Hi Guys&Gals
My last post had to do with the pitiful mileage I was (and am) getting with my 99 E-turbo. Never did figure it out even with all your help. All of a sudden, 800 miles ago, I started losing acceleration, not all the time, but I sure wasn't going to trust it to race an intersection. My mechanic tells me I need a new fuel injector, gaskets and mass air flow sensor. All to the tune of $2400. The labor is as expensive as the parts. I love this car but would like to keep the cost down. Any ideas?

 

Is your Car's computer showing any trouble codes?

(Below is about Diesel Engines but a Gas Engine can also suffer from Plugged filters and that will also cause poor acceleration.)

I am not sure if you are speaking of a Diesel or not. As there is a 99; E300D Diesel and 3 Gas Engined cars;E320, E430 and an E55 for 1999.

With all Diesel Engines the first suspect with loss of powere is a restricted Fuel Supply System.
Things that get Plugged. Primary and Secondary (Spin-on) Filters, the Fuel Tank Screen inside of the Fuel Tank and the Fuel Tank Vent (easy to test; with your Fuel Tank 1/2 full so that Fuel does not come out of the Fuel Fill pipe; remove the Fuel Fill Cap and drive with out it. If you symptoms go away you have a Fuel Tank Vent problem.)

When the Filters are changed inspect them to see if they have a lot of silmy Black to Gray crud in them. If so you could have a Fungas growing in your Fuel Tank (this is not a joke). They sell chemicals like Startron to kill and break up the dead bodies. However, this process sometimes pluggs up the new Filters and they need changing again.

To check the Tank Screen you actually need to Drain the Fuel Tank and Clean the Screen and rplace it with a new seal.

You did not say that you had rough or uneven Idle. But, if you did it would indicate an Air Leak in the Fuel Supply System. This means leaks in Rubber Hoses or O-rings where they connect. Also the Fuel Heater is prone to developing Air Leaks.

Remove what is needed so that you can see the top of your Fuel Injection Pump and see if the top of it is wet with Diesel Fuel. If so the Delivery Valve O-rings and Copper Crush washers need to be changed.

 

Thanks for replying. It is a diesel. The fuel lines were all changed out over a year ago but it didn't improve my mileage. I would assume(?) that they changed some filters when that was done. When I began having the acceleration issues, a lag when my foot is on the pedal, and not all the time, I probably stupidly added some Marvel and tried to blow out some carbon, which did not help and could've hurried the issue. Then my check engine light came on. So when I took it in they did the computer check. Also said that the pump was leaking which makes me hesitant to drive it in 95 deg. weather for fear of engine fire. My other vehicle, a 97 Trooper, is also in the shop getting a h20 pump/timing belt replaced so I am driving the MBZ gingerly and not often.
To make matters worse, I am a female, with little mechanical experience.

 

If it's leaking fuel than it for sure you have a leak. Mine if I park it up hill it lets the fuel drain back to the tank, and with a manual pump the car has to crank over to pump fuel so that is making it take longer. We don't want fuel leaking, but as long as it is not able to get onto some thing extremely hot fire is not really a big chance. Diesel fuel at low temps [95 is not high] as the side of the block won't make combustable fumes on the exhaust manifold will. What computor codes showed up that will be a big help to the guroes like Forced injection to give you advice. Any diesel leak and a paved driveway is bad news for the pavement. The female part isn't the problem the limited mechanical part is

 

I don't notice any leaks on my garage floor. The mechanic is telling me it's leaking. I've noticed no change in fuel consumption, perhaps an occasional whiff of diesel when I shut the car off. I think I will take it to get another opinion. I'm not very trusting of MBZ mechanics and their diesel knowledge.

 

If it's leaking it will make it to the floor diesel fuel does not evaporate. The only way is if it is hitting the hot exhaust manifold and smoking off

 

From what you've said about the leaking...I'm thinking that it may be another expensive "fix" that doesn't necessarily fix it. Because I'm not seeing any leaks at all. Could it be just the air mass sensor causing a lag in acceleration? Could there be another reason? It is not smoking at all so I don't think its the turbo.