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Juddering/misfiring in boost


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Hi yall relatively new to the starlet scene I've got a ep91 glanza v td04 externally gated running dasteck 

so the car was running perfect pulling well through all the gears, then going up the dual carriageway couple of months back doing some speed in 5th in lost power and started misfiring/juddering in boost(eml didn't come on)so eased off and pulled off as soon as I could and had a quick squint around the bay and everything was as it normally was pulled off and then the problem was still there in boost, it pops bangs and splutters like a twat but only in boost 

The car also used to be very rapid. Wheel spinning and really used to shift you in the seat, but now it feels like your trying to tow another car along, gutless but does not bog out, the whole running of the car has been slowed down not just in boost when the misfire happens. also, adjusting the boost controller makes the issue worse, the more boost you try and run the harder and more aggressive the fault gets, it splutter/coughs/misfires for longer in the boost stage

When car is ran through up to boost very slowly and under no hard load the miss fire does not occur. But running hard into boost the car goes into a splutter/cough/bags as if the A/F mixture or timing changes. Have i missed anything else that can alter these two variables while doing my tests?

changed and checked a lot of things so far but to no success including 

parts changed(all new)

plugs ,king lead, dizzy cap and rotor arm,igniter,turbo, boost controller

parts checked/tested 

compression test came back fine 

Tested map sensor and wiring to ecu also tried a different one

Top pin 5V
Middle pin ground Signal pin 2.6V with engine off. Signal voltage increases as boost increases. Gets to about 3.6v at around .5 bar of boost

tested the sard fuel pressure regulator holds vacuums and pressure

tested tps including wiring 

3 wire TPS, 
top pin 5v
Middle pin earth
Bottom pin 12V when throttle opened

tested Coolant sensor reading 0.5v at ECU when running, and does not change when fault occurs in boost

electricaly tested injectors 

can hear fuel pump 

all wiring removed from ecu and tested to each connector to measure resistance with no abnormal readings. Wiring was also traced and fed to light up a bulb to ensure solid connection and all did so fine

Knock sensor has not yet to be tested. I am looking for any info on expected test procedures/expected information readings.

really cooking my brain and unbelievably irritating it's getting almost un drivable hopefully someone here's had similar problems and can shed some light or point me in the right direction 

 

Any help appreciated and will try pretty much anything haha 

 

Edited by Mostyn
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Its really hard to diagnose without seeing the car but if the engine runs fine except on boost it’s usually something in the ignition system breaking down, you’ve replaced everything else so other that I’d need to see it! 

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Afraid so, I’m in Kent. I’m sure there’s a few owners around near you who could help you out! 

Have you tried the fb pages, they are a tad more active. 

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If the engine runs fine, the turbo is ok and it’s only on boost but you can nurse it through on gentle boost, I’d bet my left nut (my favourite one) that it’s leads

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1 hour ago, Jay85 said:

If the engine runs fine, the turbo is ok and it’s only on boost but you can nurse it through on gentle boost, I’d bet my left nut (my favourite one) that it’s leads

Well I'll try some different ones tomorrow and  if that is the case and sorts it out then il either post or personally deliver my left nut (also my favourite one) to you as a token of my appreciation. Hahah 

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3 hours ago, Mostyn said:

Well I'll try some different ones tomorrow and  if that is the case and sorts it out then il either post or personally deliver my left nut (also my favourite one) to you as a token of my appreciation. Hahah 

Deal! 

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  • 3 years later...
On 7/9/2018 at 2:08 AM, Mostyn said:

Well I'll try some different ones tomorrow and  if that is the case and sorts it out then il either post or personally deliver my left nut (also my favourite one) to you as a token of my appreciation. Hahah 

Hey man. Did changing the leads work out for ye?

 

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