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Discussion Starter #1
so yes i just bought a full VCDS ! i am very happy.

I made a first log test, car was idling and i bliped the throtle 3 times...i am a bit worried, the actual MAF doesnt realy change...bad maf ??
i will perform a road test soon.
 

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It's at idle and I see MAP which is manifold pressure (boost) , not MAF which is the air sensor. You won't see much boost building unless the engine is under load.
 

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Discussion Starter #3
thanks, i slowly start to learn on this.

yes it was at idle and there isnt much boost...

I will do the proper test soon, ie, maf test in 4th/5th and boost test at speed.
 

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Guys, i dont want to be a bother, but i would like your comments. I made a proper test run for both the map and the maf.

Maf seems ok, but the map test suggest that the turbo response is quite slow.

That turbo has been taken apart recently because the vnt mechanism was seized. I had to weld material on the lever, the one that gets worn all the time. It moves freely without any hicups now.
I had to mess up the adjustement of the rod. So, i am wondering if working out the rod lenght affect the boost response...

Also, i made the timing check, and for some reason the temperature never get hot enough, even after a 5 minute highway run...altough the needle in the car is dead on 90...what sensor is in fault ? otherwise the timing is in the upper range on the graph.
fwiw, i am in Quebec and it is below freezing point, i dont know if this affect the temperature reading or not...

any comments would be apreciated !!
 

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Check the coolant temp sensor - it's on the driver's side head on a coolant flange. It will make the car's computer think it's not warmed up.

Yes, the rod length affects boost response completely. It should be checked with a vacuum gauge for when it moves.

Your MAF values look fine. The MAP also looks acceptable but it could be improved. Minor deviation is fine because if you quickly step on the accelerator pedal you get a minor delay in boost response while it builds up. Check the VNT actuator position.
 

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Discussion Starter #10
Check the coolant temp sensor - it's on the driver's side head on a coolant flange. It will make the car's computer think it's not warmed up.

Yes, the rod length affects boost response completely. It should be checked with a vacuum gauge for when it moves.

Your MAF values look fine. The MAP also looks acceptable but it could be improved. Minor deviation is fine because if you quickly step on the accelerator pedal you get a minor delay in boost response while it builds up. Check the VNT actuator position.
thanks for the suggestions. I am suspecting a leak somewhere...the temperature sensor potentialy in fault is the one right under the vacuum pump right ?

i guess there is a mode in the VCDS to check it...

As a general rule of thumb, if there is ever one for that, if i shorten the rod lenght (very litle, i know !!) it should make the boost occurs faster isnt it ?
it is probably 2-3mm longer than it was before after i messed it all up when i "rebuilded" the turbo.

fwiw, that engine had the t-belt broke, so valves, lifters and all the crap around had to be replaced.
Got the parts and VCDS from Brian at roseland technical services, very nice guy to say the least.

thanks !!
 

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Adjusting the rod works to the point where it doesn't and makes things worse. Get a hand held vacuum pump and test it yourself to the specs. They're really cheap and worth the investment.
 

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Discussion Starter #12
Adjusting the rod works to the point where it doesn't and makes things worse. Get a hand held vacuum pump and test it yourself to the specs. They're really cheap and worth the investment.
i understand there is limit to respect with this adjustment, i am not expecting magic there, but was wondernig if someone had experience with such low ramp boost and by shortening a litle bit the rod, assuming it is on the "long" side of the adjustment.

thanks.
 
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