Engine Shaking at Idle

Here is the cap:  www.dropbox.com/s/5m6i8v2duihq14k/IMG-6205.jpg?dl=0

ECU is Bosch 0 280 002 005

Andy

Hi,
when I look at the lid of the cap, I believe to see scratches from a tool that has removed the lid. But I am not sure. Judge yourself.

I see what you mean. I can't tell if the cap has ever been removed.

Suppose the MPS has been adjusted sometime in it's life. Should I remove the cap and adjust it to reduce the shaking so I can drive it to a garage where they can weld in a bung for an O2 sensor?

Added J19 to my original post.

Andy

Hi Andy,

there seems to be a disease in the US that people try to "detune" those MAP sensors. Maybe because they install an oxygen sensor or maybe because they believe to get higher performance. For years I have not seen a single 0 280 100 100 MAP sensor on reimported cars in my workshops  that has not been detuned. After retuning those 450 engines mostly run well. I write mostly as there are of course also possibilities of additional problems. That is why I am always suspicious on these MAP sensors.

If you see marks of an opening of the lid, bring it to Bosch Classic in the US and ask them to send it to Bosch Classic in Germany for tuning.

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
 

Hi Andy,

excuse my direct words: You are one of those building in errors that others have to correct. When I read that you start to change transistors just because you read something on the Internet I already start to get shocked. Sorry for my clear words. There are jobs to do yourself and jobs for specialists with proper test equipment. Test equipment allows you to verify your repair for correct operation. And tuning a MAP sensor or repariring a ECU is such a specialist job.

A "4" in the middle means your MAP sensor was built in the 80s. There is a risk that it çan be so bad that even I would not be able to tune it properly. I have seen such cases before with MAP sensors after normal production time of D-Jetronic, meaning after 1976. Unfortunately some were assembeld with wrong components and can never have worked. That is why I say " Only trust MAP sensors with rivets from 70s and with untouched black caps".

Do you know someone with a proper running 450 engine around you? Then check whether he/she also has 0 280 100 100 MAP sensor and swap to see how your car runs then. That is my best advice to you.

What transistor did I replace?

Hi Andy,

I am sorry and apologize. There was something I misread on your long list. When reviewing it now I could not find what I had believed to read.

Hi Andy,

have you worked on the flywheel or vibration damper?
If yes this can cause the mentioed problems ..

All the best

Josy