life of fuel pump

[geeceed]

hello out there...... a question, does any one have an idea of the the life of a fuel pump, my car is a 1988 300e and occasionaly I have trouble with starting it, appears to be lack of fuel, once going it will miss for a bit and then go ok. I would imagine like any other part on a car it would wear out, just curious as to what the life expectancy would be. Thanks for any info forwarded.

[flinck]

Hi There

I have similar trouble, but plan to execute as follows..
If I can hear the fuel pumps when a helper turns the ignition, they are probably all right. In that case it might be one or both of the one-way-valves mounted on top of the fuel pumps. If one of these valves leak, the fule in the fuel-line is no longer under pressure, and the heat in the engine room will cause it to boil inside the pipe, developing air-bubbles leading to no-start and then rough idle for 10 to 30 sec's..

Let me know how you make out...

Regards
Flinck

[gidpor]

To answer your question, My last Bosch FP lasted only three years . Not sure why you think it is the FP by the way, it could be a bunch of other things. I would start with replacing the fuel filter - The filter is inexpensive and helps keep your fuel pump smiling. Some people say replace filter once a year, others suggest every 30 thousand miles.Hope you find this info helpful.

[geeceed]

Thanks for replies..... I have no idea what it may be,would A FUEL filter cause this type of problem on not a regular basis, only happens now and again. The motor will spin over and try to start but just fails to fire, when it does it has a bit of a miss and then eventually comes right.....it has been mention that it may be the ignition coil, what do you think of that suggestion.. thanks to all. graeme.

[Ferdman]

geeceed, various things could be causing the problem as you have already noted. It would help to have some more details about your car ... mileage, how long you've owned it, maintenance history, daily driver or pleasure use, overall condition, etc. to better analyze your problem. Has the car been serviced according to the Service Manual recommendations?

It lives until it wears out. That might be two years or 50. My 300E is over 280,000 miles now with the original pump.

Have you changed your fuel filter lately. Changing the filter regularly will keep it running good and extend the life of the pump.

How do you know you have fuel delivery problems?

Good luck,

[flinck]

As Ferdman mentions, there are many options to choose from.

However, I just remembered that I initially thought I fixed my problem by pulling the Idle Air Control Valve and cleaning it out. Did make a huge difference, but I still have the missing start with rumbling idle. Since I became aware of the issue with fuel boiling in the fuel-line when the engine is shut off, the error observations make more sense. I find it typical that starting in warm wheater or after driving a while is bad. So starting the car for a short while at night, it will fire right up next morning, but driving it home from work and leaving it untill next morning will make it tumble. So I have bought the theory on the boiling fuel and will replace the two contra valves on top of the fuel pumps.

Oh yes, I did try replacing all the ignition components (coils, HT-cable etc. )
and while it may have been due, it did not help my starting.

Regards

[geeceed]

Thanks for replies...I must point out that this has happened on only two occasions in the last fortnight, all other times runs as normal. The car is a 1988 with 194.000 ks up, i have owned it 5 years and it has beeen well cared for, serviced as per the book and it would appear that prior to me owning it, it was also serviced as per book. It is used for pleasure mainly but driven everyday. The overall condition of the car is excellent, looks and drives as new. I am not sure if this is a fuel problem or spark, it seems when turning over that it wants to start but not quiet able to do that, once going it seems to run on less than 6 cylinders and then corrects itself. I hope this extra info may help. regards graeme.

Lift out the passenger side carpet and inspect the O2 sensor connection that is under there. It will sometimes corrode from water making its way under the carpet. Without the O2 connected, the engine will stumble but not miss.

The word "miss" usually refers to a single cylinder not hitting. What you describe is more like a stumble where all cylinders cease firing momentarily.

Good luck,

[anthonyb]

Ideas more than actual diagnostic advice, but..

Had a similar problem with our '91 300E. It would crank for a couple seconds, then catch, run rough for a few more seconds, then slowly smooth out as the rpms came up. Digging through the records, it looks like they replaced the fuel injectors as well as the O2 sensor, and now it starts fine. Might want to check the O2 sensor first, since the injectors can be fairly pricey.

Could also have been the mixture, I believe they had to reset the lambda when they did the injectors, and that may have helped as well.