misfire on single turbo,fresh rebuild

[a.tapos]

Ill start at the top,ive just rebuilt my single turbo fd due to water seal failure,rebuild went well not the first one ive done used heavy duty seals and gen mazda bits no signs of damage on any housings so am pretty certain my prob isnt there,and also the water pipes dont pressurise anymore so that initial problem appears to be fixed,
 
Now for the problem,standard ecu fitted,accel warm up removed,new plugs,vehicle started up on the button then idled a bit lumpy but revved perfectly,turned off to check coolant,restarted with trouble then revved poorley and idle worse,then cat heat light come on,going on this i suspect fuel is getting to cat and maybe car is flooding but im not that good on singles,please can anybody shed light i dont want to take it out again,i will apexi and map but want to sort this first,
all ideas/similar faults welcomed,i am aware the standard ecu wont help but cant see why it would cause mis,
Thankyou very much one love and goodnight.:Santa

[BlitzBoy]

so you are running a single turbo FD on a stock ECU, what turbo are you running?
Given that your ECU is expecting signals from solenoids that dont exist anymore(rats nest removed) im not surprised it doesnt know what to do with your fueling, are you on stock ports?
Check your map sensor is all connected eg vacuum pipe to plenum has no splits

[a.tapos]

its a garret gt40r,rats nest is still connected up with whats left and is on standard ports,i have changed map sensor hose,could it overfuel enough to misfire and not clear itself :3Confused

[shaunwil]

More likely the complete opposite. To do any major mods you need an aftermarket ECU. Your running a crazy risk even firing it up on a stock ecu let alone driving it around.

Shaun

[BlitzBoy]

Given you still have a CAT I reckon it may have collapsed which can cause your symptoms as well so get that checked out.

I would do the deflood procedure, you say you started up fine then you switched it off, how long did you leave it idling after the intial start up?

[HaywardRotary]

What injectors are you running?
If you are running stock injectors then maybe you have a seal problem and are not getting decent compression which is allowing alot of unburnt fuel to get into the cat.
Regards
Carl

[royal]

Hi Carl, Can you explain that a bit more?

[ash]

Check your lambda/o2 sensor? Maybe a faulty wire from the sensor?

[a.tapos]

Right thanks for the input,as for cat thats a possibility,im starting to think it is flooded now and may have to wip the plugs out and burn them,it started and revved well it ran for 3-4 mins,then i turned it off to check coolant(maybe 2 mins) started up again this time struggled to start without throttle then revved up like a v8 with 4 pistons,
 
as for injectors they are standard,it misses and runs rough with no load on it just in the workshop,
 
i know the ecu is a problem and it will be for the bin but need to at least make sure it runs before i shell out 1000 quid for proper management,it ran before on the stock ecu so it will again if only briefly.
 
o2 sensor appears to be working,
 
thanks again to all keep it coming.

[HaywardRotary]

Hi Carl, Can you explain that a bit more?

Hi Dave,
I am meaning that if there is a stuck seal (Since it is a new engine),or the seals have been poorly toleranced then excess fuel that is not burnt properly tends to get down the exhaust and burn in the cat instead of in the engine,hence the heat light.
If on the other hand the primary injectors have been changed to larger ones,say 850cc\'s then the stock ecu will over fuel causing the same thing.
Regards
Carl

[HaywardRotary]

Sounds like a poorly seal or manifold leak maybe.
Regards
Carl

[BlitzBoy]

Right thanks for the input,as for cat thats a possibility,im starting to think it is flooded now and may have to wip the plugs out and burn them,it started and revved well it ran for 3-4 mins.

well if you only let it run for 4 minutes then switched it off after you rebuilt it then you probably flooded I reckon, yep whip the plugs out give them a good clean and do the deflood procedure

[royal]

Hi Dave,
I am meaning that if there is a stuck seal (Since it is a new engine),or the seals have been poorly toleranced then excess fuel that is not burnt properly tends to get down the exhaust and burn in the cat instead of in the engine,hence the heat light.
If on the other hand the primary injectors have been changed to larger ones,say 850cc\'s then the stock ecu will over fuel causing the same thing.
Regards
Carl

Nice one, thanks for explaining. I thought that was what you were getting at but trying to learn as much as I can just now! :King

[a.tapos]

well a couple of days in and ive decided to check compression,all good thank god,doesnt appear to be any drop in water or or coolant in chamber so am happy with rebuild,
 
suspect poor fuel quality now as it smelt awfull and floods instantly may at least be 18 months old,will try fresh stuff later,
 
also wasnt to impressed with quality of spark at plugs new plugs are installed so is making me wonder if the starter is nicking all the earth during cranking,
 
my black and yellow earth on this car is from the main loom to the centre section but im sure it was to the starter on the other,
 
begining to beleive its a series of small probs that will pee me off,,:2Mad

[shaunwil]

Its what gives you the satisfaction at the end

Have you had a multimeter across the battery when you crank the engine over ?

Shaun