Engine Shaking at Idle

And please check manufacturing date on top right rivet. If there is a 4 or higher middle digit, it is a spare MAP sensor that was manufactured in 80s or later. I have seen such MAP sensors which could not be properly tuned as they were wrongly manufactured.

Bummer. You would think someone would have worked out the procedure and shared it by now so we can fix up cars that have been messed with and keep them running without needing Bosch. Andy
 

Hi Andy,

if it was manufactured with wrong components even Bosch cannot help. And otherwise I can only tell all people to keep their fingers away from that screw. Because there would be no problem if this was not so popular to "improve" things in the US. These MAP sensors have worked for decades and then someone has published the idea of detuning them.

I can't go back in time and change what someone else did, all I can do is focus on fixing the problem I have now. I don't think it's a mystery that people start fiddling with MPSs themselves if the only option is slow and expensive (shipping to Bosch). They may stop offering that service next week for all we know and then we will all be stuck.
 

Hi Andy,

no it is just the opposite. If people would not fiddle with MAP sensors tuning, they would not be stuck. Do not blame Bosch, blame those who recommend fiddling. SInce years I see people coming to my workshops with detuned MAP sensors 0 280 100 100 . When I tune it back to normal, problems are gone. It is a sensitive procedure and often I have to take such a MAP sensor even apart to get it done properly. A type 3 MAP sensor would be mostly unbreakable if people would just let it run.

You still have not told me number on the upper right rivet.

I was referring to people in my situation - having to fix the mistakes of others.

No '4' on the rivet.

What is the tuning procedure? Take apart, clean, replace worn parts, reassemble and then tune it for a specific injector pulse width when being operated from a "paired" ECU with a known set of engine input conditions (air temp, coolant temp, etc.)?

Andy