supplier, for Chim. Would not rev past 4500 even with little load. felt like it hit a rev limiter. Fine below 4500ish.
Put old coil back on. Fine. New one back on. Not fine.
Bought new Bosch coil and ran fine. Odd that a new v8 chim coil could fail like that, but it did.

Odd thing was that the engine actually ran noticeably smoother below 3000 rpm on the rubbish black and red coil than on the new Bosch which is just a little less rough than my old one (also bosch).

Good luck

MADMAX2

2,336 posts

223 months

Thursday 25th August 2011
quotequote all
Chim Chim Cheree said:
I had exactly that when I replaced the coil. New black and red one, from big name TVR parts supplier, for Chim. Would not rev past 4500 even with little load. felt like it hit a rev limiter. Fine below 4500ish.
Put old coil back on. Fine. New one back on. Not fine.
Bought new Bosch coil and ran fine. Odd that a new v8 chim coil could fail like that, but it did.

Odd thing was that the engine actually ran noticeably smoother below 3000 rpm on the rubbish black and red coil than on the new Bosch which is just a little less rough than my old one (also bosch).

Good luck
ello jon good to see you on here catch up soon

ian

Harrytsg

1,264 posts

191 months

Saturday 27th August 2011
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Garlick,

Mine does this on occasion, I was watching the thread for some ideas of what to check when i had the time, long story short it happened this morning for the 8-9 miles to Band Q (living the high life), and was fine after the short stop there.

I havent checked inside the distributor yet, but my thought was condesation. It sat outside in the rain yesterday, under the car port last night but the car was still outside. On the few occassions its happend previously it does seem to clear after my generally short journeys (daily driver) and a restart.

I will be checking tomorrow to see if theres evidence of condensation, as well as distributor and rotor arm condition etc.

banjolucknicker

258 posts

286 months

Friday 2nd September 2011
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Have you checked the AFM? I had a similar issue on my Alfa 156 years ago, the car seemed to hit a 'limiter' at ~4K RPM. I found a friendly garage who swapped the AFM from a car that was 'good' and it cured the problem instantly.

MADMAX2

2,336 posts

223 months

Friday 2nd September 2011
quotequote all
banjolucknicker said:
Have you checked the AFM? I had a similar issue on my Alfa 156 years ago,
didn't know Alfa made cars 156 years ago!!!!

Edited by MADMAX2 on Friday 2nd September 13:19

domV8

1,408 posts

210 months

Friday 2nd September 2011
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MADMAX2 said:
banjolucknicker said:
Have you checked the AFM? I had a similar issue on my Alfa 156 years ago,
didn't know alga made cars 156 years ago!!!!
Who's alga? wink

banjolucknicker

258 posts

286 months

Friday 2nd September 2011
quotequote all
MADMAX2 said:
didn't know Alfa made cars 156 years ago!!!!

Edited by MADMAX2 on Friday 2nd September 13:19
smile It's one of the early revisions smile

Jammy Dodger

2,449 posts

184 months

Friday 2nd September 2011
quotequote all
EggsBenedict said:
Does sound like an ignition thing. Check condition of leads/plugs/dizzy cap/rotor arm. Dizzy cap can crack minutely and cause all kinds of problems. Start at dizzy end, obviously smile
i had this too at 5200 - replaced all the above and eliminated the problem

Harrytsg

1,264 posts

191 months

Friday 2nd September 2011
quotequote all
Harrytsg said:
Garlick,

Mine does this on occasion, I was watching the thread for some ideas of what to check when i had the time, long story short it happened this morning for the 8-9 miles to Band Q (living the high life), and was fine after the short stop there.

I havent checked inside the distributor yet, but my thought was condesation. It sat outside in the rain yesterday, under the car port last night but the car was still outside. On the few occassions its happend previously it does seem to clear after my generally short journeys (daily driver) and a restart.

I will be checking tomorrow to see if theres evidence of condensation, as well as distributor and rotor arm condition etc.
To update my reply, I did check the distributor cap and there was no sign of condensation so ignore my thought there. I did clean the contact areas of the rotor arm while the cap was off, and I havent repeated the symptoms as yet.
So read into that what you will.

Hope you get yours sorted.


Twistygit

800 posts

182 months

Saturday 3rd September 2011
quotequote all
maybe a plug breaking down or maybe an extender. the popping and banging is unburned fuel so probably got a miss