While in gear, sitting at a stop, my 89 300TE has a bit of a low idle, which makes for a bit of shaking. I've seen in the "E Class owner's Bible" that there is apparently a fix which is supposed to raise the rpms by 50 on cars up to 8/30/90. It involves removing the violet wire from connector 26/3 and grounding it. The bible does not show one where this connector is. I haven't been able to find it in the shop manual either. A search in the archives on this site haven't shown me anything I could use.
Does anyone know where this connector is?
TIA
Andrew

__________________
Fourings

84 Audi Coupe GT with Turbo engine, EFI (buh-bye CIS), Jamex seats, Koni's/H&R's, e-code lights. 210k and counting.
1992 Anthracite 400E, 161k, "Grey Ghost".
1986 VW Quantum Syncro, 192k, gone to the crusher in the sky.
1989 300TE 172k. (Was mine, now also Mom's car)
72 280SE 4.5 (Mom's car)

Lift the fuse panel up CAREFULLY and look down beneath it. The connector fits into a slot molded into the bottom of the fuse box. We did lots of those mods back in the good old days. It works great.

What does the mod do?

Thanks,
Sixto
87 300SDL

I'm amazed. You mean there is something worth reading in that pathetic book? I personally believe that Stu was hard up for money, so he cut and pasted a bunch of stuff from various sources and promoted it for sale.

I couldn't wait to pay my $40 and get my book. I have NEVER been more disappointed with any book I've ever bought.

Now to the problem. There are several things involved with a good idle in a 103. To begin with you need a clean engine. If you live in a major metropolitan area where they sell reformulated fuel, then you have a clean engine. If you don't, then run some techron or other reputable additive through the fuel, preferably during a good, long run. You also should pull the air cleaner and wipe down the air flap reaching underneath and around the throat as well as you can. Make sure there is nothing sticky on the edge of the flap or the throat.

Secondly, make sure you have Bosch Copper Core plugs gapped at .035.

My 300E developed a very bad idle over time. Suginami comes to our area once a year and we get a bunch of people together for dinner. I gave him a ride to dinner and he commented about my rough idle.

Not long after that I pulled out the platinums that I had put in because that was all I could get one day at the parts store, and put in a fresh set of copper cores set to .035.

Then we went on vacation and I filled up in the DFW area with reform gas and ran with the cruise control set to 70MPH for about 250 miles without canceling it. When I pulled off the Interstate for gas, it was idling SILK smooth. I can't even describe how well it was idling.

Chances are, a clean injection system and copper cores set at .035 will give you a smooth idle even with the slightly lower idle RPM.

Good luck,

I'm sure the engine is clean. Aside from the additives in the gas here, I've run BG 44k through it a couple times and noticed no difference. The previous owner complained of the problem to his tech and gave me reciepts when I bought the car for the belt dampener and new injectors. I pulled and gapped the plugs. They are Bosch copper, but aren't worn enough to warrant replacement. All of this and no improvement in the warm idle. Cold idle is good. I am hoping this might also fix the need to start the car twice when it's warm. It will start and die unless I have my foot on the gas. Second time starts and idles fine.

I found the plug in the fusebox, but there are two violet wires, one going into the bottom of the plug, one going into the top. Which of these do I remove and ground?

__________________
Fourings

84 Audi Coupe GT with Turbo engine, EFI (buh-bye CIS), Jamex seats, Koni's/H&R's, e-code lights. 210k and counting.
1992 Anthracite 400E, 161k, "Grey Ghost".
1986 VW Quantum Syncro, 192k, gone to the crusher in the sky.
1989 300TE 172k. (Was mine, now also Mom's car)
72 280SE 4.5 (Mom's car)

It might not solve your start and die problem. My start and die problem was caused by the car being to lean. I set the duty cycle to 45-50%. I thought that the double start was just something I had to live with until I did that.

This mod increases the idle speed by about fifty RPM when in "D". It does this by overriding the gearshift input to CIS-E. Of course, this mod should be done after everything else is checked, as previously stated.

Oops, I almost forgot. The male end of the wire is the one that gets grounded on 124's. On 201's it's the female end.

Fourings,

Having copper cores is not enough. The gap needs to be closed up to .035. It is VERY easy to R&R plugs on this engine. It would be easy to simply pull them and gap them to .035 and replace them. It would be interesting to know the gap before resetting.

I think the book says .038, but it was learned a long time ago and discussed on this board about the idle advantage of a .035 gap on a copper core plug.

Good luck,

Roger that. I'll double check the gap. I'm sure I went with manufacturer's specs when I did it originally.
Thanks for finding that wire for me. I never would have found it on my own.

__________________
Fourings

84 Audi Coupe GT with Turbo engine, EFI (buh-bye CIS), Jamex seats, Koni's/H&R's, e-code lights. 210k and counting.
1992 Anthracite 400E, 161k, "Grey Ghost".
1986 VW Quantum Syncro, 192k, gone to the crusher in the sky.
1989 300TE 172k. (Was mine, now also Mom's car)
72 280SE 4.5 (Mom's car)