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Humble E34 lover
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Flex disk aka guibo
I don't think a failing guibo would cause a loss of power.

OP, this will take some thought. We need a little more info please.

Do you have the M50 engine?
Where does the clicking/ticking seem to be coming from?
How many miles does it have?

One possible thought .... Your valve cover gasket may have failed causing one or more of the spark plug wells to be full of oil. There may be arcing from the coil to something other than the plug causing a loss of power on that/those cylinder(s). This is a long shot, but it is easy enough to investigate.

There are a lot of things that it could be so try to be as descriptive as possible. There are a lot of knowledgeable people here willing to help.

Steve

Oh, and, welcome to the Fest !
 

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Humble E34 lover
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It sounds like detonation to me, a timing issue. That would tick or ping, and you would lose power because of it.
These cars have variable timing controls dont they? I bet its not working right.
Pre-dteonation could be it, but that would usually manifest as a knock. Also, the 91 model does not have vanos, so there is no variable timing device. I don't think it had knock sensors either. Those would detect a pre-detonation knock and retard the timing before the driver could even notice.

Good thought thought, so OP should run premium fuel just in case you are right. If it is indeed the M50, then there is no way to adjust the timing.

Steve
 

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Discussion Starter · #9 ·
M 50 engine. 190 K miles. Can't exactly tell what part of engine the noise comes from as I'm moving when it occurs. I have been cutting back on octane lately to 89. On a side note, the engine does leak some oil, probably needs a quart every 1000 miles. Also I've noticed when using cruise control the car surges and slows down, sometimes going out of cruise. Don't know if that helps but there you are!
 

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You clearly have to do alot more investigative work and a direct unbiased Mark2 eyeballs check on your engine before getting around this problem. Before that, all we're doing is speculating - too little info here to fit too many possibilities.

After you've some thorough checks, post your observations here and we will take you from there.
 

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It sounds like detonation to me, a timing issue. That would tick or ping, and you would lose power because of it.
These cars have variable timing controls dont they? I bet its not working right.
Agreed, from the description it seems to be detonation.
No knock sensors or VVT on '91 525s though.
I'd be looking for a vacuum leak causing a lean mixture.
OP, Does it idle rough too?
 
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