Firechicken

Howdy guys. Haing some Boost issues I hope you all can help me get straight into the area (s) that needs to be looked over.

1985 Audi 5000 turbo.

OK I am having trouble getting full boost. I have a 1.8 BAR (maby it;s the 1.9 bar sure it's 1.8 though) Stiffer WG spring in, and am running a chiped MAC 10a ecu.

I have tried running both a stock and my chiped mac-10 units both do the same thing. (I have even wired in a spare MAC 07 turbo ecu and it dose the same thing as well so I think i can say the ecu isnt the trouble. and I am only seeing 1.5 BAR on the gage cluster readout. When I give it the boots it pulls good and builds boost only to 1.4ish usually 1.5BAR on the display when floored after it hits the 1.4 ish area the car seems like it's choking up and wont give me any more rpms and stops accelerating smoothly. When I back off the pedal a bit the car resumes pulling at 1.4-1.5 bar smoothly again, but I have to back off the pedal to do so once I hit 1.5 or else the car seems to be choking up and wont give me any more, at that point there are lots of rpm's left i belive it's only at around 4k rpms at that point it seems like the turbo had just started getting going and I am sure there is deffinatly ALOT more left it's not giving me as right before it starts to choke up at full throttle it just starts to pull real hard and I mean only starting then it chokes up as if maby the Fuel cut out is comming into play here? I do not know what the fuel cutout feels like so Maby you fellas can tell me if this is what it feels like when it thinks it's overboosting and Fuel cut out comes on.

I have checked over and replaced all the vacume lines, then engine is rebuilt and it is all sealed up tighter than a drum gaskets you name it it's all seaded up real well as it's all new.

Before I had put in the new stiffer spring the car would only make the stock 1.4 BAR boost on the gage cluster readout and work fine under full throttle operation and would give me full rpm ect. It NEVER EVER would make more than 1.4 on the gage. With the stiffer 1.8 BAR spring it now goes up to 1.5 but gets the trouble mentioned abouve, Chiped ECU or no Chiped ECU.

Is there anything I can check out thats going to not allow my car to deliver 1.8 BAR with the chiped ECU under Full throttle, I mean Shouldnt the wastegate with the 1.8 BAR spring be holding the gate shut till it hits 1.8 under it's own spring pressure or cloer to 1.8 maby like 1.6-1.7ish before it's overcome if the top of the WG isnt reciving the counter pressure to help it? or is that not true?

Can I Unplug my Multi function temp switch and then run the car for a test drive safely to see if it will give me full boot and full throttle or will that not work? I would be most greatful for your help in trouble shooting this as it's not making sense as I've taken every percaution before doing these mods to have all the right equipment ect so this didnt happen.

Anyways sorry for the long post I just wanted to give you alot of information on what was happening, and thanks so much for the help in advance.

Cheers,

Michael.

Katman

Take a look at the link to SJM's website..

A very comprehensive list of possible problems!<ul><li><a href="http://www.sjmautotechnik.com/trouble_shooting/boost.html">SJM's Website</a></li></ul>

Firechicken

Thank you much mate. Fiddled around today with it and seems like the two way valve as called in crappy haynes manual or guess it's more commonly called the wastegate solonoid. I could not find any info pertaining to the slightly older throttle position switches mine are the 2 white ones 1 for idle and 1 full throttle. It uses a 3 pin connector that looked the same and tried shorting accross the pins he showed for the newer throttle switch to test wastegate solonoid operation and weather or not pin 2 of the Multi temp switch is grounding. Didnt see any power at the solonoid when shorting (I tried all connections) or feel it trying to operate at all. Also didnt seem to do anything when unpluging the multi temp switch

I think my Solonoid either maby is not working or I wasnt able to do the test he shows as my switches arnt the ones he shows and didnt do it right. The WG solonoid on my car is the KH engine style still it's a little round guy plastic body flat ends like a cylinder. I only have a WG solonoid from an MC-1 engine (The all metal one slightly tapered at one end like a bullet) I'll try wiring up the different connector and try that and see how she goes.

Thaks for the link.

Cheers,

Michael.

PS. Could that cause the WG to only allow the 1.5 bar boost i'm getting as the 1.8 bar stiffer spring is trying it's damdest to hold the WG back all on it's own? Just odd i seem to get fuel cutout. fuel system is up to snuff as tested co adjusted right with a gas analyzer at the shop aswell .