Engine Power Loss after Car Wash

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Model you own: w124

Engine Power Loss after Car Wash

Post by PeterKathy » Tue 06 Mar, 2018 6:35 pm

We have a 300e 24v.
After the carwash, the engine experienced a power loss when under load.
Idle is fine, when asked for power above ~1400 - 2200 rpm, it has none.
After driving for about 8 - 10 minutes all was restored.
The day was relatively warm (for a Canberra day) approx 21 degrees.

This has happened before during the last rainstorm in late February coming from Sydney.

We have checked the rotor and dizzy for anything obvious, nothing to show....

Open for suggestions

Peter and Kathy

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Christo C
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Region: New South Wales
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Re: Engine Power Loss after Car Wash

Post by Christo C » Tue 06 Mar, 2018 7:03 pm

That sounds like water is entering your ignition system - the coil, distributor or the high tension wiring.
Water could also be entering the ignition control unit (near the coil) or the ECU (likely located on the firewall behind the battery).
If the car is old many of the ignition components deteriorate; often getting fine (invisible) cracks - replacing ignition wiring (high tension leads) and distributor cap may be necessary.
Spraying water repellant (such as WD40) around those components may help when the problem occurs.
1986 230E W124.023 M102.982 Thistle Green Saloon "Janis"
Beaconsfield, SYDNEY

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300 SLR
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Re: Engine Power Loss after Car Wash

Post by Bartman4800 » Tue 06 Mar, 2018 8:00 pm

An old trick is to run the car at night, and open the bonnet on a very dark place

You should be able to see any blue sparking where any HT parts are losing the charge to the environment.

You can spray a little bit of water on suspect parts, but if you do that switch off the engine first.

Regards, Bart
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
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Re: Engine Power Loss after Car Wash

Post by Ivanerrol » Tue 06 Mar, 2018 8:59 pm

Check your fuel pump area. Make sure water is not getting in there and causing issues.
Coil is lowest in the engine area. Have you an engine cover underneath? Some cars are missing these.
Suspect coil to distributor lead. Check that lead. It should be nice and flexible it’s whole length. If there is any hard areas along the lead replace it. Check the rubber boots to ensure there’s no cracks. Check the coil low tension side contacts for verdigris or rust. Check your battery for vertigris. Make sure your alternator connections are tight and free from corrosion.
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Re: Engine Power Loss after Car Wash

Post by brette013 » Fri 30 Mar, 2018 4:11 pm

Have you checked behind the distributor dust cover (e.g. the plate behind the rotor)? Moisture tends to get stuck behind it, causing the ignition system to be a bit crap until it dries out.

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