Turbo whining after 0.5bar

[doug9787]

Hi all on acceleration it is fine perhaps slight hesitation until the boost gauge hits 0.5bar after that as i still accelerate i get a high pitched whining noise the engine light comes on and exhaust backfiring , i had the exhaust changed a couple of weeks ago and before the the acceleration was hesitating terribly but no turbo whine . iam at a bit of a loss as to what to check first any help much appreciated

[Rice crispy]

Check for a fault code when you switch the ignition on as it may show you a code. Details in wiklec on what each means. Also when it backfires does the car lose power for a second or so? If so you are getting over boost most likely. Is the new exhaust larger bore in which case its likely the cause.

[doug9787]

Thanks no fault codes are showing but i assume the exhaust is a bigger diameter as its a sports exhaust and loud , it whines first , backfires, loses power and then the engine management light comes on ..it clears itself within 100metres or so but is very frustrating. if its an overboost problem how can i sort that out ?

[Rice crispy]

Have a look for wastegate wiggle and try that first. If that isn't the problem check for air leaks. If its due to a larger exhaust then you would need to enlarge the wastegate on the turbo.

[maz_r]

In the interest of balance, one could suggest a narrower exhaust, if that indeed is the cause...

[Rice crispy]

In the interest of balance, one could suggest a narrower exhaust, if that indeed is the cause...

Good point Max_r this would also work

[rip]

Hi Doug,

Where are you? Maybe another forum member could take a look & compare. Adding your location to your profile would help in this respect.
First-hand experience is a lot easier than diagnosing from a description.

[Enright]

As the others have said Doug - do a paperclip test (search WikiLEC from the link above), and you can find out what the fault codes are.
Then add your location to your profile because there will probably be someone nearby who can help you.

[doug9787]

thanks for your comments guys . iam in st albans and work in hendon london NW9 but willing to travel for an expert opinion i have now sucsessfully downloaded the elanscan and i have the lead thanks Geoff so when the rain stops i will plug in and have a look but you are right but listening and hearing are best as its difficult to explain
i have a crydox exhaust fitted it is 2 1/4 " or 57mm the friday before the lotus festival simon kindly met me and hooked up his elanscan at the time it was showing no boost at all , luckily at brands hatch it was found that my intercooler pipe had detached , since then like i said accelerates nicely but cuts out over .5 bar backfires and the engine management light comes on so iam sort of feathering the accelerator in the gears so it doesnt whine /backfire /cutout .

[Rice crispy]

I could possibly pop by Thursday as I may have meetings in Nottingham and could come by on the way back to Brentwood. PM me if its suitable for you and I will let you know tomorrow if my meetings are happening.
David

[doug9787]

Hi david much appreciated as this forum will not let me pm members as it says they dont exist !! i sent an email to your registered address but came back saying you are out of the office until friday thursday is good for me hendon 9-5.30 i work at a showroom almost on staples corner or from 6pm st albans but nearer m1 junc 6 please let me know steve douglas 07896 864818

[Rice crispy]

Hi, yep out in London all day tomorrow and Nottingham Thursday morning. I expect to be near M25 around 2 so could come to Henson if that suits you? Will dive you a call tomorrow afternoon on your mobile to sort out
David

[doug9787]

thanks david 2 sounds good otherwise i can drive up to meet you at the thames gateway services (used to be scratchwood). look forward to your call
many thanks

[doug9787]

So after going back over loads of lec posts ,people who have fitted a 2.25" aftermarket exhaust have eliminated the overboost problem by porting the wastegate .if anybody has any suggestions as to who could carry this out in the st albans / nw london area i would appreciate the feedback , as i thought changing the thermostat and renewing my electric coolant pump would be a 2 hour job max until i snapped the head off the bolt holding the thermostat housing !!! ..how wrong i was

[epipete]

...... i thought changing the thermostat and renewing my electric coolant pump would be a 2 hour job max until i snapped the head off the bolt holding the thermostat housing !!! ..how wrong i was

If you did this recently, and this experience is not historic, then you'll find that when you remove the second bolt on the thermostat housing, the casing will then slip off past the broken bolt which can then be easily removed with a mole grip or similar. A pair of new bolts and job done!

[Peter D]

I had the wining shorlty after installing the SAMCO induction hose.
The pressure fan had 1 bent blade. Noise pitch went with revs of Turbo.

[Fredjohn]

So after going back over loads of lec posts ,people who have fitted a 2.25" aftermarket exhaust have eliminated the overboost problem by porting the wastegate .if anybody has any suggestions as to who could carry this out in the st albans / nw london area i would appreciate the feedback , as i thought changing the thermostat and renewing my electric coolant pump would be a 2 hour job max until i snapped the head off the bolt holding the thermostat housing !!! ..how wrong i was

Without actually going back to read the loads of threads on this, I thought most over boosts occurred with 2.5" exhausts rather than 2.25" exhausts. I have 2.25" fitted with no over boost at all, but I do realise not every car with larger exhausts suffers though.

Unless you are sure it is over boost, maybe check a few other things first before going to the expense of removing turbo and having it ported.

[HJ2]

Also some 2.25" pipes caused overboost when emptying the pre-cat, installing a PCE or have another downpipe.
I'm afraid it is not just limited to the 2.5"exhaust ...