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I have a 74 450sl. Runs fine from cold start and with re-cored radiator runs at nice temp. However, if I take a long ride, turn if off, then come back in about 30min it's rough to restart and continues to miss until the engine is allowed to completely cool down for hours. Any suggestions for trouble shooting this problem?
 

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2017 Police Interceptor Utility, 2017 Police Interceptor Sedan
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I suspect the issue might be oil getting onto the injector trigger points in the...


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I suspect the issue might be oil getting onto the injector trigger points in the distributor. This is a common problem on pre 1976 electronically injected models. The issue is oil sipping though the distributor seals coating the trigger points thereby ruining the contact. This would explain why you have no problem on cold start (the oil hasn't gotten to the trigger points yet) and why it starts fine after waiting a while (the oil has dripped back down away from the points). Another possibility is vapor lock, but that is more common with later mechanically injected models.

Hope this helps

Ike

86 560SL
77 450SEL
75 230
 

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1975 450sl re-start troubles when engine is hot

I am new to this discussion but have noticed that you have helped several people. Thanks for that. I have the same re-start issue re: my '75 450sl not re-sarting when the engine is hot. It takes 15-20 mins for it to occur after being turned off and another 30 mins for it to be able to start again--and it's rough until reaching road speed. The car has also simply stalled on a warm day. I've had the fuel pump replaced and the lines checked and have stumped two mechanics with the problem. A third has indicated that there may be a problem with fuel pressure. dropping after shut-off and needing time recover (??). Do you have an opinion on that diagnosis? Can you give a ballpark cost if it turns out to the be the first issue you offer below? Is this really fixable? The car is otherwise in great running order and has about 100k on it. Thanks again.
-MJP.


[:)]

I suspect the issue might be oil getting onto the injector trigger points in the distributor. This is a common problem on pre 1976 electronically injected models. The issue is oil sipping though the distributor seals coating the trigger points thereby ruining the contact. This would explain why you have no problem on cold start (the oil hasn't gotten to the trigger points yet) and why it starts fine after waiting a while (the oil has dripped back down away from the points). Another possibility is vapor lock, but that is more common with later mechanically injected models.

Hope this helps

Ike

86 560SL
77 450SEL
75 230
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