Miss fire problem

[neo1]

Hi chaps ive uploaded a video of the problem but its hard t show due to wind or exhaust noise if you listen you can hear the surging effect it has and watch the rev counter as i pan past it etc....

http://www.youtube.com/watch?v=3wm0E...ature=youtu.be

[neo1]

Hi chaps been out in the garage again checked fuel pressure i had 85psi when running and with vac hose off ive checked the MSD set up sheet and they reckon 3.5 bar running vac disconnected and it drops to 3 bar when vac connected ive set it at that but no tried it yet....

I dont hold up much hope as less pressure will be less fuel and it seems like it needs more unless the fault ive got can be caused by too much fuel at light throttle etc i dont know im sick of it though.....

[B13 JUS]

rob when you set the fuel pressure to 3.5 bar on idle, you pulled the vac hose of and did block the end of the vac hose while setting the pressure?

[neo1]

Hi justin yeah did that VAC off and PLUGGED for sure....

OK this is todays findings guys after reducing the fuel pressure to 3.5bar as per MSD recomendations so took it the car out on test drive it was worse from the outset and as the car warmed through it was just about undriveable totally soon as you touched the throttle pedal with anything more that 10% throttle as indicated on the AVCR display it just died i had to return home limping the car back.... idle speed was surging from 600rpm to 800rpm was 10 times worse......

So not knowing what my C/O reading is i decided to leave the fuel pressure alone as it was still 3.5bar/50psi which is correct so i tried adjusting the ECU C/O screwi turned it in about 5 turns and the idle speed increased to 1600rpm i then used the idle speed screw on throttle body to reduce idle back to 1000pm seemed a lot happyier at this point.....

RESULT....went back out on test and the car still splutted as previous to adjusting the fuel pressure but it was no worse so the conclusion here i came with reducing the fuel pressure from about 8-psi to the correct 50psi and turning the C/O screw in has basically counter acted each other so im back to square one but with correct fuel pressure now at the rail... it does seem to drive better and smoother under the misfire rpm ie upto 2000rpm.....

Some points ive noticed though,,, this misfire/flatspot problem is happening at the point of -vac on the boost guage and 0 psi and also on the throttle position its around 30% to 60% on the avcr reading im lost now to be honest in pig sick of it.....



All i can think of now it trying a new throttle position sensor or try turning the C/0 screw in some more but i have notice a bit of blue smoke appearing when blipping the throttle stationary which im not sure might be a rich mixture washing oil off the bores but not sure ??????

any help guys please try''''''

[neo1]

What bore fuel lines are people using with circular of 500bhp power ????

[the youth]

Rob get the car to a cossie specalist to sort this, they have the tools/equipment to do this and it will save you time and money..
use reyland,msd,karl norris, will pedley,turbosystems..
my race car is at reyland now to fix a missfire issue

steve

[neo1]

I know what your saying steve im sick of this issue now too but would like it to run a bit better so i can run it in a bit before mapping etc...

can reyland and such work on a MSD chip etc ????

[neo1]

Whats the charateristics of a throttle pot ? its the only thing ive not replaced ???

how can you test them.....

[neo1]

anyone....

[garet]

really If you have someone close to you with IAW software try to increase CO pot....this is going to be the easiest way or try turning the screw 3 times right and then turn back 1.5,this should be close to 0....
than start car and check and if misfires from this go each check for half turn right till misfire disappears...
this should help you...ill cross my fingers..

[neo1]

i dont understand what you mean sorry ???

[lee2cossies]

We have a virtually identical fault on my mates 4x4 sapphire cosworth. But it's causing it to over fuel massively and loose power. We drove to scs and unbelievably the fault cleared on the way up but returned on the way home! All we have left to change now is map sensor and t.p.s. But the map sensor is 6 month old genuine weber. It's very annoying!

[Adamski]

still think its a map sensor buy a new one

[neo1]

mmmm ive tried another second hand one of justin didnt seem to make much difference unless that was goosed too...

[neo1]

im loosingg the plot with this car now like might break it