3B Limp mode

[BosnianS2]

Guys i need your help again
I had K26-TO4E on my 93 audi 90 that i installed 3B engine in along with big exhaust, intercooler and so on. It ran well in begining after i finished transplant, but than something happened and it ran like crap maybe one month later. After million checks and million hours of trying to find what is wrong i decided to put my old turbo back on and start from begining. I had feeling that problem may be becuse i dont have proper software and also weather here in US got realy hot. So due to not being able to find anyone to make chip for my set up i put my old turbo back on.
Well now i know what the problem is i just have not found the cause.

Well car basicly goes in limp mode. After car is started and driven off boost goes up to about .7-.8 bar just like it should, than it as soon as it warms up little bit it will ecu will turn of N75 valve and no boost. on top of that i beleive retards timing which makes cur rine like crap also.
I checked codes and there is only one code stored and that is 4343 which is carbon canister frequency valve. that is because i dont have all that emission crap on there any more and i took the valve off. I dont see how this can make it go in limp mode but i am open for any ideas.

Occasionaly when i drive from work i feel like it goes out of limp mode an di start to accelerate, boost come on again but after about 4000 rpm or so it will go back in limp mode.
I checked for boost leaks, i inspected all sensors visualy, i did ecu output test for injectors, boost valve (N75),idle valve and carbon canister valve which i dont have.

Please help i dont know what to do any more

thanks in advance

[Ski]

Clean / replace MAF
clean maf connector
clean ALL sensors you can reach
coil packs
air leaks

etc...

[rotoryboy]

3B's don't have coil packs. Check dissy, cap etc...... Could have a look to see if the plastic cog is OK.

[BosnianS2]

Thanks for the info guys
I beleive that by plastic cog you mean gear on the dissy (sorry english is my second language). I have checked that already , my dissy has metal gear. I have cleaned MAF while back, but i will do it again. Also i checked the connector several times appears to be in very good condition.
I will check for air leaks again, but if any other ideas come up please let me know
thank you guys

[DJones]

I have always been led to believe that you need the carbon canister valve at least connected to prevent limp mode being activated.

Darren.

[BosnianS2]

That may ne the case. i will try to do that and see if helps. Logicaly thinking i dont see why would engineers do that because that valve has nothing to do with performance of the engine , it only keeps the gas fumes from venting into atmosphere, but instead they are diverted into engine.
But i will try anything at this point. Thanks for all help. Any other suggestions are always welcome please.
thanks guys

[DJones]

I think it is due to BOSCH complying with emission laws for the US market.

Darren.