How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Roy Your Own Question
Roy, import/domestic specialest
Category: Mercedes
Satisfied Customers: 5136
Experience:  ASE master tech for 40 years
Type Your Mercedes Question Here...
Roy is online now
A new question is answered every 9 seconds

My 89 Mercedes 420sel is very hard to start. It turns over

Customer Question

My 89 Mercedes 420sel is very hard to start. It turns over and over and finally starts running slowly then seems to get gas and picks up. It starts fine for the rest of the day. I replaced the cold start injector and it works. When I first hit the key it fires quickly and then goes through the current issue. I have also replaced both fuel pumps and the fuel filter. Same results. Any ideas?
Submitted: 1 year ago.
Category: Mercedes
Expert:  Roy replied 1 year ago.

good evening my nae is roy and I will assist

the first thing I would do is check the actual fuelpressure to see if the pressure is working cold

you can rent a tester at a parts store.

Customer: replied 1 year ago.
OK, I'll do that. Do you know what the pressure should be?
Customer: replied 1 year ago.
Should I check it while cranking the car or just turn on the key?
Expert:  Roy replied 1 year ago.

key on engine off 90-93 lbs

Customer: replied 1 year ago.
Roy, I checked the fuel pressure today and it show 0, nothing. I went on youtube to see where to check the pressure. It showed pulling a plug from the side of the throttle body. When I pulled the plug only a few drops of gas came out. I tried it there and got 0 pressure. So, I took it at the main fuel supply line. Gas did flow out of that but it still showed 0. What now? The car will start as I said before but it takes at least 30 seconds of turning it over. Would a bad fuel accumulator cause this?
Expert:  Roy replied 1 year ago.

it sounds like you need a fuel pump. I would start there


please dont forget to rate me as it is the only way I get paid for my efforts


Customer: replied 1 year ago.
I just replaced both fuel pumps with new ones
Expert:  Roy replied 1 year ago.


Customer: replied 1 year ago.
any ideas? I can't rate you since I have no way ahead to fix my car.
Expert:  Roy replied 1 year ago.

did you check for power to the fuel pumps??? did you check the pressure???

Customer: replied 1 year ago.
not yet, will do tomorrow. Are you saying to check the pressure at the pumps?
Expert:  Roy replied 1 year ago.

thats correct. there should be a valve there to hook up a pressure gauge