Seeking suggestions on where the starting problem might lie. The engine will turn over well but won't fire. Was waiting an hour for a tow and tried numerous times to see if it would fire up. It did in about 45 mins of intermittent attempts and drove it to the shop which usually works on it. They couldn't find anything in the fault codes but on a hunch replaced the crankshaft position sensor with my approval. The car started but has failed again and is sitting in my garage DOA. I'll need to have it towed but not sure if I should tow to the same shop (they do some imports and close by), and independent import shop 20 miles away, or to a MB dealer 18 miles away?

Fuel filter was changed about 15, 000 miles ago and there is a full tank of gas from a reliable gas station.

Ideas and suggestions welcomed. I realize the shop location is my call. Thanks

 

Check fuel pump and fuses.

 

I wouldn't send it to the shop that replaced the crank sensor. With a $15 diagnostic device I think they ought to have been able to crank the non-starting engine and see that it was spinning at about 60 RPMs. If so, then that would have proved the cranks sensor was fine.

 

Latest update. I had the car towed (flat bed) to the independent mechanic (MB, BMW and Audi). He found the fuel pump had seized so replaced the pump and filter. Still had starting issues. Further examination found an issue with the engine computer not sending power to the fuel pump, intermittently.

I'm told this is a reported problem with the 2007 SL550? Input on this please.

Now at the decision point to buy new engine computer (expensive), buy used computer and reprogram, or try fo have the bad board repaired in the engine computer (long lead time, weeks).

I'd appreciate any input/advice please and thank you

 

Latest update. I had the car towed (flat bed) to the independent mechanic (MB, BMW and Audi). He found the fuel pump had seized so replaced the pump and filter. Still had starting issues. Further examination found an issue with the engine computer not sending power to the fuel pump, intermittently.

I'm told this is a reported problem with the 2007 SL550? Input on this please.

Now at the decision point to buy new engine computer (expensive), buy used computer and reprogram, or try fo have the bad board repaired in the engine computer (long lead time, weeks).

I'd appreciate any input/advice please and thank you

 

used module, virginize with KTAG (50$) and load the firmware from old to new

 

Sorry so late on this. I'm new to the forum and have been on-and-off. Anyway, I have a 2009 SL550 by which I'd experienced the same issue. The car has about 95,000 miles on it, and started perfectly fine when I bought it last year. However, over a course of time, I'd begun to realize that the car started to turn over more than usual to fire up. It continued to do so periodically during times of shopping and other errands. I didn't know why it kept doing that, but I'd assumed it had something to do with timing. I had it diagnosed and found that an "injection pump" was the issue. I replaced the injection pump and the problem still exists except one good thing, when I put the key in the ignition, rather than using the one on the gear shifter (handsfree), it starts better. If you have found the solution to your issue since your last post in January, please share. I'm curious. Thanks a bunch.

 

Yesterday I found out that the ECU was faulty and was not feeding current to the fuel pump. Was told this is an issue with 2007 SL550's. They are sending my ECU out to be repaired and should have it back in a week or so.

I'm hoping that is the issue...thanks for looking into this.

 

Thanks for the update. I’ll do the same. I have a friend at MB that could point me in the right direction