Rough running

[Warwick67]

my Chimp has just been in for a tune up, guys struggled with it because the vacuum advance isn't working and also the output from the stepper motor varies if you waggle the connecting wires.

So its been set up as best they can manage and runs OK when warmed up but tends to cut out when cold. Need to sort it, I was wondering whether I should replace the vacuum advance unit, or just replace the complete distributor, noting that there is a big price variation depending where you get one - has anyone tried one of these??:

http://www.ebay.co.uk/itm/110576385136?ssPageName=...

I guess the stepper motor prob, just needs some time to check all the connections, earths, etc...

Cheers

[jr6yam]

Check the vacuum advance unit is working by sucking on the hose
On my car the hole in the plenum is blocked!

[carsy]

Dont suck on the hose as you wont move it. You will have to suck on the unit itself to see if it is effective or not.

[Simon says]

carsy said:

Dont suck on the hose as you wont move it. You will have to suck on the unit itself to see if it is effective or not.

Not so its how us in the trade have checked those units for years I can suck 15hg of vac you need to sort your suck out Carsy

[haircutmike]

carsy said:

Dont suck on the hose as you wont move it. You will have to suck on the unit itself to see if it is effective or not.

I don't like the way this conversation is going!

Mods

[Warwick67]

haircutmike said:

I don't like the way this conversation is going!

Mods

And I was just about to suggest I get my wife to check it

How about the new Dizzys on ebay - are they any good?

[Simon says]

Just change the advance capsule, in my opinion the RV8 OE Lucas dist is very reliable for a constant energy unit I certainly have never heard of the windings or p-up failing internally even if the ext ign modules do fail occasionally

[Ribol]

Simon says said:

............ I can suck 15hg of vac ................

You have far too much time on your hands

[Simon says]

Ribol said:

Simon says said:

............ I can suck 15hg of vac ................

You have far too much time on your hands

You know it ......... Might try for 18hg later

[Ribol]

You do realise you are leaving yourself wide open to one of the "experts" posting a complete sermon on how to be good at sucking at something.

Based on their life long experiences of having excelled at it

[Simon says]

Ribol said:

You do realise you are leaving yourself wide open to one of the "experts" posting a complete sermon on how to be good at sucking at something.

Based on their life long experiences of having excelled at it

Mmmm think I may have to pull out then ..... Haircut started it

[debaron]

Warwick67 said:

my Chimp has just been in for a tune up, guys struggled with it because the vacuum advance isn't working and also the output from the stepper motor varies if you waggle the connecting wires.

So its been set up as best they can manage and runs OK when warmed up but tends to cut out when cold. Need to sort it, I was wondering whether I should replace the vacuum advance unit, or just replace the complete distributor, noting that there is a big price variation depending where you get one - has anyone tried one of these??:

http://www.ebay.co.uk/itm/110576385136?ssPageName=...

I guess the stepper motor prob, just needs some time to check all the connections, earths, etc...

Cheers

I'd be surprised if the vacuum advance is making it run rough from cold. More likely is coolant temp sensor or some other temp based sensor.
The sensors are about £6 and a doodle to change so worth doing. Make sure you get the ECU temp sensor not the gauge sensor as the gauge has no effect on the fuelling - it's just for the water temp dial.


HTH

Ryan

[debaron]

Also, you can disconnect the stepper to eliminate the problems. However this gives a high idle when warmed up. But it is a good 'quick' test

Have you given it a clean? They can get blocked. Blitzracing has an excellent thread on how to do this.

[EGB]

RV8 will run ok no problem with dizzy vac not working. Replaced my vac unit since diaphraghm was split. Made no noticeable difference to tick over, acceleration or cruising. Main problem is else where IMO.

Edited by EGB on Friday 15th June 23:18

[Warwick67]

debaron said:

I'd be surprised if the vacuum advance is making it run rough from cold. More likely is coolant temp sensor or some other temp based sensor.
The sensors are about £6 and a doodle to change so worth doing. Make sure you get the ECU temp sensor not the gauge sensor as the gauge has no effect on the fuelling - it's just for the water temp dial.


HTH

Ryan

Thanks for that, the temp gauge is a intermittent, I know its not the same sensor but if 1 is playing up possibly others are suspect too. The wiring to the stepper motor has been "re done" by previous owner, output moves all over the place when you waggle the wires, I wonder what else has been "improved"