yamapinto
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| posted on 13/5/08 at 09:49 PM |
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Carb and TB Balancing
Evening all, still out in the garage at this time.. aint Wifi great!.
Just trying to balance up our TB's and we haven't got a syncromometer,
In theory if the butterflies are all open an equal amount should they be balanced? or doesn't it work quite like that?.
Using a piece of hose to the ear they now all sound similar and much better than before... but the exhaust for cylinders 1 and 2 is unbearable to
touch yet 3 and 4 you can just about dab your hand on after 30 sec or so of running.
They should all be recieveing the same fuel from the injectors It fires all 4 at once (onto the back of the valves so not involved with airflow)
And the coil pack fires cylinders 1 and 3 and 2 and 4 so they have a hot and cold exhaust each so it shouldn't be that.
Any thoughts or observations?
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BenB
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| posted on 13/5/08 at 09:51 PM |
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Having you tried swapping round the injectors- if they're second hand they may well need a trip to an ultrasonic cleaning rig....
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yamapinto
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| posted on 13/5/08 at 09:56 PM |
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Hmm good point... we've cleaned them at home with a hobbyist type ultrasonic cleaner and there more of a jet than a misted spray like when there
in the TB's themselfes. but yeh it appears that there might be something fundementally wrong like that.
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BenB
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| posted on 13/5/08 at 09:58 PM |
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Swap the injectors and see if the problem moves!!!!
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indykid
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| posted on 13/5/08 at 10:00 PM |
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how many times per cycle do the injectors all fire at once?
is it that the cylinders aren't recieving the same mixture because of the injector sequence and fuel's left condensing at the back of the
valves?
tom
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yamapinto
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| posted on 13/5/08 at 10:05 PM |
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Bugger Megatunes just crashed... I'm pretty sure it fires all the injectors at the same time and Twice per cycle.
Wouldn't the fuel puddle fuel on opposide cylinders in the fireing order?
I think swapping over the injectors will be the first job for tomorrow.
Any thoughts on the balancing by the throttle butterflies all being open the same amout or are there lots of other factors to be considered and it
can't really be done without a syncromometer.
[Edited on 13/5/08 by yamapinto]
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MikeRJ
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| posted on 13/5/08 at 10:13 PM |
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quote:
Originally posted by yamapinto
And the coil pack fires cylinders 1 and 3 and 2 and 4 so they have a hot and cold exhaust each so it shouldn't be that.
Any thoughts or observations?
If it's a wasted spark ignition it should be firing 1 & 4 and 2 & 3 together.
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yamapinto
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| posted on 13/5/08 at 11:24 PM |
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Yup your quite right on the coil packs wasted spark fireing i'd just typed it in wrong!.
The car has run and been driven about quite a bit while trying to tune it up, its just never been completely right and a bit offbeat, its also been
eating sparkplugs as well 
Just to confirm for Tom.. It fires the injectors twice per engine cycle.
[Edited on 13/5/08 by yamapinto]
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Jenko
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| posted on 14/5/08 at 10:39 AM |
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I agree a good test is to try the other injectors and see what happens, but I can't help thinking you would be unlucky to have two
malfunction........
You could try the alternating squirt and see if that makes a difference.....But also look at the plugs / ignition.......Also, worth mentioning that
you need to figure out which is better too hot or too cold - i.e. is it the hot cylinders at fault here - My manifold get bloody hot!.....
What are your plugs like after a drive?. Are they all the same colour?...Do you have wide band to monitor your AFR?....
Pj.
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MkIndy7
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| posted on 14/5/08 at 04:29 PM |
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Before this all gets really confusing lol YamaPinto is my dads sign in name and the MS softwares on his laptop.
Thanks for your suggestions.. we've got to stick with simultaneous injection on all 4 cylinders as its running 8 injectors (2nd set don't
come in till over 3.5K revs)
I'm just about to swap over 2 injectors now, but as you say I think i'd be unlucky too.. Jout bought a balancing kit from Halfords as well
looks cheep and nasty but if it does the job!.
With the manifold heat I suspect they should all be hot and that 3&4 must be misfiring or maybe even over rich... as when things are lean they
tend to burn hotter.
Also certainly plug 4 always tends to look wet either oil or fuel fouled we checked the valve setm oil seal and could push it down further on No4 so
that might have cured that.
Plugs 1&2 are very similar but slightly sooty as apposed to having a sandy appearnce if they were completely correct.
And yes its running a LC-1 wideband Lambda, Usually shows slightly lean on idle and always on the rich safe side when driving.
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MkIndy7
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| posted on 15/5/08 at 10:12 PM |
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Well it looks like it was a combination of all sorts of things!
We swapped over the injectors on a good and a bad cylinder and the problem followed, so we cleaned up another set of injectors we had and popped them
in and it started running propperly on 3 cylinders.
And then the spark plug on the other cylinder must have been slightly fouled up, gave it a wipe and popped it in a good hot cylinder and off it
chugged!
So maybe we've always had an injector that was slightly iffy and then another one has gone and highlighted the problem so its ideling better
than ever now.
We've tried the old injectors and they all look to have pretty similar spray patters but obviously at some point in there duty they can't
be fireing all the same.
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