problem is when the revs go up to the limiter which happened for the first time yesterday then the car backfires and spits flames and misses like all hell untill i switch the car off and restarted it.... i darent try it again incase its gunna blow it up as it does not sound good atall..... only running 0.5 bar boost so cant be boost cut surely? its a stage 3 2wd cossie. any ideas as im petrified to drive it now

 

Nothing easy comes to mind, it sounds like your fuellings going mental, or possibly losing the phase signal, but once locked on at start up it should stay locked, and shouldnt need the signal after that, but I'm not ofa with the webber marrreli very well at all.
I would ask stu@msd about this, as it could be a duff ecu even.
tabetha

 

yea i think the fuelling is going crazy, after it had done that is was a bit erratic at low revs also, just pelled the cap off the dizzy and phase sensor wires look really old/brittle, going to get that replaced asap before i drive it again and try that..

please please i hope its not my ecu

 

If it doesn't detect the phase in the correct place it will overfuel massively, as I found out, I was curious so tried to see what would happen.
tabetha

 

hmm now that would explain why i get 180 miles to a full tank, cruzing mostly with my daughter in the car.....

 

Does the car buck and kick also ?
If I were you unless it is less than a couple of years old I would replace the CTS, these do bugger up, and only about £10, can have drastic effect of fuelling as it is the main corrective factor for the CO.
On stage 1(GGR/westfield chip) I was getting at worst around 160 to a tank, I can get over 400 now, after mapping, best money imo that you will ever spend.
tabetha

 

yea it bucks and kicks sometimes around the town.. cts was replaced a month ago which cured some of the other gremlins, co's perfect surely as had the emmisions checked but nowhere up here that can do any form of setup and cant afford the trip south just now, being a 400quid return trip to aberdeen onthe ferry... plus my cas not driveable thanks to the mother-in-law doing her best to ram raid the front of it!

 

I would in the meantime check other stuff like the tps reading, make sure it is nice and smooth with no dead spots, a dead spot just above idle is not uncommon as this area has the most use.
The odd bit is it "resetting" after switching off, I would also check the phase sensor is dead in line with the scribe mark on the dizzy body when at tdc, as marked by the LUG nearest the v groove, cam pulleys pointing in to each other.
tabetha

 

whats involved with checking the tps? yea theres a flat spot just above idle where it hesitates, could be down to that? i did a timing belt on it and double checked all the timing marks especially the phase in the dizzy as it was a nitemare to see!!! still not conviced im not got a leak in a boost/vacuum pipe somewhere....

thanks again for your help tabs

 

On your TPS you need to pierce into the signal wire, I know when I ran a L6 that it is the same colour as one of the wires in the phase sensor.
Just peel back the boot on the tps connector, see what colour wires are there, one is the same colour as a wire in the phase wiring(loom not actual sensor) or in any event prod the wires with a multi meter with ignition on, one will be around 4.8/5v, and another earth the last one will be low around 0.6v, this is the signal wire, this is the one that varies with the throttle position, just hook into this wire and look for a dead patch, it is the only wire that varies voltage going to the tps so can't go wrong.
What you are looking for is any positions where the meter loses the reading, due to a duff tps, it is basically a carbon track inside with a wiper arm that sweeps against it, so it wears, sometimes you can give them a little more life by rubbing a HB pencil into the track, but won't last long, just a old trick(showing me age here!!).
Any dead spots means a new one needed, but they are a fairly common resistance and fitting, ie 8mm D shaft, I use a universal one, cost £20 brand new, just needs connector changing.
tabetha

 

ok perfect explanation, i'll give that a check tomorow when i get a chance..
love the hb pencil idea/trick......

just curious where abouts do you get a universal one from?

 

You can get universal ones very easy, most are a very similar resistance, anyone really that supplies/maps ecu's will no doubt have these, I refuse to pay cossie tax if I don't have to.
I got mine from Dave Walker@ emerald, as we were mapping it at the time it went duff.
The beauty is if I ever need another the set up is simply connect then 2 mins on the laptop to scale it to the ecu job done.
tabetha