500E SENSITIVITY TO BRAND OF GAS?

Gentlemen,

I recently purchased a 1992 500E. The car has a very good service record. It currently has 91500 miles, the last service it had done was a oxygen sensor replacement at 81000. The car was dyno tested at that time and passed. After having driven the car home on the original tank of gas (gas filled up by the previous owner), I filled it up for the first time with premium arco gas. after having driven the car myselft for 30 miles, the Check engine light comes on. I don't notice any degradation in performance. I'm wondering if this car is sensitive to this type of gas or there is something wrong with the emission components. I notice that the previous owner had the check engine light checked out three times within the last 5 months.

Thanks in advance for your replies

Thanh
1992 500E
1991 735il
1988 M5 I

I dought that the gas had anything to do with it setting a code, unless the gas had water, or some other nasty contamination. In such a case, it probably would not have set a code, it would just run real bad or quit altogether.

Teh problem is most likely related to the recurring code set.

You really won't know until you see what the code is.

Best of luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

[This message has been edited by LarryBible (edited 10-10-2000).]

Is there anyway to check out the codes using just a single LED? I don't have a manual for the car yet.

Thanks
1922 500E
1988 M5

[Q]

This is not Mercedes-specific information, but I have read that some cars will set a code based on if the gas cap is not sealing properly. Since the code did occur around a fill-up, it is easy to assume that it may be related. Just for grins, check to make sure that the gas cap gasket is not cracked and that you have it sealing tightly.

[Michael]

Mine seems to run fine on any premium gas. Yeah, you need to check out the fault that's in there...when your tech checks out your system (using an HHT-Hand Held Tester or the like), before they purge the code history have them go thru it with you and let us know.

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All the best, Michael
500E
300TE

Great suggestions.

Thanx

tmnguyen,

You may want to view all posts on the "Good MB Shops" section, you will find one or two recommended shops in your area (South Orange County). If your current tech has not solved the problem, he may or maynot know your car well enough.

Also, try running a search on past topics with the "search" tool in the upper right area of this page. Use something like "code AND read" in the search words area and you should find some info on reading the codes your self.

Keep us updated, with more detailed info your problem should be fixed soon.

Good Luck.

I took the car to the dealer to have them look at the check engine light problem. They said the intake has deposits and the head needs to be removed to perform the cleaning. I need a second opinion here. Also, they said that the engine harness is damaged and needed to be replaced. I think this is more of the contributer to my problem than the intake being dirty. I heard in the past that MB replace the harness on Goodwill. It is still true?

Thanx
Thanh

Gentlemen,

I need an 2nd, 3rd, 4th.... opinion on the following diagnotic for the Check Engine light from the dealer : Follows is the excact write up:
Code 004. Air Injection. Ports for air injection plugged with carbon. checked for codes. code 004. checked to see if air injection valve has vaccum. it does. check activations. The O2 voltage should drop to below 80mV. It does not drop. See recommendations.

Recommendations:
Need to R&R both Heads and exhaust Manifolds need to clean air injection port $2600.
Engine harness cracked $800.00

I opened up the cover and inpect the harness, I could not find which section of the harness is cracked. Is there a common place where the harness can easily crack.
Thanks

Ps: beside from the check engine light fault the car runs beautifully.

Hope to here your reply soon

[Q]

Hmmm....spend $3,500 or put electrical tape over Check engine bulb, spend $3,500 or put electrical tape over Check engine bulb. Tough decision some days isn't it?

Try, Bob Dallape at Camino Import Auto Service in San Juan Capistrano, CA.

Sounds like you are getting the run'around.

[Michael]

Was your car built on or after 8/92? If so, those cars are known to have engine wiring harness issues when they operate in hot climates.

As to the cleaning of the combustion chambers, I just went thru this quite extensively. Be advised that my diagnosis was arrived at by 2 top MBZ tech guys (one Corporate, one Regional) who went thru my car at great length (and expense!!). Real easy way to tell if you have carbon buildup....how does your car idle when you just start it cold (asfter sitting overnight)? Mine was definitely rough, so I ended up using several BG products to get things under control. Their "44K" product cleans the combustion chamber, and their "air intake system cleaner", which is a high-performance throttle body cleaner, I used inside the air intake. I actually removed my throttle body and cleaned it comprehensively (it gets pretty dirty). I then re-installed it and powered up the car without starting it; after about a minute the system resets itself and recognizes the new throttle butterfly position (its position moves slightly when you remove the deposits).

BG products are hard to get, as they don't generally sell retail as I understand it. However, many many Honda dealerships carry them, so perhaps that's one route to take.

After 2 treatments my car now runs perfectly. I'll use no other product; none even touched my problem.

If this works for you, do I get a part of the $3,400 the dealer was gonna soak you for?!? Just kidding...if there were that sort of payoff here, we'd all owe Benzmac, MBDoc, Steve, Aron et.al. millions!!

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All the best, Michael
500E
300TE

Michael,

Your knowledge about the 500E is impressive. My car was build 7/2/92 and delivered 4/22/93. I went a get a second from a trustworthy MB mechanic this morning. He put the diagnostic tester and checked out the fault. It indicated a air injector fault. He said that if it was his car he is not even worrying about this. He resetted the light for me. He also said that the air injection system (particularly the pump) is only used for about 15sec upon cold start up in the morning. He suggested that he'll take care of this problem when car has about 150K miles where he will install new guides, chain..... So for now i am going to ignore the problem. The wire harness concerns me a little though. BTW my car idles fine in the morning.

Thankx
Thanh

[Ken C]

Here's another possibility, since you said that it came on very soon after filling up. It's unlikely that the added gas was so bad that it caused a problem, given that the new gas had to have been diluted with the older gas that was not troublesome.
What I think you should consider is that the gas cap was not reinstalled properly -- some cars have a system where it detects a lack of pressure integrity within the fuel system, and a gas cap that isn't properly sealed can produce a fault code.
Try replacing the cap (not buying a new one -- just take it off and put it back on, twisting it fully; also check the gasket for breaks) and then restart the car and see if it improves anything.