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75 450 SL Gas Smell

2K views 8 replies 6 participants last post by  GMB 
#1 ·
D-Jetronic. When first starting up in morning, there is a definite gas smell. It is slight but noticeable. The smell disappears after about 10 minutes. Ambient air temperature in Phoenix is not much lower than 85 F in the morning. There is no gas smell at all on hot starts thereafter. Cold start valve has been is unplugged for diagnostic purposes. There are no visible gas leaks anywhere. AAV new. All vacuum hoses are new as are the injectors and all the rubber fuel lines. So are all the relays. Car idles fine, around 750 rpm at start-up and thereafter. No missing. Idle remains steady at around 750 rpm even after gas smell disappears. WUR issue? Can WUR be serviced or only be replaced. Other thoughts? Thanks.
 
#6 ·
If any sensor is disconnected or fails such as the cold start injector, the ECU will always dump more fuel to compensate. By disconnecting the cold start, the thermotime switch is confused,which closes it after reaching 95 degrees or 12 seconds duration via grounding out via an bi-metal element therefore temp sensor 2 confused, etc... D jet will only shrug off a defect in temp sensor 1 and sometimes even run better with it disconnected.
 
#7 ·
I just repaired a similar issue in my '73 SLC. Turned out to be a small hose at the cold start valve. Would leak slightly untill the car warmed up and then would stop.
dws
 
#8 ·
Schooled by Nobby, as per ususal. NorCalSL, whose avatar sits side-by-side with Nobby's in my heart or somewhere, had the call correct. Next time I will remember to not check the cold start valve hose for leaks after the car has warmed up. Thank you.
 
#9 ·
Funny, I noticed a very strong gas smell in the car the other day. I had filled it up, ran an errand, and coming back to the car afterwards, was unpleasantly surprised by the smell of gas. Checked beneath the car, no perceptible leak. Drove home with the windows open, left them open when I parked in front of the house, and a few hours later, the smell was gone. It was still gone when I drove the car yesterday, but I thought I smelled it as I waited to get on the freeway -- the onramp was inclined. I had the windows open and stopped smelling gas once I got going and the car was on level ground. Not sure what the heck it was / is.
 
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