C200 Kompressor (W203) Fuel sender question

Tzardine

A strange thing is happening with my car at the moment. It broke down on me 2 weeks ago. Turned out to be a faulty fuel pump. I had the pump and transfer pump replaced ( PAINFUL repair bill ).

All is going well apart from two things

*When i go to start the car I have to leave the ignition on for a couple of seconds. If I dont the car will turn over but not start. If I do wait then it starts up no problems. Is it the fuel pump taking a second to start up ?

*I have noticed a good increase in fuel economy since the pump was changed but for some reason the gauge is flying through the 1st quarter of the tank and then it will sit at half tank for ages. I have let the tank run down to the warning light to see if there was fuel still there and there was. For some reason it just looks like the first quarter is flying through it ? I presume its just a gremlin in the sender.

Normally I would bring the car back to the garage but the place that fitted them was in Cork where I broke down. I live in Kildare. The two pumps were replaced with Bosch parts BTW.

Does anybody have any ideas what is going on.

Many thanks

MercMad

As far as I recall the W203 C200K has two fuel senders, as the tank has a hump to accomodate the driveshaft/diff. One of the senders has the fuel pump built into it. I dont believe there are two fuel pumps. The fuel gauge take takes the combined average of both senders to display correctly.

I doubt you are getting better MPG, if there was a delivery issue prior to the pump failing you'd have known and got a Check Engine light/poor performance etc.

IMO it sounds like the job wasnt done properly, but I dont know exactly how/why.

Tzardine

MercMad wrote: »

As far as I recall the W203 C200K has two fuel senders, as the tank has a hump to accomodate the driveshaft/diff. One of the senders has the fuel pump built into it. I dont believe there are two fuel pumps. The fuel gauge take takes the combined average of both senders to display correctly.

I doubt you are getting better MPG, if there was a delivery issue prior to the pump failing you'd have known and got a Check Engine light/poor performance etc.

IMO it sounds like the job wasnt done properly, but I dont know exactly how/why.

Thanks for the reply. It seems that there are loads of variations to these merc tanks. There were definitely two pumps/senders in the tank. I was able to see the car while in the garage and with the back seat out there were two large holes where the pumps sit.

Fuel consumption has definately increased. Going from the computer I was getting 8.4 l/km before the pumps were replaced and its down to 7.9 l/km now.

I am puzzled by the whole thing to be honest. Car is running fine however and I have put over 2500km on it in the 2 weeks since it has been fixed.

Getting a company car in January so it just has to hold out until then

burke027

I no the isdue u describe we have done quite afew and ur dead right it has a transfer pump in the tank.I can tell u now what the problem is waiting for a min of two is that the pumps need to be coded to the car via star diagnostics.I work for a specialist on nerve and bmw in kildare so I can sort it out if u wish give me a pm

MercMad

Strituck wrote: »

Fuel consumption has definately increased. Going from the computer I was getting 8.4 l/km before the pumps were replaced and its down to 7.9 l/km now.

..........that actually means your consumption has decreased as its now inly using 7.9 litres every 100km instead of 8.4 !

What year is the car again ? If you send me the chassis number I could verify but yeah it does sound like it has a main and a transfer pump. I'm not sure coding will sort it though.

Tzardine

MercMad wrote: »

..........that actually means your consumption has decreased as its now inly using 7.9 litres every 100km instead of 8.4 !

What year is the car again ? If you send me the chassis number I could verify but yeah it does sound like it has a main and a transfer pump. I'm not sure coding will sort it though.

Sorry you are right but that is what I meant. Just read my post again and see that I worded it wrong. I am getting better mileage per tank.

Its a 2001 model. It definitely has the two pumps. I took the broken ones from the garage. The mechanic was a bit surprised when I did this. He asked why I wanted them and I told him that they would be getting smashed with a hammer when I got home for stress relief after the grief they caused me.:D