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Old 05-31-2007, 03:12 AM
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Join Date: May 2007
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1988 190E 2.3 Losing Power Almost Dies

I have a 1988 190E 2.3 that loses power and almost dies, especially when climbing a hill. It has to be pulled to the side of the road to work the accelerator for awhile before rpms can be built enough to proceed (limp?) down the road until the next episode.

Last year, it was having problems running and starting and pretty much shut down during a trip until a mechanic bypassed the oxygen sensor (put in a bypass switch) and this helped for a few months. Now, it is again running as badly as ever. It does runs much better, but somewhat rough, when the computer is completely disconnected.

I am thinking of buying a computer and oxygen sensor, but not sure that if that would fix the problem or not.

Any ideas? Thanks!

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Old 05-31-2007, 07:36 AM
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Location: Cleveland, Ohio
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[QUOTE=Dquixote1217;1521434]Last year, it was having problems running and starting and pretty much shut down during a trip until a mechanic bypassed the oxygen sensor (put in a bypass switch)

That was no mechanic,,, a real mechanic would have fixed the problem.

sounds like you have a few problems that have manifested themselves into one major problem.

Do a search for Lambda, 2.3, emissions and read what's been done so far...

good luck
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Old 05-31-2007, 10:09 AM
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Additional Info

The mechanic was a pretty highly regarded one. He diagnosed the problem as a bad oxygen sensor. The problem was, I was on a trip and did not have time to wait for the part and so he rigged up a bypass switch. After that, the car ran OK for months, but then began running worse until it would finally barely go at all with weak power and frequent episodes of almost dying. Then, I disconnected the computer and it runs much better but a bit rough.

I know, I know - I should have replaced the oxygen sensor right away, but the car is a spare and I was willing to live with the bypass until it began running badly again.

I am wondering now if I should buy an oxygen sensor alone and try that or go ahead and get an oxygen sensor and computer. Or could there be something else?


Last edited by Dquixote1217; 05-31-2007 at 10:14 AM.
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Old 05-31-2007, 11:06 AM
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Join Date: Dec 2000
Location: AL
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If you know your oxygen sensor is bad, wouldn't that be the place to start?

By disconnecting the computer you have essentially made yours a purely mechanical system with no electronic fine tuning.
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Old 05-31-2007, 11:45 AM
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Thanks - that is what I thought too, but with the performance deteriorating in the purely mechanical mode, I thought maybe there might be more and perhaps someone else had been through the same thing.

OK, replace the sensor it is.
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Old 05-31-2007, 11:59 AM
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That is only the starting point! first do all the basic tune up items and see if you can isolate any other items that are defective, If you are the one doing the work you need a digital meter with duty cycle,do a search on fuel pressure and EHA. plus Potentiometer,after you check those you may also need to see if you have troubles in the cat,(being restricted) But I feel that after you replace the Oxygen sensor,reset the fuel mixture and do the Lamda check you may be fine.

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