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power loss and missing when I need it most.
dewbries - 7/6/09 at 08:01 PM

Is there any more advice on what is wrong with my car. I posted the other day but still need help and also found correct id of my carbs.

Running zetec 1.8 on zx6r carbs. Here is what happens, when I go to over take and really floor it the engine picks up really well but will then suddenly start to miss and splutter, lifting off and slowly increasing the throttle will get it to rev to 5500 - 6000 but no further.

Here is what I have had done. Car ran for 3 years on webere so timing must be OK. Carbs set up by Bogg Brother, and on the way home I noticed this problem. I have rang them thinking it was fuel starvation and then turned the regulator up. Have been told I need an air box others on here seem to run bike carbs without box and have no problems. So before I start spending time and money would appreciate any help.

Thanks Mark

austin man - 7/6/09 at 08:05 PM

have you checked that the timing sensor is clean ? I have had a similar problem before removed the sensor cleaned and refitted it et voila.

Is the TPS working and have you set it up with your ECU ? you are probably using a differend TPS now

jacko - 7/6/09 at 08:06 PM

What fuel pump you using ?
to start with i would use a bike fuel pump its the right one for the carbs

Danozeman - 7/6/09 at 08:10 PM

The first place id go would be change the fuel pump to one off a bike.

Duid boggs set the carbs and ignition up or just the carbs? Have you changed your load bins on the ign map to suit the new tps/map sensor? What ecu are you running?

dewbries - 7/6/09 at 08:14 PM

Using a facet with regulator as when it was set up at Boggs. Never had any problems like this with the webers the reason I changed was the stink of petrol and leaking carbs the car other wise runs brill.

dewbries - 7/6/09 at 08:16 PM

Danozeman have set the tps up and am running omex, i know not very lowcost.

MakeEverything - 7/6/09 at 08:32 PM

If it worked before boggs touched it, take it back!

dewbries - 7/6/09 at 08:40 PM

It worked with webers. It was leaking petrol and the smell I was fed up with which is why I changed them.

RichardK - 7/6/09 at 10:09 PM

I don't know the omex but does it have a rev limiting function, my megajolt does and I accidentally left it on a pretty low rev and got the symptoms you describe. Maybe worth a check.

Cheers

Rich

Steve G - 7/6/09 at 10:35 PM

quote:
Originally posted by dewbries
It worked with webers.


The pump may well have been fine with Webers but that doesnt mean it will be fine with bike carbs. Different requirements require a different type of pump - bike carbs only need a very low pressure but decent flow so chances are if you turn the regulator down to the 1.5psi or so required, you will get fuel starvation, and if you turn the regulator up to get the flow, you will overfuel the carbs.

Simple answer - fit a bike pump rather than struggle with a problem thats been diagnosed dozens of times before.

[Edited on 7/6/09 by Steve G]

dewbries - 8/6/09 at 06:14 AM

thanks,

Yes the omex has rev limit and my first thought was that I had set it too low but standing the engine will rev easily to 7000 Rich.

Steve is that your experience, are you running bike carbs? Bogg Bros thought it was fine.

mad4x4 - 8/6/09 at 06:49 AM

I'm having similar problesm

BogG Bros have nothing to do with my Problem.... Never have never will have.

Car revs freely but under load over 4000 RPM car stutters and misses.

Have tried advancing the ignition but no effect - Nect I will try broping the jets as I think it is over fueling at high revs.

GSXR750 Carbs
Facet Redtop Pump & Reg
Zetec 1.8
Megajolt

dewbries - 8/6/09 at 07:04 AM

Mad4x4 when you say dropping the jets do you mean lowering the needles or putting smaller main jets in?

Let me know how you go on. I have ordered a cheap air box to slap on and see if that cures it as some say bike carbs need still air. The saga continues...

PS. does it stutter all the time over 4000 or by putting your foot down slowly can you get it to rev OK?

[Edited on 8/6/09 by dewbries]

dewbries - 8/6/09 at 07:11 AM

By the way I am not complaining about Bogg Bros don't want people to think I am slagging them off. Will ring them this morning but they are a fair way from where I live so if I could sought the problem out myself it would be great.

Steve G - 8/6/09 at 08:23 AM

quote:
Originally posted by dewbries

Steve is that your experience, are you running bike carbs? Bogg Bros thought it was fine.


A previous car of mine ran R1 carbs on a cammed Zetec and wouldnt run right at particular points across the rev range until the pump was switched to an R1 pump. 2 Pinto cars i have seen commercially had similar issues also which were both cured after fitting a bike pump (ebay for £15ish) and a session on the rollers.

The issue could also be as simple as a small setup change as Boggs can never really set them up perfectly - too many variations between engines. I've seen supposedly identical crate engines needing different jet sizes to give best performance (by .05mm anyway) so its worth a final setup session always be done on the rollers. Boggs should have you 90% of the way there though.

dewbries - 8/6/09 at 08:26 AM

cheers Steve G,

Will try and get a pump.