norfolkluego
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| posted on 15/5/10 at 06:29 PM |
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Anybody want to buy a kit car before I set fire to it
Best part of 10 hours b*ggering about with the Luego and no progress at all. Over the last few weeks we've changed the fuel pump, the fuel
filter, the coil pack, leads and plugs, we've tried every Megajolt map ever written and still have exactly the same problem we started with.
Car runs a dream up to around 4500 rpm and then just seems to stop, not really a misfire, just stops accelerating properly and the engine sounds rough
(sort of sounds as though it's misfiring but I don't think it is, just sounds rough)
The only constant in all of this is the carbs, I'm beginning to wonder if Bogg Brothers jetted them properly, something suddenly kicks in at
4500 and nothing we do seems to make any difference.
Supposed to be sprinting tomorrow with a decent weather forecast too, but looks like the car has decided it doesn't want to.
Properly hacked off.
Short of taking it somewhere, leaving the car and my wallet and and telling them to sort it, anyone got any suggestions before I have a Basil Fawlty
moment and start whipping it with a (small) tree
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INDY BIRD
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| posted on 15/5/10 at 06:34 PM |
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persume thay are bike carbs,
do you think it is being starved of fuel??
have you tried washers under the needles to try to get more fuel in if that is the case,
then you could look at the jets,
check the plug gaps incase the plug is getting blown out if over fueling, do you know what fuel pressure you are running etc,
this info may help
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mcerd1
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| posted on 15/5/10 at 06:37 PM |
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have you ever had the car on the rollers ?
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deltron63
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| posted on 15/5/10 at 06:37 PM |
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check that a main jet hasn't fallen out. it happened to me this week. i only found it when i went to change the jet size.
5000 and above rpm nothing. now it pull hard to 7200!!
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pilots50
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| posted on 15/5/10 at 06:39 PM |
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quote:
Originally posted by norfolkluego
Best part of 10 hours b*ggering about with the Luego and no progress at all. Over the last few weeks we've changed the fuel pump, the fuel
filter, the coil pack, leads and plugs, we've tried every Megajolt map ever written and still have exactly the same problem we started with.
Car runs a dream up to around 4500 rpm and then just seems to stop, not really a misfire, just stops accelerating properly and the engine sounds rough
(sort of sounds as though it's misfiring but I don't think it is, just sounds rough)
The only constant in all of this is the carbs, I'm beginning to wonder if Bogg Brothers jetted them properly, something suddenly kicks in at
4500 and nothing we do seems to make any difference.
Supposed to be sprinting tomorrow with a decent weather forecast too, but looks like the car has decided it doesn't want to.
Properly hacked off.
Short of taking it somewhere, leaving the car and my wallet and and telling them to sort it, anyone got any suggestions before I have a Basil Fawlty
moment and start whipping it with a (small) tree
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David Jenkins
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| posted on 15/5/10 at 06:46 PM |
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There is a VERY well-known thing that happens with Megajolt* around 4,000 - 4,500 rpm... if the VR sensor bracket isn't absolutely rigid then it
can vibrate at those revs and totally screw up the EDIS timing, making the engine run really badly.
*Not really a MJ issue - more to do with EDIS.
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norfolkluego
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| posted on 15/5/10 at 06:50 PM |
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quote:
Originally posted by INDY BIRD
persume thay are bike carbs,
do you think it is being starved of fuel??
have you tried washers under the needles to try to get more fuel in if that is the case,
then you could look at the jets,
check the plug gaps incase the plug is getting blown out if over fueling, do you know what fuel pressure you are running etc,
this info may help
Yup, Fireblade carbs with a new Fireblade fuel pump so the pressure should be OK. Problem is I know a big fat zero about bike carbs which is why I got
BB to sort them for me, but I'm starting to think it must be them
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cd.thomson
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| posted on 15/5/10 at 06:53 PM |
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bogg bros only ever set up carbs to get the car running...not set them up to any level of perfection.
you just need to rolling road the car - thats something that everyone with a set of bike carbs has to do?
[Edited on 15/5/10 by cd.thomson]
Craig
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norfolkluego
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| posted on 15/5/10 at 06:54 PM |
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quote:
Originally posted by David Jenkins
There is a VERY well-known thing that happens with Megajolt* around 4,000 - 4,500 rpm... if the VR sensor bracket isn't absolutely rigid then it
can vibrate at those revs and totally screw up the EDIS timing, making the engine run really badly.
*Not really a MJ issue - more to do with EDIS.
That's interesting, it fits the symptoms, nothing we do with the map seems to affect it, always kicks in at exactly the same place in the same
way and make the car feel the same
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jacko
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| posted on 15/5/10 at 06:55 PM |
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Saying you live in Norfolk why don't you take it to Bogg's and have it set up in stead of messing about
When i fitted my bike carbs it ran straight a way right though the rev range but at Boggs they blocked some holes to stop the carbs / fuel /air going
week at high revs + lifted the main neddles
Jacko
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deltron63
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| posted on 15/5/10 at 06:55 PM |
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whip of the float bowls and check the jets. i wouldn't have believed it if i didn't see it myself.
the jet was laying in the bottom of the bowl.
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karlak
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| posted on 15/5/10 at 06:58 PM |
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Probably a million miles from the mark, but I had a similar problem with my previous engine and a "homebrew" air filter. I removed the
air filter and the problem disappeared. Worth a try ?
MK Indy - 2litre Duratec - Omex 600 - Jenvey throttle bodies - ETB DigiDash2
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Dangle_kt
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| posted on 15/5/10 at 07:00 PM |
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or blocked main jets - do you have a fuel filter? could have got gummed up if sat over winter - or loose jets as mentioned.
Lots of things to check - if you need me to snap a few pictures of the haynes manual for the carbs for fireblade and email them over I am happy to
help. u2u me.
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norfolkluego
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| posted on 15/5/10 at 07:00 PM |
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quote:
Originally posted by cd.thomson
bogg bros only ever set up carbs to get the car running...not set them up to any level of perfection.
you just need to rolling road the car - thats something that everyone with a set of bike carbs has to do?
[Edited on 15/5/10 by cd.thomson]
Not saying I expected perfection but I thought it would be reasonably close, or closer than just get it started but as I said, I know diddly squat
about bike carbs, starting to pine for my old Dellortos
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norfolkluego
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| posted on 15/5/10 at 07:02 PM |
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quote:
Originally posted by Dangle_kt
or blocked main jets - do you have a fuel filter? could have got gummed up if sat over winter - or loose jets as mentioned.
Lots of things to check - if you need me to snap a few pictures of the haynes manual for the carbs for fireblade and email them over I am happy to
help. u2u me.
Brand new filter so I don't think that's it but I'd love to see the piccys
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norfolkluego
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| posted on 15/5/10 at 07:06 PM |
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quote:
Originally posted by karlak
Probably a million miles from the mark, but I had a similar problem with my previous engine and a "homebrew" air filter. I removed the
air filter and the problem disappeared. Worth a try ?
Running on Pipercross filter socks at the moment, wouldn't have thought they'd cause a problem but it's worth a try without to see
if there's any difference
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mcerd1
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| posted on 15/5/10 at 07:38 PM |
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if you've got a trigger wheel rather than the std. zetec flywheel then the VR sensor problem sounds like a good place to start looking
have you got any pics of your setup at the moment ?
have you got a timing strobe to check the actual timing ?
also the filter socks arn't the best things - your much better off with a sausage filter or a good airbox and cone filter (or so I've
always been told)
have you tried a quick run without the filters on ?
bogg bros should have said to you that they'd need a run on the rollers to get them set right (even if this isn't the problem your having)
but the same is true for webbers, Dellortos or any other carbs.....
[Edited on 15/5/2010 by mcerd1]
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norfolkluego
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| posted on 15/5/10 at 08:03 PM |
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quote:
Originally posted by mcerd1
if you've got a trigger wheel rather than the std. zetec flywheel then the VR sensor problem sounds like a good place to start looking
have you got any pics of your setup at the moment ?
have you got a timing strobe to check the actual timing ?
also the filter socks arn't the best things - your much better off with a sausage filter or a good airbox and cone filter (or so I've
always been told)
have you tried a quick run without the filters on ?
bogg bros should have said to you that they'd need a run on the rollers to get them set right (even if this isn't the problem your having)
but the same is true for webbers, Dellortos or any other carbs.....
[Edited on 15/5/2010 by mcerd1]
I've no doubt it would be 'better' after a rolling road session but to be honest it runs so well up to 4500 I not sure it could be
much better, just this damn problem at that one point.
Actually wasn't having a pop at BB as they did say ideally it needed a RR session but were confident they could jet it pretty close and they
seem to have done that. I was just completely stumped as to what to do next, just wanted to get the car usable for the next few sprints then maybe
rolling road it for tweeking. We are running a trigger wheel and the sensor bracket does seem pretty firm but I'll see if it could be better,
maybe brace it to stop any high rev vibration and a run without the socks would be a nice Locost check but as for dismantling the carbs to check them
internally, I wouldn't know where to start.
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norfolkluego
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| posted on 15/5/10 at 08:04 PM |
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quote:
Originally posted by deltron63
whip of the float bowls and check the jets. i wouldn't have believed it if i didn't see it myself.
the jet was laying in the bottom of the bowl.
How do I whip off the float bowls, really honestly don't know
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norfolkluego
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| posted on 15/5/10 at 08:13 PM |
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Not sure if this is relevant or not but when we replaced the Facet with a Fireblade fuel pump we also took off the Filter King and replaced it with an
in line filter and to be honest the inlet and outlet unions do seem to be quite small, certainly smaller than the Filter King, could that be
strangling the flow rate at high(ish) revs (I'm thinking bike carbs are high flow/low pressure)
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Paul (Notts)
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| posted on 15/5/10 at 08:13 PM |
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One simple investigation to try is r7unning with a lap top connected to megajolt you can watch or data log the rpm signal from eddis.
if it levels off at 4500 then its not the vr sensor.
if at 45000 it starts to jump about and drop back to 500 rpm ish then the vr sensor is loosing signal and you would drop back to a low ignition
advance and no power.
Paul
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mcerd1
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| posted on 15/5/10 at 08:14 PM |
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quote:
Originally posted by norfolkluego
We are running a trigger wheel and the sensor bracket does seem pretty firm but I'll see if it could be better, maybe brace it to stop any high
rev vibration
how far away is the sensor from the trigger wheel ?
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omega 24 v6
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| posted on 15/5/10 at 08:19 PM |
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Dunno about megajolt but i have megasquirt and a home made vr conditioner board.
SO I had pretty much the same as you when the car reached certain revs the car just died. I started off at 2000rpm and gradually got to 3500 rpm but
could not get past that. In the end phil ringwood recommended mucking about with resistors to get to the higher rev bands. I got a few from maplins
and went to town on it and finally got a working setup that revs to the limiter (7K). It could be the same for you I suppose as the systems for the
rpm pickups must be very similar.
If you need info look at the vr conditioner for a 2.2 ms efi unit and U2U me. I'll look up my notes (got them somewhere safe LOL) and see what I
ended up doing.
If it looks wrong it probably is wrong.
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norfolkluego
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| posted on 15/5/10 at 08:21 PM |
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Interestingly (and not sure what it means, if anything) when 'the problem' starts to happen at 4500 if you dip the clutch and floor the
throttle it revs straight past 4500 with no problem, right up to the (our) red line of 6500
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norfolkluego
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| posted on 15/5/10 at 08:22 PM |
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quote:
Originally posted by mcerd1
quote:
Originally posted by norfolkluego
We are running a trigger wheel and the sensor bracket does seem pretty firm but I'll see if it could be better, maybe brace it to stop any high
rev vibration
how far away is the sensor from the trigger wheel ?
It's pretty close, certainly within their 1-3mm suggested range
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