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W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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Any chance that the ignition signal to the mass unit that tells it to prime the pumps (and to even run the pumps) in the cranking position is not getting there due to some ignition switch or wiring issue?
Sorry if this was explored earlier and is a repeat.
 

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Discussion Starter #23
That's actually a really interesting point, could very well be the issue. I've heard that the EZL provides the signal to the MAS for the fuel pumps to operate, perhaps I should check the EZL's output voltage?
 

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Discussion Starter #26
Sure thing, see below.I haven’t taken the time to snap a pic of the MAS control unit but that could be seen easily via google search.
B4617C1A-B729-4365-A192-5C3607A418CE.png
 

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1993 190e 3.0
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101 Posts
From looking closer at your posted picture, I see your car is indeed 1990 or later. These cars came with an EGR, Smog Pump and MAS relay for fuel. This also means it uses the updated EZL ignition control unit. This unit has an extra provision/plug when compared to the early style.

I'm willing to bet the motor swapped into your car has the 89 or older motor which uses a different fuel pump relay, EZL, and a Y-style thermo-vacuum valve to talk to the EZL. One can see that the front exhaust manifold is the earlier design without an EGR valve. Unless the previous owner just did a smog pump delete and front manifold swap, as I can't see the rest of your motor, you have the older motor in your newer chassis car and perhaps the EZL, ECU, Fuel Relay, and harness you have were never swapped from the swapped motor, and is too new for the motor to run properly. I am not entirely sure what needs to be done to get these different version units to communicate correctly, but I believe this may be related to your issue.

Have you ever had this car driving? Or was it purchased non-running?
 

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1989 W124 260E
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Kevin Thats sorted that out ,,you have what might be a 300E or 260E . You will have a FPR at the rear of battery .I dont know where this MAS comes from other than on engines . M104
Also CPS plays a big part in sending the message to the EZL to fire up the coil. Pull FPR and wire up pins 6 and 7 on the base of the relay and plug it back in .Do this for trial only [important ]
 

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1993 190e 3.0
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101 Posts
Kevin Thats sorted that out ,,you have what might be a 300E or 260E . You will have a FPR at the rear of battery .I dont know where this MAS comes from other than on engines . M104
Also CPS plays a big part in sending the message to the EZL to fire up the coil. Pull FPR and wire up pins 6 and 7 on the base of the relay and plug it back in .Do this for trial only [important ]
His chassis is a 90 and from 90-93 the m103 also used a MAS like the m104.98* motors in the c124 and r129
 

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Discussion Starter #31
0CF6546A-EF5D-483A-B4C5-17AA18FB7579.jpeg 2C8C278A-D09A-424C-A51E-76EDDEAF0953.jpeg B86F4787-AB3E-4EC9-8DCF-37DD06A83C5C.jpeg
Sorry if it came out messy,still learning how to use the forum but I’ve attached photos of the car’s MAS unit,EZL and what I think is the ECU.Couldn’t locate the smog pump so maybe the previous owner did in fact due the smog delete on it.
 
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