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Higher idle RPm & temp gauge


Quack

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I see now that your idle screw us on the front of the carb. Mine is on the rear!

Just have run and if it races, check all the carb  capable positions and spindle location. Pop filter off and check postings down.

What oil have you in the damper dash pot?

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Took for a drive last night, revs continue to be higher than normal, at idle of course it is fine because i adjusted the idle screw but this doesn't fix the problem for whilst driving.

As for dampener oil i couldn't tell you as it's been in there since before i had the car. So we're still at square one really, but atleast i dont have to sit in the car vibrating and humming loudly at idle lol.

I'm still putting my money on air leak, higher revs, stuttering too when idle...needle jumps about a bit and car jitters and jolts. Think best bet is to get hold of a smoke tester machine and have a look?

 

My car fits the bill for all the symptoms described here: https://www.sundevilauto.com/reasons-your-car-is-vibrating-when-idle/ so it could be any number of these, most are ruled out due to the car not being modern, which pretty much leaves me with vacuum leak.

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if you have air leak it doesnt come and go and the engine has no pre clues that you are on idle or driving 

that defect will be there all the time not as and when

do you have some slack /free travel in the throttle cable as these when hot expand and if taut will open the throttle as the heat in the engine bay builds up 

you can suck the oil out the dashpot with a straw , dont get a mouthfull  and refill with known engine oil 

has the timing or mixture ever been checked ???

Pete

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39 minutes ago, Quack said:

symptoms described here

stick to the basics of a 50 yr old carburettor engine  thats a load of myth  tosh aimed at your wallet 

spark plugs are the life and soul but you would be lucky to get 30k from the std plugs which have a replacement life of 10k 

and with infrequent and too much choke can fail very early 

pete

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The rev changes don't come and go either, it's always sitting above normal since the problem began, idle or running or whenever. There is a bit of slack on throttle but not really any on choke, will give it some slack today.

Spark plugs i replaced yesterday with no improvements, the old ones weren't too bad but did have a lot of oil on them which could indicate a leak inside? unrelated anyway.

I changed the timing a few times, just set it with timing light the other day back to standard setting. I did advance it a bit before as i'd heard it was good for fuel economy but felt a bit janky so i put it back.

Mixture never been checked, has always ran fine until recently.

Will replace the oil today and add some slack to choke 🙂

 

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choke wont be affected much by heat on its cable as there is a built in  lost movement to aid ease of pulling the control 

just to get our heads round just whats going on 

she idles ok  but when you drive , pull up at the T lights and its reading faster than normal or is it just faster all the time and wont respond to the adjusting screw 

when youre out and its got faster idles is there a gap between the idle screw and the casting 

and does it sound fast or is it your add on rev  counter telling fibs ??

Pete

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Nonono okay i'll start from the beginning

 

- the revs are ALWAYS above, whether it's idle, driving, stationary, they always sit above what they normally are. E.g. my idle is now 1500 when it should be 1000, and when im driving at 30mph in 3rd gear it would be 2000, however its now 2500.

- The only reason the IDLE is OK now is because i changed the idle screw, however this doesn't actually change anything at all when driving, this is just for the time being to add a bit of a 'half fix' whilst i locate the problem, so ignore this part of it, pretend i never changed the idle screw. The idle is still at 1500, but i just moved the idle screw for the time being, making it 1000. I'm putting it back to normal once i fix the problem.

- There is never a gap between the idle screw and casting, it always sits as it should.

- It is definitely audibly faster yes, i know this because when i screw the idle screw out, it sounds normal again and the rpms drop down to 1000 (how it's meant to sound and be). So the tacho isn't faulty, and it is reading the actual revs.

 

Summary:

- The engine is a bit jittery, appearing to 'rev itself' almost.

-The revs are higher than normal (500 above whatever they would normally be).

-The engine takes longer to start at key-turn than normal.

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1 hour ago, Quack said:

and when im driving at 30mph in 3rd gear it would be 2000, however its now 2500.

THAT CANNOT HAVE CHANGED

It's determined by the gearing and has nothing to do with engine tune or air leaks or idle speed or any of that. So unless somebody has snuck in and replaced your gearbox while you weren't looking, the engine speed at 30mph in 3rd CANNOT HAVE CHANGED.

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1 hour ago, Quack said:

when im driving at 30mph in 3rd gear it would be 2000, however its now 2500.

thats a bit   of a conundrumm  ulless you have a Daff 66 drive line you cannot change the final drive raios 

they are definitley fixed 

the only way the revs per mph can change is if the clutch is slipping or the rev counter is mis reading 

somewhere here we are all on the wrong track 

Pete

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NM & PL said what my immediate thoughts were. To me I would suspect the rev counter is over reading, no other way you are suddenly at 2500 rather than 2000.

Frustrating for you for sure but we ( the wise ones at any rate) will crack it in time.

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If the clutch was slipping you would notice it when pulling off from stationary. Where in the pedal stroke is the clutch biting? 

A bit brutal but drive along and gently apply the brake and accelerator at the same time. If the revs rise when decelerating then the clutch is slipping. 

Another edit, shouldn't your idle be around 6-700rpm?

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I dont know what's going on then, maybe it's coincidence that my idle increased at the same time as my rev counter breaking, but i am 100% certain that it is actually idling at 1500, i can hear the difference in the engine. When i adjust the screw to get the idle back to 1000rpm, it sounds how it used to sound, which leads me to believe the rev counter is functioning properly.

The rev counter reads higher than it did before at every 10mph increment. I don't know what else to say, this is just what's happening. I understand what you're saying, that its not possible, which is why im baffled. I think i'd be a fool to think that nothing is wrong with the engine, and that my idle screw has randomly slipped or something.

@Iain T my idle used to be 1000rpm when i first got it, its never been lower than that, so that was an issue from the start then, i thought 1000rpm was normal.

Below are two videos showing what happens when i try to start the car, and 10 minutes later when its warmed up. The temp gauge goes up far quicker than it used to, and the revs slowly make their way up. its at 1000rpm because i changed the idle screw, normally it would be 1500.

 

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cant fully open those but 

the common denominator here is the revs and temperature climb as you drive  which has all the clues this is 

voltage problems  the idle should be 600/700  and the idle setting has no effect when your driving 

you could have a air leak like the fourth bridge you cant change the drive line ratios 

there is some serious misconcieved ideas coming across i dont understand 

Pete

 

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if the revs  do increase then the road speed has to increase in line with that.

you dont have an elastic driveline  

why is it always at 1000  thats too fast  

do you have a brake servo ??

does she breath direct into the air cleaner or do you have a smiths valve fitted ??

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