[Mk2] [Turbo] Mk2 Turbo Running Issues

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Truzo
Posts: 57
Joined: Mon Jan 19, 2015 11:28 am

[Mk2] [Turbo] Mk2 Turbo Running Issues

Post by Truzo »

Hi I recently bought a Rev 2 Turbo ( My second one) as a slight project. It needed some body work and pretty much a tune up.

So the car still runs bad, Hesitates low down the rev range sometimes wont boost properly and when it does boost there is hardly no power.
The idle is erratic and dips from 500rpm to 1200. (Sometimes almost stalls when stopping clutch in and brake on)

So the engine had a rebuild by Rogue some time ago this included a metal head gasket, copper water pipes replaced with rubber water hose and a gutted cat and a replacement rad. This was 3ish years ago but only 4000miles by the previous owner, I also have receipts to prove this.

I have done some bits myself this includes,
New dizzy cap/rotor arm leads and plugs.
Rad fan switch and water temp switch
Engine bay fan / temp switch
O2 Sensor.
Took off cleaned out the throttle body (new gaskets also)
Second hand AFM but tested and working.
TPS again second hand but tested. (Set with the bgb guide)
New silicone hoses from the AFM back to the throttle body.
All new silicone pipes for well....everything really.
Full service (oil filters and so on)

I have checked for air leaks cant find anything.
Did a compression test from cold with the throttle open and the injectors disabled
188 175 175 175

Other issue is that the rad fan is always on and I cant figure out why,
Engine bay fan doesn't work when plugged in and throws up a fault code when hot.
(Engine bay fan currently unplugged from the thermal switch and is on constantly with no codes)

Other than that one, No other fault codes show up.
Tried putting the ecu in learn mode also.

Tried 2 after market boost gauges and both say 10psi (Put in a bleed valve to test and then both read 14 psi or whatever I set it to) It doesn't seem to hit fuel cut but I cant find a fcd anywhere.

Any advice would be awesome ! Sorry for the long post =)
mr2magic
Posts: 643
Joined: Fri Apr 09, 2010 9:33 am
Location: Hannover, Germany

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by mr2magic »

Have you checked your static timing and ignition timing?
alanmr2turbo
Posts: 2238
Joined: Wed Nov 28, 2007 7:08 pm
Location: Birmingham
Contact:

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by alanmr2turbo »

Do you have an aftermarket BOV on it that vent to atmosphere?

Front fans could be constantly on if previous owner has removed the air con and not bridge the connector in frunk (do search on here)
Truzo
Posts: 57
Joined: Mon Jan 19, 2015 11:28 am

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by Truzo »

I haven't checked the timing yet, and its a stock BOV directed to the intake.
markstevieandmads
Posts: 2025
Joined: Mon Aug 05, 2013 8:18 pm
Location: Swindon, Wilts

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by markstevieandmads »

Check the coil for cracks.
pbmr2
Posts: 929
Joined: Fri Jun 18, 2010 12:49 pm

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by pbmr2 »

you can check both coil and igniter with a multimeter for resistance. The values are in the BGB.

Also the IAC could be gummed up with crap or the sensor not working. again all info in the BGB. Can cause all sorts of probs with running.
Air leaks are common on the intake side, but they tend to make the revs hunt up and down, not always though. Plus you said you have checked.

Have seen the vacuum cylinder below the intake crack.

Fans (assuming front?)
There is a little plug on the passenger side, below the fuse box area, simple 2 pin effort, normally white. It should have a connector in the end to bridge the 2 contacts. This stops the fans going all the time. Even if the car never had AC, if this bridging connector is missing the fans will run all the time. sorry can't find a picture.

If that turns out to be ok then it could be the fan control unit.
Truzo
Posts: 57
Joined: Mon Jan 19, 2015 11:28 am

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by Truzo »

Hey guys thanks for the info and ideas.

I have had the the coil out checked the connectors are good and clean and there are no cracks.

I took of the throttle body and everything in that area to clean out. So i know the idle air valve is good and clean and i put on new gaskets. I haven't looked into the electronic side of things tho.

As for the vacuum canister, do yo mean the blue one at the very bottom of the intake plenum ?

Gonna try and test some more electronics and see if i can borrow a timing light. Ill post any results i have.

Cheers :thumleft:
pbmr2
Posts: 929
Joined: Fri Jun 18, 2010 12:49 pm

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by pbmr2 »

Download the BGB, it has the resistance values for everything. just need a multimeter then.
markstevieandmads
Posts: 2025
Joined: Mon Aug 05, 2013 8:18 pm
Location: Swindon, Wilts

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by markstevieandmads »

Check ecu for blown caps and leaks
Truzo
Posts: 57
Joined: Mon Jan 19, 2015 11:28 am

Re: [Mk2] [Turbo] Mk2 Turbo Running Issues

Post by Truzo »

Ok time for a quick update.

The knock sensor was acting up, Pulling out timing at random with no fault codes for it. so i was trying to set the ignition timing and i just couldn't.

Put in a new knock sensor and checked the timing, It was out by a mile! so i have sorted that and it runs and boosts now :D

The revs dip a bit low when it's hot and stopped with the brake on. goes down to 500rpm ish, could i adjust this with the idle air screw on the throttle body ?

Its also a bit kangaroo ish when revving down the box to slow speeds or crawling in traffic.

I'm thinking adding a little air might smooth this out ?

Cheers
Joe.
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