1985 California turbodiesel cars – Please repost the information from earlier today.

[RunningTooHot]

Someone gave some really good advice on the 1985 turbodiesel California cars, and when I went back to read it again, the posting disappeared ….POOF….GONE.

Apparently there is a different turbo (or bypass?) boost control setup used on these cars to meet the ’85 smog requirements. The poster stated that there is some sort of change that doesn’t allow the engine to build boost before 2500 RPM. I can’t recall what the hardware difference is – I’d like to know, so that I can see if it can be brought back to prior year specifications, i.e., having the boost come in sooner than 2500 RPM.

I am aware of the trap oxidizer being replaced by the oxidation catalyst, but what was the other change(s)?

Thank you VERY much for your help!

[be459]

I found some postings are missing too.

The Calif 84 and all 85 300D/SD models have an Air Circulation Valve which is built into the outlet of the turbo. That valve is controlled by a computer. The computer takes input from several sensors and decides when to activate or deactivate the smog devices. These cars have an overvoltage relay to protect the computer. I believe that the air is circulating via internal channel between the fresh air output (toward the intake manifold) and fresh air input (at the air filter side) of the turbo causing low pressure in the intake manifold, therefore, no turbo boot. The computer controls the valve via a vacuum line.

As I stated before, I just start learning things about turbocharger. Please read my statements with an open mind and ready to make corrections if necessary.

The answer is yes to your question about "brought back to prior year" but I have never tried it on any cars.


David
Los Angeles, Calif.

[Edited by be459 on 05-25-2001 at 01:36 AM]