# renault trafic carb help?



## pidge1 (Apr 18, 2010)

Hi all can any one help? i have a renault trafic t1000 1987 1721cc petrol,which has a flat spot when driving of,i have put a new carb kit in it but it still happens :? any advice would be appreciated.
Many thanks paul


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## inkey-2008 (May 24, 2008)

Have you checked the timing, plug leads and rotor not forgetting the distributor cap. Anyone of these can cause problems as well.

Andy


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## loddy (Feb 12, 2007)

Have you checked the accelerator jet in the carb, it squirts a bit extra down the venturi to overcome the said problem.
Check with a torch by looking down venturi and then open the throttle , you should see a clean stream of fuel exiting a jet, if not it can be located after removing top of carb, there should also be a non return valve down some orifice, don't open throttle with top removed or you will end up looking for bits that jump out and can end up down it's venturi. If you can't sus it look for a garage with a old bloke working there he will sort it. 

Loddy (old bloke) 8)

Edit check with engine stationary


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## pidge1 (Apr 18, 2010)

Thanks for replys,i have put new plugs,leads, rotor arm and dizzy cap.One thing i have noticed is if i pull the choke out , this flat spot does not happen.loddy does this still sound like this jet you said about?


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## loddy (Feb 12, 2007)

Yes or the carb is set very lean,

Loddy


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## pidge1 (Apr 18, 2010)

Thanks Loddy for reply, i will see what i can get done.


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## 1986trafic (Mar 19, 2012)

Hi,

I have a 86 renault trafic 1.7 with exactly the same problem you were experiencing some time ago. What cured yours, was it a blocked jet ? I replaced everything except the carb. The choke helps with mine too.

Thanks ashley



pidge1 said:


> Hi all can any one help? i have a renault trafic t1000 1987 1721cc petrol,which has a flat spot when driving of,i have put a new carb kit in it but it still happens :? any advice would be appreciated.
> Many thanks paul


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## BillCreer (Jan 23, 2010)

Hi,
Have you tested the advance retard mechanism in the distributor?
If you pull the vacuum pipe off the manifold and the suck on it you should see movement within the distributor. You should be able to check for a vacuum with your finger over the pipe that comes out of the manifold.


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## loddy (Feb 12, 2007)

Vac unit won't cause a flat spot, if you pull out the choke and it's better then I would look at the main jet being partially blocked

Loddy

Vac unit only advances the timing on cruise ( max manifold vacuum ) for fuel economy


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## 1986trafic (Mar 19, 2012)

Thanks for your advise but I think Loddy is right.

quote="BillCreer"]Hi,
Have you tested the advance retard mechanism in the distributor?
If you pull the vacuum pipe off the manifold and the suck on it you should see movement within the distributor. You should be able to check for a vacuum with your finger over the pipe that comes out of the manifold.[/quote]


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## 1986trafic (Mar 19, 2012)

Thank you for the advise. This is a job for a classic car tune up place I think. I think if I start taking the carb apart I'll probably make things worse. Do you think a bottle of fuel treatment in half a tank of fuel could unblock the jet ?

Thanks



loddy said:


> Vac unit won't cause a flat spot, if you pull out the choke and it's better then I would look at the main jet being partially blocked
> 
> Loddy
> 
> Vac unit only advances the timing on cruise ( max manifold vacuum ) for fuel economy


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## loddy (Feb 12, 2007)

No fuel treatment will do the job, you need an old bloke with a screwdriver, I could probable do it with my eyes shut

Loddy


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## 1986trafic (Mar 19, 2012)

OK, thanks for your advise

Cheers



loddy said:


> No fuel treatment will do the job, you need an old bloke with a screwdriver, I could probable do it with my eyes shut
> 
> Loddy


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## cabby (May 14, 2005)

we used to get this problem on old Fords, unfortunately the kits do not allow for the wear in the carb body and are a waste of money, as the parts you are replacing will not make up for this wear. mostly happened on the butterfly spindles, plus of course elsewhere.
we always fitted a new carb complete, to get results.
but of course we do agree with loddy that this is the first thing to do before going down my route.

cabby


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## 1986trafic (Mar 19, 2012)

Thanks for the advise. If I was to buy a new carb and put it on, would it run properly or would I still need to have it tuned ?

Thanks


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## cabby (May 14, 2005)

A new carb should be already set up from the box.a silly question, but you did check the carb gasket to the maifold.also the manifold to head gaskets as well.a little oil or fairy liquid could help here. replace the carb gasket if having a new carb as well.As the carb is not cheap, please do all other tests first.

keep us posted as to how you get on.

cabby


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## Gerorge (Sep 10, 2013)

Hi Paul and Ashley
I currently have an 87 Trafic and I am experiencing exactly the same fault as you both describe,did either of you find what courses this and a fix?
your help would be greatly appreciated.
Mike


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## Camster (Aug 24, 2016)

Hi Folks, I know I'm responding to an old thread, but in case it's useful to someone:
The problem is almost undoubtedly the 'accelerater pump' .
There is a little cam on the throttle linkage, next to the carb. that pushes a plunger. That plunger pushes a diaphragm that squirts neat petrol into the inlet to overcome the mixture weakening effect of rapid throttle opening. It's a fair bet the plunger is stuck and not pushing the diaphragm. As campervans are usually not used for months the plunger gets slightly corroded. The cam pushes it into the carb. but the spring cannot push it back. So it stays in and the throttle pump ceases to operate.
The whole sub-assembly comes offv the carb by un-doing three screws, but watch out for the little spring that pushes the diaphragm.


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