hesitant at light throttle
Discussion
Evening people.
Having driven 200 miles today in my new Cerb it all seems fine and dandy. It pulls like a train at high revs, idles well and the oil pressure is good.
It's just had a new sports exhaust fitted and while it sounds fantastic, I think there might be an air leak in the system somewhere.
When applying a very light throttle, the engine is a bit hesitant and lumpy, then it picks up. Full throttle is fine.
It also pops and bangs every single time I take my foot off the throttle, I'm not complaining
but it's a lot more aggressive than other sports exhausts I've heard.
I'm thinking it could be caused by a few things...
Exhaust not sealed correctly, causing the engine to lose back pressure.
Engine running rich (there is a small amount of white smoke when you really cain it)
Injectors need a clean or adjusting.
It just needs to be gunned a few times as the previous owner has only driven it short distances for the last few months.
The car has been run on optimax for the past 10,000 miles and I put Esso super in it on the way home. (i've now refilled with optimax but haven't driven it again since)
Any thoughts? I'm planning to put a bottle of injector cleaner in with this tank tomorrow to see if that cleans it out.
Having driven 200 miles today in my new Cerb it all seems fine and dandy. It pulls like a train at high revs, idles well and the oil pressure is good.
It's just had a new sports exhaust fitted and while it sounds fantastic, I think there might be an air leak in the system somewhere.
When applying a very light throttle, the engine is a bit hesitant and lumpy, then it picks up. Full throttle is fine.
It also pops and bangs every single time I take my foot off the throttle, I'm not complaining
but it's a lot more aggressive than other sports exhausts I've heard. I'm thinking it could be caused by a few things...
Exhaust not sealed correctly, causing the engine to lose back pressure.
Engine running rich (there is a small amount of white smoke when you really cain it)
Injectors need a clean or adjusting.
It just needs to be gunned a few times as the previous owner has only driven it short distances for the last few months.
The car has been run on optimax for the past 10,000 miles and I put Esso super in it on the way home. (i've now refilled with optimax but haven't driven it again since)
Any thoughts? I'm planning to put a bottle of injector cleaner in with this tank tomorrow to see if that cleans it out.
Could be as simple as a lead breaking down?
Mine has an intermitent 'stutter' but it's not caused
a problem, so I'll have TC look at it some time.
Go create some weather...
Graham
TCR The Cerbera Register
www.TVR-Cerbera.com
Mine has an intermitent 'stutter' but it's not caused
a problem, so I'll have TC look at it some time.
Go create some weather...
Graham
TCR The Cerbera Register
www.TVR-Cerbera.com
[quote=GCerbera]Could be as simple as a lead breaking down?
Mine has an intermitent 'stutter' but it's not caused
a problem, so I'll have TC look at it some time.
Is that Topcats in Aylesbury?
I was thinking of taking it there to have the shocks changed as they need doing. I'll get them to take a good look over the car while they are it and see what they think.
Mine has an intermitent 'stutter' but it's not caused
a problem, so I'll have TC look at it some time.
Is that Topcats in Aylesbury?
I was thinking of taking it there to have the shocks changed as they need doing. I'll get them to take a good look over the car while they are it and see what they think.
Indeed you are right Neil.
TopCats take care of mine and Brian is a wizzard with TVR's.
Go create some weather...
Graham
TCR The Cerbera Register
www.TVR-Cerbera.com
TopCats take care of mine and Brian is a wizzard with TVR's.
Go create some weather...
Graham
TCR The Cerbera Register
www.TVR-Cerbera.com
Don't know if it's related but mine drops in revs when i just touch the throttle at idle, a bit more and it picks up fine.
Joolz has mentioned to me that it is probably the throttle linkage as it tends to open one bank first then the other meaning the one side runs lean and the revs drop. He does have a very simple mod that helps to open both at the same time, more or less.
Incidentally, I've just put on bypass pipes and found that the nearside cat was missing two bolts and it was just hanging there (probably why my missus felt sick thru town if the exhaust fumes where coming into the car). Might be worth checking all the underside bolts if you suspect a leak as this was missed twice when the car was with a dealer (once while working in this general area)
Andy
Joolz has mentioned to me that it is probably the throttle linkage as it tends to open one bank first then the other meaning the one side runs lean and the revs drop. He does have a very simple mod that helps to open both at the same time, more or less.
Incidentally, I've just put on bypass pipes and found that the nearside cat was missing two bolts and it was just hanging there (probably why my missus felt sick thru town if the exhaust fumes where coming into the car). Might be worth checking all the underside bolts if you suspect a leak as this was missed twice when the car was with a dealer (once while working in this general area)
Andy
Mine use to do the same, as it had been like that since I got the car and reading previous posts I thought it was a design fault. While recently getting it serviced, the garaged called to say the same thing (Goes like a Train when accelerating but lumpy at low throttle).
They sent the inlet manifolds back to the factory and got the butterflies re-bushed as there was slight play. Only picked it up on Saturday but it seems a lot better.
Need to do a few more miles to find out for sure.
They sent the inlet manifolds back to the factory and got the butterflies re-bushed as there was slight play. Only picked it up on Saturday but it seems a lot better.
Need to do a few more miles to find out for sure.
Another thing to add to the list of possible causes then...
Having done a bit of investigation it appears to be compounded by some or all of the following.
Throttle pots: Cheap enough change to see what happens, is it just a matter of popping the old ones off and slipping on the new ones?
The fact that the throttle opens one bank before the other: Apparently Joolz can do something about that.
Clutch: The old style clutch can amplify the symptoms.
Inlet manifold butterflies: as written in previous post.
Accelerator pedal: having a very light pedal action doesn't help.
HT Leads/plugs: cheap and easyish to replace, so i'll probably do that first.
All things that can be sorted in time and I'm happy enough that the engine isn't going to go bang anytime soon.
There a few little things that need doing on my car, so I intend to send it to a suitable place to get those sorted and i'll get some investigation done at the same time, but that would mean being without the car for a week or so, and i'm not prepared to do that yet
>> Edited by trooper1212 on Wednesday 22 October 12:58
Having done a bit of investigation it appears to be compounded by some or all of the following.
Throttle pots: Cheap enough change to see what happens, is it just a matter of popping the old ones off and slipping on the new ones?
The fact that the throttle opens one bank before the other: Apparently Joolz can do something about that.
Clutch: The old style clutch can amplify the symptoms.
Inlet manifold butterflies: as written in previous post.
Accelerator pedal: having a very light pedal action doesn't help.
HT Leads/plugs: cheap and easyish to replace, so i'll probably do that first.
All things that can be sorted in time and I'm happy enough that the engine isn't going to go bang anytime soon.
There a few little things that need doing on my car, so I intend to send it to a suitable place to get those sorted and i'll get some investigation done at the same time, but that would mean being without the car for a week or so, and i'm not prepared to do that yet
>> Edited by trooper1212 on Wednesday 22 October 12:58
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