190E (W201) 1982-1993: 190E 2.3, 190E 2.6, 190E 2.3-16, 190E 2.5-16, 190 D 2.2, 190 D 2.5, 190 D 2.5 TURBO, 190E 2.5-16 Evolution I, 190E 2.5-16 Evolution II

190e 2.3 HARD TO START WHEN WARM

Old Mar 19, 2015 | 05:07 PM
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1987 190E 2.3
190e 2.3 HARD TO START WHEN WARM

My wife's 1987 190E 2.3 has only 23,000 miles on it, but after sitting for several months after she was ill, it became hard to start, so replaced the plugs, spark plug wires, rotor and cap. That did not cure the problem so took it to our MB dealer. They said the gas was rotten, so drained the tank, replaced the fuel filters, throttle linkage, air filter, added 1/4 tank of fresh gas, and tested for vacuum leaks, over a period of 3 days, charging me $900+ and admitting that they were stumped. They suggested we fill up with Chevron gasoline to help clean the fuel system. After 3-4 months the car was still hard to start, especially when warm, and also started to idle roughly like one cylinder was not firing. Took it back to the dealer, and they performed a scope test, compression and leak down test, inspected valve springs and cam, did a fuel pressure test, checked for vacuum leaks, performed an injector test (bad spray pattern), replaced spark plugs (said I had installed the wrong ones) but did not correct any of the issues. They gave me an invoice for $190 and a quote of $2,700 to replace the fuel injectors and fuel distributor.

I have now replaced the (4) Fuel Injectors, and rebuilt the Fuel Distributor myself, resulting in a smooth idle and smooth running engine. When cold the car now starts immediately, with no pressure on the accelerator pedal. However after a trip to the local stores, it still takes 3-4 tries to start the engine, acting if it may be flooded, with or without depressing the accelerator. Any suggestions as to what I should do next? I have no faith in the dealer, so will appreciate any advice you may offer. Thanks.
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Old Mar 22, 2015 | 03:15 PM
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1991 190e 2.3
Check the breather hose coming from the valve cover for oil. The fuel pressure regulator runs vacuum to this and it's common for the line to get oil in it and the regulator sees the wrong vacuum throwing the a/f mix out of wack. Also, you said you rebuilt the throttle linkage, be sure the slider to the iac valve is adjusted properly as the air coming from that is not metered by the maf diod on the front of the air box and can mess with a/f as well.
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Old Mar 22, 2015 | 03:19 PM
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1991 190e 2.3
Also, there is a ignition control unit on the fender close to the abs module. There is a vacuum lines on this that can be problematic over the years, check that as well as the ovp relay. After sitting did you have to jump start the car?
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Old Mar 22, 2015 | 06:13 PM
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1987 190E 2.3
190e 2.3 Hard to start when warm

DocWalla,
Thanks for your response. I will follow up on your suggestions, and post the results. I did not have to jump-start the car after sitting for so long, as I did run the engine every 2 weeks or so, to keep the battery up.

Can you tell me what the abbreviations are for the af mix/iac valve/abs module/maf diode ? I may be able to figure those out, but will appreciate some direction, if you have time to teach this novice.
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Old Mar 22, 2015 | 08:11 PM
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1991 190e 2.3
Af mix is air fuel ratio. Iac is idle air control, maf is mass air flow diod, abs module is antilock break model. iac is controlled by a slider with a 6mm nut and flat head screw that goes between the 3rd and 4th intake runners and is connected to the throttle linkage closest to the firewall side of it. Maf diodes on the front of the air box next to where the breather hose about 2 inches to the right of the breather. Abs module and ignition control module are directly behind the driver side head light above the ignition coil. The ignition coil has a wire that connects it to the distributor cap and the spark plug wires.
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Old Mar 22, 2015 | 08:13 PM
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1991 190e 2.3
If you didn't jump start it then the ovp relay should be fine if you don't see any check engine light or abs lights on the dash.
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Old Mar 22, 2015 | 11:51 PM
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1987 190E 2.3
190e 2.3 hard to start when warm

DocWalla,
Thanks for the advice and interpretations. I will check these items next week and let you know if I am successful.
Best Regards
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