hi chaps

hoping someone can help

i rebuilt the engine bay of my fiesta rs turbo last year with new everything, new engine(bottom end & head), gearbox, clutch, loom hidden in inner wings, fresh paint ect ect, but ever since then i've had a issue of the engine stalling only on cold strat up, once it warms up it's fine

it has all new sensors, new fuel pump(bosch 040), new fuel pump relays, no errors on my collins monitor, replaced ignition plug with soldered joints, new ignition live to ecu, the iscv is modded for ALS so that isn't a issue, management loom has been replaced with a braided one

any other thoughts, suggestions would be greatly aprichated

Paul

 

may be irrelevant but may prompt you in the right direction on my zetec turbo pectel management i have high idle issue..so a temporary fix is to disconnect my idle valve WHICH now causes EXACT same issues as you are currently experiencing. I too have too let it warm up with a little throttle.

Sorry not a direct answer but similar issue. Cosworth temp sensor has the same symptoms if you disconnect it. Hard to start from cold. Have you got the right temp sensor for the map?

 

the iscv/als valve has a duel pole switch going to it which basicly cuts the signal going to it unless it's switched on which does the same as unplugging the plug

yes i have the temperture sensor

thanks for the reply anyway much aprichated

 

Probably needs a remap if its been rebuilt, maybe it's breathing a lot more air as the head isnt coked up or something. Until you can see what the ECU thinks it should be doing, you're pretty stuck.

 

is the ISCV being used during cold start? how has it been modified? top hat? or drilled?

 

it has been mapped allready, they suspested it was a ignition related issue, eirther the ignition plug itself or the ignition live feed to the ecu, but both have been changed last week

 

no the ISCV is not being used on startup, as i said it has a duel pole switch which basicly loops the live feed via a switch, the ISCV was modified by the top hat

 

So it has been mapped since it was rebuilt? Was it returned to you in this condition?

 

I'm surprised your chosen tuner has not been able to sort this for you.

 

yes the car has been mapped since it's been rebuilt, but please remember the car was rebuilt by me, i haven't given it to someone to build it for me, obveriously the fancy bottom end, head & gearbox was built by a specialist and it was left to me to put it all together which i feel i've done a good job, the car was mapped just to see if it was anything related to the fine setup that i had no control on myself

 

Hello stuart, the engine tuner and mapper made a suggestion to the most lickly cause of the issue was, i didn't know if the issue was anything mapping related or something i've overlooked myself as it was me who put it all together

 

How do you expect it to cold start well without a functioning air bypass then? Surely you've answered your own question as to why it's bad

Engines are very inefficient when cold with the enrichened afr etc, and are easy to "stall" which is why even from the days of a manual choke a cold starting car was given an increased idle speed to aid stability and prevent it cutting out until it was warm enough to be leaned off and operate normally.

You've turned half the cold start mapping off by cutting the increased idle speed. Why do you think the valve is there?

Best thing you can do is put a STD valve back in, and mod it so it will still function well enough to give you a nice increased idle speed,
Or use 2 valves one STD for cold start, and a second for ALS

 

thanks for the reply

i really don't think the ISCV is the issue, i have run this system for the last 10 years without experencing the issues i now have, yes i agree it's a pain that i have to monitor the rpm with the throttle which i've got used to over the years this isn't a big issue for me

even if the rpm is increased it still cuts out, my best guess of the issue is a management plug that is making a weak connection and the virbration from the polly engine & gearbox mounts is causing the cutout, i could be way off on this but it's the only thing i can think of now

 

At the side of the throttle body is the idle screw get the car upto temperature until fans kick in then disconnect idle valve then adjust the idle screw on the throttle body until the revs are at 950 then retighten the idle screw nut then plug idle valve back in revs will go up then back down this is your cokd start setup i know as i have the same management as you Mate and i had the same problem not now

 

the iscv doesn't work as a idle valve as it's been converted to run anti lag so your theory unfortchally won't work

if it had a conventional iscv you would be right in what you said

thanks for the reply anyway

 

Idle valve may want a clean then up you may have a vacuum leak tbh they all do that sonetines

 

Have you had all the sensors read to see what air temperatures fueling are at idle

 

yes mate, i have a collins engine monitor that shows real time data

 

Might possibly an air leak then somewhere or

 

Chevk the gaps on the phase and crank sensors 0.2 for phase and 0.7 for crank they have to so accurate

 

already checked

 

Must be a problem with the valve itself then not opening enough to let air in is it adjustable or self adjusted

 

is there a live feed getting to the icv you ladds sound like u now what ur on about im a mechanic but i dont no much about the tuneing side of things hope this helps

 

thanks for the reply

yes there is a live feed getting to the iscv BUT!!!!!!!!! it wouldn't matter if there isn't because it can't be used as a iscv due to the modifications done to the valve to run antilag, you would eirther have a standard iscv or a antilag valve you can't have one that does both things

 

pherhaps theres nothing wrong at all and in a way it means the engine now is set up corectly bad starting without a cold start mechanism and runs sweet when warm isnt a bad thing maybe it wasnt set up properly before and theres allways been this isue but with maybe poor set up before with over rich mixture you havent noticed it

 

It does sound to me that if the ISCV was returned to normal then maybe the problem might go away, worth trying and then fix back from there...it has to be a case of check, check and check again OR give it to a tuner that knows the system and ask them to give it back working.

 

i find this stuff really intresting you can actualy learn something the fuel isnt rich enough when cold