lisa1984

I've been on a few times with a misfire that was specific to injector 4. Just to give a recap. Started misfiring on 4 about 6 months ago. Changed everything on that line the injector, the coil pack, the leads, the spark plug, the injector relay plug, and then also changed the MAF, all the vacuum tubes and the camshaft. Misfire remained. Was going to do a compression test on the cylinder then out of nowhere misfire disappeared. It returned again the next day so I never did the compression test with the assumption that if it was compression it would not of fixed itself like that and come back. I was leaning towards it being something electrical. We decided to change the injector itself again in case one of the o rings had a crack in it this past weekend. In the process of doing that we had a bit of difficulty getting injector 5 to sit in properly, it didn't feel right, was way too loose. Anyway , turned engine on and misfire now on 4 and 5 and code p0205. Sure enough there was gas leaking. So took it apart again and yes the o ring on 5 was the issue so replace the o rings and no more leak. But now it's worse then ever and still showing misfire on 4, misfire on 5 and p0205 injector open. Literally ready to set a match to it.

What's left is the following but I'm reluctant to put too much more money into it:

Gasket seal which I think it unlikely gone on both sides?
ECM which I'm not even sure if that's something I can change myself and then does it need complete reprogramming from a mechanic?
O2 sensors which at this stage I'm doubting the sensor can cause such a long standing problem that for 6 months was specific to just number 4
Fuel filter, again would this of not affected more then injector 4 the pass 6 months?

Anyone got anything?

irokdastar

Do a compression test on Cyl 4 and the one on the opposite side . This should of been done a long time ago before you threw parts into it . If the compression test comes back good then its electrical . Chase down Cyl 4 and on the opposite side wires and make sure its not grounding anywhere . Check the plug itself and make sure the leads are not rusted and your getting the proper voltage . at the plug . Check the resistance as well . If all else fails its probably the ECM , Not sure if you need to code it to your car or if you can just swap it .

lisa1984

But surely if the cylinder compression was gone it wouldn't of bounced back out of nowhere on it's own?

dzmitry

ECU (ECM) does require coding and usually expensive, but I can help you with it for free.

E55Greasemonkey

With all the money in parts you've thrown at it, you could have already paid for a professional diagnosis. At this point, the internet is not going to fix it for you. The decision you need to make now is are you ready and willing to pay for a professional diagnosis at a reputable European independent shop or MB dealership?

Fatz

Ditto!

irokdastar

Not really . the reason I say do a compression test is because its the easiest and cheapest test you can do . If it fails it there is no point to throw parts or get an expensive diagnostics . If it comes back that compression is good you can go ahead and get someone who can diagnose it for you .

Try this take a can of carb cleaners , take off the airbox and run your car . Spray around cyl number 4 and the one across from it . Spray also around the rubber hoses . IF you hear the engine change its idle . Then you have an air leak somewhere .

If the compression is good and you have no leaks the last and only thing it can be is a bad ecu or wiring . if the ecu or wiring is bad it can make the injectors put to much fuel or ignition .

You already spent to much money on this issue before you go and pay for an expensive diagnoses just do the compression test . Let us know what you find .