Ailing 600 SEC

[Graham Chapman]

I have a 1993 600 SEC with 127,000 miles on the clock. Normally it performs beautifully but has recently had performance problems. Essentially, my independent mechanic, who is very good, is convinced that it a breathing problem rather than fuel supply. When driving, the car roars under acceleration as the induction increases and really doesn't go. It has an occassional misfire but I am not convinced it is on all 12 cylinders, but it is variable. Power is well down, probably feels OK to someone not used to it but I can tell it is well off.

The rear exhaust box has been replaced as that appeared to be blocked, which has made some improvement, but it is still plainly sick.

I am trying to get the air mass meters checked, they look OK visually (doesn't mean much, I know) and the other culprit may be a blocked Cat, but at £900 each I will need to be pretty certain that it's defective!

Are there any experts out there that may have an idea as to what the problem may be?

 

[BlackC55]

I have done a set of CATs on one of these for this problem.

There are two engine sensors for everyting so diagnosis is very long winded and there are not many people around that know them anymore.

 

[Graham Chapman]

Thanks, Oliver, I believe Dave has spoken to you and many thanks. Essentially it is going into Robinson's in Cambridge on Monday for a test, looking at the AMM and the Cat's and see if we can locate the issue. Then I'll worry about the cost!

Thanks a lot

Graham

 

[television]

You could try an unplug the MAF and try it

 

[Graham Chapman]

Will do, thanks, I'll let evryone know what happens.

Cheers

 

[Graham Chapman]

Problem

The problem appears to be a leaking pipe on an air pump that sits below the alternator and injects air into the exhaust system. At the moment, one AMM is trying to run lean and one rich. I'll keep updating so you know what happens

 

[duc600ss]

You could try an unplug the MAF and try it

What would you expect to see if you disconnect the MAF and it is broken.
Thanks

 

[supercharger]

a friend of mine runs a merc indie in south wales i know its a fair treck but he,s very good with these 140,s and the 600 especially he was breaking an early 600 before christmas.the garage is called stuttgart garage he has a website and advertises in the enthusiast his name is kevin james might be worth a call.


supercharger
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