Author Topic: Cold hard start  (Read 2062 times)

toneypenna

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Cold hard start
« on: January 03, 2022, 18:32:31 »
Everyone was a great help with my electronic conversion question thanks. Ordering a distributor from 123ignitionusa.
64 230SL: My next problem: Hard cold start, the only way I can describe it is it starts as a carbureted car would start with no choke. You have to feather the gas, couple of backfire pops until it warms and then runs fine. I searched the technical manual section and came up with a possible problematic cold start valve. Do you think I'm headed in the right direction?
Again any input will be greatly appreciated.

Jim

badali

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  • 1966 230SL
Re: Cold hard start
« Reply #1 on: January 03, 2022, 18:42:18 »
My car was hard to start at one point.  I asked a question about a transmission shifting problem at a different time and Joe Alexander told me to twist my fuses first before trying anything else.  When I did this both problems went away.  It now starts at the first touch of the key.  I'm guessing the cold start valve was not engaged. The fuse going to it was probably not making good contact.
Brad

1961 220 Sb
1966 230 SL (Sold)
2019 E 450 4 Matic
2022 GLC 300 4 Matic

Lorsar

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  • 1968 280SL (US)
Re: Cold hard start
« Reply #2 on: January 03, 2022, 19:06:39 »
My cold start problem was resolved by cleaning the relay contacts per this thread

https://www.sl113.org/forums/index.php?topic=825.0
Lori
1968 280SL (US)

Pawel66

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Re: Cold hard start
« Reply #3 on: January 03, 2022, 22:13:41 »
I am not a mechanic, so do not treat me seriously, but I have been through a couple of issues with my car and perhaps I can explain as amateur to amateur.

Yes, the role of CSV is to deliver additional fuel during start (not only cold start, but that is what everybody thinks).

Assuming that your engine is properly tuned and ok (compression, valves, ignition), yes the CSV may be the issue. But then it is the CSV itself or a number of other devices that switch it on and off.

You have it all described in the manual under Cold Start Aid. There are many systems across the years, but in essence: when you turn the key to crank the engine you activate the Thermo Time Switch that, if the engine is cold, sends signal through a relay to CSV to open. So if the CSV does not work it canbe CSv faulty, TTS faulty or the relay faulty. From what I read on this forum, the quilty is the TTS, but we do not know it for sure.
One simple test is the one with lamp described under link.

The other simple test I would do would be to disconnect the wire you now have on CSV, put it aside so that it does not touch anything, take a length of wire and connect battery + to CSV connector while cranking (only while cranking and perhaps a second or two longer). See if engine starts better. If it does - need to check TTS and relay. If not - closer look at CSV - does it get fuel, is it clogged (it looks like windshield washer nozzle), does the solenoid work?
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
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