1.8t not boosting

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Jasonbill
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1.8t not boosting

Post by Jasonbill » Sun Dec 01, 2019 1:40 pm

Hello everyone...my golf 1.8t auq stock standard does not boost and if I drive it like normal there is slight hesitation over 3k revs and if I floor it there is heavy hesitation and it feel like something is holding the car back...it idles fine just that holding back with hesitation...i have changed the pic valve plus the breather pipes as well...i have a suspicion feeling about the throttle to intercooler hose if it's collapsing
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dcmk4
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Re: 1.8t not boosting

Post by dcmk4 » Sun Dec 01, 2019 2:06 pm

The pipe between intercooler and throttlebody would be pressurized so the only way that would be collapsing is if the turbo is not building any boost and somehow it is under a serious vacuum.
The easiest way to diagonose it would be to scan for codes to be fair.

Could be fueling, boost leak, misfire and the list goes on.
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Jasonbill
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Re: 1.8t not boosting

Post by Jasonbill » Sun Dec 01, 2019 2:39 pm

Ok thanx will find someone that can do a scan
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Re: 1.8t not boosting

Post by PapaJo » Sun Dec 01, 2019 5:39 pm

Waste gate stuck open??
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Re: 1.8t not boosting

Post by Jasonbill » Sun Dec 01, 2019 6:55 pm

I have pulled on the what I think is the watse gate rod and I think it's close...coz I need to pull very hard to move it
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Re: 1.8t not boosting

Post by Jasonbill » Sun Dec 01, 2019 7:20 pm

How can I test the n75 valve
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dcmk4
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Re: 1.8t not boosting

Post by dcmk4 » Sun Dec 01, 2019 9:44 pm

Jasonbill wrote:
Sun Dec 01, 2019 7:20 pm
How can I test the n75 valve
A simple test would be to unplug it and see if there's any changes in behaviour of the car.
However based on what you said, unless the N75 is stuck closed and the car is overboosting then going into limp it wouldn't cause the issues mentioned.

If they go bad they generally stop cycling and the car will run at wastegate pressure which is not much and make minimal boost.
You can also toggle it with 12v power and listen for a clicking sound to test the solenoid.
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Re: 1.8t not boosting

Post by Jasonbill » Wed Dec 04, 2019 8:17 am

Thanx I'll check the n75 over the wkend with 12v battery...can a fuel pump coz the same symptoms also
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Re: 1.8t not boosting

Post by dcmk4 » Wed Dec 04, 2019 9:15 am

It could be the fuel pump if it is dying and not supplying enough pressure. Also have a look at the fuel filter and see if it looks old, consider changing it.
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Re: 1.8t not boosting

Post by Jasonbill » Thu Dec 05, 2019 1:27 pm

Ok...when I lifted the back seat where the fuel pump is...i noticed there is only 1 srew in on the cover where the pump is...looks like somebody already worked on the pump before...
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Re: 1.8t not boosting

Post by Jasonbill » Thu Dec 05, 2019 1:31 pm

Oh sorry...yes I changed the fuel filter already and car still the same
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Re: 1.8t not boosting

Post by missioner » Thu Dec 05, 2019 1:54 pm

Jason

You need more information than what you can ascertain on your own to solve your cars problems.

1. EML is is on?
2. What is the actual boost pressure?
3. Fuel pressure under driving conditions.
4. Fault codes?
5. No other mechanical faults, like a slipping clutch?
6. Check valve timing.
7. Physical turbo inspection.

All of these things need answers in order to find the fault with your car, most of them require some type of tool or equipment to get that info for you.

If you are prepared to make or buy the tools then good for you, knowledge is at your fingertips.

If not, I then suggest that the car go to someone who has invested in the diagnostic equipment that will help get to the heart of the problem.

You didn't say where you are, we could suggest a decent service provider that can help you return all those missing ponies to where they belong.
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Re: 1.8t not boosting

Post by Jasonbill » Thu Dec 05, 2019 8:10 pm

Hello missioner I'm from knysna...and the mechs here are useless...they don't even know what a smoke test or pressure test is...and thanx for the info...ill see if I can take the car maybe to someone in George
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Re: 1.8t not boosting

Post by missioner » Fri Dec 06, 2019 2:21 pm

Jasonbill wrote:Hello missioner I'm from knysna...and the mechs here are useless...they don't even know what a smoke test or pressure test is...and thanx for the info...ill see if I can take the car maybe to someone in George
Contact Thanas on the forum.

1st he's a genius with 1.8 20VT motors and 2nd he's based in Capetown, not so far.

Ask him if he has someone close to you he can work with or if it's better to get the car to him.
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