crystaldon

Hi, I have a minor problem. Any advise would be greatly appreciated. My ML320 has been generally problem free. I rescently took it on a 400 mile trip. Half way through the trip I filled-up on gas. Later, I noticed that it was getting hard to start:

Normal was:
-Turn the key and it starts in 3-4 seconds.

Hard to start is:
-Turn the key and let it turn-over for about 8 seconds, doesn't start.
-Try again for another 8 seconds, doesn't start.
-Try again and it starts, runs rough for about 3-4 seconds, then works fine.

After running for a while (10 miles or so):
- Shut off engine and restart within 1 minute, starts normally.
- Shut off engine and restart 10 minutes later, it's hard to start.


I've run 2-3 tanks of gas through it since the trip, but have'nt seen any improvement. Any suggestions (dry gas, fuel filter, other)? Thanks for the help,
Don

saturnstyl

Lets try a fuel filter if you are just throwing parts at it. Best advice is to hook up a pressure guage and see if the fuel pressure is bleeding off while the car sits. Could be bad injectors, fuel filter, or pump. Any of them will be expensive, but if you replace the pump, you will HAVE to replace the filter also.

crystaldon

Thanks for the advice, I was considering doing the filter (with the fuel line replacements). I think I'll try that first.

On the pressure bleed-off issue, will this tell me anything:

1. Turn key to starting possition,
2. Wait 60 seconds for pressure to build-up,
3. Attempt to start and look for difference.

, or does the pressure only build during the actual starting cycle?

Thanks again for the help,
Don

saturnstyl

It should give a prime shot to the pump, but there is some mystery here. It may not *always* do this, depending on how long its been sitting since running. You can easily pull the fuel rail, and jump each individual injector and look at the spray pattern. Just cycle the key to build pressure, then jump the injector and watch it spray. If one dribbles or has poor spray patterns, its likely also leaking down.

crystaldon

I know it's been a while, but better late than never. I solved my problem by changing out the fuel filter, which was the first thing I tried. Actually, I had to do the whole filter retrofit thing, but it starts fine now.

There was one strange thing that happened though. While the original filter was giving me problems, it also appeared to be giving me excellent fuel economy. Or, at least, that's what the milage indicator was saying. This thing was getting up to 28 mpg (highway). Once I changed the filter, the fuel economy went back to 23. Unfortunately, we never verified the milage by calculating it manually. Maybe the fuel flow rate was being mis-measured while the filter was bad. Oh well, it was nice while it lasted.

Don