Do I Have the Right EZL Module?
 

I had to have it replaced about a month ago. The original one died without any warning at all. I took the car to a local reputable independent Mercedes shop and they replaced it with one from a salvage yard. The number on the original unit is 004 545 44 32 and on the replacement part it's 006 545 76 32. They visually look the same and I was told by the shop tech that they were interchangeable. Can any of the professionals here confirm this for me? My engine is knocking under even moderate acceleration and I think it's gotten worse since the module was replaced.

Thanks,

Gary

Both of those part numbers were used on early W124.030 chassis 300E's. OF course they both have been replaced by later numbers. 008-545-62-32 OR 008-545-64-32.

Unless that EZL is defective OR you are GETTING sub-standard octane fuel the engine shouldn't knock(ping).

M.B.Doc,

Thanks for the reply.

I'm using 91 octane premium from either Costco or Arco, but I've been told that, in Calif. at least, all the fuels are essentially the same because the additives are mandated by law. If there's any particular brand you'd recommend, I'll give it a try next fill-up.

Is there any accurate way to check the EZL that doesn't require mega $$ equipment?

Thanks,

Gary

Might try a timing light to see where the EZL is setting the timing at idle, should be an emission lable with that info on the core support.

Try Sunoco OR Exxon preminum for a few tanks. NOT all fuels use the same formula.

The blend of RFG II fuel used in California is essentially regulated and there is virtually no difference between brands. Some use slightly different detergent additives, but they all have to pass the same test.

In fact, in many parts of the country this is now the case. There are over 100 "boutique" blends required in various markets, and this is the reason for the rise in prices in Phoenix and the rise in prices in the Midwest a couple of years ago. Many refineries are now set up to produce only the blends required for their distribution area, so if they go down, fuels from outside-the-area refineries cannot backup. It's arguable whether all these boutique blends improve air quality, but they sure do screw up the economics of gasoline, when a refinery or pipeline goes down.

Duke

M.B.Doc,

I'm afraid in Calif. they are all the same, with some minor exceptions that really don't make any significant difference. Exxon no longer exists in California, so I'll try the next best thing, which ought to be either Chevron or Mobil. I just put a bottle of Techron Fuel System Cleaner in with the last fill-up, so I'll see if that helps at all. I'll check the timing this weekend. Any idea what amount of spark advance I should see under free revving, no-load conditions?

Gary

My 420SEL guzzles through Shell gas, to lesser extent on Chevron.

Since Atlanta has the 2nd highest(LA is first) number of smog days of any city over 1 million people, we also have "regulated" fuels & have for 5-6 years. There are still differences in octane between brands including additives that different brands add for cleaning. You might try 92-93 octane fuel or even an octane booster to reduce the knock.
You might have severe CARBON build-up on the pistons, valves & head that can cause engine knock(ping).

M.B.Doc,

I'd love to get ahold of some 93-94 octane gas but I've never seen anything over 91 octane at any station anywhere near where I live in So. Cal. Is there a particular octane booster you can recommend as being safe and effective?

As I stated in a previous post, I just put a bottle of Techroline Fuel System Cleaner in with my last fill-up a couple of days ago. Is this stuff effective at all in removing carbon deposits? If not, what is?

Short of pulling the cylinder head off, how can I tell if I have any significant carbon build-up? Would a compression test show significantly higher readings if there's enough carbon to cause pinging?

Gary