Poor start, VNT? - Alfa Romeo Forum
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(Post Link) post #1 of 11 Old 13-07-16 Thread Starter
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Hmmm Poor start, VNT?

Quick question: Could a leak/fault in the VNT system cause a poor and smokey start? Car always starts from cold but after prolonged cranking, fires nearly straight away when hot. The vehicle also smokes a bit when putting your foot down(under load/in motion), especially when you are in maybe a gear higher than you should be.

A little info: New higher rated battery, new dedicated earth from starter body to batt., EGR delete + remap, swirl flaps removed.

My only other concern is the cranking speed which isn't all that impressive despite the above^ Starter?
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Don't think vnt fault could cause slow cranking but smoke and sluggishness maybe.
What grade oil is in it?
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(Post Link) post #3 of 11 Old 14-07-16 Thread Starter
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Fair enough, bit more info is the engine management has no faults on it...

It's got the Fuchs 5w40 stuff that Autolusso sell in it

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Quote:
Originally Posted by Happax View Post
Car always starts from cold but after prolonged cranking, fires nearly straight away when hot

Glow plugs are ok?

(Wouldn't account for the smoke of course)


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Quote:
Originally Posted by Happax View Post
Quick question: Could a leak/fault in the VNT system cause a poor and smokey start? Car always starts from cold but after prolonged cranking, fires nearly straight away when hot. The vehicle also smokes a bit when putting your foot down(under load/in motion), especially when you are in maybe a gear higher than you should be.

A little info: New higher rated battery, new dedicated earth from starter body to batt., EGR delete + remap, swirl flaps removed.

My only other concern is the cranking speed which isn't all that impressive despite the above^ Starter?
Did we do the EGR & swirl flap delete??

Ned
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Quote:
Originally Posted by t3yls View Post
Glow plugs are ok?

(Wouldn't account for the smoke of course)


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You don't need the plugs this time of year.. Sure they help, but you shouldn't have issues without them until the depths of winter...
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(Post Link) post #7 of 11 Old 14-07-16 Thread Starter
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Again more info I forgot to add glow plugs are new and all have feeds supplied.

Ned you did the EGR delete/remap. I did the swirl flap delete, just took the actual flaps out and left the rest as it's the CF4 variant didn't think I'd have issues with boost leak. Vehicle is fitted with FMIC and de-cat down pipe too.
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I believe the engine runs best with a remap once the flaps are gone. Could this be your problem?
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The car went back to Autolusso to have the map tweaked as it was idling poorly and that was after the swirl flaps were removed so I guess it should be running optimally as far as that is concerned.
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A poor idle and extended cranking time sounds like an air leak to me. Added to that you have smokey running, which is when the air leak becomes a boost leak.

Neither of those things should affect the speed which your engine cranks at, that is related to battery, condition of earths/power leads and the starter motor itself.
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(Post Link) post #11 of 11 Old 16-08-16 Thread Starter
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Thanks everyone for all the responses. Oil cooler started leaking a couple of weeks back so as I was fixing that I took the opportunity while the bumper was off to get some gas leak detector on all the silicone pipe work and joints but couldn't find any bubbles. Might be a leak from the inlet manifold gasket I guess.

A new job as meant the car gets used a lot more and the starting speed is improved somewhat which makes me think it was just a bit low on voltage and coked up from short trips.
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