Discussion
So .............this is an on going problem that I have spoken about previously. I start the car and it idles at about 1000rpm then slowly pick up and sits at 1500 . I take it for a drive and when you pull up at lights/junction the reves fall to settle at 1500rpm .....blip the throttle and they settle at 1000. This happens all the time and is annoying in traffic.
So far I have ,
1) Changed the plugs to iridium. BPR6 's
2)Replaced the throttle cable.
3)Cheaked the hoses for leaks & tightened clips.
4)Cheaked E.A.V
5)Swapped A.F.M for another & made no difference.
Any thoughts ?
So far I have ,
1) Changed the plugs to iridium. BPR6 's
2)Replaced the throttle cable.
3)Cheaked the hoses for leaks & tightened clips.
4)Cheaked E.A.V
5)Swapped A.F.M for another & made no difference.
Any thoughts ?
Is it a V8? If so then have you checked the stepper motor? That sort of fault is typical of a sticky stepper. Also check the sealing washer; an air leak here can also cause your problem. If you change the gasket, make sure it's a thin one, as one which is too thick will cause problems. My stepper is sealed with silicone; this solved all my similar issues.
... or it could be a flapper = no stepper motor.
Also check (and if necessary set) the throttle air gap, after cleaning around the butterfly for crud buildup.
Check (and if necessary set) the throttle pot idle voltage plus check the throttle pot is operating smoothly, voltage varying without jumping.
Check all engine breathers are not blocked including the little hole in the mushroom breather on the rocker cover.
Check the rocker covers are sealed (blow down the main engine breather pipe, it should pressurise like a balloon.)
All - so far - free to check, just takes a few minutes each.
Also check (and if necessary set) the throttle air gap, after cleaning around the butterfly for crud buildup.
Check (and if necessary set) the throttle pot idle voltage plus check the throttle pot is operating smoothly, voltage varying without jumping.
Check all engine breathers are not blocked including the little hole in the mushroom breather on the rocker cover.
Check the rocker covers are sealed (blow down the main engine breather pipe, it should pressurise like a balloon.)
All - so far - free to check, just takes a few minutes each.
You might need a new flame trap...
https://www.google.co.uk/url?sa=i&rct=j&q=...
https://www.google.co.uk/url?sa=i&rct=j&q=...
Or something a bit more shiny...
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I would take that pressure relief valve off of the vacuum pipe to dizzy to see if that makes a difference ..Could be something sticking...Even the bob weights in the distributor...Or wear in the springs...You have checked most of the usual suspects but with no effective difference...
https://www.google.co.uk/url?sa=i&rct=j&q=...
https://www.google.co.uk/url?sa=i&rct=j&q=...
Or something a bit more shiny...
https://www.google.co.uk/url?sa=i&rct=j&q=...
I would take that pressure relief valve off of the vacuum pipe to dizzy to see if that makes a difference ..Could be something sticking...Even the bob weights in the distributor...Or wear in the springs...You have checked most of the usual suspects but with no effective difference...
mrzigazaga said:
I would take that pressure relief valve off of the vacuum pipe to dizzy to see if that makes a difference ..Could be something sticking...Even the bob weights in the distributor...Or wear in the springs...You have checked most of the usual suspects but with no effective difference...
Regarding the vacuum check valve (if fitted) in the distributor advance pipe, it has to be fitted the wrong way round to what seems logical! If it's the incorrect way it will tend to suck advance on and retain it, which is the same as the weights being stuck.Of course off the top of my head I can't remember which way IS correct for the check valve, I think it's orange end forward i.e. closest to distributor). What it actually does is to prevent vacuum advance coming on under cruise conditions, that's the job of the weights.
Wedg1e said:
Regarding the vacuum check valve (if fitted) in the distributor advance pipe, it has to be fitted the wrong way round to what seems logical! If it's the incorrect way it will tend to suck advance on and retain it, which is the same as the weights being stuck.
Of course off the top of my head I can't remember which way IS correct for the check valve, I think it's orange end forward i.e. closest to distributor). What it actually does is to prevent vacuum advance coming on under cruise conditions, that's the job of the weights.
Firstly, I'm not a V8 man, but I wonder about what you said there... from my Ford knowledge I thought those little valve thingies do a 'delay' on the vacuum advance advance to smooth out fast timing changes and/or stop pinking. (Delay can be for 'on' or 'off' or both) Of course off the top of my head I can't remember which way IS correct for the check valve, I think it's orange end forward i.e. closest to distributor). What it actually does is to prevent vacuum advance coming on under cruise conditions, that's the job of the weights.
and as we know weights work purely by RPM.
Just pointing out ...
Had this when I first brought my 400se.RCK974X said:
Firstly, I'm not a V8 man, but I wonder about what you said there... from my Ford knowledge I thought those little valve thingies do a 'delay' on the vacuum advance advance to smooth out fast timing changes and/or stop pinking. (Delay can be for 'on' or 'off' or both)
and as we know weights work purely by RPM.
Just pointing out ...
Aye... a cleverer bloke than wot I is (Joolz Lane and as we know weights work purely by RPM.
Just pointing out ...
) wrote a wordy thing some years back that explained it, something to do with manifold depression at cruising speeds vs. acceleration (so sounds like what you're saying ). IIRC the OP reported pinking as well so it's a definite maybe.
As posted in Adam's other thread:
"The valve thingy is just a restrictor that works better one way than the other. It restricts the vacuum communicated to the advance mech when on cruise conditions, so it will suck advance on, but only after several seconds of holding at light throttle. This prevents the advance coming on when you go through the cruise portion of throttle towards high throttle, when you lift off the throttle any vacuum that has been communicated to the advance unit releases quickly... the intention is not to add vac advance unless the car is definitely in a cruise state, so limiting the change of pinking under transient throttle conditions. So you should not be able to suck easily through one way and you should be able to suck easily the other way, and fit how it says on the valve otherwise you'll get vac advance sucked on and staying on as the vacuum doesn't then release quickly from the unit and you'll run with another ten degrees of advance all the time - not good."
Edited by Wedg1e on Wednesday 19th October 14:11
Wedg1e said:
"The valve thingy is just a restrictor that works better one way than the other. It restricts the vacuum communicated to the advance mech when on cruise conditions, so it will suck advance on, but only after several seconds of holding at light throttle. This prevents the advance coming on when you go through the cruise portion of throttle towards high throttle, when you lift off the throttle any vacuum that has been communicated to the advance unit releases quickly... the intention is not to add vac advance unless the car is definitely in a cruise state, so limiting the change of pinking under transient throttle conditions. So you should not be able to suck easily through one way and you should be able to suck easily the other way, and fit how it says on the valve otherwise you'll get vac advance sucked on and staying on as the vacuum doesn't then release quickly from the unit and you'll run with another ten degrees of advance all the time - not good."
I do believe that the OP was experiencing rich running also so maybe this could be another symptom of advanced timing???What about the CO adjuster on the AFM?
Had issues myself setting idle, as it would nearly not be adjustable and scraped CO-wise a few times through MOT.
Tip I got on here is, take the adjuster out and clean it.....
Cured my issues and never had any problems with setting idle, CO and MOT since then.
Like mentioned before, the throttle plate, breathers etc, gunk can result in 'funny' behavior of the engine.
Rob
Had issues myself setting idle, as it would nearly not be adjustable and scraped CO-wise a few times through MOT.
Tip I got on here is, take the adjuster out and clean it.....
Cured my issues and never had any problems with setting idle, CO and MOT since then.
Like mentioned before, the throttle plate, breathers etc, gunk can result in 'funny' behavior of the engine.
Rob
Solved it I reakon !
After spending an hour or so just playing around & taking the TPS OFF my attentions turned once again to the throttle linkage . I couldn't help but notice that something wasn't quite right with it returning properly ! I noticed the spring wasn't sitting straight and was over that nut and therefore I think not allowing the arm to move freely enough to return all the way back . I simply relocated the spring & also tightened the nut a bit .
After spending an hour or so just playing around & taking the TPS OFF my attentions turned once again to the throttle linkage . I couldn't help but notice that something wasn't quite right with it returning properly ! I noticed the spring wasn't sitting straight and was over that nut and therefore I think not allowing the arm to move freely enough to return all the way back . I simply relocated the spring & also tightened the nut a bit .
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