missing at revs

[marcusclive]

Afternoon all,
What a lovely day, just been out for petrol only took me an hour. went a bit of a long way around. What i found while having a good thrash was that when i get to above 4500- 5000 revs the engine starts to miss and depending what gear I'm in wont go any further. If I'm in 1st or 2nd it does rev but not well but once i get up to 3rd and 4th it wont rev any further.
Any suggestions gratefully received.
Marcus.

[alistair260661]

suspect your coil, low tensions wire or high tension plug leads............... presuming you have the correct point gaps................ if it gets worse when the engine (and the coil) is hot, then it is most likely the coil. another longshot is the capacitor inside the dizzy

[marcusclive]

I hope its not the coil I only replaced that last summer, I have electronic ignition so there are no points and from memory no capacitor. It doesn't seem to be any different hot or cold so I don't think its the coil. I did wonder if it might be the vacuum advance unit. Although i can suck on it and make it move it won't stay if i put my tongue over the pipe. i have to keep sucking to keep it moved, although any vacuum off the engine is continuous i do wonder if the unit should leak.

[StagnJag]

are you on electronic ignition?

One of the cars on the rolling road at the National had this problem. They did a bit of testing and the suspect was the Ignition control module. Newtronic I think.

Rgds

Dave

[marcusclive]

Yes i am and to be quite honest its not the greatest unit around, the outer cover is broken and held on with tape. it does seem to work ok though, i don't know if these units piffle about or just stop working.
By the way I like your little bug.

[Tdm]

are you on electronic ignition?

One of the cars on the rolling road at the National had this problem. They did a bit of testing and the suspect was the Ignition control module. Newtronic I think.

Rgds

Dave

I've got a Newtronic system in mine. Installed in 1996 and still going. Only problem I have had was the plastic disk inside the dizzy became cracked, so I replaced it with one of the spares that came with the system.

[flying farmer]

The coil on the TR let me down a couple of years ago and I replaced it with a standard spec one from the local auto electricians, rather than the sports coil I had previously. Total waste of money. At light throttle settings it would sing round to 6500rpm, but at full throttle the spark blew out at 4500 and it would not rev any higher. Having run various V8s since 1982, I would normally expect a good one to only last 10-15000 miles, which used to be annually when my V8 toledo was my only vehicle.
Neil

[alistair260661]

ah u r on electronic - is it newly installed and did u remove the ballast resistor? i had this problem in reverse when I removed the electronic, but didn't ensure 9v coil and ballast resistor.

[DJT]

ah u r on electronic - is it newly installed and did u remove the ballast resistor? i had this problem in reverse when I removed the electronic, but didn't ensure 9v coil and ballast resistor.

And where did you manage 4500-5000rpm in reverse??

[alistair260661]

ho ho, i mean of course the other way round!. Sorry to be so imprecise. What I meant was that when returning the car to points (from electronic ignition) I had the same sort of issues, until I recognised the need for a ballast resistor and the right coil being fitted. This recognition took a number of attempts during which I managed to burn out one (of the right lower voltage) coils. The symptoms were as described - but ended up with a classic dead coil symoptom (start from cold run 2 miles and die, cool down and repeat............) Oh what fun!

Another one I've had with these symptoms was a set of (new) crap plug leads - these, when I compared them the the old set, had virtually no resistance, and when replaced by the old ones cured the problems - perhaps worth checking? - These new ones were bought brand new from one of the "main" suppliers, they also gave no indication that there was a problem while the car was at tick over or static with higher revs - its was only under load that the issue appeared. Hope that helps

[marcusclive]

Iv'e ordered a new vacuum unit from paddocks so that should be here in a couple of days. see if that works and go from there.
With regards to Terry's sender disc on the electronic ignition splitting, how tight should these be on the shaft? mine is reasonably tight but i can turn it.

[KOY 23]

Do you mean that you can turn the plastic disc relative to the distributor shaft? If you can your timing will be out and will cause the problems you have. The disc should not be able to turn.
John.

[peterrc]

Hi Marcus, it could be a plug breaking down under load or the plug leads/distributor cap on the way out. Have a look at the plug leads and cap in a darkened garage and see if there is any arcing. A spray with WD40 never does any harm.
Peter, Cupar

[marcusclive]

Got the new vacuum today, it was on the doorstep when i got home from work. got permission to delay dinner for an hour and fitted it.
That was the problem, goes like the clappers now, just got to adjust the timing slightly as it pinks under full throttle.
Many thanks for all the help given.
Must say as well dead impressed with Paddocks service, ordered on Monday morning and here lunchtime today.

[marcusclive]

I may have a play with the disc tomorrow and see why it does turn, it may be split.