Page 1 of 1
Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 05 Mar 2011 06:43 am
by CBA
funky acceleration issue, instead of accelleration being a "straight curve", its wavy.. proper funky feeling.
any ideas.. this is a new one on me.
The more I press the accelerator the more it boings, its not under fuelleling, no misfires, its totally smooth, just boingy.
only does it occasionally.
could it be under fuelling.. I dunno.
boing..
seizing component...
feels renixey..

, air leak somewhere.
boing.. timing +-...
cyclic vacuum+-'ing
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 05 Mar 2011 07:53 am
by sven360
Sounds like the zebedee effect.
Does it mainly happen on roundabouts?
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 05 Mar 2011 09:12 am
by volvosneverdie
Carb base air leak?
Theyre known for warping.
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 10 Mar 2011 11:20 pm
by CBA
hmm... all is good airwise, maybe I was lower of fuel than I thought.
not done it since..

Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 07 Feb 2013 01:33 am
by CBA
Got it again.... zebedee effect.
It's down to a battered renix, need one.
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 07 Feb 2013 08:31 am
by Chris_C
Mine used to do a thing that felt like it was either full throttle or nothing, I guess that could be described as bouncy? Turned out it was a knackered crank sensor that was no longer waterproof.
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 07 Feb 2013 10:44 am
by CBA
I'm stripping out the whole 'ignition system', it could be vacuum leak or its a ruined vac-sensor on the renix(does appear that way...) Shall know soon
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 07 Feb 2013 03:20 pm
by CBA
This bit of old, split, perished, manky, cannibalised coolant pipe was my brake servo pipe 'connector adaptor'. Interestingly- The servo pipe fits the manifold perfectly without it. - now looking for the shortened coolant hose.....
It ticks over properly now and starts a damn sight easier when warm, doesn't surge and wane all the time - Win!
Botch-e-lism, gets everywhere....
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 22 Feb 2013 07:39 am
by CBA
Still have a hunting tickover and occasional surging/waning at partial throttle.
I'm going to disconnect the vacuum to the renix+block the pipe.. somehow I don't think it is the renix though..
Any ideas/methods to eliminate/hunt down the cause would be handy right now.
I know my dizzy+cap is tip-top.
Fuel delivery is fine.
Carb I'm not sure about.
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 23 Feb 2013 08:26 pm
by Ride_on
Should not afftect tick over unless its leaking. I'd suggest you block/pinch all the breathers. Another method is to spray WD40 around any joints and see if the tick over changes.
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 23 Feb 2013 08:44 pm
by macplaxton
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 24 Feb 2013 02:12 pm
by CBA
I do remember my saloon doing over 40mpg on a run - this one is not.. more like 10!
It needs a proper revamp under the bonnet to get the economy back: I've got some bits of new vac/breather hose knocking about luckily
Clean everything + check everything = win.
Have a bit of gasket-in-a-tube to plug leaks temporarily, see if it will run right first.
But... the carburettor - it needs a rebuild too after the 150k, standing for ages n stuff - might rejet it for modern shitty air+petrol while I'm at it. Bendy Carb pmsl! I can have the carb and manifold resurfaced very cheaply if it's warped, and gasket-sealant it to test - cheers.
Procrastinating with 3 hours of daylight left.....
b******s to it! only got 'A' bit of sanding to do before g3 cut and a light coat of fresh paint all over. Welding is done tomorrow(hope it's not lapwelded..). Will get the mot eventually... why drive it in this crap weather, skin myself etc anyway? I deserve a rest (tells self "I am not a salmon!").
Re: Volvo 340 B172 Feb 1988 Acceleration Anomaly
Posted: 24 Feb 2013 08:22 pm
by CBA
Postponed MOT to do more bodywork etc.
Got quite a bad propshaft rattle and vibration, what parts?