3.9 playing silly buggers while hot

went to pick up my new (ooooold) car yesterday from north yorkshire, and though the old girl did the 300 mile trip without anything really going wrong, i did have a few things going on with my engine toward the end of the journey, namely:

really rough idle while sitting in gear, almost stalls
sometimes will stall when going from neutral into gear
whine coming from the transmission under acceleration
rattle, clicking sort of noise from the engine under acceleration

ive been reading a couple of threads on here by people with similar issues so im guessing the first port of call is the stepper motor?
can anyone give me an idiots guide to removal and cleaning? although im reasonably proficient with the spanners most of my experience is with diesel engines rather than petrols

thanks,

Tom

oh and its a 1990 RR vogue SE

Opinions vary on what is best for cleaning the stepper but if you do a search you will find a variety of methods and you can make your own choice.

Removal is simple, disconnect the plug then using a suitably sized spanner gently undo and remove the stepper. Don't be tempted to run power direct to the stepper, I believe it runs on only 4v or 5v also, if the plunger comes out you might have to fiddle around getting it back in as there is a keyway for it.

When you put it back on, make sure the gasket isn't damaged. If it is, use RTV silicone and then do it up.

Not too sure about the other symptoms youdescribe. I would suggest the first thing to do would be a full oil and filter change on engine, check transmission fluid level (it is an auto?) Then check front and rear axle oil levels, make sure the prop shaft uj's and sliding joints are greased and free to move. Whilst you're about it maybe checkthe wheel bearings for play.

Hopefully that should get you started.

Also check the crank case breather and tube on the drivers side rocker cover is clean as a blocked one can caurse stalling and the rattle on acceleration could be a blown manifold to Y pipe gasket it's difficult to see.
I have just had mine replaced in a service as it sounded like a machine gun but was ok at tickover, so as the Y pipe has to be droped to change the gearbox filter both gaskets were replaced.

could also be the vacume hoses split or leaking that cause the lumpy low idle , I did my stepper then the hoses which improved things a bit but the throttle postion switch was what was really causing the low idle but it took me 6 months to get that sorted :doh:

mind you the split vac hose and the dirty stepper didnt help much.

thanks for the replies =) i shall have a poke around under the bonnet when i have a spare few hours and see what i can do.
also, im going to get me a haynes manual.

am i risking doing any real damage by using it before resolving these issues?

DeadTom said:

am i risking doing any real damage by using it before resolving these issues?

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As long as the oil light goes out and no other warnings pop up you should be O.K. but keep an eye out for anything unusual especially the temperature gauge. If you start getting heavy, noticeable misfire then time to head for the hills and prepare to be stopped at the side of the road.

right, have removed the stepper and given it a good clean up (reeeeally covered in crap) but the gasket ring came apart when i removed it, and i dont have any silicon sealant =/ would PTFE thread seal work instead?

Mine did too , so I made one from side of a plastic oil can , I would put some copper grease on the thread though as when I tried to take it out the next time it was corroded in and took some heavy spanner work to get it out lol

well, tried putting the stepper back on with PTFE, and if anything its now worse than it was =/
it wasnt very willing to start, and quicker to stall when i brake to a stop at junctions etc.
also when cranking the engine the brake pad warning light came on the dash, but went out as soon as the engine fired....

help? =(

the ptfe might have stopped in screwing in all the way , I wouldnt use that.

Dont worry about the brake pad light for now , its probably just becuase it wasnt running at the time but thats a job for once its running.

Anyway see my post above on the 2nd of july for my suggestions.

took the PTFE out and replaced it with a fibre washer, and its back to how it was, maybe a little better than before. also took off the air filter and hoovered it out. thinking of replacing it with a decent K&N or something, any idea if this will help the old girl breath a bit better?

I would concentrate on getting it running right as standard first unless your current filter is blocked!

It has just occurred to me there might be something more fundamental here. Check your ignition timing and also that the vac advance is working. Faulty vac advance is often a cause for stalling when coming off the gas to a stop.

i was afraid someone might say that... unfortunately i have no idea how to check either of those things.

and yeah the air filter is low down on the list of things to do, but the intake that is on there has seen better days.

see my longest post on this thread:

http://www.landyzone.co.uk/lz/f10/rough-runnin-classic-110555-5.html#post1133132

DeadTom said:

i was afraid someone might say that... unfortunately i have no idea how to check either of those things.

and yeah the air filter is low down on the list of things to do, but the intake that is on there has seen better days.

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Obviously it is best to use a strobe but if you're feeling sporty you could try setting it static. To be fair you could always try appealing on LZ to see if there is anybody near you with a strobe light who would be prepred to check and set your timing.

turns out my old man has owned a few V8's in his time, and reckons he probably remembers how to check and set the timing, however we dont seem to have a strobe anymore =/
just been trying to get the plugs out to inspect and clean them, but with the exception of one or two, either the lead wont come off, or the plug wont budge.. im guessing just yanking really hard on the lead and getting a big socket and bar on the plug will do more harm than good?
or should i just remove them any way i can and replace the lot? (its not been serviced in a year or so, but only done 2000 miles since then)

classic kev said:

Faulty vac advance is often a cause for stalling when coming off the gas to a stop.

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how does one check that the advance is working? ive had a gander and the hose, dizzy, rotor and everything looks in good condition, but not sure exactly how to test the vac advance?

check the outside of the socket isnt binding against the head and making it very hard to turn by changing the angle of the socket. there isnt much clearnace on them.

Try a box spanner and see if that is easier, just a thought but may help before you break one!

tried that already, its definately not binding on the block, i think its just being stubborn.
also, what should the plugs look like in a healthy engine?
the one i managed to get out ok looks like the top one in this pic:


though mine is not quite as covered in carbon.
according to the website i stole that pic from, if it looks like that then it could be any of the following:

Can be caused by many different conditions. Carbon deposits build up when the plug fails to fire correctly and burn them off. Air/fuel mixture too rich, choke stuck on, electrical problem, extended periods of low speed driving, plug heat range too cold. All should be investigated

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