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Old 05-21-2002, 12:05 PM
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Join Date: Nov 2001
Posts: 32
Fuel Pressure????

I have a 1988 2.3 L 190E that is having a hard start after it is warmed up. We put the fuel pressure gauge on the distributor and found that the pressure was 5.2 Bar. I was told that it needed to be about 6.2 bar.

Does anyone know if that is true? If it is true what would be the part that controls that. I have already replaced the FP regulator and that did not increase the fuel pressure. I have also done a fuel pump volume test and it pumps plenty.

If any one has any ideas that would be great. I have been trying to solve this problem for six months and I have replaced almost everything except the wires, cap, and rotor.


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Old 05-21-2002, 06:03 PM
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
The 5.2 bar is correct!! Only the 420SEL & 560'S run 6.2 bar.

Hard start hot is usually related to fuel pressure bleed-off OR a weak ignition system.
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Old 05-21-2002, 06:07 PM
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Join Date: Apr 2002
Posts: 21
Warm start problems

You may have fuel pressure leakdown, caused by a defective fuel accumulator, or fuel pump check valve. I have also been told that injectors can also cause the leakdown.

I have a 1983 380 SEL that had the same problem. It ended up being a bad fuel accumulator ($80 part) which I was told is VERY common with a car that old. It now starts up like a new car, warm or cold. If it turns out to be the same problem, be sure to buy a BOSCH; the aftermarket ones look like JUNK.
Scotty P.
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Old 05-22-2002, 02:37 PM
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Join Date: Nov 2001
Posts: 32

Thanks for the input. I am going to start looking at the ignition system because I have already replaced the fuel accumulator and the check valve by the fuel pump. There is only one check valve, right???

When it does fire, it usually is rough and there is a vast amount of fuel in the exhaust. You can smell it as it rumbles until it clears the excess fuel and then it is just fine, runs like a champ. Although, it does seem like I am getting horrible gas mileage, but I can be certain because the odometer is stuck.

Thanks again.

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Old 05-22-2002, 04:35 PM
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Join Date: Jan 2001
Location: Santa Clara, CA
Posts: 437
Sounds to me like leaky fuel injectors. They are probably leaking fuel into the cylinders when you are shut off, then it's hard to start, but runs fine when all is burned off or blown out the tail pipe.
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