v6 petrol running rough.need to eliminate possible causes

[kelv]

I still believe you have an air leak weakening the mixure somehow.
The symptoms are consist to when I had one in the past on V engine.
Have you checked for one

Hope you sort it

[hogggman]

hi all,
sorry for the long delay,but i`ve not used the bongo much recently,having started walking to work,but today i decided to test the (fairly new)lambda sensor.armed with a multimeter i checked it out,and it was giving a reading of between 0.4 and 0.8 volts,changing several times a second.from what i had read on google,that seems fairly normal.one helpful site had various pics of sensors in various conditions,and mine seemed a little sooty,which is caused by the engine running rich,according to a pic of a similar-looking sensor.
as i now seem to have eliminated the lambda senor,does anyone have any suggestions at to what i should try next?i changed the spark plugs a year ago,and definitely the problems occurred way after that,but i don`t see a connection there.when the engine seems to falter or hesitate at about 50mph or 2000-2500 rpm,i have to put my foot down a little to get past it,and very often,there`s a muffled`pop`from underneath,then the bongo is back up to speed again.if the bongo had a leak in a vacuum pipe somewhere,would it cause the engine to run rich or weak?
any suggestions?i`d be very grateful.in the new year,before mot time,i may change the plug leads/distributor cap anyway,but i always hope for a simple answer first.
thanks
jamie

[mikeonb4c]

hi all,
sorry for the long delay,but i`ve not used the bongo much recently,having started walking to work,but today i decided to test the (fairly new)lambda sensor.armed with a multimeter i checked it out,and it was giving a reading of between 0.4 and 0.8 volts,changing several times a second.from what i had read on google,that seems fairly normal.one helpful site had various pics of sensors in various conditions,and mine seemed a little sooty,which is caused by the engine running rich,according to a pic of a similar-looking sensor.
as i now seem to have eliminated the lambda senor,does anyone have any suggestions at to what i should try next?i changed the spark plugs a year ago,and definitely the problems occurred way after that,but i don`t see a connection there.when the engine seems to falter or hesitate at about 50mph or 2000-2500 rpm,i have to put my foot down a little to get past it,and very often,there`s a muffled`pop`from underneath,then the bongo is back up to speed again.if the bongo had a leak in a vacuum pipe somewhere,would it cause the engine to run rich or weak?
any suggestions?i`d be very grateful.in the new year,before mot time,i may change the plug leads/distributor cap anyway,but i always hope for a simple answer first.
thanks
jamie

Jamie - I've not read through this thread carefully so apologies if already said (although I knhow you have mentioned it above), but I recall Apole (Andy) and also I think cheffy (both these guys have V6s) having issues not too dissimilar and the cure was a new distributor head etc. Try PMing them if they don't chip in on this thread. Good luck - keep us posted

[hogggman]

hi mike,
thanks for that.i`ve just been trawling the web for distributor cap and rotor arm.i found a place called rock auto parts in the u.s. and i wondered whether this distributor cap would suit?
http://www.rockauto.com/catalog/raframe ... 203k479440

it says sohc not dohc,but the cap looks identical to mine,for the sake of twnty quid or so,i may have a go.
thanks
jamie

[hogggman]

hi,
or this for the cap and rotor..........$60 including shipping.i wonder if it`ll fit?
http://www.rockauto.com/catalog/raframe ... ttype=7054

thanks
jamie

[mikeonb4c]

I think you'd be well advised to PM Andy or Cheffy as they've been through this and are quite clued up. Me I'm just an old Dieselhead

Good luck though Jamie

[dandywarhol]

I seem to remember your valve operating parts were very worn - if the valves aren't letting the correct amount of air in then that cylinder will be starved of air but be fed it's usual amount of fuel, making it rich. Of course, maybe you've had the valve gear replaced in which case I'm talking rubbish.......................

[hogggman]

hi,
yes,of course,i have had valve problems,and no,i haven`t had them done yet-the only local reputable dealer didn`t return my equiries-but it`s on the cards for the new year if i find someone to tackle it.i just thought i`d investigate other bits in the mean time.
jamie

[mikexgough]

from 929 forum..... might help, searched with your symptoms

"My 929 did the same thing at 3000rpm esp in drive. replaced the TPS and Trans oil, same problem.

Finally checked the resistance (using analog meter) of the MAF sensor, was not smooth when the big, stupid, air hogging, I wish I had more power cone was depressed. Replaced (used/ebay) MAF sensor, problem gone."

So I would check the MAF sensor........ and after having a chat to a mate who owns a garage/MOT workshop he suggested Lamda or MAF and as you have done the Lambda....

[Ian]

hi,
or this for the cap and rotor..........$60 including shipping.i wonder if it`ll fit?
http://www.rockauto.com/catalog/raframe ... ttype=7054

thanks
jamie

If you have difficulties locating the cap & arm, the Bongo Shop should have them back in stock by the end of the week. See here (non members)

http://www.igmaynard.co.uk/bongo/mercha ... #Electrics

or here (members):

http://www.igmaynard.co.uk/bongo/member ... #electrics

Prices include delivery. Genuine Mazda parts.