Volvo 340 B172 Feb 1988 Acceleration Anomaly

[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

[sven360]

Sounds like the zebedee effect.

Does it mainly happen on roundabouts?

[volvosneverdie]

Carb base air leak?
Theyre known for warping.

[CBA]

hmm... all is good airwise, maybe I was lower of fuel than I thought.
not done it since..

[CBA]

Got it again.... zebedee effect.

It's down to a battered renix, need one.

[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.

[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

[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....

[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.

[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.

[macplaxton]

B172 Bendy carb?

See mac's post: http://www.volvo300mania.com/forum-uk/v ... =6&t=14554

[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!").

[CBA]

Postponed MOT to do more bodywork etc.

Got quite a bad propshaft rattle and vibration, what parts?