Ignition help needed...

[tritonofnor]

Hi guys,

First post here, and a plea for help, sorry but it's driving me nuts...

Car is a 1988 1108cc 5 campus, marelli ignition system, transistor assisted points. Was running a bit rough when i got it a couple of months ago, so i have changed the following:
new air filter (sealed canister type - inlet hose on summer setting by grille)
new plug leads (8mm silicon type)
new plugs (NGK)
new dizzy cap
new rotor arm.

Car was initially cutting out at tickover speed, and jerky to accelerate under wide open throttle. Also a bit gutless when compared to my old Morris 1100..

Cutting out was cured by opening the points to the recommended 0.4mm. Now getting a problem with pinking. Running the car on super unleaded, using Castrol valvemaster plus whenever I remember to put it in! Tried setting the timing to book spec (vacuum disconnected) with 8 deg of advance, (which is for once clearly marked on the bell housing), no joy.

Been playing with the advance, moving it a degree or two at a time, ever since - car goes from being absolutely gutless, zero acceleration, barely able to maintain speed on a hill (too retarded) to pinking like mad (too advanced) without any sort of fine running inbetween. Vacuum advance is moving freely when i suck on the pipe. Tried spraying wd40 around inlet manifold, no obvious air leaks.

Tried using a gunson dwell meter to set the dwell angle, then read in Haynes that dwell reading is screwed by the transistor assistance unit. Put the timing light away tonight, and tried a method we used to use on minis - set tickover to 2000rpm, then advance ignition to max obtainable revs, back off about 250 rpm, nip up the dizzy. This always worked pretty well before, but ain't no good on my little Renault. I'm slowly going mad here, and need an injection of sanity - any and all suggestions gratefully received!!

 

[Cornish4]

Hi there, welcome to the forum. I take it all the rubber hoses for the emission system are sound and not drawing air, plastic Tpiece not cracked? Thats assuming its the same setup as the 4. By the way, where on Cornwall do you live? Regards Brian.

 

[tritonofnor]

hi Brian, will check the hoses today. I'm in a village between callington and liskeard..
Ian

 

[tritonofnor]

Checked the emissions hose today - seems to be a very old school system taking the fumes from the rocker box direct to the carb. Only other visible pipes are a vac pipe to the servo, which is also fine. There is no visible cracking in any of the hoses.

Did a little research at lunch time today. The vac advance seems to be giving nearly ten degrees of advance at a 750rpm tickover, which seems like an awful lot to me..

Tried advanciing and retarding the ignition a couple of degrees either way, and it seemed to make no little or no difference to the pinking. It was almost ok at one point, with minimal pinking, but little acceleration, but when I checked the timing with my light, (and the vac disconnected) it was set to a couple of degrees after tdc!

Does anybody have the factory figures for the timing for this particular set up? Is there any way to check the transistor box on the bulkhead is functioning properly? Obviously the figures will be for leaded fuel but it will at least give me a base line to work from. Have got so confused and frustrated this week that I think I should set it up to the factory figures and start again..

Thanks in advance.

Ian

 

[malcolm]

Do you have the Haynes manual? I've not had a good look through but it says timing is controlled by that transistor thing and is not adjustable. I could be getting confused - not familiar with the later 5s. If you have it well worth following the transistor section through. If not there will be plenty of the manuals on eBay.

 

[barnfind]

Could this be a fuel mixture issue? The old lean burn technology that predated catalytic converters as an anti pollution measure, often led to rampant pre-ignition if the mixture was not spot on.

 

[Simon Healy]

My 5TC 956cc had exactly the same problem with pinking. Only drove well when it was pinking its head off. I just spoke to the guy I sold it to. He said he cured the pinking by cleaning out the carb. He uses the car daily now. Can't believe it could be so simple to solve but it worked for him.

 

[lazyduck15]

Ian

I have had some experience with this issue sometimes solved by a carburetor cleaning and tunning on a R5 (Points) and an Alliance (Electronic), I may say it is something to check in the first place.
But if it does not work, regarding moving the advance, On the Alliance car the pick up sensor is attached in front of the flywheel and seems to be movable to advance or retard the signal. See attached picture. It is not done moving the distributor shaft.
Locally here some people has adjusted it that way. Chances are it may apply to your R5.

 

[politeperson]

Hunting

From the age of the car, it sounds like a classic case of air being drawn into the inlet manifold from a cracked rubber pipe as described as above.

Plug up a few holes, or twist some pipes, with the engine idling to see if it makes any difference.

 

[mr-reno-139]

firstly worth checking that mechanical advance is not siezed or bobweights sticking magnetti distributors not best choice
try twisting rotor arm should spring back if ok
other than that you could try removing transistor unit and modding wiring to run old school as they used to mess about and only really extend life of points from burning which was ok when you could buy good quality points

 

[tritonofnor]

Thanks for all the help guys - finally tracked it down to the emissions piping - the y piece where it enters the carb was loose - pushed back in and hey presto - it's sorted! In the meantime I'd replaced points, condenser, leads, plugs, air filter etc, checked the bob weights, and given the carb a clean, so at least it's had a service!
Still think the transistor unit isn't great, and see some early clios use a unit with the same part number but a different plug, might have to investigate that one further..
Ian