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View Full Version : After-start problem solved inadvertently


Alex
12-15-2005, 03:52 PM
This is a report that might help others with a related problem.

For at least two years my '81 300TD would quit running after starting in cool weather, unless the accelerator was held down lightly for the first minute or so.

My late mechanic adjusted the valves twice and was reluctant to mess with the timing chain, which he though might be the cause, so he sort of gave up, as did I.

Then I read a post here, which implied that a possible solution is to replace the rack damper screw. So when I brought the car in recently to a new local mechanic, to have the rear brake calipers replaced (they were seizing up the wheel slightly,) I asked the mechanic to replace the rack damper screw. He said he wanted to determine for himself whether this is the right solution before doing this.

During the course of replaceing the brake calipers and hoses, the mechanic discovered a small fuel leak in a hose junction near the fuel tank, which he replaced. Then he said he saw a badly rusted fuel line, which he also replaced. After he started up the car the next day in his garage, where it was cold in the morning, he had no problem with stalling, he said.

When I picked up the car, the after-start problem was no longer there. Evidently the rusted fuel line impeded the flow of fuel sufficiently to cause this problem.

So the punch line is that a cold rusted fuel line may allow starting but slows things down a bit. Rust - bah! Humbug!

VLayton
12-15-2005, 04:03 PM
Good information, my 1981 300TDt does the exact same thing, which seems to be most common anedotally on the 1981 300TDts.

I thought it may be a particular to that car issue possibly as it was the first of the W123 series to get the turbo motors. The 1981 300TDT also seems to be the only W123 model and year I have come across on which has an electronically relayed speed indicator, verses the cable I found on every other W123, including later TDs. I understand at least some of the 300SDs (not W123) had the same set-up as the 1981 300TD system.