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Old 09-10-2017, 06:58 PM
chinny4290 chinny4290 is offline
I love German Cars
Join Date: May 2008
Location: USR, NJ
Posts: 105
1974 450SEL D-JET - Failed Pertronix attempted, restored points, now no start

Hi All!

I summon the wonderful and resourceful minds of you all to help me with my 1974 450SEL.

I attempted to fit the Pertronix II Ignitor while retaining the stock switch gear (Ignition Control Unit) as POINTS REPLACEMENT. I have not by-passed ICU with Flamethrower COIL.

Prior to the attempt, the car ran pretty decently with stock points. It was typically missing below 2K which meant to me that the points needed replacing. I said screw it and went with the Pertronix.

This is what I did.

ATTEMPT ONE: Installed Pertronix into Distributor. Followed instructions that came with the box, connected both PERTRONIX leads to a brand new OEM Bosch Ignition Coil.

Result: CAR RAN AMAZING. It literally felt like it was the best thing I did.
Problem 1: Tachometer stopped working.

I also realized I forgot to add a DISTRIBUTOR GROUND WIRE from the distributor to the NEGATIVE BATTERY LEAD.

So I parked the car and removed the Battery over night to tackle the project the next day (it got dark out).

(Car drove fine for 25 minutes around town).

In Between Attempts:
I went and spent a good two hours searching and reading for Pertronix install information here and other Merc forums.

Found these to fix my Tach:

(LINK 1) -

(LINK 2) - Pertronix install - 1975 450SL - Mercedes-Benz Forum

(LINK 3) - Pertronix Install with and without Switchgear - Mercedes-Benz Forum


I followed LINK 3 to the T and this is what I did:


FALLBACK ATTEMPT: To see if the car still ran I replaced the points and the Green Point wire from ICU and now the car won't start PERIOD.


Question 1 - Did I Fry the Pertronix unit by accident?
Question 2 - Did I try the ICU unit by accident?
Question 3 - Did I fry both by accident?
Question 4 - Is there a chance I flooded the engine from the failed Ignition?

Other - Fuel system is fine. Fuel pump runs when you turn the key and try to start.

PLease help guys! I was just so happy when the car ran beautifully. Now I'm really bummed the car isn't running at all!
1975 W116 280S - SOLD
1994 W124 E320 Coupe - Gone

CURRENT - 1974 450SEL - 1987 560SEL

Last edited by chinny4290; 09-10-2017 at 07:25 PM.
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