[Momo08]

I’ll keep looking and let you know what I find. Thank you for replying btw

 

[rayhennig]

It’s points me to a box that looks more like a module.

That sounds like the MAS box and that contains the fuel pump relay. 6 months ago a would have said that the MAS box is OK. For me, a quarter of a century with the same one. But I had a 'no start' and that was solved by changing the MAS.

So, yes, the MAS box contains the fuel pump relay. Sorry I cannot be much more use.

RayH

 

[Momo08]

No, thank you for any bits of info. Everything helps so I don’t go in completely blind trying to fix it.

 

[Momo08]

So I just went and took out the MAS module. This is what it looks like in there.

would the pin having all that gunk on it have anything to do with the symptoms on the car? Are this modules rebuildable? The cables under there look fine but not sure if I need to dig deeper.

 

[rayhennig]

would the pin having all that gunk

Maybe but my more general advice with these (and probably any) cars is to clean electrical contacts whenever and wherever you can get at them. Buy a good quality contact cleaner (NOT ordinary WD40) and spray, plug, unplug several times then repeat, to make sure all pins and sockets are cleaned.

R

 

[Momo08]

Good morning, so today I went to bypass the fuel pump relay. Made a bridge to pins 1 and 2, I hear the fuel pumps bussing in the rear, or I think that’s what it is. I go to crank the car and No start. So is this a MAS module issue, a fuel pump issue or something completely different? Please advise

 

[UncleWolfy]

No, the car used to start and stay on for a while before it just fine, before it would unexpectedly cut off. After the ovp issue, it starts and dies right away. Correct me if I’m wrong, I’ve looked for fuel pump relay location here and it shows me that there is no relay for my car. It’s points me to a box that looks more like a module. Is this the correct part? And if not, where is the fuel pump relay located on a 93 300sl? Thank you again

It is incorporated in the MAS module, which is located in the ECM box on passenger side.

 

[UncleWolfy]

But if your MAS works, you will hear a short fuel pump noise (1-2 sec) from under the right rear axle when you switch the ignition on.

 

[Momo08]

Could bad fuel pumps be causing the car to suddenly cut off and also while under load? The thing that confuses me is that the car when it cut off it doesn’t give me a chance to try to press on the gas to try and keep it on. And even when it’s idling and I press on the gas to rev it up, when it cuts off it just does it and pressing on the gas doesn’t keep it from turning off.

 

[UncleWolfy]

Sorry, I am not good at guessing.

 

[isthenew]

The fuel cut off due to the fuel relay will be immediate. The crank position sensor can cause the same thing. They rarely go bad on the I-6 engine, but it does happen. Have you tested that?

 

[Momo08]

I keep hearing about the crank sensor and no, I have not taken a look at it yet. I’ve been stuck on the thought that this would be a fuel issue. I’ll check it when the weather lets me and come back with results.

 

[rayhennig]

I keep hearing about the crank sensor

Highly unliekly in my experience.

You can measure its resistance by unplugging at the EZL. 750 to 1100 Ohms, if I remember correctly. Measure it hot and cold.

RayH