Recovered by AA ... Miss firing, bunny hopping, back firing

[Carrmonkey]

Morning guys

I was recovered by the aa last night due to a strange fault. Car starts no problem but after a a couple of minutes it starts to blip and miss fire. This gets worse and keeps developing into large back firing to the point the car is not driveable. There's a smell of fuel in the cabin as well.

I'm going to change disi cap, plugs leads and rotor arm to see if that solves it. Have any of you had a similar issue?

Any thoughts appreciated

Cheers Mark

[mep12345]

Possible overheating of the ignition module - a common fault if not fitted correctly with heat transfer paste. But start with the usual (as you indicate) before challenging that awkward job. If you get to this I can help with advice on how to get to it without removal of the distributor and also some fault diagnosis articles. PM me if needed If you are close could potentially even help with spares for fault diagnosis.

Mark

[Carrmonkey]

Thanks Mark

I have been reading the S bible this morning trying to locate the ignition module. Can you tell me where it's located?

Cheers

[fozzy280472]

Hi there , sounds very similar to when I had left one ignition lead off after changing the manifolds , so as stated it may be best to check the basics first , dizzy cap , lead condition , rotor arm etc .
hth cheers Paul.

[johnnywgk]

Had similar Last year, it was the fuel regulator over fuelling. Are your exhaust pipes at the back full of black soot.

As the others say, check all the normal stuff 1st.

[Carrmonkey]

Hi
Thanks for the tip I will take a look
Cheers M

[Carrmonkey]

Hi the

Have checked the pipes and there is black soot. Did you manage to change the fuel regulator yourself?
Cheers Mark

[johnnywgk]

Can be done easy, had Problems with the car, I took it to Austec, they put it on their rolling road
and found it was over fuelling and fitted a new one. Problem solved. They are good by the way

Edited by johnnywgk on Sunday 28th July 11:55

[mep12345]

As we've all said - usual stuff first but ignition module is on the back of the distributor, it is the bit the wires plug into. Note I am assuming you have a 2.9 V6 as your profile and the post doesn't say which model you have

[Carrmonkey]

Yes a 1990 2.9. Thanks for the info
Cheers

[Carrmonkey]

Guys thanks for all our responses

I have now serviced the car and the fault has disappeared. I found the centre contact within the distributor cap very loose and the throttle pot looking a little tired. I have replaced all and all is working fine. I also found the idle speed control,valve loose and the gasket looking tired. I repaired this but the car is still idling strangely. I now find the car runs much better with the idle speed control valve disconnected.

Does anyone now a good place to buy an idle speed control valve? I have checked on eBay and they have valves for a TVR 8? Are these correct?

Cheers Mark

[Roy C]

Carrmonkey said:

Does anyone now a good place to buy an idle speed control valve? I have checked on eBay and they have valves for a TVR 8? Are these correct?

No. It is specific to this engine.

The Idle Speed Control Valve (AKA Air Bypass Valve) allows more air into the engine and therefore more fuel, so it works like a choke.

They usually respond to a good clean. Take it off and clean it up. It's probably gummed up after 20 years of operation.

[phillpot]

Carrmonkey said:

Does anyone now a good place to buy an idle speed control valve?

Try Amazon....and you can have it gift wrapped

[wizzer]

Had similar symtoms, traced it to a very slight air leak in the air hose between the air flow meter and throttle body. Over the years they had rubbed together and caused a slight air leak.

[S2Mike]

Could be far too simple but mine had similar symptoms. Started fine then after 5 miles or so spluttering miss fire etc.
I found that the dizzi cap had worked itself loose, nipped up the screws and all has been well since.