The acceleration is very strong right up to 130 mph, but it almost seems like I hit a wall at that speed. Are the electronics limiting the car from going faster?

I know that I don't 'need' to go faster, but the top speed of a 400E should be more than 130.

Thanks in advance for the replies.

I have new wires and Bosch +4 spark plugs, new caps & rotors. As previously mentioned, the acceleration is very strong right up to 130 mph, which should indicate that the engine is running well.

OK, first, I have to get this out of the way: "Only" 130mph? WAAAAAAAAAAHHHHH! OK, seriously, I think there is a top-speed governor that may kick in at 130mph due to the stock H-rated tires. I'm not sure though. If you get a chip, that may cure it. I've heard the 400E chip helps quite a bit for part-throttle power but it's not cheap ($400?)


HTH,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

I made almost the same post about my 190E a week ago. I was on the HWY at 100mph thought I was about to break down. I need new ignition wires and spark plugs

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89 190E

FWIW, if those BOSCH +4 sparkplugs are "platinum" get them out, and replace with the proper BOSCH copper-core plugs.

Pre-1997 MB's were not designed for platinum plugs, and those who have tried them have had poor performance and bad idling.

:-) neil
1988 360TE AMG
1993 500E

Yeah, pull those "platinum" plugs ASAP !!

They will foul extremely fast ! !

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1994 E500 (MY SUNDAY DRIVER)
1993 190E SPORTLINE LE W/ M104 SWAP
1997 C230
2002 ML320
2000 BMW 528I (WIFEY'S CAR)

"Excuses are crutches for the unfounded."

Why are platinim plugs so bad for older MB's

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89 190E

Here's the thread you're lookin for:

bosch platinum+4 plugs 420 sel

The engine runs very smooth with the Bosch +4s. No hesitation, and the acceleration is very strong at any rpm.

I have pulled a spark plug out to inspect and found that there is no fouling visible.

The thread listed in a previous post refered to older MBZs than mine, so I am not sure if it will be applicable to my situation.

Don't get me wrong....I have had personal experience with switching back to copper core plugs after having rough idling with Bosch +4s in my 2000 Jeep Wrangler. Going back to standard copper plugs made a BIG difference.

I just don't understand why Bosch +4s are available & marketed as higher performance plugs! When I purchased my +4s, at my local Pep Boys, they were listed as compatible plugs.

BOSCH copper-cores are so inexpensive, I would replace the platinums ASAP.

Upto 1997, all LH, HFM, CIS cars were designed with the "copper-cores" and their larger flame-path.

Your 1994 400E will not run optimally until you change to "copper cores".

Just because it's in the BOSCH, PepBoys, McParts book doesn't mean it's compatible. Can you say MORE PROFIT.

Of course, you won't see fouling. Your Platinums are virtually new.

:-) neil
1988 360TE AMG (copper-core)
1993 500E (copper-core)

In all our testing of Bosch Platin we have never seen good results except when the original plugs were shot. but on the dyno we have never seen a performance gain plug for plug. We have seen a performance decrease in top end with the platin plugs.

We seen a lot of the platin plugs drop the little center wire out!
and where that little piece goes? hmmmmm.

The only real Bosch platinums we seen work are the ones porsche uses but they don't fit many cars and are too cold for other cars. (mostly turbo heat range)

I agree it is all BS marketing.

BUT you know what is a really good performance plug?
ACCEL and it is cheap. It is really a ND plug. (Nippon Denso = Bosch of Japan). So it is really a Japanese made German Plug.
I seen them selling as low as $2 each. It is also a U-Groove design.

Part# for the 400E is #0416

O.K., I will get a set of copper core Bosch plugs and give them a try. At around $2 each, I guess it's worth a try.

Although I appreciate your suggestion, I don't think that I will try the Accel plug just yet.....I want to first try if the O.E.M. copper plugs work better than the Bosch +4s.

I can only strongly echo take those plats plugs out. I experimented with various plugs, and the only plug that you can use and improve your performance are the Siverstone plugs. Plug number for a 92 400E is S3F.

Concerning top speed, yes your 400E will and should go over 130, like 150+.

enjoy your drive, timreid

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timreid
1992 400E
euro lights
500E sway bars
210 16in wheels