Hesitation / Loss of Power
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Junior Member
Joined: Oct 2007
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S500
Hesitation / Loss of Power
I have a 1989 190E 2.6. The car hesitates a lot when I'm driving in the city. It runs fine when it finally opens up on the highway. When pushing down on the gas pedal it seems like I'm pushing air. The car losses a lot of power then pickups up again. The problem comes and goes. The biggest problem is when I'm entering the on-ramp of the highway the car won't go faster than 40 mph for a least one mile then it kicks in and is fine the rest on the ride on the highway until I get off then the hesitation starts again (intermittingly). One mechanic had me change the plugs, distributor cap, wiring, and air flow meter. The dealer couldn't find the problem. They had the car for two weeks. They said they test the fuel pressure, back pressure and that the O2 sensor and coolant sensor were borderline, but believed to be okay. Any help would be appreciated!!
Member
Joined: Dec 2007
Posts: 101
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From: Chicago
1989 W201 1999 W210
It sounds like your fuel pumps are ready to go. Clean the contacts off, hopefully you just have some nitty gritty on there thats making a bad connection, but you should probably get that checked out soon. It will come and go, but one day it will come and stay and you won't be able to start your car.
Thread Starter
Junior Member
Joined: Oct 2007
Posts: 20
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S500
Here is the paperwork I got back:
Replaced wires
Replaced plugs
Replaced dist cap
Replaced rotar
Replaced air flow meter (adjusted potentiometer)
Tested Fuel Pressure (system 80 psi, L/chamber 75 psi
Tested EHA current 20 ma key-on, 2-5 ma @idle, fluctuates w/accel-decel
Tested Lambda Control - good occilates
Tested Temp Sensor - 2.94 52@ 70F
Tested Fuel Volume - Good
Tested Fuel Sample - Good
Tested Both Fuel Pumps - Running
Tested Exhaust Back Pressure - OPSI @idle & 3000RPM
Tested Temp Sensor - Good
Tested O2 Sendor - Good, but is lazy EHA
Didn't check Fuel distributor or for vacuum leaks.
Replaced wires
Replaced plugs
Replaced dist cap
Replaced rotar
Replaced air flow meter (adjusted potentiometer)
Tested Fuel Pressure (system 80 psi, L/chamber 75 psi
Tested EHA current 20 ma key-on, 2-5 ma @idle, fluctuates w/accel-decel
Tested Lambda Control - good occilates
Tested Temp Sensor - 2.94 52@ 70F
Tested Fuel Volume - Good
Tested Fuel Sample - Good
Tested Both Fuel Pumps - Running
Tested Exhaust Back Pressure - OPSI @idle & 3000RPM
Tested Temp Sensor - Good
Tested O2 Sendor - Good, but is lazy EHA
Didn't check Fuel distributor or for vacuum leaks.
Member
Joined: Dec 2007
Posts: 101
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From: Chicago
1989 W201 1999 W210
What type of gas and brand do you put in?
You could just have a bunch of sediment and garbage in your gas tank. Here is what my mechanic just did for me because I had the same problem.
He took my tank out and cleaned it. I ran BP Ultimate fuel religiously, but he told me Mobil is the best way to go. So he took it out and cleaned out all the sediment and whatnot, then ran Mobile gas. He said he filtered everything out , going through 3 fuel filters to make sure everything was clean. My tank was so bad he said.
I said fuel pump before because that played a small role in my hesitation upon stepping on the gas. After my tank was cleaned, there was absolutely no hesitation at all and it feels like it should... a clean, smooth ride.
Good luck
You could just have a bunch of sediment and garbage in your gas tank. Here is what my mechanic just did for me because I had the same problem.
He took my tank out and cleaned it. I ran BP Ultimate fuel religiously, but he told me Mobil is the best way to go. So he took it out and cleaned out all the sediment and whatnot, then ran Mobile gas. He said he filtered everything out , going through 3 fuel filters to make sure everything was clean. My tank was so bad he said.
I said fuel pump before because that played a small role in my hesitation upon stepping on the gas. After my tank was cleaned, there was absolutely no hesitation at all and it feels like it should... a clean, smooth ride.
Good luck
Thread Starter
Junior Member
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S500
They said the tank was fine.
But, it happened again this morning. I start the car and need to drive about 10 blocks to get on to the highway enterance (alls fine). I ALWAYS catch the same light right before I enter the highway, when the light changes it then starts to happen the car struggles to reach 50mph when I'm entering the highway and when it does reach 50mph it then starts to lose power. (I think I'm going up hill). Then drops to about 20-30mph and I have the pedal to the metal. This continues for about 1-2 miles then it starts to pickup, then it's fine for the rest of the highway ride.
But, it happened again this morning. I start the car and need to drive about 10 blocks to get on to the highway enterance (alls fine). I ALWAYS catch the same light right before I enter the highway, when the light changes it then starts to happen the car struggles to reach 50mph when I'm entering the highway and when it does reach 50mph it then starts to lose power. (I think I'm going up hill). Then drops to about 20-30mph and I have the pedal to the metal. This continues for about 1-2 miles then it starts to pickup, then it's fine for the rest of the highway ride.
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Joined: Sep 2006
Posts: 6
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Looks like The MAS unit contains among other things, the fuel pump relays you can eliminate ignition as the problem. That leaves fuel and air. I had a similar problem, not quite as chronic, but hesitation and stalling. I took the MAS unit out, wire brushed the contacts and replaced it. Haven't had a problem since (two months ago). The MAS unit contains among other things, the fuel pump relay/s. The good part about this is it doesn't cost you anything except an hour of your time. Good luck.
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2008 Black Out C350 Saks Edition / 87 VW GTI
I have a 1989 190E 2.6. The car hesitates a lot when I'm driving in the city. It runs fine when it finally opens up on the highway. When pushing down on the gas pedal it seems like I'm pushing air. The car losses a lot of power then pickups up again. The problem comes and goes. The biggest problem is when I'm entering the on-ramp of the highway the car won't go faster than 40 mph for a least one mile then it kicks in and is fine the rest on the ride on the highway until I get off then the hesitation starts again (intermittingly). One mechanic had me change the plugs, distributor cap, wiring, and air flow meter. The dealer couldn't find the problem. They had the car for two weeks. They said they test the fuel pressure, back pressure and that the O2 sensor and coolant sensor were borderline, but believed to be okay. Any help would be appreciated!!
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Just read my post and noticed I had overtyped part of the first sentence. Sorry for the confusion.
Looks like you can eliminate ignition as the problem. That leaves fuel and air. I had a similar problem, not quite as chronic, but hesitation and stalling. I took the MAS unit out, wire brushed the contacts and replaced it. Haven't had a problem since (two months ago). The MAS unit contains among other things, the fuel pump relay/s. The good part about this is it doesn't cost you anything except an hour of your time. Good luck.
Looks like you can eliminate ignition as the problem. That leaves fuel and air. I had a similar problem, not quite as chronic, but hesitation and stalling. I took the MAS unit out, wire brushed the contacts and replaced it. Haven't had a problem since (two months ago). The MAS unit contains among other things, the fuel pump relay/s. The good part about this is it doesn't cost you anything except an hour of your time. Good luck.
