After a search of the 300E idle problem links on this site and replacement of some of the common ailments (OVP, Fuel Pump Relay, Vacuum Hoses, Coil....etc.) I am making the relatively small investment and changing the fuel injectors on my 1989 300e with 205K. I figure the mileage more or less matches some of the other cases that have been posted on this site that warranted the change. I was wondering how valid these steps are. they seem to tie to the manual have pretty closely, just wondering if there are any insider tips prior to starting this project this weekend. (got the parts at parts shop. thanks guys!)

Tools needed:

(2) 13 mm open end wrenches.
5 mm Allen Hex
10 mm open end wrench


1.Remove air filter

2.Loosen gas cap (to remove pressure)

3.Use a 5mm allen to remove injector holders.

4.Loosen the 10mm bolt on the fuel distributor that corresponds with the injector

5.Once removed, use the two 13mm wrenchs in order to loosen each injector.

6.Replace injectors, and the injector seals.

I would like to say thanks for all of the technical support with regard to my question. In the words of Al Pacino in the movie "heat" I am over-blanking-whelmed.

Too bad, you guys have helped me out in the past but I was left hanging on this one.

Enough complaining, here is what happened and what I learned, hope it helps someone else out:


First, I would recommend an assortment of 5mm Allen tools to reach the bolts on the FI retaining clips.

You will need a 16 mm and a 14mm open end wrench. I used the 16mm around the injector AND the retaining clip, it's a lot easier than attempting to squeeze in a 12mm to hold the injector while you remove the fuel line with the 14mm.
Injectors 5 and 6 had some rust like residue on the injector tip. Not sure if it was rust as the injectors are brass or if it came from the tank. (I hope not)

The car runs great, the idle problem is 80% better. It use to stumble at idle and surge mildly when the cruise control was set at 80. Now it seems to just be a consistent low idle problem, no more surging. I have to have the mixture adjusted as it was adjusted by my tech prior to the FI change.

I put 200 plus miles on the car this weekend and it appears as if the gas consumption is either the same or slightly better. All in all a simple,relatively inexpense, fix.

did the injectors have to be "popped" or opened by a special machine before you inserted them? Someone recently wrote that this was necessary for the car to start.

__________________
87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)

Nope, straight out of the box. When i first started the car I turned the key, let the fuel pump run and cranked for about 20-30 seconds and it was off to the races. No problems since then. Just about through the first tank and its running great. to modify my last post, I think my mileage has improved slightly given the mileage on this tank thus far.

Also, it starts up on the first crank in the mornings. Prior to the new injectors, 70% of the time it took two cranks to get the 300e up in the morning.

I would estimate the time to complete was about 2-3 hours. I spent a lot of that time looking through my tool box for all of the different 5mm allen keys in my collection. I have one of those magnets on a telescoping stick, best money I ever spent on a tool.